Race Tracking Your Supra - Information exchange

[Levophed]

Sweeatttttttttt…. That’s cool you know & found that information. I don’t know the numbers and just drive the damn thing. But it doesn’t take a much to hit the ABS threshold. Hence why it’s good to find that point early on when starting to track her (or any car with assisted brakes for that matter). So a bit off SIM car topic but…. do you know if the brake booster can be turned off easily on our Supras without causing the computer to go grape ape? I’d love to have greater lbs of pressure for real world track application. My previous S2K track car didn’t have power steering or brakes and it was fantastic! It was also a lot lighter. So just dialing it down would probably be ideal, for this car.

I know the MX5 Cup cars were the same way. Without power assist. If you could find the info for the Supra GT4 Cup cars & what they use, I bet that would be a great sweet spot.

I’ve been chasing a stiffer brake feel as well, ever since I got into tracking. It’s been really difficult for me to trail brake with my left foot because the pedal just feels too soft and vague. I’ve already done the usual stuff master cylinder brace and Endless RF650 fluid but it still doesn’t give me the firm feel I’m looking for.

I’ve got a set of Project Mu Club Racers waiting to go on, so I’m hoping those help a lot once they’re on Before this, I was deep into sim racing and ran 65kg on my load cell pedals, so I got used to needing real pressure to slow the car down. Translating that feel into real life has been tough.

Anyone else run into the same issue or find a good way to get a more solid pedal feel in the Supra?

side note: seems like I will probably have to do a rotor change with project mu CR based off comments here. My rotors are still pretty clean from stock pads anyone have experience with this?

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[AHP]

side note: seems like I will probably have to do a rotor change with project mu CR based off comments here. My rotors are still pretty clean from stock pads anyone have experience with this?

Waste of time and money to swap perfectly good rotors. Just send it.. You'll have a session or 2 of shudder and will go away once you power through. Even my 2nd set of PMU were grumpy for a session or so on the same rotors as the first set. Bedding issues aside, I've found these pads to be at their practical limit on a 220TW on a brake intensive track. They ain't all that, hoss....

 

[FLtrackdays]

side note: seems like I will probably have to do a rotor change with project mu CR based off comments here. My rotors are still pretty clean from stock pads anyone have experience with this?

I went from OEM rotors straight to Hawk DTC60/30 w/out issue.

Only time I had a problem was when I didn’t bed in a different compound properly when switching from the Hawk to a Winmax. Like eating a Monarch butterfly, I didn’t go back after that. It helps that the price of rotors have come down significantly. I can’t afford to have my few track weekends thrown out the window for something as cheap as rotors.

Maybe when I’m retired, I’ll try it again someday ?

 

[noogie]

Hi guys I have an interesting request.

I’m trying to figure out how much actual pedal force (in kg or lbs) it takes to reach full braking in the A90 Supra — as in, hitting 100% brake pressure or triggering ABS with the brake booster active.


I'm tuning my sim rig and currently have my load cell brake pedal set up to require 46 kg (101 lbs) of pressure to reach full braking input. But I realized that’s probably simulating a non-boosted system, which isn’t accurate to what the real Supra feels like.


Since the A90 uses an electro-hydraulic brake booster (BMW’s iBooster), I’m assuming the actual pedal force needed in the real car is lower maybe around 28–32 kg? But I haven’t been able to find any hard numbers, and unfortunately I don't have capability to tap into canbus to log brake pressure data.


Has anyone measured this or have a good estimate of:

How much force a driver actually applies to the pedal at full braking?
Whether 46 kg is overkill for simulating the Supra?
Any real-world data from track use or telemetry setups?

Would love to get as close as possible to the real pedal feel. Thanks in advance for any insight!

I also have a sim rig with load cell and prefer the stiffer pedal and using muscle memory to modulate the pedal. Just like a real race car.

unfortunately street cars will never achieve this feel since they’re meant to be comfortable. I believe the entire pedal box is replaced on gt4 cars, which bypasses all the factory boosters etc and allows you to tune the stiffness of the pedal.

fortunately in a real car, you can also rely on g forces as another input to know when you’re about to hit the ABS. So probably a combination of g forces and pedal distance to do your modulation.

 

[garudathree]

fun pov on track:

 

[Rensuhlo]

Waste of time and money to swap perfectly good rotors. Just send it.. You'll have a session or 2 of shudder and will go away once you power through. Even my 2nd set of PMU were grumpy for a session or so on the same rotors as the first set. Bedding issues aside, I've found these pads to be at their practical limit on a 220TW on a brake intensive track. They ain't all that, hoss....

Brake coding fixes some of the PMU shudder complaints, if you haven't already done this.

 

[Levophed]

Brake coding fixes some of the PMU shudder complaints, if you haven't already done this.

What is brake coding? Searching on forums and online don't give much info

 

[Rensuhlo]

What is brake coding?

Utilizing Protools to change the AL-Gore-ithm from OEM BMW coding to make the brakes feel more generic like most cars. Improves trail-braking and feel. One gentleman will likely find this comment and post about how it's nothing new or groundbreaking, as the f80s been doing it a hot minute.

But it's available with a search in here. Otherwise you can leverage those of us with protools to remote in and do it all for you (myself included if you are ok with leveraging LMI and buying your own dongle)

 

[Levophed]

Utilizing Protools to change the AL-Gore-ithm from OEM BMW coding to make the brakes feel more generic like most cars. Improves trail-braking and feel. One gentleman will likely find this comment and post about how it's nothing new or groundbreaking, as the f80s been doing it a hot minute.

But it's available with a search in here. Otherwise you can leverage those of us with protools to remote in and do it all for you (myself included if you are ok with leveraging LMI and buying your own dongle)

Are you essentially changing DSC and ABS settings? Defo interested in this. Was under the impression that the "full Traction control click" turned off all DSC and TC? Is the brake shudder issue from the pads triggering ABS prematurely?

 

[Vtec13]

The TT4 winner that weekend made note that he always knew he'd lose if you were at any of the same events ?.

Here's the fast lap on RE71RS. I put on my A7's for the morning session the next day but couldn't find any more time and wasn't driving very well. Optimal had me at 2:14.75 on the RE71RS which I'll be glad to chase. I think a 2:13.x is a nice stretch goal for me for next year.


Bonus footage of hunting the C8

where is your camera mounted?
i cant seem to figure out how to get mine to not be over exposed out the front windshield.

 

[Traxion]

where is your camera mounted?
i cant seem to figure out how to get mine to not be over exposed out the front windshield.

It's on my harness bar behind the seats (same thing as the OEM silver bar). If you have a gopro you need to focus on something outside the windshield and then exposure lock. I use a DJI Action 3 on 1.6x zoom and I put the ISO on 100-800 and Exposure Value at -1. I then manually adjust the exposure in Davinci Resolve to brighten/darken as needed.

This is my mount: https://www.amazon.com/dp/B0CB5JKTBH

 

[AHP]

where is your camera mounted?
i cant seem to figure out how to get mine to not be over exposed out the front windshield.

If you're using a GoPro, set the EV comp to -2. That eliminated the outside image from being totally blown out for me without any other hacks or tricks.

 

[Vtec13]

It's on my harness bar behind the seats (same thing as the OEM silver bar). If you have a gopro you need to focus on something outside the windshield and then exposure lock. I use a DJI Action 3 on 1.6x zoom and I put the ISO on 100-800 and Exposure Value at -1. I then manually adjust the exposure in Davinci Resolve to brighten/darken as needed.

This is my mount: https://www.amazon.com/dp/B0CB5JKTBH

thank you, i have a similar mount, but i will mess with the settings more

 

[razorlab]

If you're using a GoPro, set the EV comp to -2. That eliminated the outside image from being totally blown out for me without any other hacks or tricks.

The key is actually EV lock out the window. Then fine tune with EV comp.

In my videos I EV lock right into the passenger side window.

 

[Davo307]

The key is actually EV lock out the window. Then fine tune with EV comp.

In my videos I EV lock right into the passenger side window.

That Vette is a dick face driver. Video quality is fantastic though

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