Rear unstable under heavy braking

[OneTimeAccount]

Haven't taken my 2021 Supra to the track yet but am in a couple weeks, so I am posting this here in hopes of learning more before track day.

I did some heavy braking from a high speed down to about 50-60 MPH the rear end became unstable, going all over the place compared to my 718. Was working hard at keeping it steady. What can be done to improve the stability in the rear under heavy braking?

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[VA90]

I've not experienced that but suggest checking alignment. There is a surprising amount of variation from car to car from the factory.

Other than that, you probably need more data points before making setup changes to the car.

 

[antonio88x]

A lot of cars came with their alignments out of whack. My car is pretty solid braking from 120mph to 60mph. I'd take it to a performance shop that knows what they're doing.

 

[OneTimeAccount]

I've not experienced that but suggest checking alignment. There is a surprising amount of variation from car to car from the factory.

Other than that, you probably need more data points before making setup changes to the car.

Glad to hear from two people that it's could just be an out of whack alignment which is what I figured. Happens pretty reliably which is good, because knowing how the car will react under certain circumstances is better than not knowing when braking and heading into a turn.

I have an alignment scheduled for tomorrow but I think I will hold off until my wheels and lowering springs get installed. I'd rather have the alignment done after those two things get done, which I cannot wait for

 

[ogun228]

I came from a 2009 997S. I experienced the same instability until my Indy
gave me an alignment. Different car...Would venture to advise getting used to the car before modding...You might feel differently after a proper alignment, save headaches and money.

 

[OneTimeAccount]

I came from a 2009 997S. I experienced the same instability until my Indy
gave me an alignment. Different car...Would venture to advise getting used to the car before modding...You might feel differently after a proper alignment, save headaches and money.

Well that's another vote for possible alignment issue! Glad to hear you got it sorted just by getting an alignment. Interesting how these vary so much from factory and how it can change the car drastically. I am still going to get some Swift lowering springs (I found some!) and 18" Apex SM-10 wheels with Advan A052 tires.

 

[Okvilln]

Another vote to get an alignment. I brought the Supra in for an alignment and swapped out the factory brake pads for carbon ceramic. The bedding process requires 5x aggressive and 5x moderate braking to properly bed-in the pads. Front and rear end felt stable during braking.

 

[bsandoe]

I came from a 2009 997S. I experienced the same instability until my Indy
gave me an alignment. Different car...Would venture to advise getting used to the car before modding...You might feel differently after a proper alignment, save headaches and money.

Did you use OEM specs or something more aggressive?

 

[jorligan]

I found similar differences. I came from a Cayman, GT3 or 4C. My alignment was correct. I think that the difference is the greater sense of stability from the mid engine / rear engine vs the front engine with the associated weight shift. I have changed to KW coilovers and also changed the brakes in the Supra, tracking at Mid-Ohio next week and will see if this is the difference and the changes make an impact.

 

[OneTimeAccount]

I found similar differences. I came from a Cayman, GT3 or 4C. My alignment was correct. I think that the difference is the greater sense of stability from the mid engine / rear engine vs the front engine with the associated weight shift. I have changed to KW coilovers and also changed the brakes in the Supra, tracking at Mid-Ohio next week and will see if this is the difference and the changes make an impact.

That makes sense! The 718 Cayman was very balanced when braking. I find it interesting how many people who had or have Porsches got the Supra. Will be curious to know your thoughts after you take it to Mid-Ohio.

How are you liking the Supra compared to the other three cars you mentioned?

 

[ogun228]

" I find it interesting how many people who had or have Porsches got the Supra."

My 2021 replaced a 2009 C2S and I have to admit that it took me quite a bit of time to stop comparing as it is useless, diff. layouts and philosophy alltogether.
After an alignment, the Supra became more stable at least for me.

The Supra was (is) the closest I could come to a genuine sport car w/o spending 80+ k.

 

[jorligan]

That makes sense! The 718 Cayman was very balanced when braking. I find it interesting how many people who had or have Porsches got the Supra. Will be curious to know your thoughts after you take it to Mid-Ohio.

How are you liking the Supra compared to the other three cars you mentioned?

No comparison between the Supra and the GT3-The GT3 is confidence inspiring. You feel that you can never reach the limits of the car. It feels incredibly planted and stable. The GT4 which I have driven is similar. Very high price but also incredible performance.

Supra vs 4C. 4C drives like a Miata on Steroids. Very light, huge torque, super stiff chassis so very responsive. Weakness is the brakes compared to Supra and the feeling that you run out of power. Remember driving the car at Summit Point and being passed on the straight aways, then catching everyone in the turns - felt the frustration of the Miata guys.

Haven't driven 718 Cayman, had Vision Motorsports tuned 3.8 L 987 Cayman. Drove almost like a GT4

Supra is a great car! Daily driver phenomenal and incredible bargain price / performance. For relatively reasonable money, phenomenal track performance. I bought this car as daily driver and track toy, eventually going to my son in 2 years. Afterwards, possibly GT4 or Corvette ZO6

 

[OneTimeAccount]

No comparison between the Supra and the GT3-The GT3 is confidence inspiring. You feel that you can never reach the limits of the car. It feels incredibly planted and stable. The GT4 which I have driven is similar. Very high price but also incredible performance.

Supra vs 4C. 4C drives like a Miata on Steroids. Very light, huge torque, super stiff chassis so very responsive. Weakness is the brakes compared to Supra and the feeling that you run out of power. Remember driving the car at Summit Point and being passed on the straight aways, then catching everyone in the turns - felt the frustration of the Miata guys.

Haven't driven 718 Cayman, had Vision Motorsports tuned 3.8 L 987 Cayman. Drove almost like a GT4

Supra is a great car! Daily driver phenomenal and incredible bargain price / performance. For relatively reasonable money, phenomenal track performance. I bought this car as daily driver and track toy, eventually going to my son in 2 years. Afterwards, possibly GT4 or Corvette ZO6

Curious, did you own the GT3? That seems like a car that if I had, I’d never want to get rid of.

I agree the Supra is a great value for both a fast daily and a performance track toy. With a few modifications and added aero, I’ve seen them throw down lap times close to corvettes and vipers on some tracks.

 

[jorligan]

2018 GT3 with PDK, Agate grey with Xpel Stealth film on entire car so it looks matte. Got it for a great price since it came with the 18 way seats, replaced them with the GT2 seats. Still own the car and drive/track it occasionally. Keeping it indefinitely. Manual transmission in the GT3 is great but went with the PDK as it is faster on the track and my boys have no interest in driving a manual.

 

[OneTimeAccount]

2018 GT3 with PDK, Agate grey with Xpel Stealth film on entire car so it looks matte. Got it for a great price since it came with the 18 way seats, replaced them with the GT2 seats. Still own the car and drive/track it occasionally. Keeping it indefinitely. Manual transmission in the GT3 is great but went with the PDK as it is faster on the track and my boys have no interest in driving a manual.

Awesome. I bet it’s a joy to drive. My 718 had a PDK. Best transmission ever, don’t care if it isn’t manual because it was amazing.

I’ll for sure be back in a Porsche after I have some fun with my Supra. Trying to get my Supra to be quicker than my 718 around a track!

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