My E90 M3 Dedicated Track build (with pix!)

[admranger]

Originally Posted by roastbeef

i wish we could have a track day where different brake companies send out representatives with a variety of pads and we could just have a brake pad test day- where we just take a couple hot laps and then come in an try a different set of pads. that way we could try all the flavors at once. wouldn't that be nice?

Bimmerworld did that with an E46M3 and stock calipers (grassroots motorsport article iirc). I can't remember if they put on new rotors for each pad or overlapped and bedded in the new pads to get a proper transfer layer.

It's a logistical nightmare even with a crew to do the changes for you, but yeah, it'd be nice.

w/o data acquisition you're going on feel though. In my experience, butt dyno's are rarely well calibrated.

[PrimeBMW]

Originally Posted by admranger

Bimmerworld did that with an E46M3 and stock calipers (grassroots motorsport article iirc). I can't remember if they put on new rotors for each pad or overlapped and bedded in the new pads to get a proper transfer layer.

It's a logistical nightmare even with a crew to do the changes for you, but yeah, it'd be nice.

w/o data acquisition you're going on feel though. In my experience, butt dyno's are rarely well calibrated.

I should dig up this article. I don't remember the details but do remember the preferred pad manufacturer. It's interesting considering the testers.

[M3 Number 86]

Originally Posted by admranger

Bimmerworld did that with an E46M3 and stock calipers (grassroots motorsport article iirc). I can't remember if they put on new rotors for each pad or overlapped and bedded in the new pads to get a proper transfer layer.

It's a logistical nightmare even with a crew to do the changes for you, but yeah, it'd be nice.

w/o data acquisition you're going on feel though. In my experience, butt dyno's are rarely well calibrated.

You need to download the latest firmware to recalibrate the dyno (why does it have to include the word firm) lol

Anyways, I think pads are all about preference. Some people love extreme initial bite some like modulation. I actually hate it when the brake pedal feels like it's on Sport+++++++ mode. When I first started I loved it that way, slam on the brakes in a straight line. Now I like it more linear, where I can trail it in pretty easily. Maybe I just like air bubbles in my fluid.

[jritt@essex]

Originally Posted by Chuck's M3

Should remember it as the bottoms up approach.

Nice...consider that officially stolen!

[jritt@essex]

Originally Posted by admranger

It's a logistical nightmare even with a crew to do the changes for you, but yeah, it'd be nice.

This. Brake testing can be a logistical nightmare for sure. For any type of brake shootout you'd need stacks of fresh tires, fresh discs, fresh pads, fresh fluid, labor hours...would be extremely high cost. If you don't have everything fresh, blank slate, apples-to-apples, people will pick apart and discredit any results. Heck, if you show people perfectly clean scientific data in person, they'll still find a reason to not believe it.

I once instructed for Mercedes AMG at Pocono back around 2003 or so. They had every AMG car out there, full gaggle of factory mechanics, and you would not believe the number of tires they had on-hand. Every time tires got slightly worn they brought the car in for a fresh set, as they wanted the cars putting their best foot forward for potential buyers. The amount of rubber that was burnt and trashed that day was truly staggering. I caught an e55 AMG's brakes on fire, smashed out a fog light by hitting a cone at about 125mph, drove through the dirt on the infield sideways with three passengers...good times. Oh, and I got paid!

[roastbeef]

it was mostly a fantasy thought. i figured since it was a fantasy, i might as well make it a good one. lol

[dogbone]

Originally Posted by roastbeef

it was mostly a fantasy thought. i figured since it was a fantasy, i might as well make it a good one. lol

c'mon roastbeef----your fantasy was missing one important element. All those poor F1 Grid Girls need a new gig. Essex could be the hero that saved the day! Hire all those poor starving women and get them into the pits and doing brake changes on brake demo days! Problem solved!

[roastbeef]

Originally Posted by dogbone

c'mon roastbeef----your fantasy was missing one important element. All those poor F1 Grid Girls need a new gig. Essex could be the hero that saved the day! Hire all those poor starving women and get them into the pits and doing brake changes on brake demo days! Problem solved!

i think i could help supervise this.

[admranger]

Originally Posted by dogbone

c'mon roastbeef----your fantasy was missing one important element. All those poor F1 Grid Girls need a new gig. Essex could be the hero that saved the day! Hire all those poor starving women and get them into the pits and doing brake changes on brake demo days! Problem solved!

This is the kind of creative thinking we need around here. Don't forget, brake dust makes great smokey eye shadow...

[dogbone]

I participated in the Speed Ventures Bimmer Challenge this weekend at Chuckwalla. First, I want to say thanks to all the guys who put in the time and effort to organize it. The list of sponsors you guys put together this year is amazing!

I signed up for both Saturday and Sunday with two goals in mind: 1. Try to win Bimmer Challenge. 2. Try to set a new personal best. The weather actually looked better on Sunday, so I figured on Saturday, I would get the flow of the track back in my head and compete in the Bimmer Challenge. And then on Sunday, go for a new PB.

I was able to win my B1 class in the Bimmer Challenge, so that was cool.

Saturday night a huge wind kicked up and blew a ton of sand on the track. The first session on Sunday was quite slippery. All the cars had rooster tails of dust billowing behind them, and a 991 GT3 bent two rims and got stuck inside one of the turns, so the first session was a bummer.

The second session, I went out and I was able to hit a new personal best--1:53.64 (0.2 sec better than my previous best in October.) I was pretty happy because the tires were not fresh at all.

Here's the video and data with two laps: 1:54.2, 1:53.6. I'm liking my new convex mirror! It stays out of the way of the in-car video and doesn't vibrate while on track. Today, I'll post the in-car video so you can check out my awesome new mirror that is not in the way. I still need to see if it's possible to get some of that black stuff off the windshield.

And of course, we can't forget the bumper cam! My trusty 6-year old GoPro Hero 2 just wasn't the same after I bashed a cone with it at 80 mph at Inde Motorsport Ranch in January. Amazingly, the suction cup mount stayed on the car. Just the little connector between the case and mount broke. The camera flew and bounced around. The SD card flew out of the camera. (I had a skeleton case with open sides.) We found both the camera and the SD card later! Both still worked!---although the camera wasn't the same--wouldn't record audio, buttons were very sluggish to respond, it turned off randomly.......hehe.....so I bought a used Hero 2 and we're back in business! I'm not ready to give up the bumper cam. I always love how hectic the bumper cam looks. It looks so calm in the car by comparison:

The new front brakes continued to work well. I was pushing them fairly hard. The wear characteristic on the brake pads looks good. I now have three days on them and they look fine.

Anyway, it was a fun weekend. I was laughing with a couple guys about how baller it would be to wake up at Chuckwalla, drive a couple sessions, pack up, head toward home and along the way back on the 10 Freeway, stop at the Speed District event Auto Club and turn a few laps there! haha! I would absolutely have done it if I had fresher tires. I was passing Auto Club at 2:00PM. I would have gotten there just in time for Speed District's two hours of Open Track! Oh well......no baller status for me.

[roastbeef]

i like the interior view best, it allows for a better view of the track as it is being revealed to the driver.

[inTgr8r]

Originally Posted by roastbeef

i like the interior view best, it allows for a better view of the track as it is being revealed to the driver.

Me too, plus I like seeing steering inputs.

[The-Traveler]

Congrats, this is a truly amazing and inspirational build! Hopefully I can follow in your shoes, a few years from now.

[dogbone]

Originally Posted by The-Traveler

Congrats, this is a truly amazing and inspirational build! Hopefully I can follow in your shoes, a few years from now.

Thanks! Hopefully some of the stuff in this thread can help you make choices as you go down the path of motorsport modding. This is the first car I ever put on track, so I've enjoyed doing mods one at a time to learn the effects of each change.

If you choose the E9x M3 as the platform for your mods, I think you will enjoy it. First of all, BMW made a very reliable platform. In general, very little goes wrong with these cars when you pound on them. And for me, it has been rewarding to drive--the noises, the balance, the performance, the looks---they all work for me. While others have come and gone on this platform, I just keep plugging away with this car. People tell me all the time, "man, I can't believe you're still driving this thing!" hehe That's just me I guess. I like to stick with things to see how far they can go. And the beauty (and frustration) with motorsport is that the changes and tweaks NEVER end. In fact, if you stick with it long enough, you'll find that you have to make tweaks for specific tracks. A suspension setting or aero setting might work great at one track, but hold you back at another.

Anyway, good luck and have fun!

[dogbone]

My goal at Buttonwillow 13CW for quite some time has been a 1:47. In Feb of 2017, I got as close as 1:48.07 on brand new Yoko slicks. So close. Throughout 2017, I felt like I steadily continued improving as a driver. There's really no secret---more practice, better results. As I've become a more competent driver, I've been willing to simply push harder. Changing to the Essex AP Racing front kit resulted in even more confidence while slowing the car. Aside from the brakes, the overall car hasn't changed much in quite awhile, so it feels familiar and consistent to me. All these things were building confidence in my driving habits.

In the last 6 months, I've been running mostly used Pirelli DH slicks, which are fun to drive and get good lap times, but for one reason or another, I was JUST missing that 1:47----1:48.16 a few weeks ago.

I knew the answer-----buy new Pirelli DH. The used ones were getting me oh-so-close. I figured I should be able to find one second in the new ones.

So, I decided to commit to a set of new Pirelli DH 305/645/18 square. I found a day with favorable weather this week, and I went to Buttonwillow 13CW to see what I could do with these fancy new tires. I achieved my goal with a 1:47.21.

Here's the in-car 1:47.2 video:

But the car's transmission was struggling all day and the transmission would constantly dump into that limp mode of shifting to only even-numbered gears. The first four sessions---the cherry laps on these tires---were largely wasted due to the transmission issues. I could not get a complete clean lap without shifting problems. Even on my 1:47.2, the car shifted by itself into 6th gear before Sunset, and it took an extra moment to get it into 3rd gear on the front straight after Sunset. I actually started accelerating down the front straight in 4th, and then the car finally shifted into 3rd and I was able to salvage the lap.

When you're on fresh slicks, you don't want to see this on your dash.....actually, you pretty much don't ever want to see this....



I changed my driving style later in the day to try to keep the revs lower and downshift later in the corners. It helped. I also did some setup adjustments which I believe helped too. I had one session in the afternoon where I was finally able to avoid transmission issues for three hot laps. I ran a 1:47.3. I think the 1:47.3 driving is actually better driving than my fast lap, but by the afternoon the tires weren't in their cherry prime. I ended up running 4 laps in 1:47---1:47.2, 1:47.3, 1:47.7, 1:47.9.

So, while it was a successful day as far as lap times, I don't feel like I maximized what the tires are capable of due to technical issues. I know the car is able to do 1:46. And I am confident that I can do it too now. The AIM data shows my fast lap was on a 1:46 pace before the auto-shift to 6th at Sunset. (Looking at my best segments of the day, the AIM says my virtual best was 1:46.8.)

So, TIME FOR A NEW LONG TERM GOAL!!!! Now that I hit the 1:47's and got so close to 1:46, I would like to see a 1:46 someday!!!! On new tires, I know it's possible if the transmission will just cooperate. So, now I gotta get my car looked at.....see what the heck is going on with the tranny.


Here's the 1:47.3 in-car video. The cornering speeds are better in this lap. 103mph minimum around Riverside, 127 mph at the braking zone for Phil Hill, 83 mph over Phil Hill, 136 up to Sunset, 66 mph through Sunset. I believe these are new bests for me. I was shifting just a bit earlier than usual and waiting to downshift in corners to ease the burden on the DCT.

For me, feeling a new level of grip from a high performance tire is one of the most satisfying experiences in motorsport. The sensation of the car holding the ground like it's super-glued is just amazing. Every time I have moved up in grip, I have said, "THIS is how the car should drive ALL THE TIME!" haha! I felt that sensation again this week on the new tires. Too bad they don't keep that cherry feeling for long; the grip level falls off after a couple sessions. Ah yes, how nice would it be to drive these tires new all the time?

I can still remember at GTA's Super Lap Battle at Buttonwillow in 2016, the 14 year-old kid who drives the Lambo Huracan Super Trofeo received a FedEx shipment at the track of a full pallet of brand spanking new Pirelli DHC tires. What is a Pirelli DHC? Exactly. No one else at the time had even heard of that tire.....hehe

[roastbeef]

So what's the next step? One of those deeper billet pans? An in-line heat sink?

[dogbone]

Originally Posted by roastbeef

So what's the next step? One of those deeper billet pans? An in-line heat sink?

To be honest, I don’t know what the next step is. I’m taking it to the shop this week and we’re going to look at it.

The car drives completely fine under light and medium loads, but under heavy loads it definitely is getting finicky. And it can’t be an overheating thing for the transmission because it’s happening on the first hot lap. Maybe the nine-year-old car that’s been on track for six years is starting to show a bit of age. I have never serviced the transmission in this car other than replace fluids and change the DCT cooler. I would not blame the car if it needed some kind of refreshing in the drivetrain.

Anyway, hopefully we can find at least some kind of answer this week.

[Melchior]

The extra grip from the sticker tires was probably causing the pump pickup to starve at times. I had a similar issue a couple years ago when changed the DCT fluid, filter, and pan. I topped it off using the correct procedure (certain temp on a level surface), but I had the same problems of only shifting through odd gears on track that I’d never had before. I ended up overfilling the DCT by about .3-.4 liters and I haven’t had a problem since.

[roastbeef]

Is a DCT one of those things you don't want to overfill because of foaming? I don't have much more than basic knowledge of the inner workings.

[Melchior]

The biggest concerns with overfilling a sealed unit is expansion leading to built up pressure causing a seal failure. But the pan gaskets leak no matter what you do, so is it really sealed ?

I’m not suggesting significantly overfilling his to fix it, but it seems like he added more grip and now he’s having a problem with shifting. Maybe he has a seeping pan that’s lost a little oil over the years?

[dogbone]

Originally Posted by Melchior

The extra grip from the sticker tires was probably causing the pump pickup to starve at times. I had a similar issue a couple years ago when changed the DCT fluid, filter, and pan. I topped it off using the correct procedure (certain temp on a level surface), but I had the same problems of only shifting through odd gears on track that I’d never had before. I ended up overfilling the DCT by about .3-.4 liters and I haven’t had a problem since.

Thanks for the feedback. I really appreciate it. It would be awesome if this were to remedy the issue.

[dogbone]

After my track day last week with the new Pirellis, I’ve been thinking about the car’s performance aside from the DCT issues—basically turning over different moments in my head. One aspect I keep thinking about is the braking. I have 4 days on the Essex AP Racing Radi-Cal front kit, and now that I’m getting used to them and trust them, I feel like I’m more assertive on the brake pedal. The feedback I get from these new calipers has been giving me the confidence that I can push the brakes harder than I used to.

You know that moment when you press a brake pedal and you get that solid feedback through the pedal that the car is going to slow the way you want it to? This is the feeling I'm getting. These new AP brakes give me the feeling that I’m not using their upper limit. The harder I press, the later I brake, the more they brake and everything stays in control; more-so than I’m used to with the old AP kit. I feel encouraged to work them harder. This week, I virtually stood on the brake pedal doing a leg press and the car was in complete control while grinding the speed down. These days, after I press the brake pedal, often times I think, “I didn’t need to press the brake pedal so soon. I need to try a bit later next time.” They have tons of power, they’re super smooth, the modulation control feels good, ABS is not engaging. I have to keep reminding myself that I’m using the EXACT same brake pad as before—same shape, same thickness, same compound. These changes are coming from the calipers and rotors!

So does this sensation translate into something that I can see in the data? Am I braking harder? Later? What are the G-forces like? Or is it simply a “butt dyno” thing?—I spent a bunch of money, so it must be better….. So, I jumped into the AIM Solo DL data, and it seems there’s data to support what I’m sensing.

The first chart we’re looking at is of Buttonwillow, before and after the new brakes. Let me setup the chart. The purpose of this chart is to see whether I am pressing the brake harder with the new kit, and if I am getting more G’s out of my efforts. The blue lines are the new brakes and the Red lines are the old brakes. I pulled up the 2 fastest old brake kit laps and 5 of the fastest laps with the new kit. (All these brake presses and G's are from quick laps, meaning no bad mistakes like jamming the brakes to get a high G and ruining a lap. The slowest lap of the 7 laps on this chart is a 1:48.16 on Buttonwillow 13 CW.)

In this chart, the lower part of the chart shows my brake pedal presses. In all 7 braking zones, the blue lines are higher which means I am pressing the pedal harder than I was with the old kit. The top part of the chart shows my braking G-forces. The lower the line dips, the more G’s that are being generated in each braking zone. In all braking zones except the one at Phil Hill which is an uphill braking zone (8500ft), I am generating more braking G’s with the new kit than before. You can see 6 of the 7 dips show the blue lines go lower. I don’t really worry about an uphill zone because the forces are crazy there. In fact, I’m trying to brake less at Phil Hill so I can try to go over the hill faster.



To me, this shows that I am braking harder and getting more G’s. When the tires are warmed up, I'm generating up to 1.5G's of braking force on flat, straight braking zones. And most importantly, the car is staying completely in control, otherwise the lap times would reflect it.

The next question I had was: Am I braking later with the new kit? The answer is yes. In the following 6 charts, I’ve zoomed in on the above chart’s brake presses to see how far down the track I’m braking. Again, Blue lines are the new brakes and Red lines are the old brakes. In all cases, the Blue lines start later than the Red lines, meaning that I am braking later with the new kit. In some cases, it’s very close, but I’ve only had the brakes for a couple days at Buttonwillow. The old brakes were on there for 6 years. I think I’m adapting fairly quickly—at least for me. And I believe I can push these zones even later in some cases.







So, I think from this data, I can say that I am braking later, I’m pressing the pedal with more force and I’m getting more G’s as a result while still keeping the car completely in control. This is helping me to achieve better lap times. And again, I've only been on the kit for 4 days. I'm hoping to gain even more confidence with them as time goes on.

I usually like to make modifications to the car one at a time so I can isolate the changes and feel what each change does to the car. In my original approach, my next experiment was going to be a more powerful brake pad in the rear now that the front seems to be more powerful. But I’m so impressed with these Radi-Cals, I really would like to get the rear kit too. My rear rotor has less than 20% life left on it, and the rear calipers will need to be rebuilt soon, so instead of doing $1000 maintenance on them, I am looking at moving to the Essex AP Racing 9449 rear kit. The pad on the rear kit is a different shape and size from what I run now, and the Essex 9449 kit rotor is 1.5cm smaller (355 vs 340mm) than my current AP Racing rear kit, so I’m curious how the new rear kit will affect the setup—strong stiff asymmetrical caliper, J-hook rotor, lighter setup, but smaller rotor. (I've been told that the piston bore sizes of each kit would give indications on the power of each kit, but I don't know how to get all that info.) Typically changes in the rear kit are more subtle than the front. On my original AP kit, I drove the front kit for 2-3 months before installing the rear kit. When the rears went on, the car squatted and settled better than with the stock rear kit, but I would not call the difference in my braking experience to be night and day like when the fronts went on 6 years ago. I think I will go up in torque on the rear pad to the XR2 regardless of whether I get the new kit or not. Oh no, is that two changes at the same time????——kit AND pad???? It’s getting crazy around here!