My E90 M3 Dedicated Track build (with pix!)

[Inflame]

Fantastic thread, love every page.

[dogbone]

Originally Posted by Inflame

Fantastic thread, love every page.

Thanks!

Over the years, I have learned many valuable things on this forum. People are generous with their knowledge, and there's no doubt I have benefited quite a bit from that willingness to share.

I don't approach motorsport with a tower of knowledge. I've been learning as I go. So, I've decided to document my experiences, whether they are good or bad, and I hope they can be helpful to someone else going through the process.

[Inflame]

And that's the best approach! When people have an ego and think they know everything, it's the first step to losing respect.

One helpful tip would be to plot vehicle speed along with your wheel speeds, this will help to show just how much the wheels are slipping on top of how much they are slipping against each other.

I also noticed you haven't looking into Vortex Generators! I run these on my E36 M3 track car - http://www.airtab.com/index.htm

Here is a video showing before and after testing with the VG's -

I don't have perfect before and after test data on the track, but with your detailed analysis, I'd be curious to see if they would help you!

[dogbone]

Originally Posted by Inflame

One helpful tip would be to plot vehicle speed along with your wheel speeds, this will help to show just how much the wheels are slipping on top of how much they are slipping against each other.

The AIM data can show that fairly easily. What does the wheel slipping tell us? I know comparing the rear wheels with each other can illustrate diff performance. But what does slipping tell us?

Originally Posted by Inflame

I also noticed you haven't looking into Vortex Generators! I run these on my E36 M3 track car - http://www.airtab.com/index.htm

I don't have perfect before and after test data on the track, but with your detailed analysis, I'd be curious to see if they would help you!

I have never considered vortex generators before. They look interesting. Do you run full aero on the E36? My wing is fairly high up—-near the roofline’s height. I wonder how much effect you would feel with the wing so high.

Thanks for the heads up! It’s always fun to learn about new things.

[inTgr8r]

Originally Posted by 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.

............

Excellent!!!

I was wondering if you have also coded out the dynamic brake control (DBC)?

[dogbone]

Originally Posted by inTgr8r

I was wondering if you have also coded out the dynamic brake control (DBC)?

No, I haven't touched that. I've never heard this come up before. Have you?

[roastbeef]

It's pretty amazing and makes a bold statement that you switched from one set of racing brakes to another, and felt such a big difference.

Same set of pads? How are they looking?

[inTgr8r]

Originally Posted by dogbone

No, I haven't touched that. I've never heard this come up before. Have you?

Yes somewhat recently....
http://www.m3post.com/forums/showthread.php?t=1469774
http://www.bmw.com.kh/asia/en/insigh..._brake_control

I've done a little digging and it explains a lot of what I've experienced with my Z4MC.
On those corners where you come off throttle fast, and just want to breath on the brakes to settle the car forwards and the peddle is so damn sensitive....
Its DBC kicking in that builds extra pressure.

I will be coding it out on both cars.

[dogbone]

Originally Posted by roastbeef

It's pretty amazing and makes a bold statement that you switched from one set of racing brakes to another, and felt such a big difference.

Same set of pads? How are they looking?

Yeah, I'm more impressed than I thought I would be. If you look back to my comments before I drove the Essex kit, I didn't anticipate much change. That's why I've tried to solidify what I'm sensing by showing data so that we can all see it (or not see it if there's nothing there.....)

Yes, I am still using the original 18mm pad that went into the calipers during the caliper install. I now have 4 days on the pads. I would say I'm still less than halfway down on the front pads.

I am going to predict that I will get around 8-9 days from the 18mm pads. I was getting 13-14 days from these same pads in the Stillen non-Radi-Cal calipers. But, as I have been clearly trying to demonstrate with my charts, I am pressing the brake pedal harder, using a J-Hook rotor that is more intense on the pads than before, and getting more G's from the same pads. Nothing comes free, and the price here is more pad wear. But it's not unusual or bad.

And, my kit is the 25mm kit, so for just a few bucks more, I can run the thicker pad that will last quite a bit longer. So, I'm quite satisfied that the wear rate is reasonable. I would love to slam the 25mm pads in there and just get going, but I'm keeping the 18mm pads in there as a test. If they start to get low and I want to drive fast, I may pull them out early. I've already proven to myself what I need to prove----that the 18mm can last a decent amount of time, and that the 25mm will be great.

[dogbone]

Originally Posted by inTgr8r

Yes somewhat recently....
http://www.m3post.com/forums/showthread.php?t=1469774
http://www.bmw.com.kh/asia/en/insigh..._brake_control

I've done a little digging and it explains a lot of what I've experienced with my Z4MC.
On those fast corners where you're on full throttle and just want to breath on the brakes to settle the car forwards and the peddle is so damn sensitive....
Its DBC kicking in that builds extra pressure.

I will be coding it out on both cars.

Interesting. I looked at both links you sent. I don't think I've ever knowingly felt "hyper-braking".

The Cobalt Friction XR2 pads give me good bite and good modulation. But I've never felt a situation that I would call "hyper-braking"......

For now, I don't think I'll be coding anything like that out. But I'm glad to know about it.

[macdude357]

Originally Posted by Inflame

I also noticed you haven't looking into Vortex Generators! I run these on my E36 M3 track car - http://www.airtab.com/index.htm

I don't have perfect before and after test data on the track, but with your detailed analysis, I'd be curious to see if they would help you!

That's quite a difference between the two. Not sure how I'd interpret that data though. One thought would be that it looks like the VG's cause the air to stick to the windshield instead of buffeting around. That's good for drag but I would think that would create a low pressure area on the windshield which would increase lift. Now, if that air was then directed onto a wing (like the WRX has), then I would think that would counter the lift by increasing downforce on the wing. However, if you just have a spoiler, I'm curious how that would change things.

[roastbeef]

yea, i don't know how to feel about the vortex generators- besides curious... there was some discussion and video in the aero tech thread in this forum about roof spoilers generally doing more harm than good. not sure where these fall in. aero stuff at our level is a guessing game.

[admranger]

Originally Posted by 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 ?

Maybe the flappy paddle gearboxes are different from manly manuals <cough> but every manual transmission I've pulled has a vent on top so you can't build up any pressure per se. I don't see the harm in overfilling it by 1/4 liter and see what happens (after all, it's not my transmission). It should leak excess out the vent hole it it's a problem. I don't think overfilling will cause any foaming as that's more of a crankcase issue (slapping the crank through all that extra oil). Good transmission oils should have anti-foaming agents in them...

Originally Posted by 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.

Fantastic stuff in your write up and in the data. What I'm trying to get my head around is how, with the same tire compound, are you generating additional braking g's? It must be the brake application is smoother (does the data support this?) resulting in better tire load up, hence more grip. Thoughts?

[roastbeef]

if i had to theorize- i would say that he is able to get closer to the threshold without triggering ABS.

another thing i'm curious about is if he dogbone noticed more bite when going from slotted rotors to the J-hook rotors.

it might also be the cumulative differences- the more rigid caliper, less weight (maybe i don't know), j-hooks, better cooling ability. i'm still blown away by it.

[admranger]

Originally Posted by roastbeef

if i had to theorize- i would say that he is able to get closer to the threshold without triggering ABS.

another thing i'm curious about is if he dogbone noticed more bite when going from slotted rotors to the J-hook rotors.

it might also be the cumulative differences- the more rigid caliper, less weight (maybe i don't know), j-hooks, better cooling ability. i'm still blown away by it.

There's only so much grip the tire can generate before it'll slide (or ABS kicks in). My guess is that that the new brakes allow for a more consistent and accurate application of the brakes so the threshold is more optimally approached.

[roastbeef]

That's what i meant, but you said it better.

[dogbone]

Originally Posted by admranger

Maybe the flappy paddle gearboxes are different from manly manuals <cough> but every manual transmission I've pulled has a vent on top so you can't build up any pressure per se. I don't see the harm in overfilling it by 1/4 liter and see what happens (after all, it's not my transmission). It should leak excess out the vent hole it it's a problem. I don't think overfilling will cause any foaming as that's more of a crankcase issue (slapping the crank through all that extra oil). Good transmission oils should have anti-foaming agents in them...

We drained the fluid this past week and it was nasty looking. geez...it hadn't been in there THAT long.... During the refilling process, we put extra fluid in it. Minicorsa decided on a not-too-invasive 1st round course of action that involved replacing several transmission supporting pieces---DCT filter, pan, and a number of other things that were accessible without disassembling the transmission. If this round doesn't help, then I'm going to assume that something more invasive will be necessary.

Originally Posted by admranger

Fantastic stuff in your write up and in the data. What I'm trying to get my head around is how, with the same tire compound, are you generating additional braking g's? It must be the brake application is smoother (does the data support this?) resulting in better tire load up, hence more grip. Thoughts?

If you're asking my non-expert opinion------I believe that the Radi-Cal caliper being more stiff and specifically designed for torsional stresses allows it to apply the braking force more evenly and consistently along the surface of the rotor and you get a better result. The pedal just feels more solid----the more you press it, the firmer it gets, and the speed grinds down in a predictable way. This feeling encourages you to press harder. My whole commentary on this began because it felt different (in a good way) and I was wondering if there was data to backup what I was sensing.

I guess I could have pressed the brake pedal with more force on the old setup too, but it wasn't giving me the feedback that it would be ok to do so. One could say that maybe I don't know the proper signs, but then why did I start pressing the brake pedal harder almost immediately once the new setup was on? I was getting positive feedback and I built up the pressure and braked later fairly quickly. And it's not like I became a totally different driver in the last few track outings. My braking behavior has been consistent for quite some time. But something in these new brakes---the feel of the pedal and the way the car is slowing is giving me the feedback to brake harder and later. This is what gives me the confidence to search for new limits. For whatever reason, I felt like I was at the limit of the old setup---maybe not the limit of tire grip, but the limit of proper control. Whether I was right or wrong, I don't know.

(In fairness, the older AP CP5555 caliper has been around for a long time. I have a technical drawing of a CP5555 caliper that has a date of 1997 listed on it. (Doing a quick Google search, I couldn't find a release date for the CP5555.) The Radi-Cal for a production car showed up more than 10 years later. I would hope that braking technology has continued to improve in that time.)

As far as tire compounds and braking grip, I guess we have to say that the tires had more braking grip in them the whole time, but that I wasn't applying the brakes hard enough to use them to full capacity. (I've only been running DH scrubs since October.) I remarked in this thread after the first day with the new calipers that I was making the Pirelli DH howl on the front straight at Buttonwillow, and I don't recall doing that before. Why wasn't I using it all before? I don't know. Again, it's based on feel. I'm assuming the new caliper makes it easier to deliver more pressing forces onto the rotor.

And it's also worth noting that currently, I'm using the wimpy springy quick-release pad tension clip instead of the two bridge bolts and 4 block spacers that clearly make things at the top of the caliper more solid. I'm betting I can get even more stiffness and power out of the caliper if I put the bridge bolts back in there to help resist the caliper flexing, along with brand new 25mm pads that push the pistons all the way back into the caliper and reduce their potential for flex. I started on this kit with new 18mmm pads. So, who knows, maybe even more power is waiting. I'm now thinking that I may switch over to the 25mm pads and the bridge bolts the next time I go out (and not wear down the 18mm all the way to count all the days because, after 4 days, I have a sense of the wear rate now). I don't really need quick-release pad clips because I don't change pads very often. The novelty of not needing any tools besides a pad spreader was cool, but I'm over it---especially if the caliper can be even stiffer with the bridge bolts/block spacers in.

[dogbone]

Originally Posted by roastbeef

another thing i'm curious about is if he dogbone noticed more bite when going from slotted rotors to the J-hook rotors.

To be honest, I don't know. The braking is very smooth, though, which is mildly surprising since the J-hook surface has so many features on it.....what magic is this??

[admranger]

Good stuff dogbone.

[SYT_Shadow]

Originally Posted by dogbone

. I'm now thinking that I may switch over to the 25mm pads and the bridge bolts the next time I go out (and not wear down the 18mm all the way to count all the days because, after 4 days, I have a sense of the wear rate now). I don't really need quick-release pad clips because I don't change pads very often. The novelty of not needing any tools besides a pad spreader was cool, but I'm over it---especially if the caliper can be even stiffer with the bridge bolts/block spacers in.

I would have loved to see your impressions of the PFC Z54/45 kit for this car.

It's funny because BBK's are bought many times due to their easier pad changes, but with my 28mm PFC11 compound pads I literally swap after 30-40 track days. I don't swap them out for the street either as this compound is somehow quiet.

The data-driven approach you have is fantastic. I hope you get to the bottom of the DCT issues you're having. It's annoying you keep running into a wall there. Maybe a baffled pan would help?

[derbo]

:bravo.

I only got to page 11. Will continue more when I have time.

Truly amazed at the conversations here.

[dogbone]

Originally Posted by SYT_Shadow

I would have loved to see your impressions of the PFC Z54/45 kit for this car.

It's funny because BBK's are bought many times due to their easier pad changes, but with my 28mm PFC11 compound pads I literally swap after 30-40 track days. I don't swap them out for the street either as this compound is somehow quiet.

The data-driven approach you have is fantastic. I hope you get to the bottom of the DCT issues you're having. It's annoying you keep running into a wall there. Maybe a baffled pan would help?

I have always heard good things about PFC brake kits. I've never driven one.

I started down the path of AP Racing 6 years ago because I had an opportunity to get a used kit. At that moment, the Stillen AP kit was by far the best bang for the buck BBK I could afford. And the "used" kit was actually not really used----the fronts were entirely new--replaced by AP for the original owner, and the rears were completely refurbished by AP in England. So, the kit was in incredibly good shape for the price. That Stillen kit always treated me well. It was the most reliable mod on the car. I'm going to keep it and put it on my street E92 M3.

hehe 28mm pad on the PFC....super beefy!! I just installed the 25mm pads into the front calipers of my Essex AP kit today. I hope that they last a decent amount of time.

Check this ridiculousness out: It looks like I stuck a thick-cut piece of banana bread in my caliper!!!!


As far DCT issues, yeah.....it's a bummer....but in fairness to the car, I am pushing it beyond what BMW intended, and stuff like the transmission is completely stock, which is pretty impressive when you consider the fact that all the track days on this car have been done with a supercharger on there. I give BMW a lot of credit for making a car that has held up so well to all of this nonsense. Hopefully, I'll be able to drive the car later this week and see if our first round of maintenance helped the situation.

Regarding a baffled pan, I have also been wondering about that. As I have been reflecting back on this topic, I'm seeming to realize that most of the shifting issues happen after left turns/bends. It's not 100% of the time, but it's probably more than 90%. I've started asking where the suction from the pan occurs, wondering if it's on the left side of the pan and maybe as the fluid sloshes to the right that the system is starving, but I've been told the suction point is in the middle.....dang...I haven't given up on this line of thinking yet though....As I mentioned, we overfilled the system, so we'll see. I talked to SSP Performance last week. Nice guys. We had a good conversation.