Eastern Creek circuit setup for R34 street car

[ChrisW434]

Hi all,

i'm chasing some assistance on chassis setup for track days.
Attacking my first track day later in the year and would like the car to have a decent setup with alignment, coilover settings etc. so i have a solid base to start with.

Its a GT-T (will be 5spd), entry level BC Racing (BR) coilovers, adjustable GK Tech bits, the usual stuff.
 

It should be making good hp, so i'm expecting that will overpower the chassis and my driving ability fairly easily at first haha. 

Goin to get some sticky tyres of some description too... suggestions?
 

What ride height, spring preload, comp/rebound, tyre pressures are guys running?

Any help/info is appreciated 👍🏻

 

Thanks in advance!

[Tobz]

So many variables! It would be impossible to say for a few.

If you can get a laser thermometer they are only $20 on eBay. Every tyre has its own sweet spot for pressure. What you want to check is the following for each tyre asap once you get off the track (a tyre pyrometer would be better but costs $$$)

Inside temp

Centre Temp

Outside temp

 

You want the temps to be even across the whole the tyre. If the centre is lower than the inside and outside you need to add more pressure. If the inside and outside is higher then the centre , then you need to remove psi

If the outside is higher than the middle and inside you need more camber

If the inside is higher than the middle and outside you need to remove camber.

Suspension wise I run

Front camber -2.5

Caster 9 degrees

Tow 1.5mm out

350mm height 

 

Rear camber -1

Toe 0

340mm ride height.

 

Usually I'll start with both front and rear shocks on the centre settings. Get the tyre pressures right first and then adjust as following:

Try and work out based on feel if there is too much roll in the car, you need the car to roll side to side to generate grip, but also you need it to be nimble and also not roll so much that you run out of suspension. Hard to explain how you feel this

 

after this I will then adjust per the following:

Too much understeer (stiffen the rear or soften the front)

Too much oversteer (soften the rear and stiffen the front)

 

If the suspension is not getting to where you need then you can:

Too much understeer (remove psi in front of add psi in rear tyres)

Too much oversteer (add psi in front and remove psi in rear)

 

Check your pressures after every run. This is critical! When you buy the tyres the dealer should be able to give you an idea on estimated warm pressures for your tyres. Remember these pressure are measured warm not cold!! Adjust from this base.

 

For smsp I usually run the front a little stuff so it will understeer a little at the limit, gives me confidence for T1 knowing the rear won't snap

[ChrisW434]

9 hours ago, Tobz said:

So many variables! It would be impossible to say for a few.

If you can get a laser thermometer they are only $20 on eBay. Every tyre has its own sweet spot for pressure. What you want to check is the following for each tyre asap once you get off the track (a tyre pyrometer would be better but costs $$$)

Inside temp

Centre Temp

Outside temp

 

You want the temps to be even across the whole the tyre. If the centre is lower than the inside and outside you need to add more pressure. If the inside and outside is higher then the centre , then you need to remove psi

If the outside is higher than the middle and inside you need more camber

If the inside is higher than the middle and outside you need to remove camber.

Suspension wise I run

Front camber -2.5

Caster 9 degrees

Tow 1.5mm out

350mm height 

 

Rear camber -1

Toe 0

340mm ride height.

 

Usually I'll start with both front and rear shocks on the centre settings. Get the tyre pressures right first and then adjust as following:

Try and work out based on feel if there is too much roll in the car, you need the car to roll side to side to generate grip, but also you need it to be nimble and also not roll so much that you run out of suspension. Hard to explain how you feel this

 

after this I will then adjust per the following:

Too much understeer (stiffen the rear or soften the front)

Too much oversteer (soften the rear and stiffen the front)

 

If the suspension is not getting to where you need then you can:

Too much understeer (remove psi in front of add psi in rear tyres)

Too much oversteer (add psi in front and remove psi in rear)

 

Check your pressures after every run. This is critical! When you buy the tyres the dealer should be able to give you an idea on estimated warm pressures for your tyres. Remember these pressure are measured warm not cold!! Adjust from this base.

 

For smsp I usually run the front a little stuff so it will understeer a little at the limit, gives me confidence for T1 knowing the rear won't snap

Thanks heaps for all that info, exactly what i was after. Great explanations as well.

one question : your ride heights of 340/350; what point are they measured from?

cheers! 🙌🏻

 

[Kinkstaah]

They are measured from the guard line above the center of the rim, downward to the center of the rim.

Expect that you will need to lower your pressures for the track day. If you go out with 32psi cold for your first run, this can end up being 50psi when you are at the end of that session due to the heat put into the tyres.

So expect the first session to be pretty greasy. Expect to have to let considerable air out. Can you do this before and go out on like 25psi cold before you go? Yeah you can, but you need to kind of know where to set it, lest you take too much air out and not get them up to the right pressure when hot.

Don't sleep on this and be like "ah it'll be fine" the difference between a 50psi tyre when hot and a correctly inflated tyre when hot is massive, and these are keeping you on the road out there when you're doing 200+. Spend the couple minutes after the session and check them 😛

[ChrisW434]

16 minutes ago, Kinkstaah said:

They are measured from the guard line above the center of the rim, downward to the center of the rim.

Expect that you will need to lower your pressures for the track day. If you go out with 32psi cold for your first run, this can end up being 50psi when you are at the end of that session due to the heat put into the tyres.

So expect the first session to be pretty greasy. Expect to have to let considerable air out. Can you do this before and go out on like 25psi cold before you go? Yeah you can, but you need to kind of know where to set it, lest you take too much air out and not get them up to the right pressure when hot.

Don't sleep on this and be like "ah it'll be fine" the difference between a 50psi tyre when hot and a correctly inflated tyre when hot is massive, and these are keeping you on the road out there when you're doing 200+. Spend the couple minutes after the session and check them 😛

Yeah thanks for that. Sounds good, i'm keen to do it right and try to avoid those little mistakes so i can concentrate on the driving, and not have little things get in the way of a good time 👍🏻