SCTS Racing M4 Race Car Build

[spongbobsquarepants]

Absolutely incredible build - thank you for sharing the progress with us!

[horsepower_and_hounds]

Loving every post!

[jetbill]

Originally Posted by scottn2retro

Here you can see why we machined out notches in the 'Bat'Leth'. We now have room for the MCS adjustment knobs and the max camber angle on the TC Kline camber plates.

With the notch in the aluminum brace, how much camber can you get with the TC Kline plates in the max position?

[scottn2retro]

Thanks everybody. We were the only M4 at Sonoma, so I believe that we are the first team to have an M4 in a BMW Club race.

But at Laguna Seca, the guys at Strom Motorsport brought their M4 that they've been working on for about a year and a half. We actually managed to finish ahead of their M4 in 3 races on Sat. and early Sun., but by Sunday afternoon their more developed car was able to show its speed.

[scottn2retro]

Originally Posted by jetbill

With the notch in the aluminum brace, how much camber can you get with the TC Kline plates in the max position?

About -4.4 +/- .15 deg. (it wasn't quite the same on both sides)

[SakhirM4]

Why don't the front of your hood and the bumper line up in the Leguna Seca pics? Looked fine before that.

[scottn2retro]

Originally Posted by SakhirM4

Why don't the front of your hood and the bumper line up in the Leguna Seca pics? Looked fine before that.

We had a little contact in one of the late Saturday races. Here's one of the earlier pics at Laguna Seca. You can see I went cheap with the tow hooks for the first time out (used the OEM tow hook in the front and bought a 2nd one for the rear)

[Powaup]

Wow.... great job! keep it up

[Donger Kim]

loving this thread!

[scottn2retro]

Thanks all - we may start looking into our electrical issues this weekend. We believe the fuel gauge is related to taking out a section of the KCAN-2 bus when we removed the entertainment harness.

[wakdady]

not sure if this was addressed or asked, but what exactly is your wheel and tire setup? I can see they are apex ec7, but the width and offset all around? and tires/tire sizes?

[larryn]

Originally Posted by wakdady

not sure if this was addressed or asked, but what exactly is your wheel and tire setup? I can see they are apex ec7, but the width and offset all around? and tires/tire sizes?

Asked and answered in this very thread a couple times...

http://f80.bimmerpost.com/forums/sho...7&postcount=91

[wakdady]

that's what I get for not searching. Thanks!
and great build, happy for your success!

[scottn2retro]

Originally Posted by wakdady

that's what I get for not searching. Thanks!
and great build, happy for your success!

I still don't think we've come up with our final fitments yet. I think we'll be in a better position at the next race to do some actual testing of the 270's up front vs. the 300's. The drivers at Laguna Seca thought the car might actually turn easier with the smaller tires up front (less sidewall rollover on the 10.5" wide wheels) and may handle better later in races with more tire in the rear of the car.

[HP Autosport]

Originally Posted by scottn2retro

About -4.4 +/- .15 deg. (it wasn't quite the same on both sides)

That is a healthy dose of camber.

Let's get you some horses soon!

[BMW M4 PWR]

Out of curiosity doesn't stock M4 GTS's do 1:37's around Leguna Seca? And both the stock new Mustang gt350R and even Camaro SS 1LE even slightly quicker times than that in full road trim?

[scottn2retro]

Originally Posted by BMW M4 PWR

Out of curiosity doesn't stock M4 GTS's do 1:37's around Leguna Seca? And both the stock new Mustang gt350R and even Camaro SS 1LE even slightly quicker times than that in full road trim?

I don't have any info on that, but with Bill Auberlen driving, maybe. I'm sure if he was driving our car, it would be seconds faster than what we posted.

[HP Autosport]

Originally Posted by BMW M4 PWR

Out of curiosity doesn't stock M4 GTS's do 1:37's around Leguna Seca? And both the stock new Mustang gt350R and even Camaro SS 1LE even slightly quicker times than that in full road trim?

The conditions were likely very different. There was likely no traffic ahead and no one filling his rear view and/or your side mirrors. Fresh car just set out for one fast lap.

[MPACT]

I read through the thread but didn't see your current weight? Loving the build just wondering how much lighter it is than e90 in race trim.

[scottn2retro]

Originally Posted by MPACT

I read through the thread but didn't see your current weight? Loving the build just wondering how much lighter it is than e90 in race trim.

Next time I get to the trailer, I'll get the weight reading we took at Sonoma.

In the mean time, we are making some progress on what we've done to the vehicle electrically after the cage install. We had no control of the wipers or headlights and the fuel gauge was not working.

We subscribed to BMWTIS and got some schematics and from those Craig was able to figure out what we did:
1) Removal of the Entertainment Harness had never been a problem in past cars but on this car, it carried the KCAN-2 bus to the rear of the car.
2) To help remove all harnesses from around the driver's seat area we cut the connector off the driver's side seat harness. The KCAN-2 bus loops to the seat connector and then back out to other areas of the left side of the car.

It's a good think we've kept some of the wiring we removed from past cars. KCAN-2 wires are a twisted pair of yellow wires, one with a red stripe and the other with a brown stripe. Luckily, in our bin of old BMW wiring, we had some of that same twisted pair wiring.


First, we patched into the the wires to the Front Electronics Module:
Connector: A173*10B (This connector was removed when the entertainment harness is removed.)
Pin 10 K_CAN_2H (yellow/red stripe)
Pin 11 K_CAN_2L (yellow/brown stripe).


And ran those wires back to the rear fuse box Connector: X382*3B
The other side of this connector was removed when the entertainment harness is removed.
Pin 6 K_CAN_2H (yellow/red stripe)
Pin 1 K_CAN_2L (yellow/brown stripe)


Then spliced together the KCAN-2 loop back wires where we cut off the driver's seat harness connector


Doing all of that we were able to regain control of the headlights and wipers and the fuel gauge also works now. We still have some issues - the transmission sport mode button does not seem to be working and it looks like our scan tool cannot talk to the DME.

[carno]

I just wanted to point out that the pair of wires in the last photograph that isn't connected to anything looks like they may be K_CAN2 but we'll have to trace them to see where they go.

Once we got A173*10B connected to X382*3B and spliced the wires from the seat harness, the headlights, wipers and fuel gauge and radiator fan started working correctly (the lights, radiator fan and wiper motor had been constantly on while the ignition was on).

*** Removed incorrect paragraph - EKPS (fuel pump control) is on PT_CAN) ***

Obviously, the setup in the photographs is temporary. Because we got rid of the entertainment harness, we had to buy a replacement for the A173*10B connector so we're waiting for that to arrive. The wires at the other end can be cut and spliced because there's nothing else that needs to be connected.

The wires that I spliced for the seat harness were all copper and the wires that I left unconnected are steel. We'll post an update when we trace those wires.

[scottn2retro]

Originally Posted by MPACT

I read through the thread but didn't see your current weight? Loving the build just wondering how much lighter it is than e90 in race trim.

The weigh in at Sonoma was 3446 lbs. with a 160 lb. driver. We thought we were about 3300 lbs. at BW with nobody in the car, so we came out about 14 lbs. or so less after the cage install and removal of the weight we could shed before the O'fest races. So we think the car is about 3285 lbs.