[Pete.J]

I have been a member of the forums since 2012, and recently I have been thinking about creating a build thread to consolidate all the mods I've done to my car, entail my experience with certain mods, and also keep a track record for myself to look back at in the future.

About the car:

E92 335i Coupe, Automatic transmission (later on converted to manual), it was built on June/2007 at the Regensburg assembly plant in Germany, as a result it had the stronger bolted big pumpkin differential and the larger driveshafts to suit from factory .

I really wanted to buy a manual, but it was out of my price range at the time. Manual E92 335i's carried a $10,000 price tag over the equivalents automatic cars with the ZF 6HP21 transmission. I thought if I am buying an auto, I should at least buy one built after 03/2007, so I can flash the Alpina B3 TCU flash on it. N54 cars produced before that build date had the 6HP19 ZF auto transmission which had a different TCU and the Alpina TCU flash couldn't be flashed on it (this was well before the days of xHP TCU flash).

In terms of exterior body colour, I wasn't too fussed, as long as it was a dark colour, any shade of grey or black. For the interior leather colour, I was also only interested in black leather.

I ended up finding an E92 335i for sale in Sparkling Graphite Metallic and black interior. The only problems, it was an auto and it didn't have the M Sport Package. I went to check it out regardless, 3 months have passed driving around in a $200 shitbox, and I was starting to get itchy to buy something. I inspected the car, and I like it, the seller accepted my offer immediately, and I took delivery of the car on the same week. OHHHH! the joy of that first week of ownership

Advertisement pictures at the time of purchase:

Certainly nothing appealing in stock form.







Couple of pictures after roughly ~3.5-4 years into ownership:





Pictures as it stands now











Current list of mods:

Engine:
- MSD81 DME with the IKM0S from the 1M and correctly working ///M button on the steering wheel (originally my came with MSD80, I upgraded for peace of mind)
- Wagner EVO2 Performance FMIC
- Custom MHD tune
- AR Design catless 3" downpipes
- Turbosmart Kompact diverter valves with 24mmx3.5mm thicker diverter o-rings
- S55 oil filter
- VAC Motorsport sump baffle
- PE mod rear muffler (only done on the valved side like the Genuine BMW Performance exhaust)
- M3 Microfilter cowl with custom 8AN brake booster line
- Silicone vacuum lines
- Billet cylinder head ->thermostat hose coolant fitting
- RB External PCV with blocked head ports, accompanied with Mishimoto OCC (attached to the off-boost/low side of the PCV system only only)
- MHD Stage 2+ flash tune (removed)
- AFE Stage 2 Magnum Force DCI intake (removed)

Transmission:
- Manual Conversion (link to incomplete conversion thread, I'll finish it off when I have time)
- UUC Black transmission mounts
- UUC DBO delrin shifter carrier bushings
- Turner motorsport rear carrier shifter bushing
- 335is/550i clutch
- Clutch Delay Valve (CDV) delete
- AD Engineering oil block off
- XHP Stage 3 - when it used to be automatic (removed)

Diff:
- Hardrace solid rubber diff bushings
- I kept the 3.46 final drive after the manual conversion (manual F87 M2 and M2 Competition also have a 3.46 final drive and the same manual transmission gear ratios as manual N54, so mine is still sort of a factory setup).

Suspension and Handling:
Electronics
- M3 DSC Module (with all the nannies coded off)

Dampers and Springs:
- Öhlins Road & Track coilovers with custom spring rates
- Front Swift springs 8kg 7" long, and rear Swift springs 14kg 9" long
- Bilstein B12 Prokit (removed)
- Front Swift springs 7kg 8" long, and rear Swift springs 12kg 9" long (removed)

Front axle:
- Dinan front camber plates
- E93 M3 front sway bar (28mm)
- M3 Steering rack (discussed in post 3)
- M3 tie-rods
- M3 strut brace
- M3 front lower control arms
- M3 front tension struts
- German Autosolutions (G.A.S.) Monoballs pressed into the M3 tension struts

Rear axle:
- 23.6mm E93 M3 rear sway bar
- Nolathane polyurethane rear subframe bushings
- Hardrace rear toe arms (fully ball-jointed at both ends)
- Hardrace rear guide rods (fully ball-jointed at both ends)
- Hardrace rear upper camber arms (fully ball-jointed at both ends)
- Monroe rear upper shock mount kit
- 22.5mm E92 M3 rear sway bar (removed)

Brakes, wheels and tires:
- Ferodo DS2500 front and rear brake pads
- Genuine 437M BMW wheels forged, super lightweight with hollow spokes (off F82 M4), front : 9" ET29, rear 10" ET40
- Michelin Pilot Sport 4S 245/35/19, 265/30/10
- DBA slotted and cross-drilled factory replacement (to get me by for now until I find a reasonably priced BBK)

Exterior mods:
- Full respray at BMW dealership (Bundoora BMW Bodyshop in Melbourne, link)
- Full M Sport Package retrofit, including undertray panels, done completely OEM down to every screw and bracket
- Rear M Sport diffuser painted gloss black (by Bundoora BMW Bodyshop)
- Genuine 437M BMW wheels forged, super lightweight with hollow spokes (off a F82 M4)
- E92 M3 side skirts
- Genuine E92 shadowline window surrounding trim
- Genuine BMW Performance E92 carbon fibre boot lip
- E92 LCI taillights
- Genuine BMW Performance gloss black kidney grilles
- LED angel eyes (cheapos off eBay, but planning to replace with LUX 180 H8 7000K soon)
- Philips 7000K HID bulbs
- GP Thunder 7000K cornering lights to match
- Foglights deleted and coded off, and 335is air ducts fitted instead
- 313M wheels (removed)

Interior mods:
- BMW Performance alcantara steering wheel with white stitching and yellow stripe
- E92 M3 cluster
- Aluminium oxide dash and door trim
- F10 M5 illuminated gear knob
- Armrest phone cradle replaced with the rubber tray for more storage space
- Black M Sport anthrazite roofliner complete retrofit with all its parts.
- BMW Performance alcantara shift boot with white stitching (to match the stitching on the steering wheel)

Entertainment and electronics:
- CIC iDrive (unlocked to have BMW Apps, Internet and BMW Live)
- Combox

Maintenance:
1- Low kilometre secondhand Genuine turbos
2- New Genuine Valve cover
3- New OEM Pierburg Boost solenoids
4- New Genuine Index 12 injectors
5- New OEM Eldor coils
6- New Genuine Oil cooler lines
7- New Genuine Radiator top hose
8- New OEM Rein Radiator reservoir overflow hose
9- New Genuine Engine head to thermostat coolant hose
10- New OEM Continental electric Waterpump and thermostat
11- New Genuine Vanos solenoids
12- Walnut blast
13- New OEM Elring Oil pan gasket
14- New OEM Continental serpentine drive belt with four new belt pulleys
15- New Genuine Power steering pump pulley
16- New OEM Lemforder Strut top mounts
17- New Genuine sunroof surround rubber/felt seal and new Genuine front and rear windshield seals
18- Secondhand good condition black rear parcel shelf (old one started discolouring from the sun)
19- New OEM Brembo rear rotors

I will retrospectively review and post info on every retrofitted and upgraded part listed above. Luckily I have taken plenty of photos over the years of owning this car, and I have DIY'd everything myself, and I remember all the details It's certainly a long list to cover, stay tuned

[Pete.J]

Next day after I bought it, I did a major service my myself at home; I changed all fluids, filters, spark plugs… etc., and fitted the AD Engineering thermostat block off.



Naturally, I was curious how much power it made bone stock, before starting the mod journey.

It made 205rwkW (274.9hp) at Nizpro in Bayswater in Melbourne. The event was organised by tawfeeqh (thanks again mate, and sad to see you sell your car, and leave the platform).

This was the highest stock N54 record, on average they seem to do in the ballpark of 170-195rwkW (228-261.5hp). Nizpro’s own development car pulled 168rwkW (225.3hp) on the same dyno, so that was interesting to know. My car must have been built on a Wednesday haha

Knowing the motor was very healthy was certainly a good start to a lengthy modding journey to come.





Video of the run:

[Pete.J]

I installed an E9X Servotronic M3 steering rack on my car, it's by far one of my favourite mods to date! Highly recommended in my opinion! The M3 steering rack has a quicker ratio of 1:12.5 vs the standard non-M steering rack which has a ratio of 1:16.

Part numbers:
1- M3 steering rack - 32102283632
2- M3 billet steering shaft (optional) - 32302283432
3- M3 tie-rods (optional) - 32102283461 (left), 32102283462 (right)

*try to get a complete rack with tie-rods, steering shaft and everything in one package. It’ll work our way cheaper. The seller I got mine off included the steering shaft and tie-rods free of charge.

The M3 rack is wayyyy faster, and makes the steering feel so responsive. The M3 steering rack is Servotronic, i.e. it has variable assistance, at low speeds it gets lighter, and at high speeds it becomes heavier. To achieve this function, it has a solenoid valve on it, and the valve is controlled by the JBBF module, I haven't wired the solenoid valve to the JBBF module yet (on the M3, the Servotronic steering weight is controlled by the MSS60 DME, lucky there's an alternative way to control it on non-M cars, on the 1M and other N54 vehicles the JBBF can control the steering assistance).

To achieve a heavy steering, it closes the valve, which restricts the flow of the pressurised hydraulic fluid coming from power steering pump, and for light steering, the solenoid valve is fully opened. At its lightest setting, the steering is significantly lighter than the stock 335i steering weight, and it’s heaviest, it’s also significantly heavier than the stock 335i steering.

Overall the steering feel has been majorily improved. No wonder all the media reviews keep describing the E92 M3 to have that magical steering feel that no other car has got haha

Currently it's running at the heaviest possible setting, it's a fair bit heavier than the standard 335i steering, I hated it initially, but now I got used to it, and I absolutely love the meaty steering feel. Not sure if I'll ever get around to wiring it tbh, we'll see. I might do it on a quiet Saturday afternoon, and code the JBBF module to have a custom assistance curve, i.e. specify how heavy I want the steering to feel at different speeds (can be done through JBBF NETTODAT hex file coding ).





I faced an issue with installing the M3 rack, the M3 tie rods are too long, which means that even when they're fully winded in, I had significant amount of toe-out. When I swapped to the original 335i tie-rods, I was uncomfortable with how short they are, to achieve my desired alignment (zero toe), the inner and outer tie-rods were only screwed by a couple of threads, which wasn't safe in my opinion.





The solution was to cut off 2-3mm off the M3 inner tie-rods, and screw them all the way inside the outer tie-rods, that way the arm is very strong with plenty of thread contact in-between the two pieces, and I can achieve my desired alignment.





The issue originally rose because the E9X M3 received different knuckles to non-M cars, and the tie-rod attachment point sits further out than on the M3 than on non-M cars, hence why the M3 has longer inner tie-rods to make up for the distance.



The M3 rack also comes with a nice billet piece steering shaft, this is a solid piece, unlike the standard non-M E9x which is a hollow tube. This was done so that the steering shaft could clear the header of the S65B40 V80 motor. After initially looking at it, it seemed that it could help with fitting bigger outlets on RHD cars, but if you take a close look, the U-joint section is actually more bulky on the M3 steering shaft. So I'd say it won't help much for that purpose. The steering shaft swap is optional, it doesn't have to be swapped with the M3 rack (you can grind off a small plastic tab, and re-use the standard steering shaft). I still fitted it either way, it's a nice looking piece of metal, and it's significantly stronger than the stock piece, it also has a beefier universal joint on it.







Just for reference, here are the steering rack ratios of some other performance cars on the market:

You'll notice that the E9X M3 has by far the quickest steering rack out of any modern production sports car!

E9x M3 and E82 1M: 12.5:1 (they use the same rack)

Non-M E9x 3er: 16:1
Non-M E8x 1er: 16:1
E46 M3: 15.4:1
E46 M3 ZCP/CSL: 14.5:1
E46 330ci ZHP: 13.7:1
E86 Z4M Coupe: 12.8:1 (the closest to the E9x M3)
F82 M4: 15:1
F87 M2: 15:1
F10 M5: 16:1
W204 C63 AMG: 13.6:1
W205 C63 AMG: 14.1:1
B6 and B7 RS4: 13.1:1
B6 and B7 S4: 14.5:1
EVO X MR: 13:1
VA (4th gen) WRX STI: 13:1

It's interesting that the newer ///M cars have much slower steering ratios than old school cars, this could potentially be due to the electric motor used in the Electric Power Steering system not being strong enough to turn the wheels. The quicker the steering ratio, the more energy is needed to turn the steering wheel (a simple gearing leverage situation). An alternative thought, it could be due to efficiency reasons, putting a very quick steering ratio and a strong electric motor behind to turn the wheels might ruin the benefits of changing over to EPS. EPS found its way into modern cars to save energy (fuel) and lower emissions.... etc. So the engineers might have been forced to slow down the steering rack ratio to find a good balance between efficiency and functionality.

[Aus335iguy]

Working m drive..........spill it ! What was the trick ?

[Socket]

Great built Pete and beautiful example of a thoughtfully modded E92
Cant wait to read more mate

[ozmonday]

Thanks for sharing your knowledge and experience, Peter. keep up the wonderful work!

[jzx_andy]

Great thread and nice car looking forward to reading more! Really tempted to grab an M3 rack now haha

[Pete.J]

Time for some suspension talk, I'll start with the front axle. But before I dive into what mods I have done to my front suspension, I need to discuss some positive design features and limitations of the front suspension on these cars.

E8x/9x have MacPherson struts at the front, when you think MacPherson struts, you think cheap cost-cutting Toyota Corolla or Hyundai i30 sort of suspension!

But BMW engineers actually used a special variation of the MacPherson struts called "Double Pivot MacPherson strut".

BMW's modification to the standard MacPherson design - Double Pivot design:

Instead of having one triangular shaped control arm at the bottom connected to the knuckle, there are two separate control arms that form the shape of a triangle, attached to the knuckle at two separate points (check diagrams below).

The two control arms are also made of lightweight forged aluminium. Control arms are considered unsprung weight, as in they sit below the springs, and their weight is not carried by the springs, therefore, it is important to keep them as light as possible! (same with brakes, tires and wheels, I'll discuss that whole sprung mass later on in the build thread).



(the above diagram is investigating the circled part on this diagram)


Other cheaper MacPherson strut designs used on econoboxes/cheap small cars:

You can see the there's one lower control arm, called the "Triangular Link", made of steel usually, and it connects to the bottom of knuckle at only one point.



(ignore the white arrows on the below picture, I took it from a Toyota Corolla training manual, that's why)


Advantages of the double pivot MacPherson strut that BMW uses, over other cheaper designs:

1- Further reduces body roll while cornering

2- Reduces front end dive tendencies during severe braking situations

3- Increased caster angle, which instigates more centreness feeling to the steering wheel, and improves straight line stability at high speeds, also improves the steering wheel return/self-straightening after turning.

4- It also adds positive steering offset, which improves control when friction levels while braking are different between wheels (turning and braking at the same time for example).

*Positive steering offset means that if you were to draw an imaginary straight line from the steering axis and extend it down, it will sit inside the tire centre line (check the diagram below). You only want a very small positive steering offset.

*That's why fitting wheels with aggressive -ve offset that poke out a lot more (or spacers), might not be the best idea tbh, because you'll be changing the positive steering offset these cars have from factory (you'll make it a lot more positive). You need to take some precise measurements, and try to maintain the tire centre-line point to be roughly the same as stock if you were to replace your wheels.

The E9x M3 received completely different knuckles at the front, that had different steering axis, that way the slightly positive steering offset is maintained in-conjunction with wider wheels and tires, clever Germans



I thought laying out the above information was important before digging any deeper, because these cars always get bagged for running the "mediocre" MacPherson strut design at the front, like all cheap Korean small cars do haha

The general advantages of the MacPherson struts:

1- Compact, and can be fitted to small cars

2- Lightweight and simple design

3- Cheap to manufacture, although there are expensive variations of it, like the Double Pivot version discussed above. BMW and Porsche use the Double Pivot design on their cars (yes a 911 GT2/GT3 RS has the same "mediocre" MacPherson struts, can you believe it?! ). Honda also came up with a very clever variation of the MacPherson strut, that helped them eliminate the torque steer on the new Civic Type R (beyond the scope of this thread, but worth having a read on it imo).

4- MacPherson struts design are the better choice for racing applications even though it has some limitations (I'll discuss why I think it's the way to go for competition race cars later on).

The general disadvantage of the MacPherson struts (there's only one major one in my opinion):

They see large camber changes in their compression and extension cycles, i.e. the more you compress the front suspension, the more they gain positive camber (upon initial compression, they actually gain a bit of negative camber, but then they quickly snap into positive camber), positive camber will reduce the tire contact patch with the asphalt.

Imagine you're turning at a high speed, the car will naturally lean, as a result of the leaning alone, you're already driving on the outside edge of the tire, and you already have a reduced tire contact patch, it'll look something like the below photo.



Body leaning aside, the front suspension will also compress because of the weight acting on it mid-corner, as mentioned above, MacPherson struts gain positive camber when compressed, the problem has now been further worsened.

You're not just riding on the outer edge of the tire because of body lean alone, but you also have positive camber getting induced by the MacPherson struts when compressed. You're now really riding on the outer edge of the tire with a very compromised tire contact patch with the asphalt , your contact patch will look something like the below diagram.



As a result, you won't be taking advantage of the full tire contact patch, and you will experience dreading understeer. Understeering is probably the worst and most frustrating handling characteristic. You turn the steering wheel, and the car just disobeys and ploughs straight! It's a result of low front-end tire grip. It's not really the tires fault in this case, it's the suspension that's not positioning the tire on the asphalt in a way to have a complete contact patch with the road.

The solution to the above mentioned shortcomings:

1- Run significantly stiffer springs at the front, that way when the front end suspension is subject to stress, it will not compress by a large amount, and therefore, this limits the positive camber gained upon compression.

2- Run static negative camber at the front, that means with the car resting at standstill, you have negative camber dialed-in, for example -2.5 degs. Therefore when the front suspension eventually compresses under stress, and positive camber is gained, the net result will end up being somewhere around -1.0 degs of -ve camber. Which should be sufficient to maintain a full tire contact patch mid-corner, even with a bit of body lean involved.

An example to the above solutions, look how much -ve camber this racing 135i is running , and of course it'll be on super stiff front springs too.

Only you can decide how many degrees of -ve camber you need, based on your own driving style. The more aggressive you are as a driver around corners the more negative camber and stiffer front springs you'll need.



My next post will be discussing and reviewing the mods I've done to the front axle on my own car to attempt to mitigate the shortcomings of the front MacPherson strut design, I'll discuss how much camber I am running and spring rates, and what changes these mods had on the car and overall driving experience... etc.

[Pete.J]

Originally Posted by Aus335iguy

Working m drive..........spill it ! What was the trick ?

My ///M button on my steering wheel is only working with the same functionality as it does on the 1M, not like the E9x M3 (i.e. engages ///M drive). But at least I sorted my DTC and "DSC off" issue after retrofitting that M3 DSC module, and I also managed to get the cruise control working again.

On the 1M's, the ///M button on the steering wheel doesn't engage ///M Drive like it does on the M3, instead it provides a sharper throttle response. Here's a handy screenshot explaining the difference.



Regarding the ///M Drive and MDM (M Dynamic Mode) functionalities, these are predominantly controlled by the DME. It’s up to the DME to forward the signal to the DSC and JBBF (to control Servotronic) or not, once you press that ///M button on the steering wheel. For example the IJE0S N54 ROM just ignores the ///M button signal completely and the button doesn’t do anything. The MSS60 DME in the M3 forwards the signal to JBBF and DSC, and enganges ///M Drive.

The ///M Drive presets are actually saved directly in the DME memory, and the when ///M button is pressed, the DME recalls the saved presets, and sends the correct signals to the DSC and JBBF. For example if you have “SPORT” steering selected in iDrive (heavy weight steering), the DME will have this stored in its memory and it will send a signal to the JBBF asking it to apply heavy steering weight. The JBBF will then close the solenoid valve on the M3 rack, which restricts the flow of hydraulic fluid, and provides heavier steering, same applies to how the DME calls the DSC to activate MDM or turn off DSC completely based on what preset is selected in the iDrive and saved in the DME memory... etc.

There are tables in the DME 1M ROM to control the functionality of the ///M button (very basic compared to the M3, just applies a more sensitive accelerator pedal). The MSS60 DME in the M3 also has tables to control the ///M Drive and MDM (///M Dynamic Mode) functionality.

The tables are found in different memory locations in both DME’s, as they’re completely two different ECUs. We can potentially copy the ///M Drive functionality tables from the MSS60 to the 1KM0S ROM, and achieve the same ///M Drive and MDM functionalities as the M3. This is quite an involving and time consuming task to look up all the required tables, it's on my list, but not sure when I'll get around to do it tbh. Car is running flawlessly as is now

Also, if you haven't bought a M3 DSC yet, I can now custom flash the M3 DSC software on the standard 335i DSC, good if you'd like to attempt retrofitting for the DCT Drivelogic. All the memory locations across the DSC modules are identical, so you can flash any DSC software from any car on this platform to any DSC module you got on your hands. Keep in my mind that the modules are not physically identical though, M3 DSC have a stronger hydraulic ABS pump to provide more braking force to the larger calipers and tires. Kinda of expected really, the M3 has wider tires and wheels with more grip, you definitely need a more powerful ABS bump to pressurise the brake lines and apply enough brake force to the caliper pistons.

Would be nice to be able to store your favourite setting on the iDrive and call them whenever you need with the press of a button on the steering wheel , I'll look into it in the future when time permits.

[Aus335iguy]

Wow Pete! That's a better answer than i was hoping for. I assumed the DME stuff and the same with the DSC stuff i guessed you could just flash it and i was in the process of securing a spare before i gave up on the whole shebang. Can you confirm that its just a normal flash job via the standard tools or does it require some trickery?
Also theres a whole swag of people that would pay to have the /M drive working properly so if you want some cash......
Lastly, did someone help you with this or have you just figured it out for yourself ?

[LMB335IS]

Really good read. My 335is DCT somewhat mirrors your car in many aspects. I'm running the M3 GWS and GTS flash on my DCT with working drivelogic and and the center console pieces that go with it. Full M3 drivetrain with a 2.81 gear, about as high as I can go and still play nice with the software.

I'm using a M3 ABS/DSC unit coded to the car as a M module so I'm guessing you used the same work around that I did with some VO magic. Now my center console DSC is directly wired to the DSC module, and I'm not sure how it actually works on a M, but mine is either on or off, no intermediate step. And of course with the M module there is absolutely no electronic interference close to what a non M DSC module has. The rack is next on my list.

I'm also running a custom IKM0S ROM, through MHD though. The M button does work as far as lighting the dash icon but I had my tuner just set all my throttle tables to the most aggressive sport mode values so it really doesn't matter. I'm super keen on getting those MSS60 tables incorporated into the ROM and I suppose a custom XDF would be needed to manipulate those values, but that's all well above my pay grade.

The rest is fairly standard stuff. All M suspension pieces with BMW Performance springs, struts, and shocks, although I have the camber links, comp springs, and Bilstein B6s ready to upgrade the rear. F & R M sways with poly bushings, poly subframe bushings, F30 M Performance brakes all the way around. M cluster, SZL, blah, blah, blah, lol.

Definitely going to follow this and see where you are headed with this. Very interested in getting M Drive and MDM functional myself.

[Pete.J]

Been a while since I've updated my build thread, the backlog of mods to review is very lengthy, and I am very time poor. I have lately been flat out busy between work and sorting out the race car as we approach the biggest production car race in Australia, held over the Easter weekend (wish us luck). Couple of photos of that beauty:





Moving on to my car, I will continue the front-end suspension discussion started earlier in this thread later on, as it's time consuming doing suspension mods reviews properly. Let's talk N54 tuning bins, and in particular focussing on the IKM0S from the E82 1M.

Background:

The N54 engine was managed by three DME's, MSD80, MSD81 and MSD87:

-MSD80, came on 2006-2007 E9x 335i
-MSD81, 2008+ almost all N54 cars except for the F01/2 740i
-MSD87, F01/02 740i (beyond the scope of this thread)

The above DME's has different bins running on them:

MSD80:
-I8A0S bin = all standard E9x 335i

MSD81:
-IJE0S bin = all standard E8x 135i, E9x 335i and E71 X6, including N54 cars tuned with the BMW PPK (Performance Power Kit)
-INA0S bin = 35is cars, i.e. 135is, 335is and Z4 sDrive35is (135is and 335is were USA only models)
-IKM0S bin = 1M (this is the one you need to remember )

Problem:

Speak to any manual N54 owner, and they will all tell you how hard it is to rev-match a N54. Pretty damn hard! The motor is just so damn lazy to rev up freely when it's not under load, I actually need to floor the accelerator to the carpet to blip the throttle when downshifting from 3rd -> 2nd, just to bring the revs high enough, and even then it's still very slow to build revs. When downshifting You have to hold down the clutch for longer waiting for the revs to rise before you can release the clutch pedal.

What's interesting, is that the DCT transmission had the ability to blip the throttle on the N54 extremely fast when it's downshifting this gave it away that the motor is actually capable of being revved up super quick and other electronic factors were playing a role to hold it back. Moreover, after driving an E82 1M, I noticed that throttle response is very sharp and precise on it.

Theory 1:
The standard N54 has a very heavy dual mass flywheel, and that's why you can't bring the revs up quick enough when free-revving the engine between shifts. The 1M has a lightweight flywheel, hence why it has a better throttle response, sounded promising enough to try at least.

As a result, you see heaps of people upgrading to a noisier lightweight single mass flywheel to hold more power, and also hoping the motor gains a sharper throttle response. On my car I used to have Motiv SST twin-plate clutch with a 25-30% lighter weight single mass flywheel. But I was disappointed to see that this barely reflected on an improved throttle response, I expected the motor to rev freely A LOT more , at this point, I knew 100% that there's another factor involved. (Btw, I don't think running this clutch kit was a good idea on a street car, apart from the fact that it's stupidly difficult to drive, it ended up failing after a few thousand kilometres, look in my sale thread here for photos).

Theory 2:

The N54 has a very long air intake tract, and as a result, it's super lazy to spin up quickly, because air has to travel a long distance round and round until it reaches the throttle plate. So from the moment you press the pedal, by the time air volume actually exits the turbos, goes through the outlets, then intercooler, charge-pipe and eventually arrives at the throttle body, it takes time, hence why the motor is lazy. Tbh at the time this made the most sense to be the reason behind the lazy N54 throttle, because when I drove a friend's M140i with the newer 3.0L 6 cyl B58 engine, the throttle response was very sharp and precise, it almost feels naturally aspirated, in my limited understanding at the time I attributed the good throttle response to the short intake tract of the B58.

Below are the N54 vs B58 air intake tracts lengths side by side, unfortunately I couldn't find the same type diagram for both, but you can still see the N54 has significantly longer air travel path from the moment it leaves the turbos, until it reaches the throttle plate:



Theory 3:

The speed at which the throttle plate opens is electronically controlled, and regardless of how fast you stab the accelerator with your foot on rev-matching while downshifting, it'll still open slow!

This by far made the most sense to be the cause of the issue, because the lightweight single mass flywheel that I had in the past, didn't reflect in making the motor spin up quick enough. It didn't make sense that I reduced the mass of the flywheel by ~30%, and the motor only feels like it revs 5-10% quicker. From an engineering point of view, it just didn't add up.

I turned around to ask everyone I know that is familiar with tuning N54's about this, and they all responded that there's nothing in the XDF's reflecting throttle plate movement speed, or on the contrary some sort of throttle plate actuation speed inhibitor.

I gave up at this point and just decided to live with it UNTIL I tried the 1M tune bin on my car....

Solution:

A few months ago, I picked a M3 DSC unit (module + pump), in an attempt to retrofit ///M Drive to my car. ///M drive is explained above in post #9. For the ///M button on the steering wheel to work, it needs either the MSS60 DME from the E9x M3, or MSD81 DME with the IKM0S bin loaded on it from the E82 1M.

Obviously my car being N54 powered, I can only flash the 1M tune to it. The 1M bin can only be flashed to the MSD81 DME (refer to the start of this post to workout which DME you have and which bin is loaded on it from factory).

What I discovered next was a nice surprise , the IKM0S turned out to have extremely sharp throttle response, it still remains as a linear throttle, i.e. 10% throttle = 10% torque request, but the IKM0S opens the throttle plate to the required angle IMMEDIATELY! If you tap the throttle very quickly on and off with your foot, the whole car will just jerk as the engine responds to the momentarily opened throttle plate, turned out that all the the standard N54 bins (I8A0S, IJE0S and INA0S) have built-in throttle dampening, which means they slow down the throttle plate movement to give you a more comfortable, more relaxed driving experience.

The 1M IKM0S bin feels amazingly satisfying to drive, I put 534km of pointless unplanned driving on mountain roads the day I discovered it, just for the sake of sheer driving pleasure. Ohhhhh I cannot describe how precise and how accurate the rev-matching and downshifting feel now, very satisfying! I love blipping the throttle in my flip flops and rev-match like a pro when slowing down LoL. I pretty much rev-match every single downshift now, it just feels gold

Looking through the 1M technical documentation, and I found this:



I can imagine BMW ///M engineers saying "Was ist das für eine Scheiße?" (What is this shit?) when a standard 135i got handed to them to use as a base for creating the 1M . At the end of the day, the N54 was developed by BMW AG to be used on standard passenger cars, the whole 1M thing and using the N54 in a ///M car was an afterthought, there was no need to tune it for a super fast/super responsive throttle plate actuation from the start, if anything, comfort was probably the goal when this engine was getting developed.

To make this factual, I did two logs on the same exact custom tune that I am running to examine the difference in the actuation speeds of the throttle plate, on one log I used IJE0S European E92 PPK bin, and on the other I used IKM0S European E82 1M bin (both running the same exact custom tune):

IJE0S (standard N54):



IKM0S (1M):



You can see that the throttle curve is steeper and sits closer to the actual pedal position on both opening and closing on the IKM0S (1M) bin, if you look at the time off the graph required for the throttle plate to go wide open in both cases, the IKM0S is faster by about 0.41s to fully open up to the maximum angle (i.e. WOT). Which is hugeeee in terms of feel and response when you're behind the steering wheel. This alone, has transformed the whole feel of the car for me

I noticed when I drove on bumpy roads, my foot wasn't very stable on the accelerator, the whole car jerked and surged lightly as my foot was pressing the throttle and releasing very tiny amount due to the bumpiness of the road. The standard N54 bins (I8A0S, IJE0S, and INA0S) all tend to ignore those tiny and brief accelerator inputs to provide an overall smoother ride for the occupants. But IKM0S (1M bin) will change the throttle plate position immediately with even the tiniest accelerator position change, and you can certainly feel it in the seat. In other words, all the standard N54 bins have a dampened throttle input for comfort, which is also the culprit for lazy throttle feel, and making it very hard to rev-match and blip the throttle quick enough on this particular motor as discussed earlier... etc.. But the 1M bin being developed by BMW ///M for a sports car, has been properly remapped to sort that, and to make it behave like a proper sports car should.

The DME tables that manage the throttle plate dampening or inhibition are not in the public XDF's, they're probably not even discovered yet, MHD Tuning do you know about this?

Once they're discovered, this feature can also be applied to standard N54 bins, but until that happens, running the 1M bin is the only solution to obtain a quicker throttle plate actuation.

Be mindful that throttle plate response and its actuation speed are a completely different thing to the "Linear Throttle" option that can be ticked in MHD, and of course different to turbo lag too. I only ever use linear throttle on my car under any case, not to be confused with the transient throttle response of an engine which is being discussed here.

🚨 NOTE: The IKM0S 1M bin will not work by just flashing it onto a regular 135i/335i. It has internal checks that it performs against the DME (powerclass coding... etc.) to verify that the car it's getting run on, is indeed a 1M. There are ways to turn off these internal checks by changing certain bits in the bin, all info on how to get there and migrate from I8A0S, IJE0S, INA0S to IKM0S in my next post, post 13. Now MSD81 car can run IKM0S

Last thing to consider, the 1M was the most powerful production version of the N54 motor and the most motorsport-oriented, naturally you'd expect it to form the best base tune foundation to use for a custom tune. If you're considering a custom tune, basing it on the IKM0S is the way to go (or the PPK IJE0S, but you'll miss out on the awesome razor sharp throttle response associated on the 1M bin).

[Pete.J]

If you're after upgrading from MSD80 to MSD81 read Part 1, otherwise if you're only after migrating from I8A0S (MSD80) or IJE0S/INA0S (MSD81) to IKM0S (1M bin) jump straight to Part 2.


Part 1: MSD80 -----> MSD81:

My car originally came with MSD80, it's a 2007 E92 335i, I've since upgraded to MSD81, I will discuss what's involved in the upgrade process in this part.

Starting the engine, how it actually works, a tale of a DME and a CAS:

There's a secret key called ISN Key, the DME and CAS (Car Access System) modules must have the same key stored in them. Without having a matching ISN Key, it's impossible to start the engine (remember this for now, we'll need it later).

For the engine to be started, a request and response procedure known as "Challenge-Response-Authentication" must first be carried successfully.

Those who work in the IT Security industry will be familiar with the challenge-response authentication technique. For those who don't know, briefly, a server (or a car module in this context) will send a challenge to a client (another car module), if the client successfully resolves the challenge, the challenger then grants access to the client to authorise it to perform a certain task.

To apply this to the context of our cars, as soon as you put the key in the key slot and the ignition turns on (also known as Terminal 15 state), the DME will challenge the CAS3 by sending it an random number, and asks the CAS3 to resolve it, and send back the result it came up with.

On the DME side:

The DME uses a random number generator each time the engine is started (also known as rolling-code). The DME will use the ISN Key (mentioned at the start) stored in its memory to hash both numbers together (random generated number + ISN Key), the DME uses a secret hash function to come up with a result value from these two numbers.

The DME will then send to the CAS3 that same random generated number, and challenges the CAS3 to hash it and send back the result value.

*Discussing hashing is off topic to this post, but just think of it that the DME solves the two numbers (random generated number + ISN Key) against each other via an equation or a secret function that no one knows about. The outcome of this hashing process will be saved temporarily in a volatile memory in the DME.

On the CAS3 side:

In the meantime, the CAS3 will receive that same random generated number from the DME, and it will do with it the same thing. It will use the ISN Key stored in its memory and use the random number it received from the DME, and hashes them together using the same hashing function that the DME used. Therefore, if the CAS3 has the same ISN Key stored in it as the DME, the final result value will be the same as what the DME came up with.

The CAS3 will send its answer to the challenge back to the DME, the DME will compare it to its own result, if they're both identical, therefore the CAS3 has responded successfully to the challenge that the DME proposed, so it must have the same secret ISN Key as the one stored in the DME, and authentication is approved, immobiliser is disabled, and the engine will fire up

The key point to take from this is, the DME and CAS3 must have the same ISN Key stored in them, otherwise the challenge-response authentication will fail. If the final result value that the CAS3 comes up with doesn't match the value the DME calculated, the immobiliser will remain active, and it's impossible to the start the engine. Even if you turn the engine manually, or power up the starter motor with an external power source, the DME will refuse to provide ignition and fuel (both coils and injectors are directly controlled by the DME), and the engine will stall immediately. So there's literally no way of starting the motor unless the above process succeeds.

The BIG Question:

You're probably thinking why doesn't the DME just straight up query the CAS3 about its stored ISN Key instead of all this challenge-response and hashing functions bullshit?! and if the CAS3 has the right key, authentication will be successful, if the CAS3 responds with the wrong key, authentication will fail.

Valid question, but the answer lies in two key points:

1- The ISN Key should never be broadcasted or sent across the CANBUS or any other communication channel within the car. It must only be stored internally in the DME and CAS3 modules themselves. If the ISN Key falls in the wrong hands, they can very easily steal your car!!

So for the security reasons, the ISN Key must NEVER be broadcasted outside the DME and CAS3 modules. The biggest benefit of the challenge-response authentication, it's a clever method to verify that the DME and CAS3 both have the same ISN Key stored inside them, but without having to actually broadcast this ISN key publicly, and without having to send messages to each other via the CANBUS to query if the other module got the same ISN Key or not... etc.

2- You might also wonder, if the random number initially gets sent publicly to the CAS3 by the DME on the CANBUS, and CAS3 responds back to the DME with the result value publicly via the CANBUS as well, wouldn't it just be very easy to use initially sent random number and the result to work out what is the secret ISN KEY value that the CAS3 used to resolve the challenge?

Logically it sounds like it's a security hole, but hashing functions got us covered . Hashing functions cannot be reversed. So if you know the random number generated and sent initially by the DME, and you also know the result value after hashing it with the secret ISN Key, you can never reverse engineer the hashing function to find out what's the secret ISN Key that the CAS3 used to come up with this result

Hash(Random number + ISN Key) = Result value

You can connect a listener device and use it to read all the data packets being sent through the CANBUS, this will get you the two numbers coloured in green, but you can never reverse engineer the hash function to come up with the one in red, which is the one that matters, the ISN Key.

Remember that the ISN Key is never ever broadcasted or sent via any of the communication channels in the car. It's kept totally secret inside the DME and CAS3.

Viola, that's it, that's how your car actually starts!

CAS-DME-EGS Diagram:

Here's a network diagram to see how all the modules involved in this process come to communicate with one another.



So how does BMW intend for faulty DME's to replaced?:

As discussed earlier the ISN Key must match between the CAS3 and DME, BMW AG has a large database of all the VIN numbers and the ISN Keys associated with each VIN. Identical ISN Key will be stored in each car's DME-CAS3 combo when it rolls out of the assembly line.

The way BMW intended for DME's to be replaced is, your local dealer orders on your behalf a brand new MSD81 DME from BMW AG in Germany using your VIN, BMW AG will get a brand new virgin MSD81 from Siemens/Continental and lookup your VIN in their database, to see what's the original ISN Key that is stored in your CAS3 module the day your car left the assembly plant. They'll upload the correct ISN Key to the new DME to match what your CAS3 got, and ship it to your local dealer. At this stage, it's just plug and play, and the car will start straight away.

So BMW AG never had the intention for the ISN Key to be changed on a secondhand DME, and they never had the intention to reuse a secondhand DME to replace a faulty one. The reason behind this, if they were to do that, then that means they'll have to allow the ISN Key to be publicly broadcasted on the CANBUS for the purpose of exchanging your faulty DME with another secondhand one. As mentioned earlier in the post, the ISN Key should never be broadcasted on the CANBUS, and there should never be a legit method to allow the ISN Key to be broadcasted on the CANBUS. For obvious security reasons mentioned earlier.

That's why, for any CAS module failure, or any DME failure, brand new modules must be ordered. Copying the ISN Key across from a DME to a faulty CAS, or from a CAS to faulty DME isn't permitted, and it's not an approved way to replace neither DME or CAS!

How we do it:

There are special ISN programmers that can be bought to copy the ISN Key from the DME to the CAS module.

To name a couple, Autohex II, BMW-Explorer, CGDI... etc.

Previously I contacted a couple of local electronics and Locksmith shops that specialise in European cars, and they had no clue what I was talking about

Eventually, one of those shops, referred me to speak with a company called "Injentronics". I called them up, I spoke to someone who seemed to know a little more about this than the Locksmiths I contacted earlier, but he still wasn't very familiar with the whole process. Eventually I asked him if they have an ISN programmer, he said yes, I asked for the model and looked it up online and it had the MSD81 and CAS3 listed as compatible!

Injentronics wanted $450 AUD for this, I thought it was a bit too much given that they didn't actually know what's going on, and I had to explain the process to them. So I am basically paying $450 to use their ISN programmer, but I am the one providing them with what needs to be done, no thanks hahah

Around the same time I bought my secondhand DME, my good friend vtl bought a CGDI Programmer to add to his arsenal of tools. CGDI is the cheapest out of all the ISN programmers mentioned above, but it does the job. So that was the ISN programmer I used for this.

How does the CGDI work:

Firstly, none of these tools are authorised by BMW AG, or developed by any of BMW partners. All these ISN programmers are developed by cracker/hacker to exploit security holes in the DME and CAS3.

-Preliminary task: open the DME box, swap the MSD80 with the new MSD81.

The way the CGDI works, is it flashed a dodgy DME software on my secondhand MSD81 DME. This dodgy software forced the poor MSD81 DME to spit out the secret ISN Key stored in its memory straight away.

As mentioned above, the DME and CAS3 are designed to absolutely never broadcast the ISN Key publicly on the CANBUS. But because the CGDI flashed a dodgy compromised software on my MSD81 DME, it compromised the DME security and forced it to spit out the ISN!

Now I have the secret ISN Key from the new MSD81 displayed on the laptop screen, all what's left now is to copy it to my current CAS3 module, that way the DME and CAS3 will have the same ISN and engine will start. But we faced major delays with this step, and spent two days trying to solve it

It turned out because I always keep all the software on my car up to date, I had flashed the latest CAS3 ZB number firmware that came in the V66 Daten a few months earlier. BMW has plugged a security hole that prevents writing an ISN Key to the CAS3, as mentioned earlier officially you're not meant to read or write ISN Key to neither the CAS3 or the DME.

The solution was very easy, I used WinKfp to downgrade my CAS3 to an earlier software version, and afterwards the CGDI programmer could successfully write the ISN Key from new MSD81 to my CAS3 with one click.

Before starting the car, I flashed my DME with the latest ZB number available for European WB72 E92 335i (Just the standard IJE0S for now to test), because I didn't trust starting the engine with the dodgy DME software from the CGDI flashed on it LoL , and also I updated the CAS3 again to the latest firmware found in V66 Daten (for security reasons due to the latest software being harder to read or write ISN Key to the CAS3 as proven already)

That's it, all done and all working perfectly, if you're in Australia, and looking to migrate from MSD80 to MSD81, I highly recommend vtl, I've known him for many years. My car was the first car we do this on, but after my car vtl has done a few, and there was absolutely no issues and all worked very smoothly. The only hiccup we faced when we did my car, was my CAS software was too new, that's about it. Btw I highly suggest you update your CAS software to the latest for security reasons.

Some pics of the process:

Shiny DME, I polished it with Autosol Metal Polish haha, why not?! I like everything clean and shiny, I wouldn't be surprised if I was the only person that ever polished a MSD81 metal case lmao :



CGDI connected to my car doing its thing:



My DME box was disgusting, I took everything out it and gave it a good clean, it had all this fabric tape that is used to bundle wires together in the DME box fallen at the bottom of the box.

There's also a suction fan to cool the DME where the red arrow is pointing, lucky none of that fabric tape got caught in it.



All cleaned up, I also put in new fabric tape to bundle the wires together like it was originally. I put small cable ties over each tape bundle so it never comes off again.



That was it, closed the DME box for good, and hopefully I never have to open it ever again!

Part 2: I8A0S, IJE0S, INA0S -----> IKM0S (1M):

DISCLAIMER: this goes without saying of course, but I am sure you all know you are responsible for any harm you cause to yourself or your vehicle following information and advice from this post

I thought about whether I am going to post this publicly or not, and eventually decided to post it to help push the platform develop. The issue with the N54 and other similar BMW platforms, is information hoarding! No one shares anything or any new discoveries, it's crippling the development of the platform, and I wouldn't want to play a role in that. I discovered how to flash the IKM0S myself with the help of two of friends, so I own the rights to the information you're about to read below, and I chose to post publicly to help others that are interested to head in the same paths.

Look at all other performance car platforms, JDM cars, EVO's, WRX's, Muscle cars... etc. they're all well developed and well understood, because people don't hoard information and they don't hide discoveries like the case on turbo BMW's platforms!

In the name of freedom of information for everyone

The DME has a coding parameter within it called "OLULCODIERUNG", which stands for "Power Class Coding".

All N54 cars, are Low-Power Class (hex data 00), except for the 1M which is Medium-Power Class (hex data 01), and the Alpina B3 is High-Power Class (hex data 02).

It doesn't matter how hard you try to change this coding data using standard tools like NCS Expert, it will never write to the DME memory the new data you entered.

Notice how on the screenshot below, it says to change the Power Class Coding in the DME, another parameter called "STAT_BSZ_WERT" must be equal to "0"?



STAT_BSZ_WERT is the number of working hours that the DME has worked since the day it was manufactured.

You can run a function in Tool32 called "STATUS_BETRIEBSSTUNDENZAEHLER", which will display the current working hours of the DME. The result of this function from my secondhand MSD81 DME is displayed below.



This is a screenshot with the description of the function for those interested:



There's also another function in Tool32 that can reset the working hours (STAT_BSZ_WERT) back to ZERO. And once the STAT_BSZ_WERT=0, then the DME Power Class Coding can be changed from Low (Data 00) to Medium (Data 01) using NCS Expert, as shown in that screenshot above.

But there's a problem, the DME working hours can't be reset to ZERO, unless the DME has done less than 10 hours of work only! And of course there aren't any secondhand MSD81 DME's that you can buy, that will have less that 10 hours on them.

So to recap:

1- You need to change Power Class from 00 to 01 in the MSD81 DME to be able to run IKM0S on your 135i/335i.
2- To do that, the working hours of the DME (STAT_BSZ_WERT) must be equal ZERO
3- To reset the working hours using Tool32 and a standard OBD or ICOM cable, the DME must have only worked for less than >10 hours since it was new.

Absolute mess!! And this is how BMW controls using the same DME across different car models with the same engine but with different power levels. The tune map loaded on the DME will check the Power Class Coding as soon as you put the key in the ignition, and if it finds a different Power Class stored in the DME than what it expects, it'll hit limp mode immediately, and remain stuck in limp mode indefinitely until it's sorted.

In the context of our cars, once you load up the IKM0S to your DME, it'll check the Power Class Coding of your MSD81, it'll find Low-Power Class (Data 00), and it'll be expecting to find Medium-Power Class (Data 01) like the 1M. So it'll enter limp mode and remain there.

This isn't exclusive to the N54, this is how BMW universally manages different power levels across the same engine using the same DME. A classic example is the N52 engine, the E60 5er exists in 523i, 525i and 530i forms, and all three use the same 3.0L N52B30 engine. All three use the same DME (MSV70 or MSV80 later on), the 530i has High-Power Class Coding in its DME which allows it to run a tune map that makes the most power out of the same motor, the 525i has Medium-Power Class Coding in its DME with a tune map to match it, and the 523i has Low-Power Class Coding in its DME with a tune to match to match it, If you flash a tune map that doesn't match the DME Power Class, the engine will enter limp mode and will stay there. (sometimes there are physical variations between the motors too, in case of the N52, the high power output versions had a 3 stage intake manifold that can vary the length of the intake runners to help with low end torque and top end power... etc. off-topic to this post).

The workaround:

A lot easier than you might think, there are two bits in the IKM0S bin, that toggle the Power Class checking on/off, by switching them off, the IKM0S will stop checking for Power Variant and Tuning Variant... etc. And it'll run on any MSD81 DME regardless, without interrogating or questioning the DME about its Power Class, Tuning Variant and Power Variant)

As easy as the fix sounds, finding it wasn't easy at all, the hardest part in this whole process, is to find out exactly which bits require changing, and that involved heaps of trial and error to get it right! Initially I had more bits defined on the XDF, and I had to try many different combinations until finally I hit the jackpot, and came to the conclusion that only these two bits require to be changed. I removed the others that didn't work from the XDF.

I have attached the XDF with those two bits defined at the end of this post, and I've explained in the steps below how to get there.

How to get IKM0S on your car:

1- You need to find out the correct ZB number for the 1M sold in your region, there's a few ways to do this, I prefer to look it up myself in the KMM.DAT file in the Daten folder. In my case, the 1M sold in my region will be European RHD with typschlüssel (type code) UR92. The correct ZB for Australian delivered cars and most likely all other European cars is: 8619148

2- Once you find out the correct ZB number, you'll need to use WinKfp with an ICOM cable or a trusted OBD cable and flash it on your MSD81. Follow the same instructions as flashing MHD, car on charge, don't open and close doors so you don't interrupt the CANBUS communication... etc.

I used an ICOM cable for this (BimmerGeeks OBD cable works fine for this too, can't comment on others)



3- Once it finishes flashing successfully, install MHD on Stage 0, and read the stock 1M bin with MHD and save it on your Android device. At this point, you'll have an error stored saying "2FA4 - DME: Incorrect data record". And if you take the car for a drive, it'll be in low power mode, and no boost. That's all expected at this stage.



4- Using the stock (Stage 0) 1M bin you saved from step 3, download the IKM0S XDF I attached to the end of this post and change the two bits; "Logical constant to disable check of power variant coding" from '00' to '01', and change "Logical constant to disable check of tuning variant via swt" from '00' to '01'. Save it and flash it back to the car, there will be no errors and the car will drive normally, just like a 1M, that's it! YOU NOW HAVE IKM0S FROM THE E82 1M RUNNING ON YOUR STANDARD N54 CAR

That's how it should look like before and after changing:

Stock 1M bin:



Modified 1M bin:



5- Change the diff ratio from 3.15 in the 1M tune to whatever your car has (3.46 for ZF auto, 3.08 for manual, 2.56 for DCT).

6- Port your custom tune across from your old IJE0S, I8A0S or INA0S. Remember that the memory locations are completely different between ROMs.

7- The 1M only came in manual, so the AT and DCT tables are populated with generic data from previous ROMs. Make sure you check them and compare them to your older I8..., IJ... or IN... bins, to make sure it's all alright.

8- This is the most important step, crack a cold one, stare at your car and admire all your hard work!



*Btw, this is only possible with a custom tune, unless you're happy to run with the stock 1M Power. The reason for this being that all MHD OTS maps are encrypted and cannot be modified using TunerPro, so you won't be able to change those two bits mentioned above using my XDF that I attached to this post. So if you flash MHD Stage 2+ on top of the 1M ZB number flashed using WinKfp in step 2, the car will still be in limp mode

Getting the ///M button on the steering wheel to work on your car:

You need to replace the steering wheel cluster with all the switches on it (one part) to the one from the 1M or the one from E9x M3. All 1M's had the correct part, however if you're getting this off an E9x M3, you need to make sure that it had ///M Drive. Because ///M Drive was optional on the early E9x M3's.
The 1M/M3 steering switch unit routes the signal differently than the standard part from non-M cars, hence why it has to be changed, cause that signal from the M button would otherwise go to the iDrive using the steering switch unit, but we need it to go to the DME.

The correct part no. is: 61319123060 (based on my car being a European RHD E92 335i with rain sensor... etc. Makes sure you perform your own checks before purchasing).



I managed to find a ///M button for my steering wheel, but even if you don't replace the button and kept your standard radio button (or whatever your car has instead), your old button will still function fine as a ///M button, it'll just have the wrong logo on it.



Lastly for the M Mode to work, you need to flash the 1M or M3 DSC software on your standard 135i/335i DSC module, I'll discuss this another time.

I also got a M3 cluster for my car, that way I can see the ///M symbol whenever ///M Mode is engaged. You don't have to replace the cluster, but that means you won't be able to tell whether M Mode is on or off. 135i owners will need a 1M cluster. The cluster programming is a completely different topic to all that, I'll discuss some time in the future.

That's how it all looks on my car atm:

[R.G.]

This thread

[Socket]

Originally Posted by R.G.

This thread

+1

[Aus335iguy]

Keen to hear how to flash a 335i DSC with m3 ZB .... is it as easy as I guessed (but never tried) ?

[Pete.J]

The throttle tables mentioned above in post 12 have been discovered and defined in the XDF’s with the help of vtl, thanks again chief , you’ve always given to this platform without any personal gain or reward.

Now IJE0S (MSD81) and I8A0S (MSD80) can also enjoy a more responsive throttle without the need to migrate to the IKM0S bin from the 1M as I did on my car, although I’ll probably continue running the IKM0S bin on my car. The 1M was the most powerful production N54, it certainly a move in the right direction to use the IKM0S as a base for my custom tune.

vtl will do a public announcement and release the XDF’s after all testing has been conducted. Currently vtl, titium, Socket, DR-JEKL and RJ019 are running the throttle fix on their cars. Between these 5 cars, we have a top mount single turbo, a low mount single turbo, aftermarket twins, and stock twins, and we got MSD80 and MSD81 with IJE0S and I8A0S bins. All working well so far , and everyone is enjoying the new discovery. No one had to migrate to IKM0S like I did, and their throttle feels just as great as it feels on my car (and same as the 1M too).

Without going into too much technical details, the tables that have been discovered act as a filter to the driver accelerator input.

These tables govern how the accelerator will respond in the following situations:

1- If the car stationary
2- If the car is moving at high/low speeds
3- If the car is reversing
4- Whether the clutch pedal is pressed in or not
5- Sport Mode on DCT and Auto (still have a slower throttle plate actuation compared to the 1M tables)

For example, if reverse is engaged, the throttle response will be very numbed down. This makes sense of course, because it’s assumed that when reversing you need to exercise care, and look around… etc. There's no need for a more responsive throttle, or a throttle plate that opens quicker once the accelerator is pressed.

Interestingly, the 1M throttle filtering tables are all ZEROED out! i.e. there’s absolutely no throttle corrections or filtering regardless of the situation that the car is in, doesn't matter if it's reversing, doing 250km/h or crawling at 10km/h in a car lot, there's no throttle correction by the DME

This makes the throttle feels super responsive, the accelerator also feels very consistent, as it always behaves in the same manner regardless of the situation, and it actuates the throttle plate very quickly to open/close (read post 12 above on a more thorough review after I migrated to IKM0S on my car).

Lastly, this throttle response fix is not the same as switching linear throttle on/off, people don't get it! Linear throttle option in MHD has to do with torque request table in the tune bin. I.e. if you press 10% throttle, the DME will target 10% of the available torque at the current rpm. Linear throttle means a 1:1 relationship, so 20% accelerator travel = 20% of the available torque, 40% accelerator = 40% torque... etc. The reason MHD included the linear throttle tick box is because from factory these cars have a non-linear throttle, for example: 10% throttle is 20% torque, 40% throttle is 80% torque... etc. by the time you get to 60% accelerator travel, the engine is already producing 100% of its torque, so it's basically full throttle at only 60% accelerator pedal travel, and the remaining 40% of the pedal travel is just a deadzone that doesn't do anything. In my opinion, ticking that MHD linear throttle option is a must, specially when these engines are tuned, the torque is very hard to control, and the longer pedal travel really helps applying the torque smoothly on corner exit without spinning the wheels.

The throttle fix that has been recently discovered is completely different to the throttle mapping and torque request tables, I thought I should clarify that because it's very easy to mix between a sharp throttle response, and a stupid bloated over-reactive accelerator input where 30% accelerator travel is equal to 60% of the available engine torque.

[Pete.J]

I had the pleasure to work on the Secure Wealth Advisers’ BMW F20 M135i race car for the Bathurst 6 Hour. Australia’s biggest production car race.

The Bathurst Motor Festival is an annual motor racing event held at the Mount Panorama Circuit in Bathurst, New South Wales, Australia during the Easter long weekend. The motor festival includes GT-1 Australia, Improved Production racing categories, and of course production car racing which I was involved in. There were also some other support racing groups, like Porsche racing club, and historic car racing.

Improved Production and Production Cars are two different categories, in Improved Production there are no limits to modifications, you can do anything you want to the car as long as it fits on the body of the car. The production car racing that I raced in has limitations on tyre size (only allowed two sizes up up from factory), limitations on boost (only allowed to run the maximum boost that that specific motor left the factory with in any variation or form, in our case that was 1bar/14.5psi which is found on the N55 in the BMW M2), and a few others, like limitations on intake manifold and intake piping, type fuel to run... etc.

I am not going to bore you with all the details on the limitations to modifications, but I'll just say that I enjoy Production Car racing the most out of any racing category atm. Due to the limitations to modifications, this means that you need to start with a decent base before converting it to a race car, and that makes it more challenging. In my opinion, modern turbo BMW's make a fantastic starting point to build a race upon . Conversely the Improved Production series has not limits to modifications, it becomes a game of who has the deepest pockets to dump endless funds on the car and build a 1,000hp racer

At the race, all three drivers put a fantastic show driving the car across the famous Bathurst Mount Panorama Circuit. We fluctuated between 2nd and 3rd outright positions throughout the 6 hour long race, and eventually finished at 7th position (out of 44) due to an issue with the rear brakes and a swollen tyre wall.

Earlier this year, I flew to Sydney and coded out all the DSC nannies on the race car, and I got very positive feedback from all the racing drivers. Since all the nannies got turned off the car didn't participate in any endurance races, but instead was driven multiple short stints around different circuits to test out the suspension and the overall setup. Unexpectedly, we found ourselves chewing through rear brake pads during the race, still not sure if that's related to coding out all the DSC nannies or not. We are using ENDLESS Competition brake pads, which we were told they will last the full 6 hour duration of the race easily (they're proven to last on the EVO's for the same duration on the same track driven just as hard), but unfortunately the rears were completely worn down to the backplates after only 3 hours through the race. By the end of the 6 hour race, the second set of rear brake pads that we installed in the pits during the race were down to 1mm, and the front pads which have lasted throughout the whole race were also down to ~2mm (front right pad looked slightly thicker than front left, this variation in wear between front left and front right could have been due to the EBD, Electronic Brake-force Distribution, I could have switched it off by coding, but I thought it wouldn't hurt to just keep it on as it would help with braking in the wet).

The team did a phenomenal job to minimise the impact of the brakes issue we had, by replacing the sizzling hot brake pads in the pits during the race, and got it done in under 4 mins!! The gloves were smoking when I held the pads, but we had no option but to replace them while hot. The AP Racing calipers made this very easy too, just needed to pull out two pins and the pads could be taken out. The race car has AP Racing Radi-CAL forged calipers installed, absolute state of the art race caliper technology. You can enjoy reading about them in this article, engineers will be drooling as they read through hahah.

The car was in great mechanical condition after the 6 hour race, just shows how well-built those German cars are . Can’t wait long enough for our next racing event! (most likely Phillip Island 600km endurance race).

I drove from Melbourne to Sydney, then Sydney to Bathurst, and on the way back I took the same route, Bathurst to Sydney, then Sydney to Melbourne. I thoroughly enjoyed the drive through the Blue Mountains on the way to Bathurst, breathtaking views and very windy mountain roads All up it was around 2,600km of driving until I got back home, touch wood no dramas for my car throughout the whole trip.



Filling up at 4:30am, before jumping on the motorway



Prior to the trip, I did the following preparations to my car to reduce the wear and tear on the tyres, and reduce driver fatigue.

1- Raised the ride height to reduce -ve camber at the front and rear, for better hwy stability, and less tyre wear.

2- Pumped tyres up to 39 psi to reduce the rolling resistance for better fuel economy on the hwy.

3- Eye-balled my wheel alignment to make sure I got even toe on the left and right sides of the car.

4- Backed down the dampening on the Öhlins coilovers for better hwy comfort (and reduced driver fatigue). Getting ready for Sydney’s beautiful roads too haha

5- Torqued down all wheel bolts, all front and rear control arms bolts, front and rear subframes' bolts and steering rack, steering column... etc. to make sure nothing is loose.

6- General check up on all fluids, and confirm there are no leaks... etc.

7- Take a spare wheel and a jack with me.

Hume hwy is such a monotonous boring road, doesn’t matter what car you’re in, it’s boring as hell, I would have definitely flew up if I didn’t have to lug so much tools, computers and cables with me to Bathurst. These cars seem to be very well suited for hwy cruiser duties though.

There’s also a drastic change in asphalt quality once you cross the NSW borders. It’s much harsher, there’s a lot more tyre noise in the cabin, and it feels more abrasive on the tyres. But it’s probably a lot more durable on the long run so they don’t have to keep resurfacing the road every few years.

I didn’t notice any sizable additional fuel consumption due to the 12% shorter final drive gearing (3.46 current, up from 3.08). Still did a bit over 800km per tank, there might be a 5-8% fuel consumption increase, which is negligible. Manual F8x cars M2/3/4 have the same 3.46 final drive ratio and also same transmission gear ratios. So my car is still sort of within factory specs.

As you can see in the below photo, the engine will sit at ~2,750rpm at 110km/h, not a challenge for the N54 to constantly sit at near 3,000rpm for 11 hours, these German cars are designed to sit at 250km/h on the Autobahn for prolonged durations. So there was no worries there. Turbos were barely spinning either as it's a low load situation (open wastegates).



I stopped at Gundagai in NSW for food, coffee and fuel, couldn't help but take a couple of photos of the striking beauty of the classic E92 body shape, I do like the Sparkling Graphite Metallic colour too





Some footage and photos that I captured during the week I spent camping in the pitlane garage:

6 nights before the race. we had to replace the transmission, because it started crunching badly when downshifting to 2nd gear, and occasionally in 3rd too. Those ZF GS6-45BZ are very weak compared to the older GS6-53BZ/DZ manual gearbox found in the old school N54 cars and E9x M3. In theory the GS6-45BZ is more advanced (has Synchromeshes with carbon friction linings which provides more precise shifting, and lowers the drag losses in the geartrain, also has shorter gear travel which results in shorter gearstick travel without having to use a ssk), but it's just so weak! Plenty of 1M owners and N55 powered 135i/M135i/M235i/335i/435i owners have broken theirs, there was even one here on the forums that broke reverse gear hahah, how does that even happen?! It's not like anyone shifts aggressively into reverse .

Even though I would have loved to convert the race car to use the older and stronger GS6-53BZ/DZ N54 box from the E8x/9x 135i/335i, there was no time for that conversion. The boxes are a different length, so it'll need a custom prop-shaft made up or swap the output flange across which requires a special puller tool to remove, and in the case of the N54 gearbox, the female end of the pilot bearing is on the transmission input shaft instead of the flywheel. So we would have had to find an old N54 flywheel, and press the male end of the pilot bearing out of it and press it into our flywheel. Cool project, and we'll definitely do it in the future, but for the sake of this race, there was no time and we just wanted to get it running. After failing to locate a F series N55 transmission to fit the M135i race car , we had to settle for a manual gearbox from the E82 1M. Both are identical GS6-45BZ and similarly weak, but the 1M box doesn't have a gear position sensor.

We bit the bullet and fitted it to the car, and cable tied the connector for the gear position sensor under the car, and hoped for the best. Lucky the lack of the gear position sensor didn't throw the engine in limp mode. It just had an error stored about the gear position sensor signal missing, but everything else worked perfectly.



5 nights before the race, we corner balanced the car, and set the wheel alignment using threads:



With 4 nights to go to the race, we arrived at the pitlane garage and camped there with the car, countless hours of work on the car, and staying up till 1am to finalise things, 6am starts every morning... Motorsport is definitely a lot more hard work than what it appears to be from the outside.





Over the following 3 days leading to the race, we had 4 practice sessions to perfect our car setup, and for the drivers to get a good chance to adjust to the car and track, and provide feedback on how the car feels. After the practice sessions finished, we had a qualifying session, this dictated our starting position on the grid.





In between our practice sessions, GT-1 Australia were also conducting a practice session. It was awesome seeing GT3 racing cars close up, and hearing them going full throttle down pitlane straight from couple of metres away





GT3 race cars full throttle flyby down the straight (VOLUME UP):

Pics from race day, 6 hours endurance race













Pic of the brake pads (ENDLESS Competition pads) after 3 hours into the race, we have ordered a different brand competition pads made of harder material and we'll see how those go. The j-hook AP Racing rotors had very little wear on them, so we're assuming that they're probably very hard material, and the pads ended up copping all the wear instead.



Also, we had a tyre failure about about 3 hours through the race too, the driver felt vigorous vibrations through the steering wheel, asked him to pit ASAP and we got it replaced in 1min and 28secs.



Close Up shots of the car mid-corner shows that the front right tyre was getting tormented through corners.



Media coverage:

I uploaded the whole 6 hour race to my YouTube channel, it was originally broadcasted on FOX Sport, enjoy!

I thought this was very funny haha This has to be the most awkward moment in Australian Motorsport! I had to cut it out and uploaded separately.

[gmx]

Sounds awesome, well done!.
Uneven pad wear is normal on circuits Depends on whether the heavy braking zones lead into left-handers or right-handers but overall influenced by the direction of circuit; clockwise, anti-clockwise etc.

[Aus335iguy]

Man that was awkward!

[Pete.J]

This is a retrospective post, I already replaced my turbos, replaced my sump gasket and installed VAC sump baffle last November 2018.

At the time I had a coolant leak from the rear turbo coolant upper line, the leak wasn’t major, and I could usually go a week or so before needing a coolant top up.

But this meant that I couldn’t enjoy the car the way I like it, it would be too risky to take it to the track with any kind of coolant leaks, even a minor one.

To change the busted coolant line, I needed to drop the front subframe, and support the engine from the top. I thought if I am already there, might as well replace my turbos, change my leaking sump gasket and install a sump baffle.



Unfortunately I faced a very annoying hurdle, one of the turbo manifold studs was seized on the engine head. The Torx head of the stud broke upon removal, and there was no way to put a tool on it to turn it. Those studs are made of carbon steel, which is pretty soft and malleable to protect the threads on the engine head from getting cross-threaded or stripped by over-torquing the studs. As it’ll be a much more costly repair damaging the threads on the engine head. The downside, if the stud is done too tight, or seized on the head, it’ll most certainly shear on removal.

That’s the seized stud, couldn’t be in a worse location



I spent hours and hours trying to use different sizes and types locking pliers, I tried putting two nuts against one another and spin the inside nut, I dremelled a small section on the stud to fit a screwdriver onto it, and absolutely nothing worked. Eventually, I had to call all the local welders within 10km radius, and see if someone can come to weld a nut on the stud, and then I can put a spanner on it. A mobile welder came within two hours and welded a nut on it, which broke upon attempting to turn it. We then welded a stronger brass nut (old exhaust nut), and heated the surrounding engine head with a torch. This caused the engine head to expand, and slowly the stud started turning. It was an absolute nightmare getting it off.

Finally the bastard is out, I threw away all the old hardware, but I’ll be keeping this one for memory



The rest of the job went smooth, the steering rack is a bit of a pain to slide back on the steering column, but eventually got there after a few trial and error attempts.











Also, DO NOT torque new turbo manifold studs when inserting them into the head, there is a lot of wrong advice going around online saying that these should be torqued to 10Nm or 15Nm. ISTA/D doesn't mention anything about this. The right way to bolt these studs, is to treat them like standard head studs, basically spin them until they bottom out in the head, and that's it. Then slip the turbos on, and torque the flange nut to 20Nm. The flange nuts are what actually provides the fastening force for the turbos to the head, not the head studs themselves. So there's no point doing the studs too tight, it increases the chances of seizing them on the head and breaking the torx bit on removal in the future.

Car drove fantastic on the first test drive , turbo rattle is completely gone now, not existent on cold-starts either. I forgot how great these cars sounded without that dreaded rattling noise (this alone is worth replacing the turbos for haha ).

From a predominantly performance perspective, the new turbos only seemed to increase peak performance by 10-15%, full throttle feels a tad stronger, BUT it improved the response time massively, reduced the lag and significantly sped up the initial spooling. I also noticed that the car pulls stronger at partial throttle applications, that’s probably because the wastegates are more closed at partial throttle on the new turbos, due to the firmer wastegates’ arms’ bushings. My old turbos had wastegate arm free-play and the dreaded rattle, which meant that the wastegates are less shut at partial throttle due to them playing around more freely.

Moving on to next task





While I was there, I also installed a baffled sump, I’ve been planning this for a while. A few months ago, I bought a spare N54 sump from the UK, and I bought a VAC Motorsport baffle from the US. I got the sump sandblasted, and took it to Rev Speed Auto for welding based on recommendation from mates.

Ray’s welds are very clean, and I definitely only want top notch work on my car



Old pan vs new pan



The concept of a baffle is very simple, it has two small gates that are free to open and close, based on the g-forces the engine is getting subjected to.

Under hard cornering and acceleration, the gates are closed to prevent the oil from slushing around everywhere inside the engine sump. This ensures that the oil pump pickup constantly has oil to suck, and reduces the chances of sucking in air bubbles or having an inconsistent supply of oil to the rest of engine components.

I also fitted the oil filter from the S55 engine in the F8x M2 Competition/M3/M4, been running it for just over 20k kms now.



Realoem entry for the S55 filter part no.:



Lastly, I got my outlets modified, this is a very common mod, just makes life easier for the rear turbo to puff air through. The stock rear outlet is squished on RHD cars for some reason. Some people reckon it’s to clear the steering rack, but I doubt it, since even if you straighten the pipe like I did, it still clears the rack fine. Unless BMW just wanted to be more cautious.







Stock outlets



After about 33-36 hours of labour, she's back hauling ass on Melbourne's roads again

[Aus335iguy]

Great write up Peter!
With the outlets the presumption is at certain steering wheel adjustments the angle of the shaft fouls on the outlet. I'm surprised to hear it doesn't. I'm curious, Was this before or after your M3 rack install ?