Track forum general chit chat.

Do the stock rear calipers have a track record of binding up? I’m getting a really strong vibration from the passenger rear wheel under braking. I can also see a pretty splotchy transfer layer on the rear rotor. A shop told me that the single piston rears have a tendency to get jammed in the cylinder bore, and while I don’t understand how that would lead to this, it’s the only thing I can think of at this point.

Is that a thing or are they making stuff up again?

They aren’t warped? The transfer pattern is pretty even. Is it uniform on both sides?

kolosy wrote

Do the stock rear calipers have a track record of binding up?

I've seen a front caliper piston mushroom from the heat at the track.

If the rotor runout wasn't bad, service the caliper and push the piston back to see how it moves, check torque of the caliper brackets while there. Hopefully you can spot something.

kolosy wrote

Do the stock rear calipers have a track record of binding up? I’m getting a really strong vibration from the passenger rear wheel under braking. I can also see a pretty splotchy transfer layer on the rear rotor. A shop told me that the single piston rears have a tendency to get jammed in the cylinder bore, and while I don’t understand how that would lead to this, it’s the only thing I can think of at this point.

Is that a thing or are they making stuff up again?

i think even if you saw no signs of issues on the piston, i think you might end up needing a new caliper (or like new) or just rebuilding the old one with new pistons and seals..

but this would maybe be one of the few cases of it being known.

Hi everyone, I decided to go with the Strom uprights with oem arm. I’m struggling getting more than -3.2 front camber. I also have adjustable rear arms. So I think this is constricting my ability to setup the car for a track dot tire or slick. It seems people are able to achieve a lot more with similar setups. Any thoughts or ideas to get me -4.0 degrees in front? The car has MCS coilover and vorshlag camber plates. I’ve also attempted to trim the strut tower lip for the nut clearance…

Thanks everyone
Ryan

roastbeef wrote

They aren’t warped? The transfer pattern is pretty even. Is it uniform on both sides?

I ran a dial gauge and they do seem out of spec. I need to redo it and confirm. Transfer pattern is real splotchy around the 2/3rds in mark and there’s a groove there.

tdott wrote

I've seen a front caliper piston mushroom from the heat at the track.

If the rotor runout wasn't bad, service the caliper and push the piston back to see how it moves, check torque of the caliper brackets while there. Hopefully you can spot something.

Yeah I’ll measure the rotor but this is a good ide.

omgzirra_exe wrote

i think even if you saw no signs of issues on the piston, i think you might end up needing a new caliper (or like new) or just rebuilding the old one with new pistons and seals..

but this would maybe be one of the few cases of it being known.

I’m just debating if I get new rotor rings or just go for the back bbk.

rTrackM3 wrote

Hi everyone, I decided to go with the Strom uprights with oem arm. I’m struggling getting more than -3.2 front camber. I also have adjustable rear arms. So I think this is constricting my ability to setup the car for a track dot tire or slick. It seems people are able to achieve a lot more with similar setups. Any thoughts or ideas to get me -4.0 degrees in front? The car has MCS coilover and vorshalg camber plates. I’ve also attempted to trim the strut tower lip for the nut clearance…

Thanks everyone
Ryan

You need adjustable arms to get more camber. I run MCS/Vorschlag (oem uprights) with SPL arms and have over -4 camber without my top hats being maxed out.

kolosy wrote

Do the stock rear calipers have a track record of binding up? I’m getting a really strong vibration from the passenger rear wheel under braking. I can also see a pretty splotchy transfer layer on the rear rotor. A shop told me that the single piston rears have a tendency to get jammed in the cylinder bore, and while I don’t understand how that would lead to this, it’s the only thing I can think of at this point.

Is that a thing or are they making stuff up again?

Possible especially if the piston is compressed unevenly.

You should get more pad and rotor life out of the fronts with a BBK in the rear.

bigjae1976 wrote

Possible especially if the piston is compressed unevenly.

You should get more pad and rotor life out of the fronts with a BBK in the rear.

Yeah I’m wondering that too. I’ve gone through 4 or 5 sets of pads on the fronts since I’ve done the rears, and the rears still look new.

My last rear caliper, OEM, piston was sticking and caused the piston side of the caliper to wear the pad to the backing plate after 4 or 5 race weekends......outter pad still had 50% of the oem thickness remaining.

Yes, the OEM caliper, especially if originally equipped, can stick over time (the boot or even the slider bushings all have shelf life...and drastically reduced if in high heat race conditions)

RalliartRsX wrote

My last rear caliper, OEM, piston was sticking and caused the piston side of the caliper to wear the pad to the backing plate after 4 or 5 race weekends......outter pad still had 50% of the oem thickness remaining.

Yes, the OEM caliper, especially if originally equipped, can stick over time (the boot or even the slider bushings all have shelf life...and drastically reduced if in high heat race conditions)

Thinking I need to do a rebuild on my front calipers. My right front has started to produce additional pad wear/brake dust compared to my front left, along with some additional heat.

omgzirra_exe wrote

0 tie front just a bit toe in the rear.

1/8th inch or something toe in.

I’m always tramlining 😂

275 square zero front toe tramlines like a mofo. On bad road surfaces like we have here, it's like the car is trying to kill me by suddenly and randomly steering into the nearest obstacle. I had to run just a smidgen of toe-in to avoid hitting something.. 😅

Redd wrote

275 square zero front toe tramlines like a mofo. On bad road surfaces like we have here, it's like the car is trying to kill me by steering into the nearest obstacle. I had to run just a smidgen of toe-in to avoid hitting something.. 😅

My eyes are locked on to every crack in the road and freeway in SoCal 😂

rTrackM3 wrote

Hi everyone, I decided to go with the Strom uprights with oem arm. I’m struggling getting more than -3.2 front camber. I also have adjustable rear arms. So I think this is constricting my ability to setup the car for a track dot tire or slick. It seems people are able to achieve a lot more with similar setups. Any thoughts or ideas to get me -4.0 degrees in front? The car has MCS coilover and vorshlag camber plates. I’ve also attempted to trim the strut tower lip for the nut clearance…

Thanks everyone
Ryan

Are you sure you need that much static camber with such geometry correction the uprights offer?

You could remove the shock adjuster and just use an Allen key to play with your shocks

RalliartRsX wrote

My last rear caliper, OEM, piston was sticking and caused the piston side of the caliper to wear the pad to the backing plate after 4 or 5 race weekends......outter pad still had 50% of the oem thickness remaining.

Yes, the OEM caliper, especially if originally equipped, can stick over time (the boot or even the slider bushings all have shelf life...and drastically reduced if in high heat race conditions)

So pad wear is even inside and out.

But now I’m back to wondering if this is a bearing issue? Was trying to measure runout again, and noticed that it would jump a lot when I rotated the rotor but would then return to roughly the same spot. At around 0:44 you see me start to just apply lateral load to the studs without trying to turn the rotor and the same thing happening. I had originally suspected the bearing and got ready to replace it, but when I pulled the axle out there was no noticeable play. Maybe it’s not dead yet but dying by track standards?

omgzirra_exe wrote

i think even if you saw no signs of issues on the piston, i think you might end up needing a new caliper (or like new) or just rebuilding the old one with new pistons and seals..

but this would maybe be one of the few cases of it being known.

While doing the caliper rebuild, don’t forget to add solid brass brake caliper guide bushings.

PACarGuy wrote

Following my HPDE (on OEM staggered setup - 265/245), and based on all the threads here, I'm thinking about getting a square 18x10 setup w/275's, and I'm trying to understand how different the front end of the car will be with it.
Pleased to read it doesn't result in snap oversteer, but how much sharper does it make the car? I believe I have decent car control, trail braking technique, etc. but I don't want to be on a knife edge every lap or feel like one small bad input is going to pitch me into the weeds. Does it dramatically change the handling behavior, or is it just a slight sharpening?

Thanks for any feedback!

275 square does a good job of reducing the built-in understeer but if you experience any oversteer it will be progressive, no snap oversteer. The car communicates this information well so it’s easy to stay ahead of the progressive breakaway characteristic, if it gets that far. It also helps with braking grip so you can go a little deeper into braking zones before getting hard on the brakes. Initial turn-in, or change of direction in general, is significantly improved with a 275 square setup compared to 245/265. With 200TW tires, I run front -3.5 deg camber and -1/16th total toe, and on the rear -2.0 deg camber and +1/8th total toe rear.

M3SQRD wrote

275 square does a good job of reducing the built-in understeer but if you experience any oversteer it will be progressive, no snap oversteer. The car communicates this information well so it’s easy to stay ahead of the progressive breakaway characteristic, if it gets that far. It also helps with braking grip so you can go a little deeper into braking zones before getting hard on the brakes. Initial turn-in, or change of direction in general, is significantly improved with a 275 square setup compared to 245/265. With 200TW tires, I run front -3.5 deg camber and -1/16th total toe, and on the rear -2.0 deg camber and +1/8th total toe rear.

Forgot to mention the added weight from the extra money in your wallet. Monitor tire wear and you'll figure out the best time and way to rotate tires to maximize tire life. In many cases, you can get 1-2 extra weekends with a carefully rotated square setup. Not to mention you only NEED one spare tire just in case.

turbo_joe wrote

The DTC 70 is pretty on/off and works better on Hoosiers/slicks IMO. Thats what I run front and rear. The DTC60/30 combo is great for street tires, especially if you can go the FCP route. I would buy two sets of front to always have a spare and just replace them when you get down to 25% pad left. The rear pads last forever on these cars.

Absolutely. The CoF on the DTC70 is extremely high and works best with really sticky tires and performs even better with downforce. I’d recommend chalking each wheel and tire because the max brake torque, before and after ABS kicks in, will rotate the tire on the wheel if braking hard enough.

M3SQRD wrote

Absolutely. The CoF on the DTC70 is extremely high and works best with really sticky tires and performs even better with downforce. I’d recommend chalking each wheel and tire because the max brake torque, before and after ABS kicks in, will rotate the tire on the wheel if braking hard enough.

My wheels will rotate inside the tire at least 5-6”s over a couple sprint races. Running 18x11 with 315 Hoosiers and dtc70

M3SQRD wrote

275 square does a good job of reducing the built-in understeer but if you experience any oversteer it will be progressive, no snap oversteer. The car communicates this information well so it’s easy to stay ahead of the progressive breakaway characteristic, if it gets that far. It also helps with braking grip so you can go a little deeper into braking zones before getting hard on the brakes. Initial turn-in, or change of direction in general, is significantly improved with a 275 square setup compared to 245/265. With 200TW tires, I run front -3.5 deg camber and -1/16th total toe, and on the rear -2.0 deg camber and +1/8th total toe rear.

Great info. Exactly what I need, thanks!

Is there any consensus about water pump maintenance ? I'm doing an OFHG and alternator soon, debating whether or not to do the water pump while I'm there.

Any thoughts on the metal impeller (Rein) vs plastic ?