R33 Gtst Handling Advice

[White GTS-T]

Even the OP has stated that it is exhibiting both. I'm no suspension engineer, but you can see and hear that the car has corner entry and some mid corner understeer. And it seems like most of the oversteer is at corner exit. I think a more neutral setup will help alleviate both. But I agree with Neil, by making small changes, I think a lot could be gained. Such as some wheel alignment tweeks i.e. Some more positive caster up front or adjusting the ride height.

[Neil]

I am going to peg rear camber back to about 1 degree if this fixes the rear end grip then maybe i can adjust sway bars to reduce understeer (softer in the front or harder in the back although the links on the whiteline kit seem to only fit in some positions)

I use the standard factory sway bar links and have had the same problem trying to get them to fit the rear holes on the sway bars. Now I know the front ones are side specific and looking at them I think if you use right for left and visa-versa you can access the other holes. Not sure on the rears but give me a couple of days and I'll confirm it.

Cheers

Neil.

[Littlehorn]

Yeah there is definitely some corner entry understeer and mid corner to exit oversteer. To me personally it feels like the oversteer is more the limiting factor because i cant step on the gas more to increase corner speed and exit speed.

However the entry understeer will be next on my list if i can dial out the oversteer by improving contact patch in the rear then i will work on sway bars and maybe some toe out in the front as suggested.

Have also been doing some reading on this site, very informative.http://turnfast.com/tech_handling/handling_tuningtable

[Littlehorn]

I use the standard factory sway bar links and have had the same problem trying to get them to fit the rear holes on the sway bars. Now I know the front ones are side specific and looking at them I think if you use right for left and visa-versa you can access the other holes. Not sure on the rears but give me a couple of days and I'll confirm it.

Cheers

Neil.

Interesting please do let me know. I believe there was also a beefed up end links kit i did wonder if you had to get that to get all the adjustment.

[White GTS-T]

I'm running their HD links front and rear. They're a good bit of gear.

[Neil]

Yea but your only running a 2 hole adjustable sway bar,,,I'm of the belief we are talking about the 4 hole puppies which for the links is a different situation all together. Your link is way badly bent and in my opinion would never fit our back 2 holes.

Here's 2 pics of mine and the same sided links will not adjust to the 2 rear holes. We might have to make rose jointed links to make it all fit properly,,,but I will on the weekend work some of it out and post my conclusions.

Cheers

Neil.

[BOZ22N]

Set your centre of wheel to guard height at 340-350 mm. Make sure your bump stops are half the height of std.

Your wheel alignment is way to neutral. Toe out the front to 3mm or so (you may want more) and toe the rear in 1 mm as this will even out on acceleration. You might also find that with these settings and the correct tyre pressure you could stiffen your front bar.

Your set up is very similar to mine, and should be a lot more stable on the turn in and exit.

As Neil said make small changes write them down and keep a log of your opinions of the changes and cars feedback so you have history.

Enjoy.

[ARTZ]

Even the OP has stated that it is exhibiting both. I'm no suspension engineer, but you can see and hear that the car has corner entry and some mid corner understeer. And it seems like most of the oversteer is at corner exit. I think a more neutral setup will help alleviate both. But I agree with Neil, by making small changes, I think a lot could be gained. Such as some wheel alignment tweeks i.e. Some more positive caster up front or adjusting the ride height.

sounds like its just too high and being a boat

[Dale FZ1]

Bump steer front and rear. I agree with an earlier comment about this.

Those pretty LCA and tie rod ends don't show true perspective but if they're running on different planes then it's going to do silly things as the suspension goes through its travel range.

Same thing goes for the rear.

[White GTS-T]

Neil, can you mount the link up from the other side? If you had links that pivot, assuming they didn't foul on anything, that would gain you considerable length.

[Littlehorn]

Yea but your only running a 2 hole adjustable sway bar,,,I'm of the belief we are talking about the 4 hole puppies which for the links is a different situation all together. Your link is way badly bent and in my opinion would never fit our back 2 holes.

Here's 2 pics of mine and the same sided links will not adjust to the 2 rear holes. We might have to make rose jointed links to make it all fit properly,,,but I will on the weekend work some of it out and post my conclusions.

pic164_01.jpg

pic165_01.jpg

Cheers

Neil.

Mine is set to second softest of the 4 on the front i can move it one more adjustment forward. I cant access the front most or rear most.

Set your centre of wheel to guard height at 340-350 mm. Make sure your bump stops are half the height of std.

Your wheel alignment is way to neutral. Toe out the front to 3mm or so (you may want more) and toe the rear in 1 mm as this will even out on acceleration. You might also find that with these settings and the correct tyre pressure you could stiffen your front bar.

Your set up is very similar to mine, and should be a lot more stable on the turn in and exit.

As Neil said make small changes write them down and keep a log of your opinions of the changes and cars feedback so you have history.

Enjoy.

Cheers for that i will measure it up tonight so you can all have a laugh!

Should i cut down the standard bump stops?

Bump steer front and rear. I agree with an earlier comment about this.

Those pretty LCA and tie rod ends don't show true perspective but if they're running on different planes then it's going to do silly things as the suspension goes through its travel range.

Same thing goes for the rear.

Hopefully lowering will fix this when i originally set the ride height i did notice the arms were on a slight upwards angle from the wheel to chasis. I assume that level is optimal.

Unfortunately the car came with a fiberglass bumper. Nice and light but it protrudes quite far out the front and actually slants forward so the lowest point is right at the front edge not towards the wheels as with the standard bumper.

[ARTZ]

Get the grinder out and fix that.

[Littlehorn]

Ride height is currently set at 350mm guess i will go down to 340 and see how that goes.

[Dale FZ1]

The further away (lower) from standard ride height, the more pronounced rear bump steer becomes.

It is countered by installing and adjusting rear adjustable links - the forward/upper ones sometimes referred to as "traction arms".

[ARTZ]

I never had a bump steer issue and front of my car was lower than most...I had bump stop issues, but not bump steer...

My car had Stock swaybars, all stock suspension arms, bilstein suspension...camber 3 and 1.5 just from lowering, toe set pretty much neutral, I think 1 degree of caster..17 x8,9 and 245/40, 255/40 tyres...It always handled great and exceeded my expectations..I know some people are doing quick laptimes with much the same setup too but better brakes and bigger balls...

my next step was sways bars and some extra caster, but I didnt see the need to do much more to it, it was simple and it worked...Not to stiff, not too soft..

The new owner said he has some issues with the front being too low, because he lives in the bush and has crappy roads though..guess it depends where you drive most and how good the roads you drive on are...But on the track and around Melbourne I never had an issue and my crossmemebr was maybe 120mm off the ground...I know it was just above legal height anyway..

[Dale FZ1]

OP was complaining about oversteer hence the comments about rear end adjustments and ride height.

Depending on what is fitted/changed (or not) it is possible to achieve bump steer ie. dynamic toe change as the suspension goes up/down at either end. Altered ride height does affect things.

Open to conjecture but I'd be looking into it if I was the OP. Harry was onto it early in this thread. Investigating and/or fixing it may mean having someone do it for him if he's not sure how.

[ARTZ]

Open to conjecture but I'd be looking into it if I was the OP. Harry was onto it early in this thread. Investigating and/or fixing it may mean having someone do it for him if he's not sure how.

[r33_racer]

With those spring rates I would be dropping the rear sway bar off totally. If it does roll a little then stiffen up the front bar, though I doubt it will.

Run about -1.0 rear camber with about 3-4mm toe in overall.

There is also an inherent flaw in the rear end design of the r33's when the tire travels from a drooped state to loaded state, the toe essentially becomes dynamic rather then staying at what you set it too statically when doing a wheel alignment.

[Littlehorn]

With those spring rates I would be dropping the rear sway bar off totally. If it does roll a little then stiffen up the front bar, though I doubt it will.

Run about -1.0 rear camber with about 3-4mm toe in overall.

There is also an inherent flaw in the rear end design of the r33's when the tire travels from a drooped state to loaded state, the toe essentially becomes dynamic rather then staying at what you set it too statically when doing a wheel alignment.

Interesting regarding dropping the rear sway bar, I will see how i go this weekend maybe drop of if the rear camber hasn't made a big difference.

Car is set to 340mm front and rear. Alignment set as follows:

Camber front -3.1 deg

Toe front -2.8 total

Camber rear -1 deg

Toe rear 2.5mm total

Running a test day this Sunday at Pukekohe, will post up the results next week.

What are your thoughts on removing vs adding weight into the rear. Is this going to increase or decrease oversteer. Ie if i leave my spare tyre in.

[r33_racer]

With those alignment settings you usually want 2-4mm toe out on the front, are you saying have 2.8mm of toe out or toe in?

Honestly at this level, dont worry about weight balance yet. If it was me I would be just pulling all the weight I can out to reduce overall weight. R33's are not the best circuit car, they are heavy and cumbersome....but they are fun!