SCTS Racing M4 Race Car Build

[scottn2retro]

Had the car out at the Extreme Autofest in San Diego before the next round of work and racing

[scottn2retro]

At the Apex Race Parts open house, got to put the M4 in their car photo studio

https://www.facebook.com/pg/sctsrace...39284919594155

[scottn2retro]

Got some pics back from the APEX Race Parts car photo studio

[bracer]

On the MCS shocks, what spring lengths are you running? Looks like a 6" long spring? Spring rates?

[scottn2retro]

Originally Posted by blackey

On the MCS shocks, what spring lengths are you running? Looks like a 6" long spring? Spring rates?

To be honest, I forgot. I do know that we are thinking of going softer because of the MCS shocks. We are hearing from other racers that the MCS work better with less stiff spring rates.

[QuickOne]

Pics aren't working!!!! Why does life hate me so much!?

[Race82]

Car looks awesome - what are your final rim sizes, offsets and spacers up you landed with to fit 300's all round...

[ashmostro]

Originally Posted by awbmw

Car looks awesome - what are your final rim sizes, offsets and spacers up you landed with to fit 300's all round...

Great question!

Related would be if the fenders were rolled and if the oem inner arches are still mounted.

[scottn2retro]

Originally Posted by awbmw

Car looks awesome - what are your final rim sizes, offsets and spacers up you landed with to fit 300's all round...

We have 18x10.5" on the front with offset in the 20's and I believe 12mm spacers (I'll have to check)

We have 18x11 on the back with offset 44 and 5mm spacers.

[scottn2retro]

Originally Posted by ashmostro

Great question!

Related would be if the fenders were rolled and if the oem inner arches are still mounted.

We don't really need more tire than that. In fact, we like the staggered setup where we are using something smaller than 300 on the front.

[scottn2retro]

Originally Posted by blackey

On the MCS shocks, what spring lengths are you running? Looks like a 6" long spring? Spring rates?

Here are the rear springs. I'll get a pic of the fronts. I believe (based on observing how much the car bounces on bumps) that we could drop the rear spring rates slightly

[scottn2retro]

We had a good shakedown at Cal Speedway to get ready for the 2018 race season. Our Schedule for 2018 is

March 17 Las Vegas, NV
April 21-22 Buttonwillow, CA
May 26-27 Auto Club Speedway (Fontana, CA)
July 6-8 Oktoberfest/Pittsburgh Vintage Grand Prix - Pittsburgh, PA
July 13-14 Lime Rock, CT
July 27-29 Laguna Seca, CT
September 8-9 Sonoma, CA
October 13-14 Buttonwillow, CA
November 10-11 Thunderhill, CA
December 1-2 The 25 Hours of Thunderhill, CA

[scottn2retro]

We thought we'd try something that could:

1) read OBD codes for us real time when on the track
2) make it easy for us as crew to read the codes (touch screen menu) when the driver brings it down pit lane
3) monitor Engine Temp and some other parameters
4) give us max values for RPM, Eng. Temp,

With an end of year sale price, we decided to give the Banks i-Dash model 61204:
https://www.bankspowerproducts.com/B...ge-p/61204.htm

We mounted it where the old Nav display was


The driver preferred this display layout with RPM, Eng. Temp and Fuel Level:


How it looks on track

[x.shell]

Originally Posted by scottn2retro

Here are the rear springs. I'll get a pic of the fronts. I believe (based on observing how much the car bounces on bumps) that we could drop the rear spring rates slightly

1025 lb/in is pretty darn stiff. Not surprised that it can create an annoying bounce on the curbs/bumps/undulations.

When you go to a softer spring, you may need to go to a 9" length to keep the same shock travel -- as the spring will compress more. If the 9" is a little long, you can remove the OEM cup that you guys left in there to make a bit more room. My guess is that you can just leave the set up as is and adjust the perch down to make up for the change in ride height.

[hellrotm]

Originally Posted by scottn2retro

We had a good shakedown at Cal Speedway to get ready for the 2018 race season. Our Schedule for 2018 is

March 17 Las Vegas, NV
April 21-22 Buttonwillow, CA
May 26-27 Auto Club Speedway (Fontana, CA)
July 6-8 Oktoberfest/Pittsburgh Vintage Grand Prix - Pittsburgh, PA
July 13-14 Lime Rock, CT
July 27-29 Laguna Seca, CT
September 8-9 Sonoma, CA
October 13-14 Buttonwillow, CA
November 10-11 Thunderhill, CA
December 1-2 The 25 Hours of Thunderhill, CA

You need to get a COTA event in that schedule.

[scottn2retro]

Originally Posted by BlackJetE90

You need to get a COTA event in that schedule.

We have been to COTA 3 times and like the track and the facility. But 10 events (with some coast-to-coast travel) keeps our little club race team pretty busy

[scottn2retro]

Originally Posted by exo-shell

1025 lb/in is pretty darn stiff. Not surprised that it can create an annoying bounce on the curbs/bumps/undulations.

When you go to a softer spring, you may need to go to a 9" length to keep the same shock travel -- as the spring will compress more. If the 9" is a little long, you can remove the OEM cup that you guys left in there to make a bit more room. My guess is that you can just leave the set up as is and adjust the perch down to make up for the change in ride height.

We're really, really close on the setup. I may try dropping the rear springs in 50 lb/in increments. Just need to get them down to where the dampers are effective for the current setting

[scottn2retro]

Originally Posted by exo-shell

1025 lb/in is pretty darn stiff. Not surprised that it can create an annoying bounce on the curbs/bumps/undulations.

When you go to a softer spring, you may need to go to a 9" length to keep the same shock travel -- as the spring will compress more. If the 9" is a little long, you can remove the OEM cup that you guys left in there to make a bit more room. My guess is that you can just leave the set up as is and adjust the perch down to make up for the change in ride height.

Okay, based on what we've heard (that MCS shocks like lower spring rates) and what we've seen of the rear bouncing, we decided to try some lower rear springs. But the car setup is really close, so we didn't want to make a big change. We had Eibach send us some 950 lb/in springs


But exo-shell raises a good question. How much to raise the ride height adjusters to compensate for the lower rate. We decided while the car was on the lift to measure the compression of the 8" springs on the car. But we had to get the trailer/lift level in the paddock at Buttonwillow with crowned paddock roads. I had an idea- use the garage ramp




We measured the compression of the 1025 lb/in springs to be down to 7.25". So 3/4" compression.


Time to change the springs. At 12 turns/in, we figured we needed to raise the ride height about .1" or 1 turn on the ride height adjusters.


It seems to have worked. Ralph took the car out on Saturday and it looked less bouncy and Ralph said the car felt great!

Ride height looks okay

[x.shell]

Originally Posted by scottn2retro

Okay, based on what we've heard (that MCS shocks like lower spring rates) and what we've seen of the rear bouncing, we decided to try some lower rear springs. But the car setup is really close, so we didn't want to make a big change. We had Eibach send us some 950 lb/in springs


But exo-shell raises a good question. How much to raise the ride height adjusters to compensate for the lower rate. We decided while the car was on the lift to measure the compression of the 8" springs on the car. But we had to get the trailer/lift level in the paddock at Buttonwillow with crowned paddock roads. I had an idea- use the garage ramp

We measured the compression of the 1025 lb/in springs to be down to 7.25". So 3/4" compression.

Time to change the springs. At 12 turns/in, we figured we needed to raise the ride height about .1" or 1 turn on the ride height adjusters.

It seems to have worked. Ralph took the car out on Saturday and it looked less bouncy and Ralph said the car felt great!

Ride height looks okay

Glad to see it was an improvement. And I love the creative way you used the trailer to calculate the compression rate to ride height.

[chili cheese]

Beautiful build! I was at the CCA event at BRP last weekend and got to take a look as well as drive next to it on track. Sat next to Stephen in the Race School Classroom.

[Race82]

Originally Posted by scottn2retro

We never had to keep the airbag module before, but on this car the software is such or there is actually some type of accelerometer in the unit (notice its position in the car) where if you pull the airbag module, you get an ABS system error.

LATE EDIT: That module is actually called the ICM or Integrated Chassis Module and it does have some type of motion sensor in it.

Did you end up leaving the ICM plugged in or disabling it? Have just installed race seats and wondering how to code out the SRS errors...

[mcvaughan]

Originally Posted by awbmw

Did you end up leaving the ICM plugged in or disabling it? Have just installed race seats and wondering how to code out the SRS errors...

Contact Alex @ Alpine.