My E90 M3 Dedicated Track build (with pix!)

SYT_Shadow wrote

The F8X rear hubs are beautiful parts, but they are too lightened for serious track use. I've seen two break, so if yours broke as well, that's three.

The F82 GT4 Endurance package received upgraded rear hubs, which are available for all the F8Xs. I don't know whether that fits the E9X.
The F82 GT4 Endurance rear hub looks almost identical to the E9X stock rear hub, so keep that in mind.

dogbone wrote

Let’s file this one under: sigh—tough day.

Some days, things go your way. Other days, ummm no. Friday at Buttonwillow 13CW fell firmly into the latter category. Let’s dig in.

For many years, I have wondered if Michelin S8M 30/65/18 would fit on my car. I've run 27/65/18, but they're pretty narrow. I finally decided to give them a try because okusa was having success with some Michelin N3 30/65/18 scrubs. Once they were mounted on the rims, they looked only 1-2mm wider than the Pirelli 305. Great. I was hoping they would be super fast. (They are.) Buuut they are quite a bit boxier than DH.

The day started very promising. Weather was gonna be 50°F for the 8AM session. Decided to run the new tires right from the start because the weather was gonna warm up pretty quick.

Went out first session and the tires felt FANTASTIC. FANTASTIC!! First hot lap——finally, I will get that elusive 1:46. And I was on pace to do it——until I caught a blue M2 in the final turn and had to back off. Result: 1:47.5 (impeded). Couldn’t do any better that session. And——the whole time I was hearing quite a bit of rubbing noises. I wear earplugs, but it seemed to come from the rear. I’ve heard plenty of rubbing noises in my time, so I drove through it even though it was fairly distracting. Well……this rubbing was different. Came into the pits and found that on both rear tires, the outer edges were quite destroyed. Argh….brand new tires…. Turns out, on both sides of the car, there’s been a little metal threaded post used to attach the fender that’s been lurking under there. The DH don’t hit them, so I’ve never known they were there, but the boxier Michelins do. Casey from Racewerkz was at the track with his new McLaren Artura. He looked at the tires and said, “My on-the-record advice is, don’t run them anymore. Off-the-record….[redacted off-the-record advice].”

Let’s look at the scorecard after 1 session: PB? Nope, got blocked in the final turn. Tires still good? Nope, trashed.

After staring at the tires for awhile, I decided I would try one more hot lap with the rear tires if I were to grind down those two little posts. Casey lent me a grinder.

Went out 2nd session and heard way less rubbing. But the damaged tires were on my mind and so the lap was garbage. Also, temps were in the mid-60s already. Didn’t even finish the lap. Just came in.

I decided to abandon any hopes of running fast, so I put on some old DH and went back out just to do some driving. New problem: the car was vibrating when I’d turn the steering wheel. Every time the car loaded up a little in any kind of turn, it was vibrating. It got faster as the car got faster, and slower as the car got slower. And I didn’t feel it when going straight….. I thought maybe one of the old DH was going flat or something. Checked the PSIs when I came in and they were fine……hmmmm So I switched to another set of rims/tires. Went back out, and the vibrating was getting worse. So, it wasn’t the tires or rims. What was it? Couldn’t see anything that would cause it. No control arms were loose or anything like that. (We had just done a bolt check before this track day.)

The car was undrivable at this point and it was still early, so I decided to leave the track and take the car to Minicorsa. They put it on the lift…..annnnnnd it’s the rear hubs. The bearings are bad and the wheels wobbling. Argh! I just replaced the rear bearings and hubs last summer! What the heck!

The question is: why do these keep going bad so quickly? I think this might be the 4th set of bearings going on the rear hubs…..the original bearings and hubs lasted 9 years. And they were still fine when we replaced them. It was just done out of caution/maintenance.

For now, I’m just going to replace the bearings and, if needed, the hubs. If they go bad again quickly, I guess I may have to look at replacing the wheel carriers/uprights. Perhaps the hole that the bearing presses into is not perfectly round anymore? I dunno…..this is a weird one.

I checked with Bimmerworld and Turner to see if anyone makes an upgraded bearing for motorsport for the E9x M3 platform. No one knew of any. They do make an upgraded bearing for the F chassis.

Anyway, I walked away on Friday knowing that, even with the deteriorated pavement, I could still do a 1:46. But man, talk about a goal eluding you……it’s been fascinating [yet sad] to see how, for one reason or another, the cards just haven’t lined up. I also figured out why I caught a car on my 1st hot lap. The grid boss was trying to be nice and sent me out a minute or two early. I was the only one in the grid. The problem was that I needed 2 scrub in laps for the new tires, not just one warm up lap. If I just needed one warm up, I would have been fine. Everyone started to trickle out onto the track and then there were people in front of me. So, I've learned a new lesson: in the future, don’t go out a minute early. Just wait for the grid to stack up normally and have everyone start at the same time.

On a positive note, the new remote-flashed transmission tune seemed to work well.

Next up: Speed Ventures’ Bimmer Challenge Chuckwalla CCW March 15-16. I’m looking forward to it. It should be a fun B1 competition. As a primer, a couple weeks ago at Bimmer Challenge WSIR, okusa and FK both set faster times than the time I set a month ago. I know okusa is going, but don’t see FK signed up yet. okusa has spent all winter dialing in his new E90 build. His car seems good-to-go now. FK is on an F-chassis that seems quick.

My tire situation will not be ideal at Chuckwalla. I guess I’ll run the 2 good Michelins on the front, and run my older DH in the rear. I think the DH are still decent enough. Hopefully I can be in the mix at Chuckwalla Bimmer Challenge!

Chuckwalla will wrap up my winter in CA. I may drive my rig home to CO at the end of the weekend.

PS: A note for anyone who runs 100 octane at Buttonwillow: the track keeps running out of 100 octane. They ran out again on Friday. This was the 2nd Speed District event in a row where they ran out of 100 octane pretty early in the day. I guess the 2nd track is placing higher demands on the sole gas station at the track. There’s a Chevron station being built across the street from the track, so I would guess a lot of people will go over there for 91. But 100 seems to be an ongoing issue now. I called the track and asked them what the situation was. They said they’re trying to deal with it, but that VP doesn’t take Buttonwillow too seriously because they’re small. I asked them to communicate better with event organizers. If they’re running low on 100 octane, let the organizers know so that they can communicate the shortage to the drivers before they come to the track. We all spend a lot of time and money to show up at a racetrack. For 13 years, Buttonwillow has ALWAYS had 100 octane available. It’s what we’re used to. But it doesn’t seem guaranteed anymore. So, if you run 100 octane and you’re going to Buttonwillow, I might recommend showing up with some of your own gas as a backup just in case they keep running out.

amg6975 wrote

Yes, the F80 GT4 hub fits the E9x and the wheel bearing itself is the same. If there is an upgraded bearing for the F80 it should work in the E9x.

roastbeef wrote

do you have any pictures of the tabs your tires were making contact with? i have the fender liners out a the moment and want to clean it up.

ninekrpm wrote

FK (NINEKRPM) will not be at chuckwalla...family obligations (spring break, yada, yada, yada). But look forward to meeting you ( more like chasing you) in the near future; hope to see you back in SoCal soon.

You and OK... have 2 insane 4-door builds.

dogbone wrote

Ah, bummed that you won't be there. My kids are in college.....my weekends are always free now! That is a liberating feeling when, after 20 years of weekend commitments, you realize there are never any plans on the weekends.

Anyway, it should be a fun weekend. Weather isn't hot yet, and hopefully it'll be a fun Bimmer Challenge. okusa and I will be there, and I've heard that Andrew Lim is trying to sort out his E46. If so, there will be several fast cars throwing down some good hot laps in B1. Looking forward to it. I just need to get my hubs fixed first. Just waiting on the GT4 hub flanges.

This Chuckwalla event will be my last weekend of the winter in CA. After the event, I will trailer the rig back home to Colorado for the Spring/Summer. Usually, if the car is working, I return it to California late October, and then it stays the winter in CA. So, I guess I won't be able to meet you until the Fall.

I just discovered your build thread this evening. Very intense! And it seems you do most of that work yourself? Wow. Now that your build is coming to fruition, I'll be interested to see how the car and your times continue to progress. What is your tire of choice?

Anyway, I'm glad to see several E/F M3/4 chassis intense builds getting finalized. Sheesh, it's about time! My build was done in 2015----it only took you guys 10 years to commit! hahaha Heck, half the time---when my car is breaking, I'm ready to retire my build. And now all you guys---KF, okusa, bernoo---are showing up with gleaming, super light, spanktastic new builds. I feel like I'm sitting here like Han Solo hoping the Millennium Falcon just fricking holds together. Which reminds me......need to buy some more zip ties.....

ninekrpm wrote

Not used to the TA culture in the west coast, its interesting...back then, it was simply NASA and the TT groups; but still not the same as TA events.

Anyhow...look forward to getting more seat time this year and venturing out to other tracks, especially buttonwillow and chuckwalla.

For the tires...mostly using Pirelli scrubs, however, last weekend at willows, I only had a set of Yokohama scrubs to use, and they were the hard compound (lets say slow). Which I did not like...just got a shipment of Michelin scrubs, look forward to trying these...something tells me that they will be faster.

Hope you get your car sorted by this weekend...

dogbone wrote

Yeah, an organizer like Global Time Attack attracts some very fancy builds. People go all in. It's amazing how much $$$ is spent putting some of those builds together. My car looks like a bucket of bolts at GTA events---especially Super Lap Battle.

Regarding tracks in the area, I saw on your thread you didn't really like Buttonwillow 13CW. Gasp! How dare you say such things?! hahaha I'm sure you already know, but Buttonwillow 13CW is kind of the benchmark measuring stick in SoCal. People come from all over to throw their build against that course. Many leave worse for the wear. It's a humbling track. It's a tough course that throws a little of everything at you---lots of different corner styles/challenges in each turn, some elevation stuff, you need to put that car on the berms to be fast, it has odd turns that seemingly have no "best" way around them---even after a lot of laps, it's bumpy, and now the pavement is really deteriorating so grip is down and tires get chewed up pretty fast.....And still----people throw everything at that course. I threw brand new Michelin slicks at it a couple weeks ago and was finally on pace to hit a new PB, only to be impeded in the final turn. And then the hubs broke two sessions later......haha one more person leaving 13CW worse for the wear. But I'll be back!!

If you like Willow Springs, I'm gonna guess that you'll really dig Chuckwalla. It's a true momentum course. Light cars with aero do very well at Chuckwalla. (If I read your scales pix correctly, I believe your car is 100 lbs lighter than mine.) Chuckwalla is quite unpleasant in the summer---can go up to 120ºF. And Buttonwillow is no picnic either when it's 105ºF. So the "prime season" of winter tracking in SoCal is sorta ending soon.

Pirellis are really good on my platform. Yokos are just not my favorite slick---in any compound.....had to run many sets when GTA made us run Yoko. Michelins S8 are fast, but they drop off quick and wear out really quick. Not a good value, but if they get you the lap time you want when they're new, then who cares I guess..... Which Michelins are you running?

We're supposed to get the hubs "mid-week", so the nail biting begins now I guess.

ninekrpm wrote

yup...not a fan of BW (I know, not a popular local statement). no doubt it is a drivers track first and test both the driver and car.

having grown up in the midwest and spent a lot time out east; my home tracks were FIA type tracks (Road America, VIR, Road Atlanta, and Seibring). Hence why I tend to like big willow...BW felt like a go-kart track when I first tried it...

I know that track takes a lot of seat time...and in total, have only been there 6 or 7 times with a best lap time at 153-154 (I am sure you get the drift). I need a lot more seat time there...the B1 guys will leave me in their dust (LOL). However, I plan to get out there a few times this year...let me see if I can get to a sub 150 by years end...

No events this month...but have 2 days planned at BW and 2 at Big Willow in April...and may do a Friday T&T day at Chuckwalla before its gets blistering hot there. Will be running the Michelin's (which are S9M).

well, hopefully get the car sorted for this weekend and get to finish the winter strong in SoCal.

dogbone wrote

Road America is on my list. Would have already gotten there with SYT_Shadow if my engine hadn’t sidelined me all of 2023 and 1st half of 2024. The challenges and vibes of VIR actually remind me of Buttonwillow. I like VIR a lot.

If you decide to commit to Buttonwillow 13CW, I am quite certain your car is capable of at least a 1:46 based on its weight, power and setup (perhaps a 1:45 on fast fresh tires.)

Don’t know if you’re familiar with S9, but in my experience, S9 (Hard) takes a lot of laps to warm up and isn’t very fast. They can run for as long as you want to stay on track and be quite consistent in the lap times they produce, but they’re just not particularly fast. Anyway, my $0.02 FWIW.

dogbone wrote

It turns out both of my rear hub flanges have cracked. It's a weird story I guess. The AP rotor hats were not drilled out for 14mm studs. They seemed to fit over the studs originally, but I guess over time, somehow the hats seized onto the studs. To make it worse, not only did they seize, but they seized away from the hub flange which probably stressed the studs and the hub flanges. It's almost like I was running a 10mm spacer with the hat not sitting up against the hub flange.......this might be why the Michelins rubbed those tabs. Man, what a pooch screw.....

I've ordered the M4 GT4 hub flanges, but no one seems to think the upgraded M4 motorport bearing will fit because they're just fundamentally different.

Here's the E90 M3 rear hub bearing:
IMG]http://www.epicscore.com/online/E90M3-rearhubbearing.jpg[/IMG]

And here's the F80 M3 rear hub bearing:
IMG]http://www.epicscore.com/online/F80M4-rearhubbearing.jpg[/IMG]

amg6975 wrote

Oh my bad, I didn't realize the rear F8x bearing was a bolt in ordeal.

dogbone wrote

Yep.

And, as always, things don’t go as planned. My tech ordered the hubs over a week ago from his parts supplier. As of yesterday, still no hubs. After looking into what’s going on, my tech calls saying that his parts supplier finally told him that BMW blocked the shipment of the M4 GT4 hubs until they got a VIN to confirm the car they were going on……..what!!! Was anyone going to tell us this?

So, I immediately called Bimmerworld, who I knew has them in stock. (I was originally just going to order them from Bimmerworld, but my tech said he already had ordered them from his parts supplier, so I just let his order stand instead of him having to cancel his.) I was hoping I could still get something shipped out yesterday for today arrival. Nope. Missed UPS by 2 hours. So, now they won’t show up until Friday, which delays everything.

The original plan on Friday was to pickup the car from the shop in the AM and scurry out of LA before Friday rush hour. (3 hour drive vs 5+ hours.) Ah well…..better get some yummy snacks in the truck and get ready for the stop-and-go slow-motion long haul across the oh-so-friendly LA freeways. Thanks BMW!

(I looked into 8:30AM UPS delivery vs 10:30AM delivery. 8:30 is $350. 10:30 is $59….. )

So, to anyone who wants M4 GT4 hubs, just buy them from Bimmerworld.

And let’s hope UPS delivers as scheduled, otherwise things really get messy. hehe I’m flying into LA before I know the parts have even been delivered. C’mon UPS! I’m counting on you!

dogbone wrote

Let's file this one under: Please---anyone reading this---please make sure you keep a full set of fuses with you. yowza.

Had a super busy weekend at Chuckwalla this weekend. Saturday was a shakedown day to see how the new hubs were. They were great.

Saturday started with drama. I put my good tires on which was a mismatch of Michelin S8m in the front and Pirelli DH in the rear since I destroyed the rear Michelins two weeks ago. I drove to the grid area early, shut the car off, and then as it was getting near the time to get ready to move into the hot pit to line up to go out on track, I started the car, and it dumped into limp mode. Engine light graphic flashed up on the dash. Uh oh. Turned the car off and on twice. No help. Started up in limp mode. So, I exited the grid in limp mode, drove the car on the track entry road, shut the battery entirely off, turned the car on.....annnnnnd it was was fine. Wtf. I looked at the AIM suspiciously---you know because I've had odd AIM issues in the past. Unhooked the AIM from the CAN bus. (I don't believe it was AIM now.) The car seemed fine so I went back to the grid and went out last. Putting the good tires on was a mistake. The track was sandy. The session wasn't super great. So, I made a mistake putting a session on the good tires. Oh well.

I was chasing tech stuff down all day. The car was still rubbing on the rear tires. It never rubbed the DH before. I just don't know what's going on there. It must just be sitting a bit lower. So I raised the spring perch three turns to raise the car. That seemed to help. I suspect the MCS dampers need to be rebuilt. They've been on the car for 5 years. I don't see any any oil leaks, and the nitrogen is holding fine, but man, something is going on. The car just seems a bit low. I also decided to remove the rear fender liners finally. But that took some work because things that were hidden behind the liners now had to be zip tied, etc.

I didn't have great tire options throughout Saturday. Old A7's were terrible. Old Pirellis that I've had since summer were terrible. But I just wanted to get some laps in, so I drove all my terrible tires and just tried to get into the flow.

Bimmer Challenge was on Sunday. Had prepped the car on Saturday, so I was planning on a nice mellow start to the day. Jump in the car to get it out of the trailer, annnnnnn it won't start. The engine turns over, but no ignition. Uh oh. I didn't have a ton of time before the 8AM session. So, I get the Launch scanner out, read the codes, and it says no electric fuel pump. I'm hoping it's a fuse. So, I search the internet to find out which fuse is the electric fuel pump---fuse 70. I search the net again to find out where fuse 70 is. I pull the fuse, and okusa said it best----it looked like it had been barbecued......I run into the trailer and grab another fuse, pop it in, annnnd the car fires right up. Phew. I'm guessing now that the fuse may have caused the limp mode the previous day. (I left the AIM disconnected all weekend......didn't feel like experimenting.) So, I highly recommend everyone keep some fuses with them. Saved my day.

I go out and ran a 1:47.6 first session, 1:47.4 second session, was running a tad faster 3rd session but the DH in the rear were not up to the task and let go in the Turn 5-4 combo. It was good enough for the B1 win. I was sad that okusa had a tech issue with his ABS and didn't get a lap in. So, we weren't able compete.

It was a fairly social weekend. Got to see Bernoo's new build. Looks really insane. (Oddly, he was having ABS issues too.) Andrew Lim was back up and running with the E46. Was fun to see everyone out there. sigh---I guess it was good to see redpriest in his 992 GT3RS......I guess......hahahahaha I gotta tell ya----he gets so much love with that car. Holy cow, there's always a crowd around it drooling on it. I guess the bright yellow doesn't hurt. Ok, it is a good looking car.....I guess.....

I'm bummed to see that people who have thinned out their wiring harnesses are having ABS issues. Is it the thinning process? Something else? Seeing everyone doing it, I've been considering thinning out the harness, but now that people are having troubles, I'm hanging back until they figure out what's going on. It's a bummer to have mysterious tech issues......I know all about that.....Anyway, I hope everyone can get their stuff sorted out soon. Looks like EAS will have the pleasure of dealing with all the ABS issues......I'm sure Steve is very excited to go to work to today. But he's the man!

On my end, I drove the rig back to CO Sun/Mon. I may go to High Plains once to goof around with my CO motorsport community, but I think I'm gonna take the car off-track for a bit to do some maintenance. I think I'm going to send out the dampers for rebuild, the diff for rebuild, put new rotors front and back, etc.