[RCKYMTN M34OI]

Just wanted to share some data and info on my most recent track day.
6/1/24 High Plains raceway in Byers,CO
BMW CCA Rocky Mountain Chapter Driving school
2020 M340 x drive on Hankook ventus 280tw tires. 255/35/19 square
Project Mu PS pads x4 and turner SS lines w/Motul 600 fluid
13/15mm wheel spacers
KC designs mid/front/rear frame braces.
Stock tune w/speed limiter removed and max cooling mode(MHD)
4x20 min sessions

Lesson learned(other than driving techniques): Check brake pad temp ranges. Aluminum valve stems all around.

Datalog:
https://datazap.me/u/rckymtn-m340i/l...1-42&solo=3-12
Videos:

^The dragy lap timer was a great tool and the most accurate as far as speeds etc. Highly recommend for an entry level lap timer/data tracker
Max temps on 80f day
Coolant:235
Oil:277
Trans:241
Project Mu PS pads WERE NOT up to the task. Experienced low brake torque and fade after my 1st session. (I did not experience any of this last year with the same setup and stock brake pads)
After my 1st session and a cool down lap my front rotor surface temp was 800f.
So In their defense they are rated up 932f which i suppose I was exceeding by quite a bit on the track
I also experienced a valve stem failure my last session which resulted in low psi. It was my only rubber valve stem. the other 3 were aluminum and held up fine.
Car burned ~.5qt of oil throughout the day

Other than that the car handled the day like a champ! No real concerns for future track days.

Insight from my instructor that may be relevant to some of you who aim to track your car

"The car has an INCREDIBLE amount of power and this, combined with the Sport+ setting that Travis has to use in order to get the automatic mode transmission to shift properly, sets up a situation where extremely precise throttle control is required. I recall driving his car at the previous school and finding such precise control to be exceedingly difficult to achieve myself.

Goals for the next school:
- practice on the street with the transmission in manual mode so we can be shifting manually on the track
- eliminate the use of Sport+ throttle sensitivity on the track"

I highly recommend finding your BMW CCA local chapter and attending events like this. Excellent people and experience

[prostcfc]

Thanks for the write-up. Those PS pads sure wore unevenly. My PMU HC-CS pads did well; wore evenly too, but quickly, and I think I have one track day left (only did two on them). I had the same issues last year with Sport and Sport+; this year I did Manual mode in Sport and it was a game changer. I'm sure with Sport+ it will help a lot too.

Are your front calipers green yet? Are the dust boots cracked? All of the above happened to me after my recent track weekend. I have a track day coming up in August, and I'm going to try out TI shims and then the brake ducting setup I have off of the MK5 Supra.

[RCKYMTN M34OI]

Originally Posted by prostcfc

Thanks for the write-up. Those PS pads sure wore unevenly. My PMU HC-CS pads did well; wore evenly too, but quickly, and I think I have one track day left (only did two on them). I had the same issues last year with Sport and Sport+; this year I did Manual mode in Sport and it was a game changer. I'm sure with Sport+ it will help a lot too.

Are your front calipers green yet? Are the dust boots cracked? All of the above happened to me after my recent track weekend. I have a track day coming up in August, and I'm going to try out TI shims and then the brake ducting setup I have off of the MK5 Supra.

Yeah i know the PS pads aren't track pads but was shocked they broke up like this considering the oem pads didn't have any issue on my last track day. Figured they'd be better than stock. Still need to pull off and inspect the rears.
This was my first Pmu pad and probably just going to move on to something else considering shipping takes forever.


My calipers are fine after a good cleaning. They were ceramic coated a couple months ago and i did another application the day before track day to preserve them after reading some feedback here.

What TI shims? and can you link the brake cooling kit? I'd be interested in doing something like that for future track events.

Also, do you ever log your temps on track runs? i'm guessing what i'm seeing is pretty typical. Don't love seeing timing corrections throughout the run (i was running E20 to try and prevent this) but with 130-150f IATs it's understandable.

[prostcfc]

I haven't done any sort of logging. I have Bimmerlink, but haven't gone through the effort of looking into how to log, what to log, etc., but I need to do this. I did scan for codes afterwards to see if anything was tripped. I got a few for high brake temps and torque limitation active (combustion engine), but no active codes or anything particularly alarming.

There's a couple vendors for TI shims; they're probably the same. Anything MK5 Supra should be a direct fit. Here's one: https://paragonbrakes.com/paragon-pp...ake-pad-shims/

For the ducting, I was pointed to this company by another forum member. I reached out to them directly and they sold me the backing plates and 6' of tubing for ~$350. I haven't mounted yet, but I will post pics when I do.
https://www.verus-engineering.com/sh...pra-1956#attr=

As another data point, I posted in the r/cartrackdays subreddit about something and an instructor responded back to me saying his student this past weekend had similar braking issues in his M340i and had to manage his braking and do periodic cool down laps.

[cyam]

So why not use Sport Individual with everything sport+, except engine set to just Sport?

Those pads look like they were not installed correctly though..

Interesting about the PS pads, I was going to try them but if stock is better or good enough, I might just stick with stock as I only very occasional am on the track.

Was also thinking of adding piping from the brake cooling ducts to the center hub but keeping the current backing/dust shields. Not sure how much of a difference it'd make. I dont won't the nice blue to turn green so maybe it'd help prevent that.

[RCKYMTN M34OI]

Originally Posted by cyam

So why not use Sport Individual with everything sport+, except engine set to just Sport?

Those pads look like they were not installed correctly though..

Interesting about the PS pads, I was going to try them but if stock is better or good enough, I might just stick with stock as I only very occasional am on the track.

Was also thinking of adding piping from the brake cooling ducts to the center hub but keeping the current backing/dust shields. Not sure how much of a difference it'd make. I dont won't the nice blue to turn green so maybe it'd help prevent that.

What indicates to you they weren't installed properly? I drove them on the street for ~1k miles prior to tracking and they performed fine. The missing material is just a result of exceeding the temp capacity of the pad and the tapered wear pattern is typical for our cars due to the uneven cooling pattern.

I'm wondering if these could be fit to the G20?
Good bang for the buck if so

https://www.bimmerworld.com/BimmerWo...F8X-M3-M4.html

As for the sport+ setting . . . 1)I wanted to make sure the adaptive suspension commanded the stiffest setting
2) When in sport the car would not be in the optimal gear exiting a turn which would result in having to stab the throttle to command a downshift. I guess manual tapshift is the way to go to get the best of both worlds.

[cyam]

Originally Posted by RCKYMTN M34OI

What indicates to you they weren't installed properly? I drove them on the street for ~1k miles prior to tracking and they performed fine. The missing material is just a result of exceeding the temp capacity of the pad and the tapered wear pattern is typical for our cars due to the uneven cooling pattern.

I'm wondering if these could be fit to the G20?
Good bang for the buck if so

https://www.bimmerworld.com/BimmerWo...F8X-M3-M4.html

As for the sport+ setting . . . 1)I wanted to make sure the adaptive suspension commanded the stiffest setting
2) When in sport the car would not be in the optimal gear exiting a turn which would result in having to stab the throttle to command a downshift. I guess manual tapshift is the way to go to get the best of both worlds.

Sport Individual- if you set everything to the Sport or sport+ setting where available (engine and gearbox) then it is came as sport+.
If you then set engine only down from sport+ to sport, then you still have the gearbox in the sport+ setting. Suspension only has comfort or sport nothing else, same with steering.

With your pads, they were not fitted properly, they were installed on an angle. I've done this by mistake once. Nothing to do with uneven cooling - that causes the inside pad to wear more than the outside pad but each pad is even. Never should one pad have one end wear more than the other. That's an install error.

[RCKYMTN M34OI]

Originally Posted by cyam

Sport Individual- if you set everything to the Sport or sport+ setting where available (engine and gearbox) then it is came as sport+.
If you then set engine only down from sport+ to sport, then you still have the gearbox in the sport+ setting. Suspension only has comfort or sport nothing else, same with steering.

With your pads, they were not fitted properly, they were installed on an angle. I've done this by mistake once. Nothing to do with uneven cooling - that causes the inside pad to wear more than the outside pad but each pad is even. Never should one pad have one end wear more than the other. That's an install error.

I disagree. My stock pads(installed at the dealer)had the same tapered shape after the same event last year. For that to happen the pads would have to resist the press of the piston to make an uneven contact angle. And clearly the whole pad was making contact with the rotor, but couldn't handle the temps. I would've had to make the exact same mistake installing all 4 pads. Pretty unlikely IMO

[cyam]

Then maybe a caliper issue, but even then I'd only expect one caliper to be an issue not both the same. I've never seen or heard one end of the pad wearing faster than the other like that, regardless of temps.

Is like two pistons are pressing harder than the other two.

[RCKYMTN M34OI]

Originally Posted by cyam

Then maybe a caliper issue, but even then I'd only expect one caliper to be an issue not both the same. I've never seen or heard one end of the pad wearing faster than the other like that, regardless of temps.

Is like two pistons are pressing harder than the other two.

Well these are 4 piston calipers so 2 pistons on each side would have to fail to create this type of wear. The Supra racing community has reported the same uneven wear pattern. I really believe the pads just couldn't handle the stress which exaggerated the issue.
Anyhow i ordered some hawk DTC 60 pads.

[peelerec]

It’s worth noting that this particular track has plenty of fast, long sections that have you smashing on the brakes for an extended period of time to bring you down from that high of speed vs tighter, smaller road course that requires only little braking just to help rotate the car.
Seems like a fun course and glad to see besides pads, all is well and in order.
When is the next track day? Any other modification in mind?

[RCKYMTN M34OI]

Originally Posted by peelerec

It’s worth noting that this particular track has plenty of fast, long sections that have you smashing on the brakes for an extended period of time to bring you down from that high of speed vs tighter, smaller road course that requires only little braking just to help rotate the car.
Seems like a fun course and glad to see besides pads, all is well and in order.
When is the next track day? Any other modification in mind?

Yeah there's certainly some hard braking zones. Ordered some DTC60 pads just cuz they're pretty proven and easily accessible. Don't feel like waiting for shipping from Japan.

I might do some open lapping days at the same track. There's also a couple other tracks not too far away I'd like to explore. I just hate beating on the car in the dead heat of the summer so might hold off til fall. Trying to limit the abuse since it is my daily.

No immediate mod plans at the moment. I'm in CO and do a lot of mountain driving in the winter so lowering isn't practical. Next logical mods would be
Sway bars- think i could tackle install by myself
Monoballs- although the increased NVH is a bit of a concern
Camber plates- Not sure alignments pre/post track is worth it though. Could possibly measure/mark and do that at home too

[peelerec]

Originally Posted by RCKYMTN M34OI

Yeah there's certainly some hard braking zones. Ordered some DTC60 pads just cuz they're pretty proven and easily accessible. Don't feel like waiting for shipping from Japan.

I might do some open lapping days at the same track. There's also a couple other tracks not too far away I'd like to explore. I just hate beating on the car in the dead heat of the summer so might hold off til fall. Trying to limit the abuse since it is my daily.

No immediate mod plans at the moment. I'm in CO and do a lot of mountain driving in the winter so lowering isn't practical. Next logical mods would be
Sway bars- think i could tackle install by myself
Monoballs- although the increased NVH is a bit of a concern
Camber plates- Not sure alignments pre/post track is worth it though. Could possibly measure/mark and do that at home too

Some other pads worthy for daily and track are the CSG endurance pads that Chris was running, and turned me towards them. They are great at not eating up the rotors and suitable for daily use with minimal squealing.
If you ever make your way out west, let us know. Plenty of tracks in the Bay Area & relatively near (Sonoma, laguna seca, thunderhill, buttonwillow, willow springs), and you could feel my car with the dinan monoballs.

[RCKYMTN M34OI]

Originally Posted by peelerec

Some other pads worthy for daily and track are the CSG endurance pads that Chris was running, and turned me towards them. They are great at not eating up the rotors and suitable for daily use with minimal squealing.
If you ever make your way out west, let us know. Plenty of tracks in the Bay Area & relatively near (Sonoma, laguna seca, thunderhill, buttonwillow, willow springs), and you could feel my car with the dinan monoballs.

absolutely will do and thanks for the offer!
What's the pricepoint on the CSGs? I remember having sticker shock last time I looked into their options.

[peelerec]

Originally Posted by RCKYMTN M34OI

absolutely will do and thanks for the offer!
What's the pricepoint on the CSGs? I remember having sticker shock last time I looked into their options.

Yep, I still have sticker shock! about $900 for all four corners.

[prostcfc]

Originally Posted by peelerec

Yep, I still have sticker shock! about $900 for all four corners.

That's, uh, rather expensive. How many days are these lasting? It's an endurance pad, so I assume several, which could make it worthwhile if you break down cost per track day. My current pads are on 2 days and I can get a third from them, unlikely a forth.

[Dan B]

It has been a few years, but many years of racing behind me, and countless brake pads, and I the only time I have seen that is when something binds. Pull everything apart, clean and lube it really well.

However if this is a known issue it may be a design issue. Which would really suck.

[prostcfc]

I'm with OP and I think having the same issue on both front calipers because of install error and/or caliper issue is unlikely. TBH I'm not even sure how you could install the pads incorrectly. Maybe if you took the caliper off and didn't torque one of the bolts back to spec and did so on the other, but otherwise not seeing how anything would "catch". The different size pistons in our front calipers (40 mm and 44 mm) is supposed to help prevent tapering.

Anyway, this is a good thread describing taper. The guys at Essex always seem to have good information on braking questions I have researched https://f87.bimmerpost.com/forums/sh....php?t=1598156

[peelerec]

Originally Posted by prostcfc

That's, uh, rather expensive. How many days are these lasting? It's an endurance pad, so I assume several, which could make it worthwhile if you break down cost per track day. My current pads are on 2 days and I can get a third from them, unlikely a forth.

I have 3 track days and 4-5 months of daily driving and they’re @70% life left according to my shop with even wear.

[RCKYMTN M34OI]

Originally Posted by prostcfc

I'm with OP and I think having the same issue on both front calipers because of install error and/or caliper issue is unlikely. TBH I'm not even sure how you could install the pads incorrectly. Maybe if you took the caliper off and didn't torque one of the bolts back to spec and did so on the other, but otherwise not seeing how anything would "catch". The different size pistons in our front calipers (40 mm and 44 mm) is supposed to help prevent tapering.

Anyway, this is a good thread describing taper. The guys at Essex always seem to have good information on braking questions I have researched https://f87.bimmerpost.com/forums/sh....php?t=1598156

Exactly. These are about the easiest pads to install. . . properly. Never removed the caliper. And I made sure to thoroughly clean any area the pads require to move/slide. Mainly just where the tabs seat in the caliper.
Anyhow . . . just installed my Hawk DTC60 pads up front today. Took all of 30mins start to finish including raising/lowering the car.
Initial impression on bed in and maybe a 20 mile drive:
-They freakin bite pretty hard-make the tires squeal with a hard press.
-Noise not too bad so far- light squeaking coming to a stop and rarely some loud groaning at mid level cruise braking(I did transfer over my old brake shims to the hawk pads in hopes it would help noise)
-Cold performance seems pretty solid. 80f rotor temps on the initial drive didn't leave anything wanting right off the bat.
-Quite a bit of dust- but this was including the bed in period so I would expect that. Even so, I think they'll be dusty pads. We'll see if i can live with them for daily use.
I'll provide updates