Traction issues on e85, 45psi boost

[moh47]

Hi,

i have a 2020 supra, ets 7275, pure stage 2.
currently pushing 45psi of boost.
rears are 305/45r17 mickeys ss on 20psi warm. Spins 4th with or without rolling antilag.
will et street r make a difference on the street? Any other tips?
stock springs, stock height

4.8 60-130 spinning 4th

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[DVMKV]

What are your alignment settings? If you're on ~-2deg camber your contact patch will not be ideal. I faced similar issues and have significantly better traction with an aftermarket suspension set and alignment. Running ET Rs.

All advice is for track-only purposes, of course.

 

[TBK]

45psi of boost.

I think I found your problem OP

 

[Thraxbert]

> 45 PSI
> Street
> Bad traction

 

[razorlab]

Time to think about setting up your suspension for the task.

 

[itzTang]

i think at 50 PSI boost traction will return

 

[ntfrendlyGR]

Care to share your build and numbers if you have them

 

[moh47]

What are your alignment settings? If you're on ~-2deg camber your contact patch will not be ideal. I faced similar issues and have significantly better traction with an aftermarket suspension set and alignment. Running ET Rs.

All advice is for track-only purposes, of course.

I think when stock it’s slightly negative camber

 

[moh47]

Care to share your build and numbers if you have them

Its a built engine, ets kit (2port) with 7275. Ams intake with id 1700 pi. Dual in tank fuel pumps. Stage 2 pure trans.
should be making around 1000whp on e85 and meth

 

[moh47]

Time to think about setting up your suspension for the task.

any tips?

 

[AJRMKV]

What are your alignment settings? If you're on ~-2deg camber your contact patch will not be ideal. I faced similar issues and have significantly better traction with an aftermarket suspension set and alignment. Running ET Rs.

All advice is for track-only purposes, of course.

Wha are your alignment specs?

 

[SmurfA90]

Hello from Doha, I think we raced during the roll races event in QRC.

I have a 2023 Supra, Doc Race 6870, Spool Stage 2, Dual Pumps w/ return line, ID1050. I am lowered on springs, dif mount and ET-R tires on 20psi.

 

[DVMKV]

Wha are your alignment specs?

Rear
0.5cam
I think .1toe, I think, I forget. Paperwork is in the car but it's stored until spring.

 

[FitmentIndustries]

Hi,

i have a 2020 supra, ets 7275, pure stage 2.
currently pushing 45psi of boost.
rears are 305/45r17 mickeys ss on 20psi warm. Spins 4th with or without rolling antilag.
will et street r make a difference on the street? Any other tips?
stock springs, stock height

4.8 60-130 spinning 4th

At your power level, spinning 4th isn’t really surprising. A 7275 at 45 psi on stock springs is asking a lot from the chassis, especially on the street. At this point it’s less about “not enough tire” and more about the rear suspension unloading when the torque comes in.


As far as ET Street SS vs ET Street R — yes, the R will help. The carcass is stiffer and it handles higher-gear torque better. You’ll likely see better consistency and a little more stability in 4th, but it’s not going to be a night-and-day fix by itself. It’s an improvement, not a cure.


The bigger issue is suspension. Stock springs at stock height just aren’t meant to manage this kind of power. The rear squats inconsistently and then unloads, which is why it’ll spin even with rolling anti-lag. A drag-oriented rear spring or coilover setup will do more for traction than swapping tires alone.


Boost control matters a lot here too. At 45 psi, feeding torque in gradually (boost by gear, ramping instead of slamming peak boost) usually works better than trying to rely on the tire to save it. Most fast Supras aren’t hitting full boost instantly in 3rd/4th.


On tire pressure, 20 psi warm on SS isn’t crazy, but it’s worth experimenting slightly lower (18–19 psi) and logging wheel speed vs boost instead of just setting it once.


Bottom line:
ET Street R = worthwhile upgrade
Suspension + boost management = where the real gains are


Your 4.8 60–130 looks traction-limited, not power-limited. Once the chassis is sorted, the car should pick up noticeably.


Hope that helps someone else chasing grip at this power level.

 

[razorlab]

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