My E90 M3 Dedicated Track build (with pix!)

[dogbone]

Originally Posted by Richbot

blue flag honestly

You mean the Passing Flag? Yeah----that was out. He just could not give less of a shit. In fact, that dude who held everyone up.....he ran to the organizer as soon as the session was over to complain that people were unpleasant on track. I went over to the organizer to complain that the guy did not have any track awareness or manners, and that's when I found out he had already been to the organizer to complain about the rest of us!

[Richbot]

5 place grid penalty

[dogbone]

Originally Posted by Richbot

5 place grid penalty

hehe damn I wish. The sorry truth is that he showed up to the grid late, and then they slammed him out on track right in front of us when we were done with with our warm up lap.....sigh....HPDE----how do you win those again?

[Richbot]

The only winning move is to buy a spec racer ford and race with the scca

/sermon

But please don't then we won't have cool track E90 posts to read

[dogbone]

Originally Posted by Richbot

The only winning move is to buy a spec racer ford and race with the scca

/sermon

But please don't then we won't have cool track E90 posts to read

As long as the E90 is able to run, I'll keep running it! Driving that car is a lot of fun. I know it's not pulling 3G's like some open wheel beast, but it's still fun!

[dogbone]

Went to Buttonwillow 1CW this weekend with PCA-San Diego. Had a really nice time.

First up: The Voltphreaks battery. It sat for three weeks between events without any trickle charging. The car fired right up. No hesitations at all. Excellent. Very happy with the battery so far.

Second up: The AIM Solo 2 DL continues to impress with it's accuracy. My friend and I both have AIM Solo 2 DLs and at Buttonwillow, they were within 2/100ths of the transponder all weekend long. Very cool. But I gotta reiterate——if you get an AIM Solo 2 DL, make sure it’s connected to power in the car. If you leave it tied to the CAN bus all day without power, the device will be dead long before the day is over.


I had not run 1CW since 2012, so I had some homework to do on the Star Mazda turn. The turn itself wasn't too complicated, but going up the Esses from Star Mazda instead of Sweeper is QUITE different. I took my time to build speed there. That is not one section of track where you want to experiment and have it go wrong…..The tire wall is famous for eating a lot of cars. I have more time to gain there in the future.

The car ran great. I had three sets of Pirelli scrubs with me. I wanted to try all three sets, so I ran each set twice on Saturday. They were all fairly similar. I spent Saturday gaining confidence and ran my fastest lap of the day on my last hot lap. I was happy about that. Day 1 fast lap: 1:54.7.

On Sunday, I was hoping I could build on what I learned. The weather was COLLLD in the AM. It was 38ºF when we went out on track at 8AM. I got the tires up to temp and first session got a 1:53.2. Boy does the car accelerate like a monster in those cold temps. And honestly, after a few laps, I was not having any problems with grip in those cold temps. People always say there is no grip when it’s cold……I’m not so sure about that…..I had plenty of grip.

Second session, I set my personal best: 1:52.9. Temps were in the low 50's, and I just drove more consistently. And it wasn't a totally clean lap because at the beginning, I had to pass a car, so my entry into Turn 1 was not ideal, and looking at the data, I lost about 0.4 sec. Regardless, I was happy to get into the 1:52's on scrubs, and that lap was the fastest lap of the weekend/event.

Here's video of my fast lap:

As I mentioned before, there was a time trial that I was looking forward to. Hehe---that ended up being an adventure. I was in the first group that ran the time trial. The way PCA runs it, you get a warm up lap, two hot laps and you exit the track immediately after you cross the line after your second hot lap——no cool down lap. Hot lap #1 was ruined because as soon as I pressed the brakes for Cotton Corners, the car started skidding. I’ll post more on this in an upcoming post with data because it was definitely weird. Maybe someone else can help me to understand what happened. Perhaps there was something on the track? Someone else said that turn's entry was squirrelly for them too. I don’t know……Anyway, that first lap was blown. So, I drove the second lap a bit more conservatively just to get a time in. It was ok: 1:54.4 on my AIM. After my run, I cooled the car down by driving around slowly in the paddock since there was no cool down lap. After that, I was getting gas, and I hear on the track PA, "If you ran in the first time trial session, please come back to grid because we did not record your times and you need to run again." Ok…… So, I get gas and run back to grid.......and then they made us sit there for well over an hour while they ran EVERYONE ELSE.......My first run was at 11AM. My make-up run ended at 1PM.....Honestly, I was sorta happy to have a do-over because my first run didn't go that well. But it was quite a bit warmer an hour and a half later for the second run. I ran another 1:54.4. It was good enough for the time trial win.

One thing that was really nice about this particular weekend——I had a lot of open/clean laps. I credit the grid crew for that. I had never seen this crew before. It turns out they had never worked together, but they were AWESOME. They ran a VERY tight ship. It was a crew of all ladies and they weren't taking shit from anyone. It's amazing the difference a great grid crew can make.

My friend took this video from the observation deck on Sunday. For reference, as I’m going past the start tower, I’m going 125mph. Max speed at the braking zone is 131mph. Figured this was a good example of what my car sounds like on track:

I’ll be back at it this coming weekend for Bimmer Challenge at Chuckwalla on Saturday. This should be an interesting event. (Is there really ever an Uninteresting track weekend? ) A couple people are signed up in my class that I’ve never heard of. That always introduces a big unknown element to the event. One of the cars in my class is listed as an E36 M3 with 400hp and race tires……that sounds formidable. Plus, they’re running Counter-Clockwise (CCW) this Saturday which I have run many times before, but not recently. My first visits years ago to Chuckwalla were all CCW, but it’s been all CW after that. So, I’ll have to get the track back in my head quickly. Should be fine.

I’ve done 5 events with Bimmer Challenge this year in the B1 class. I’ve won all 5. The series counts your top 7 performances out of the 11 events offered. Looking at the math from the standings so far, I don’t need to win all 7 events to win the whole series this year, but I’m doing my best to make a good showing at each event. I drove poorly at the Sonoma event at the end of September. (I did enough to win, but my times were not great.) I hadn’t driven for 4 months prior to that event, and during the Sonoma event, I was coming down with the flu…..each session I felt progressively worse, but my times kept improving haha……so, I’ll give myself a break on that one. After this Chuckwalla event, there's a final event right before Christmas back at Buttonwillow 13CW.

Anyway, I really enjoyed the PCA event last weekend, and I’m looking forward to a fun and challenging event this coming weekend.

[dogbone]

Ok, ready for investigation time? I'm curious if someone with experience can weigh in on this one.

The question is: why did my front brakes lock up in the braking zone going into Cotton Corners in the Time Trial on Sunday? I pressed the brake pedal in a fairly normal way compared to other presses, but as soon as I did, the calipers grabbed the rotors hard and locked the front wheels. The car started sliding immediately. I basically kept the car on track....maybe a wheel dropped into the dirt, but what the heck happened??

My friend was video taping from the observation deck. From a distance, he caught the tire smoke from the locked front wheels. I slowed the video down. After I turn the corner a small rooster tail of dirt went up from either hitting dirt on the edge of the track or dropping a wheel.

Here's what it was like in the car:

The AIM Solo 2 DL was able to capture the event, so let's look at a few screenshots.

First, let's look at a normal example of going into Cotton Corners:

In the picture above, there are three charts. The top chart shows the wheel spinning speeds of all 4 wheels so you can see the wheels decelerate into the corner. The middle chart shows how the calipers are activated. The bottom chart shows my brake pedal press. On this normal chart, on the bottom, you can see my brake pedal press is smooth, the calipers act in a reasonable way and you can see the wheel speeds slow down smoothly and all together.

Second, let's look at the skid:

The charts are setup the same as the first example. The brake press starts ok, but look at how the calipers activate----the front calipers go CRAZY and spike super high meaning they grab super hard! In the top chart, you can see the two front wheels locked because their speed lines drop so dramatically down to almost 0mph while the rears slow down smoothly.

Third, I made a chart for direct comparison between the two. It's a bit messy but I made it just to show that my initial brake press wasn't panicked or too late. Red is the skid and blue is the normal:


So, the question is, why did the computer go crazy and lock the front wheels? If something slippery was on the track, wouldn't the computer actually press the calipers LESS? Wouldn't ABS kick in and prevent locking?

Another driver said the track felt squirrelly there. He said he was sliding on the entry to Cotton Corners. But every time I try to reason through it and look at the AIM, it doesn't make any sense.......and that was a lot of tire smoke! You could feel the front tires mildly flat-spotted after that adventure. Steering wheel had a bit of a shake......blah.

I'm curious to hear your thoughts.

[ThunderMoose]

Originally Posted by dogbone

Ok, ready for investigation time? I'm curious if someone with experience can weigh in on this one.

The question is: why did my front brakes lock up in the braking zone going into Cotton Corners in the Time Trial on Sunday? I pressed the brake pedal in a fairly normal way compared to other presses, but as soon as I did, the calipers grabbed the rotors hard and locked the front wheels. The car started sliding immediately. I basically kept the car on track....maybe a wheel dropped into the dirt, but what the heck happened??

My friend was video taping from the observation deck. From a distance, he caught the tire smoke from the locked front wheels. I slowed the video down. After I turn the corner a small rooster tail of dirt went up from either hitting dirt on the edge of the track or dropping a wheel.

Here's what it was like in the car:

The AIM Solo 2 DL was able to capture the event, so let's look at a few screenshots.

First, let's look at a normal example of going into Cotton Corners:

In the picture above, there are three charts. The top chart shows the wheel spinning speeds of all 4 wheels so you can see the wheels decelerate into the corner. The middle chart shows how the calipers are activated. The bottom chart shows my brake pedal press. On this normal chart, on the bottom, you can see my brake pedal press is smooth, the calipers act in a reasonable way and you can see the wheel speeds slow down smoothly and all together.

Second, let's look at the skid:

The charts are setup the same as the first example. The brake press starts ok, but look at how the calipers activate----the front calipers go CRAZY and spike super high meaning they grab super hard! In the top chart, you can see the two front wheels locked because their speed lines drop so dramatically down to almost 0mph while the rears slow down smoothly.

Third, I made a chart for direct comparison between the two. It's a bit messy but I made it just to show that my initial brake press wasn't panicked or too late. Red is the skid and blue is the normal:


So, the question is, why did the computer go crazy and lock the front wheels? If something slippery was on the track, wouldn't the computer actually press the calipers LESS? Wouldn't ABS kick in and prevent locking?

Another driver said the track felt squirrelly there. He said he was sliding on the entry to Cotton Corners. But every time I try to reason through it and look at the AIM, it doesn't make any sense.......and that was a lot of tire smoke! You could feel the front tires mildly flat-spotted after that adventure. Steering wheel had a bit of a shake......blah.

I'm curious to hear your thoughts.

Was DSC off?

[rhyary]

Excellent usage of AiM's data.
I am looking forward to be able to do the same.

[dogbone]

Originally Posted by ThunderMoose

Was DSC off?

Yes, DSC is always off these days. I turned it off in Nov 2015 and haven't driven with it since.

[dogbone]

Originally Posted by rhyary

Excellent usage of AiM's data.
I am looking forward to be able to do the same.

This is what the AIM data excels at---showing in clear terms what's happening. I love that. Without data someone could say the car skidded and most people would just chalk it up to something on the track. But in this case, the car locked up the wheels.....I can't make any sense of WHY it reacted this way. What was the computer doing?? That was a lot of tire smoke!

[OG Shark]

Originally Posted by dogbone

This is what the AIM data excels at---showing in clear terms what's happening. I love that. Without data someone could say the car skidded and most people would just chalk it up to something on the track. But in this case, the car locked up the wheels.....I can't make any sense of WHY it reacted this way. What was the computer doing?? That was a lot of tire smoke!

My theory - you have achieved something very few have ever done. You are now so fast that you have scared the computer and it is trying to slow you down. Well done sir, well done.

[dogbone]

Originally Posted by jktx

My theory - you have achieved something very few have ever done. You are now so fast that you have scared the computer and it is trying to slow you down. Well done sir, well done.

Haha! Man, I hope that ain’t it!

[Adrian g.]

Google "bosch ABS ice mode". Just a guess, but it is not uncommon on track cars with the stock street ABS.

[dogbone]

Originally Posted by Adrian g.

Google "bosch ABS ice mode". Just a guess, but it is not uncommon on track cars with the stock street ABS.

I'm generally familiar with ABS Ice Mode because the Porsche guys seem to talk about it a lot.

But Ice Mode is more about the ABS not being able to deal with a bumpy/wavy track, and then it pulsates the calipers to not lock up over a rough surface. So, it activates the calipers less than you want in terms of grabbing power.

This is the opposite of what I'm seeing. In my case, the computer is actually massively activating the caliper and briefly locking the rotor.

I've been thinking about this more, wondering if I've ever had this happen and I just chalked it up to the track surface. It turns out, it has happened once before. January 2018, I was at Chuckwalla CW, going down the front straight, hit the brakes, started skidding immediately and slid right off the track. I assumed it was something on the track. Again, someone behind me said they felt something odd on the track too. I looked at the data today and found the lap where it happened. It was the same thing. Big caliper activation that led to the wheels locking.

Maybe it is something on the track the computer interprets in a weird way.....

[Adrian g.]

Sounds like an ABS related issue, to me - but I certainly do not have an explanation. You stated the brakes locked up and the car slid. Should this not happen with ABS, I would think.

[dogbone]

After a couple of conversations with some knowledgeable people, it seems a reasonable course of action is to replace the wheel speed sensors on the car. The ones on the car are original and they've seen quite a bit of action. I seem to recall a couple years ago, one of them tossed out an error code but it was intermittent and we never did anything about it.

We're gonna replace all of the them tomorrow.

[StripclubDJ]

This has happened to our race cars

Once was the battery post center 5mm Allen that holds the negative terminal came loose on the antigravity mini battery and car had a voltage spike, resulted in 2 rear brand new Hoosiers being destroyed in 2 laps

Just a thought but I'm sure you got that covered already

You check for wheel speed sensor codes or pending errors? Drive the car with scan tool showing wheel speed and all wheels match the same speed as one another?

[StripclubDJ]

But , as a side note, if your car is solid mounted everything with a mini style bolt on post battery
If a cable is shifted in any way they come loose
Always put a key or socket on them before each event to save yourself the headache

Going into turn 2 at laguna and your negative coming off is a NO JOKE

[ThunderMoose]

Originally Posted by StripclubDJ

But , as a side note, if your car is solid mounted everything with a mini style bolt on post battery
If a cable is shifted in any way they come loose
Always put a key or socket on them before each event to save yourself the headache

Going into turn 2 at laguna and your negative coming off is a NO JOKE

I had something similar happen but the AIM data showed the rpms going to zero when it happened which I don't see here.

In my case, the wire to main fuse panel had come loose. I had done some wire thinning the previous year on my E46M3. I fought an ongoing issue where DSC kept turning itself on. I just disconnected the yaw sensor which "solved" the issue for a while. However, I was at Hallett and ended up smoking the front tires really bad in a heavy braking zone. Read codes but I still couldn't figure what was going so I ended replacing the DSC module, but next time out DSC turned itself on again. This time I kept car running and read that I had a low voltage code that had cleared. I grabbed and pulled the bundle of wires to my fuse box since car is gutted and low and behold car stops and restarts on its own. Pull out fuse box and tighten the main wire terminal and never had the issue again. I went back through my data and could see now via RPM channel where power had been cutting out.

As I said earlier, Dogbone's data doesn't look the same but I'd definitely check all of the connections.

[dogbone]

Thanks guys. Appreciate the input.

It happened once in January and once November. I had a MiniCooper battery in January and a Voltphreaks in November. So, two different battery setups on the two occasions it's happened.

I just checked my rpms in the AIM---nothing unusual there.

I looked on the AIM for the battery voltage and it's consistent throughout the whole lap from 13.8 to 14.1 volts. Power seems stable, but I will check connections.

In the AIM data, I can see the wheel speeds of all 4 wheels. They generally look similar when I'm going down a straight---within 1-2 mph of each other at 125mph. Anyway, we'll start with the wheel speed sensors and see what happens. This occurs so infrequently that it may be awhile before I can make any conclusions.

I have slid off at Turn 2 at Laguna----twice----one of the times I could drive out of the rocks; the other time, I had to be towed out of the rocks......Both of those offs are on me, not the car. The first time, when I needed to be towed out, I was experimenting with braking late.....yup, too late. The second time, I sorta missed the brake pedal with my foot and only pressed with the tips of my toes.......I couldn't press hard enough to slow down quickly enough---just barely tipped into the rocks......hehe whoops.

[FuzzyPeaches]

Would you be willing to share your data file? I'm just starting to explore this stuff and this issue would be a real interesting one to sift through to see what all the car was doing.