Suspension Set Up

[Ronin 09]

Hi guys

Yesterday I went to Sandown for the day and have some queries with the handling.

The car seems to be nosing over and pitching a lot to the front right, and really chewing out the outside of the tyre. Also not great on turn in, and getting a bit of understeer.

Any suggestions for set up?

The current list of parts / settings are as follows:

Ohlins adjustable shocks

F 8kg R 6kg springs

Ride height 355/350 (ish) front and rear

Whiteline front and rear bars, set on mid for both

Front toe / camber / castor - 0 / 1.5neg / 5pos

Rear toe / camber - 0 / 0.5neg

Is it under damped?

Thanks

[BHDave]

I'd be inclined to say more camber front and rear, min 3 front 1-1.5 rear as it sounds like you are rolling over on the outside wheel a bit

I like toe out on the front but i have a gtst and don't know if it translates to gtr. It certainly improves turn in.

What's it like on corner exit? oversteer or under? Possibly tighten the rear bar if it's understeering. That should also improve turn in

[djr81]

Front bar to soft, rear to hard.

Try & find some more -ve camber at the front. (Note than caster is +ve, not -ve).

Lower the rear to 345 or thereabouts.

[Roy]

Give me the car for the Cup Day sprint

I think a lot of the problem would be in the front ride height. There seems to be a trend with quick GTRs where their fronts are higher then rears. Also, maybe tray a track like Winton before getting too worried about it using the outside front right tyre. its naturally the case at an anti clockwise track like Sandown...but abit more camber would not hurt.

Thing is due you want it to be a nice road car that uses its tyres well, or a track car that looks after tyres at the track but eats tyres on the steet? Its hard to get a good compromise

[ferni]

Or take it to Benno and give him large wads of cash.

haha yeah agree with Troy - what do you want to lean towards track or street....

[Ronin 09]

probably want it to be a nice road car, but it does so few kms it's not a huge issue with camber tyre wear etc.

but still want it to be fun around a track at the same time

looks like the perfect setup - street and track friendly... it's the mirage

BHDave: thanks for the advice - my suspension guys reckon i should stay away from toe out for the moment b/c I'm a track spastic and the car can get twitchy. Corner exit it's a little understeery, probably a bit too much rear grip, it feels like it is pushing a bit

Rich: doesn't softening the front bar increase the roll and incidence of falling over the front right? thanks re castor - see above - I'm a spastic

I'm trying to get a pic of it coming onto the main straight to see how much it is pitching

[Beer Baron]

yeah if you want it to be nice on track you need to man up and go with:

front toe out. at least 1mm each side, more if you are brave

front neg camber. 3 degrees will be nice.

soften front bar

stifen rear bar

bit more rear neg

and start playing with your endless combos of bump and rebound damping.

but it will be pretty average on road (unless you are well up it).

[Ronin 09]

man up - I am too scared.

[NickR33]

is +5º castor enough?... I dunno if its the same with 32GTRs but my car loved the extra 2º castor...

[Duncan]

what tyres are you using?

have you tried turning in a few metres later?

[Ronin 09]

ahh yes, forgot that part - 245/40/18 RE55s

not sure what you mean duncan - as in brake then turn in?

[Beer Baron]

he just means late apex. we often get sucked into turning in to early. you really need to wait...wait...wait.. TURN IN NOW!

also with the GTR it really likes the slow in fast out approach. going in too hot means you will be moving around a lot under brakes and probably still trailing a little brake at turn in which is not good for business. I am majorly guilty of all these faults...and more.

so getting the thing slowed up enough before the corner, then tip it in nice and late, then on the power early may cure it. sometimes adjustment in driving style can negate some of the need for suspension change.

[Duncan]

yeah mate. We of course aren't allowed to change anything on the race car except ride height, toe and tyre pressure - so as a result I always look at how I am attacking a corner first instead of trying to change the suspension.

gtr is a heavy car, has great traction and good power. All that together means brake hard, balance mid corner nice and smooth, then on the gas hard and early for corner exit, let the 4wd pull you out (4wd controller really helps a 32)

thats if the problem is mid corner and exit understeer. If its understeer on turn in try a little front toe out - it will make it feel a little twitchy but nothing dangerous. Rear toe out is a different story it can be exciting

[ferni]

Are you not even allowed to change camber Duncan?!?

[Beer Baron]

arms must be stock, stock arms don't have camber adjustment.

[Ronin 09]

what about eccentric bushes in standard arms?

[Beer Baron]

*cough. well that is a touchy subject I'd imagine.

[tacker]

he just means late apex. we often get sucked into turning in to early. you really need to wait...wait...wait.. TURN IN NOW!

also with the GTR it really likes the slow in fast out approach. going in too hot means you will be moving around a lot under brakes and probably still trailing a little brake at turn in which is not good for business. I am majorly guilty of all these faults...and more.

so getting the thing slowed up enough before the corner, then tip it in nice and late, then on the power early may cure it. sometimes adjustment in driving style can negate some of the need for suspension change.

Yep i have the same problem so going to try a little more agressive settings, different shocks, different bars, 350mm hight in front 340mm in rear. And if that dont work another pilot.

King of understeer signing out.

[Ronin 09]

damn pesky porker.

looks like you're not running very much camber or castor at all...?

[tacker]

LOL here we go again.

Not the best pic but it is a banked corner at 16 degrees. I did purchase neg 5 degree cusco upper arms or so the package said?

Still it was just a mixed and matched set of suspenssion componants and car was to low and body roll was at an all time high.

going to correct that and be free of understeer forever :-) and yep damn pesky GT2 porker they are quick and light, handle well look good, cost grillions, chick magnet and i am going to spank it next time out