Jump to content
SAU Community

Recommended Posts

Hey, I have been slowly building up an R33 Gtst track car over the past 5 or so years. I feel that the car is just about where it needs to be in terms of upgraded/strengthened/adjustable parts now but i am having trouble dropping my lap times mostly due to oversteer.

I am hoping there is some knowledge out there that you might be able to share with me.

Here is a video of how the car goes at the moment which also should give you an idea of its handling characteristics.

https://www.youtube.com/watch?v=PeUwsz22pOU

and here is a basic rundown on the car and setup.

It is a 96 S2 Gtst with a steel wheel holset core and about 240kw

Interior

- Stripped interior about 180kgs removed

- 8 point roll cage

Handling

- Bilstein shocks valved for track work

- Springs 350 front 550 rear

- Ikeya formula front upper (front set to 3.2 negative)

- Ikeya formula rear upper (rear set to 1.6 negative)

- Ikeya formula rear toe (pretty sure toe was set to neutral)

- Alloy subframe bushes

- Polly bushes just about everywhere else

- Nismo 2way LSD

- Hicas Lock bar

- Height adjustment set to about stock

- 20mm spacers

- Federal FZ201 semi slicks (about 34psi hot in front and 32psi in rear)

There are other RWD cars running similar setups and power to weight lapping 3-4 seconds faster, now obviously the driver is going to have a big impact here, but looking at there videos they seem to have a lot more corner grip and stability.

Link to comment
https://www.sau.com.au/forums/topic/444856-r33-gtst-handling-advice/
Share on other sites

either im blind or you dont mention sway bars.

these are a must.,

if you do have them, soften the front sway a little, it will correct the oversteer.

just my little 2c on the limited knowledge i have.

The initial understeer is what worries me,,,gts-t's don't usually suffer from that. It's certainly not the tyres,,, FZ's are great but your tyre pressures are way different than me,,,I use on a hot day 38 all round and constantly adjust them till I get it. Zebra's on drugs,,,no way is your diff contributing,,,no way. I'm running close to 0 camber on the rears and about 4.5 on the fronts from memory. Artz is right she needs to be lowered,,,big time.

Just do little changes,,,or you will never know what fixed it.

Cheers

Neil.

The initial understeer is what worries me,,,gts-t's don't usually suffer from that.

Yeah hard to recommend changing swaybars when the car is exhibiting both under and over steer.

I found this interesting camber vs tyre pressure info that I will have a go at next track day http://www.turnfast.com/tech_handling/handling_pressure3

I will also lower it a couple of centimetres just a pain for road driving.

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)

You stated the tyre size, but size wheels are you running front and rear? If you're running narrower front wheels and tyres, try running the same front and rear. I think you'll find it makes the handling

a lot more neutral. Also, a bit of toe out on the front will help with turn in and that corner entry understeer. Goodluck, and keep us posted.

You stated the tyre size, but size wheels are you running front and rear? If you're running narrower front wheels and tyres, try running the same front and rear. I think you'll find it makes the handling

a lot more neutral. Also, a bit of toe out on the front will help with turn in and that corner entry understeer. Goodluck, and keep us posted.

You are correct on rim size im running 8" on the front and 9" on the rear.

Interesting I need to get some lighter rims current are about 9ks a piece, will take this into account when i upgrade.

What do you reckon 9" front and rear running 255s?

this counters understeer not oversteer.

Nope, softening a front sway bar will correct understeer..so I just figured stiffening it will help with oversteer...

ED*

though if you look at the graphs below ther eis no clearcut solution really as softening and stiffening can fix it, depending on situation

I have been reading up on this all week man cause the cressy is understeering mid corner, been looking for a solution :P

Hey, I have been slowly building up an R33 Gtst track car over the past 5 or so years. I feel that the car is just about where it needs to be in terms of upgraded/strengthened/adjustable parts now but i am having trouble dropping my lap times mostly due to oversteer.

That's what I would be doing. And then, if it still has mid corner understeer, soften the front sway bar one notch.

thats what i read it as.....why are we all talking understeer now?

Also i dont think rim size is going to make alot of difference, mine felt perfectly stable with 8s and 9s..dont get me worng it will help, but i dont think it is something to really be concerned with.....

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • There's plenty of OEM steering arms that are bolted on. Not in the same fashion/orientation as that one, to be sure, but still. Examples of what I'm thinking of would use holes like the ones that have the downward facing studs on the GTR uprights (down the bottom end, under the driveshaft opening, near the lower balljoint) and bolt a steering arm on using only 2 bolts that would be somewhat similarly in shear as these you're complainig about. I reckon old Holdens did that, and I've never seen a broken one of those.
    • Let's be honest, most of the people designing parts like the above, aren't engineers. Sometimes they come from disciplines that gives them more qualitative feel for design than quantitive, however, plenty of them have just picked up a license to Fusion and started making things. And that's the honest part about the majority of these guys making parts like that, they don't have huge R&D teams and heaps of time or experience working out the numbers on it. Shit, most smaller teams that do have real engineers still roll with "yeah, it should be okay, and does the job, let's make them and just see"...   The smaller guys like KiwiCNC, aren't the likes of Bosch etc with proper engineering procedures, and oversights, and sign off. As such, it's why they can produce a product to market a lot quicker, but it always comes back to, question it all.   I'm still not a fan of that bolt on piece. Why not just machine it all in one go? With the right design it's possible. The only reason I can see is if they want different heights/length for the tie rod to bolt to. And if they have the cncs themselves,they can easily offer that exact feature, and just machine it all in one go. 
    • The roof is wrapped
    • This is how I last did this when I had a master cylinder fail and introduce air. Bleed before first stage, go oh shit through first stage, bleed at end of first stage, go oh shit through second stage, bleed at end of second stage, go oh shit through third stage, bleed at end of third stage, go oh shit through fourth stage, bleed at lunch, go oh shit through fifth stage, bleed at end of fifth stage, go oh shit through sixth stage....you get the idea. It did come good in the end. My Topdon scan tool can bleed the HY51 and V37, but it doesn't have a consult connector and I don't have an R34 to check that on. I think finding a tool in an Australian workshop other than Nissan that can bleed an R34 will be like rocking horse poo. No way will a generic ODB tool do it.
    • Hmm. Perhaps not the same engineers. The OE Nissan engineers did not forsee a future with spacers pushing the tie rod force application further away from the steering arm and creating that torque. The failures are happening since the advent of those things, and some 30 years after they designed the uprights. So latent casting deficiencies, 30+ yrs of wear and tear, + unexpected usage could quite easily = unforeseen failure. Meanwhile, the engineers who are designing the billet CNC or fabricated uprights are also designing, for the same parts makers, the correction tie rod ends. And they are designing and building these with motorsport (or, at the very least, the meth addled antics of drifters) in mind. So I would hope (in fact, I would expect) that their design work included the offset of that steering force. Doesn't mean that it is not totally valid to ask the question of them, before committing $$.
×
×
  • Create New...