Race Tracking Your Supra - Information exchange

[Todday1]

Nice to know. I think the 10 “ rims may only go up to 285 but if I could get 295 on the rim I might give it a try.

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[kaj]

295 seems to be a pretty good width for these cars. They don't seem to use any more rubber than that.

 

[razorlab]

295 seems to be a pretty good width for these cars. They don't seem to use any more rubber than that.

Nankang CR-S 295 are supposed to come to the USA this year and I am excited.

 

[kaj]

Nankang CR-S 295 are supposed to come to the USA this year and I am excited.

Jackie keeps promising....
I figure by the time I'm done with my 275s, we should be good to go.

 

[DanzBurG]

295 fits fine. You can even stuff a 315 under all four corners with no fender mods. Of course, this means you need to be running coilovers for more tire to spring clearance and a good amount of negative camber, which you should be running anyway for track use.

I ran a square set of 295/30/18 on my 18x10.5 +35 wheels with zero issues. I have a friend that runs 295/35/18 on 18x10.7 +38 with zero issues as well.

Here where my 295/30/18 for reference:

Wow that looks really sharp! I was under the assumption (atleast from the little research I've done) that Titan7 and Apex were the only ones to have these specific specs for the platform. Other than the Enkei's you're running do you know of any others? I could've sworn I've seen someone run TE37 Saga's in a similar spec with 295/35/18 square but I seem to have lost where I found that..

 

[razorlab]

Wow that looks really sharp! I was under the assumption (atleast from the little research I've done) that Titan7 and Apex were the only ones to have these specific specs for the platform. Other than the Enkei's you're running do you know of any others? I could've sworn I've seen someone run TE37 Saga's in a similar spec with 295/35/18 square but I seem to have lost where I found that..

I don't pay much attention to RAYS wheels because they cost a fortune.

As you said... Enkei GTC02 have several sizes available for the A90 Supra. I personally run the GTC02 in 18x10.5 +35 square.

My second set of track wheels are TSW Imatra 18x10.5 +35 (same spec as the Enkei) as well as some other TSW models.

Konig make the Hypergrams in 18x11 +40

and a bunch of others I am forgetting right now.

 

[FLtrackdays]

The tire availability and ability to rotate the tires is what really drew me to the 275/35-18 square setup. I honestly was concerned about grip initially. Not anymore…. it’s awesome! However with the larger tires up front, you do have to be a bit more careful when scrubbing & counter steering, she can obviously grab quicker. If I could go a pinch smaller up front, I probably would if the same tires & wheels were available. Just from my personal background in the S2K & MX5. Not a deal breaker by any means but just some input if anyone else is coming from more playful lighter cars or split tire setups like me. Or just want to feel the car rotate a bit easier.

I also prefer a slight front to rear brake friction split. I started with Hawk DTC 60/30s and now on a Paragon split. Last thing I want is to feel those rear brakes grabbing too hard while trail braking. Just my 2 cents on a new platform to me that’s a bit heavier and way more powerful from my previous track cars. She‘s soooooo much fun!!!!!!

 

[Todday1]

So now that you brought up brake pad combo split. I will share my final conclusions on what is best after toasting many break pads and rotors and break dust seals etc. even then going to a big break kit, primarily dealing with heat. I have verus brake ducts on the front and a vented fender as well. So everyone says to do what you advised dtc 60/ dtc 50 /30 etc on the rear. Which I have tired both. The break bias on these cars/ wight balance is almost 50/50. Bias cannot be adjusted unless you were to get rid of ABS and go to a full race ABS system. So it is really closer to something like 54% front and 46% rear. Some one smarter than me can look it up but I can tell you I am close from my burnt up pads Front brakes get to hot, once you get to TT levels of times. I got in the 1400 degree range which is on the edge of pads as well. So first went to DTC 70 front and 60 rear. and that evened out the heat load between front and rear. I also went to dtc 60 front and dtc 70 rear which I believe is the best balance for heat and stopping. So I am sure there will be lots of opinions on this, but I can just share what I have tried. At a min - use same compounds front and rear and I think it will work better.

 

[FLtrackdays]

I’ll try that with the Paragons next time! The Hawks only come in DTC 60/30 in the 3.0 premium size I believe. In my twitchy S2K it was awful having too much friction in the rear. But glad you have tried so many different setups and are going by ”feel”. That’s exactly what I’m looking for (response wise)!!

Edit: My bias was also dialed down by the race kids in my S2K. Lots of variables and I really need to get one of those guys in my car ASAP - just for fun, feedback and a baseline reference

 

[Todday1]

Look at hawk direct - and search for pad shape not by car - HB916 and HB917 I think you can find rears for 60 or 70. Fronts for sure are more common.

 

[Afterfire]

Heres some reference for the Apex 18x11+40 square on 315 RT660s. No spacers but after using them for a weekend, I recommend at least a 3mm spacer, as others have said, when using these wheels with tires bigger than 295. Heres a comparison to 265/35 rt615k+.

 

[Todday1]

Nice pic for everyone so they can see what we are talking about on clearances. Thanks for that. Nice shocks!

 

[Todday1]

I forgot that I have the big brake kit on rear and have been able to get DTC 60 and DTC 70. For stock, I could not find higher than dtc30. Someone should try to find a source that will order them from Hawk as they can make them. In the mean time then DTC 60 are available for the front and the DTC 30 rear. So is not bad. Someone should try to get a hawk supplier to order the rears from hawk with 60/70 compounds as no once carries them. They will make them. Then you could get to using these on both front and rear.

 

[razorlab]

The break bias on these cars/ wight balance is almost 50/50. Bias cannot be adjusted unless you were to get rid of ABS and go to a full race ABS system. So it is really closer to something like 54% front and 46% rear.

I think you might be confusing brake pressure bias and weight distribution, and also static bias vs dynamic bias. The braking system uses a lot of factor in calculating pressure bias. If it was close to 50/50 all the time you would lock up the rear brakes very easily depending on circumstances.

Under normal straight hard braking, I would say the balance is much more to the front, but again, it depends on what the system is doing. Under actual braking, it's dynamic bias.

Here is an example from my Supra with the same brake compound front/rear, which changes static bias. Of course this is just showing brake pressure front/rear so not the full story but at least it gives us some glimpse into what is happening.

Here is threshold braking in a straight line from 130 mph, creating around 1.3g of deceleration. 1285psi front brake pressure, 875psi rear brake pressure.

I also have logged instances where the pressure bias moves around when the car is getting a little squirrely under braking (dynamic bias). Modern braking systems are pretty amazing.

You also have to remember our brake rotors are pretty close to being equal size front/rear.

 

[Todday1]

Thanks - see I new someone smarter than me would jump in! So this makes sense. If you put a stronger pad on the front then with the way it brakes the rears are not working as hard. So basically putting a stronger pad rear, and lighter front balances it a bit, even with those same pressures? All I have been looking at is how hot the rotor/ calipers are running front an rear and trying not to over heat them. I have not been boiling fluid, so no brake fade, but is close if you run a full 20 min session. Hence why I am still trying to figure out brakes. I actually have a Brake guy locally designing/ building a custom Wilwood big brake kit - 15" front and 14" rears ( 6 piston/ 4 piston) so will share once this eventually gets done. It will be all track level stuff and then replacement rotors and parts should be more easily available and better on the wallet.... All the ones you find out their today are big bucks and then replacement rotors are crazy priced as well.

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