Race Tracking Your Supra - Information exchange

[Levophed]

I'm apples to apples with you. OEM 19s for the street, 18x10.5 with 275s on the track.

What Bryan said is correct - suspension geometry doesn't change between those 2 sets of rims/change in ride height. I had a friend beat this into my head a long time ago. Your scenario brings up a bunch of questions and potential issues, with alignment being a bit less likely of a cause than some others.

1> Is this a track that you are familiar with and have tracked the car there before? (i.e. is this inherent in the track surface, vs being your car)

2> What do your tires look like (odd wear patterns, etc.)?

3> Is the pull to one side consistent across Morning/Afternoon, Cold tires/Hot tires?

4> Had you picked up speed in that section, requiring you to brake harder, unload the rear a little more, etc.?

5> If this is a familiar track, what are the differences between this trip and the last time you were there? (tire, car setup, temp, weather)?

Thanks for your input I appreciate you.

1.Yes I am familiar with the track it's streets of willow CW configuration. Although I just started tracking this year. If you are familiar with the track it happened around T2 right before the right hairpin.

2. They were brand new Kumho V730's 275/35/18 square.

3. It fishtailed left to right and centered it's self. It was my last session of the day in the middle of the session. Was a very hot day.

4. Definitely had weight shifted forward with the hard braking. I was probably going like 100ish? into a right hairpin.

5. My last track day at streets. I was on OEM wheels, PS4s 255-275. Other wise everything else is the same just a set of Verus camber plates. I was running 1 click TC both days.

Weather wise it was much hotter than the first time I went.

Thanks

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[razorlab]

Thanks for your input I appreciate you.

1.Yes I am familiar with the track it's streets of willow CW configuration. Although I just started tracking this year. If you are familiar with the track it happened around T2 right before the right hairpin.

2. They were brand new Kumho V730's 275/35/18 square.

3. It fishtailed left to right and centered it's self. It was my last session of the day in the middle of the session. Was a very hot day.

4. Definitely had weight shifted forward with the hard braking. I was probably going like 100ish? into a right hairpin.

5. My last track day at streets. I was on OEM wheels, PS4s 255-275. Other wise everything else is the same just a set of Verus camber plates. I was running 1 click TC both days.

Weather wise it was much hotter than the first time I went.

Thanks

My 2020 would shift around under braking until I went to aero. Then it all basically went away.

Brake coding could help as well. Worth trying before going to aero.

 

[Levophed]

My 2020 would shift around under braking until I went to aero. Then it all basically went away.

Brake coding could help as well. Worth trying before going to aero.

Going to do a rotor and PMU CR pad change soon. Will most likely do one day without the coding and if I get shuddering and all that I'll go ahead and try to code it.

And yea aero is on the list one day! Far in the future but one day hahaha

 

[Evolution]

Going to do a rotor and PMU CR pad change soon. Will most likely do one day without the coding and if I get shuddering and all that I'll go ahead and try to code it.

And yea aero is on the list one day! Far in the future but one day hahaha

I can do the brake coding next time we meet up at the track. If you dont like it, its super easy to revert back.

 

[Levophed]

I can do the brake coding next time we meet up at the track. If you dont like it, its super easy to revert back.

Yes dude! We gotta link up one of these days.

 

[tomfree]

Thanks for your input I appreciate you.

1.Yes I am familiar with the track it's streets of willow CW configuration. Although I just started tracking this year. If you are familiar with the track it happened around T2 right before the right hairpin.

2. They were brand new Kumho V730's 275/35/18 square.

3. It fishtailed left to right and centered it's self. It was my last session of the day in the middle of the session. Was a very hot day.

4. Definitely had weight shifted forward with the hard braking. I was probably going like 100ish? into a right hairpin.

5. My last track day at streets. I was on OEM wheels, PS4s 255-275. Other wise everything else is the same just a set of Verus camber plates. I was running 1 click TC both days.

Weather wise it was much hotter than the first time I went.

Thanks

Most likely NOT alignment. Just about guaranteed you were going faster on the Kumhos vs the OE Michelins, therefore you're braking harder and unloading the rear more than you're used to. A 200tw like the Kumho will be MUCH more likely to follow imperfections in the track...in addition to you having the rear unloaded under harder braking than you're used to.

I don't know streets of Willow, (I used to live in Norcal...so I know Sonoma and Thunderhill). What you're describing is what happens to me on the back straight at VIR. The @ss end of the car moves around a LOT in the braking zone. I plan to do the braking coding mod, and I'm adding a bunch of aero.

 

[zackarybyrd]

Most likely NOT alignment. Just about guaranteed you were going faster on the Kumhos vs the OE Michelins, therefore you're braking harder and unloading the rear more than you're used to. A 200tw like the Kumho will be MUCH more likely to follow imperfections in the track...in addition to you having the rear unloaded under harder braking than you're used to.

I don't know streets of Willow, (I used to live in Norcal...so I know Sonoma and Thunderhill). What you're describing is what happens to me on the back straight at VIR. The @ss end of the car moves around a LOT in the braking zone. I plan to do the braking coding mod, and I'm adding a bunch of aero.

#this

VIR was the first track I ran after I switched to 200TW and in my case I had also added camber plates and was running a lot of negative camber for the for the first time at that event also. Too
Much change all at once in retrospect. The back straight at VIR was exactly the spot. I had just gotten aligned before that event. I don’t think it’s alignment either and I DO think It gets better as you get better also-at least that’s how it seems to be going for me without any significant aero.

After that event I was convinced it had to be alignment so I went and got another alignment right after and it was right and didn’t need changed.

Negative camber can increase tramlining too so if you’re like me and did both of those at once maybe that’s what you’re feeling. My vote is if your alignment is where you want it stick with it and have some faith.

I have decreased the target negative camber I’m running a tiny bit based on pyrometer readings at various other events since that time but that’s probably a different thing.

 

[Evolution]

@Levophed which configuration were you doing? If you were going CW, a lot of the braking zones arent in a completely straight line and what you said would make sense. If CCW, most are in a straight line and wouldnt make sense.

 

[Levophed]

@Levophed which configuration were you doing? If you were going CW, a lot of the braking zones arent in a completely straight line and what you said would make sense. If CCW, most are in a straight line and wouldnt make sense.

It was the CW configuration. Before T2 the right hairpin which I think is a straight braking zone? I say "I think" since T1 is that fast right hander where you just have to lift and I always enter kinda diagonally. (no idea if this makes sense or is correct lol)

 

[Evolution]

It was the CW configuration. Before T2 the right hairpin which I think is a straight braking zone? I say "I think" since T1 is that fast right hander where you just have to lift and I always enter kinda diagonally. (no idea if this makes sense or is correct lol)

You make sense to me! But after turn 1, you are supposed to hug the left side of the track up to turn 2. That whole section curves to the right. Granted, its not much of a curve but you should not have the steering wheel completely straight which will cause it to feel weird when braking with no aero.

 

[spaghettihoes]

I can do the brake coding next time we meet up at the track. If you dont like it, its super easy to revert back.

Can you provide some more info on this? I've been having minor shudder issues with hot brakes as well even after new rotors and Project Mu CR pads.

 

[spaghettihoes]

Doing some reading about intake panel filters along with general intake stuff, it appears like a stock tune car with a panel filter is fine, but there might be other options (full intakes) for slightly more power that don’t affect IAT. mostly it was me being annoyed there only seems to be oiled options for the panel filter as I’m a big fan of the AEM dry flow stuff.

I read about the MAD intake/inlet and was curious if it had similar IAT as the stock box. The S2 rules allow intakes up to the turbo inlet and if it’s good for a few more hp without hurting IAT then I’d be interested. If it has the same heat soak issues as the other intakes then I might just stick with a panel filter.

for the panel filter, I’m guessing they’re all about the same and it’s just pick your favorite brand and don’t over oil it?

I chuckled as my intake muffler cap design for the stock box is just about done now too.

I use the MAD intake (cause it's cheap) with an AEM Dryflow filter (cause I don't like oiled filters). The filter I got was AEM 21-205DK which fits easily in the box with no modification needed.

Performance hasn't increased at all and the IATs were a lot worse than stock. I put the Verus heat shield on which helped but even then I think stock performed better. It's pretty much for sound or looks especially if you're on the stock turbo.

 

[i3igpete]

Can you provide some more info on this? I've been having minor shudder issues with hot brakes as well even after new rotors and Project Mu CR pads.

Shudder only when hot but back to normal when cold typically points to rotor thermal expansion. You can either live with it, or try replacing the rotors with a different brand. If you really can't stand it, you'll need to switch to a floating disc rotor. The design of the bolt and nut allows the outer ring to expand radially without being constrained by the inner hat

If shudder remains after the rotors cool off, then it's pad deposits

Actual Rotor warp is fairly uncommon

 

[Evolution]

Can you provide some more info on this? I've been having minor shudder issues with hot brakes as well even after new rotors and Project Mu CR pads.

Like Pete said, the coding wont help with the shudder. Its just a common thing with the PMU CRs. Happened to me when I was running them for the first 4 or so track days. Then they slowly got better. The PMU 999s have been shudder free for me at least.

 

[Vegas17]

I’ve noticed this as well on my pmu cr’s. I feel like they get better after 3-4 runs. It still shudders a bit but much less as they wear in. This was on fresh pads and rotors after a razorlab suggested gnarly bed in process.

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