Need Some Help With The Handling Of My Gtr

[nismo6]

Ok so my car has adjustable every thing. It's just been in and had a wheel alignment drives ok but handling is a problem. What I want to no is how low can a r33 Gtr be before it changes it's handling and will the lower control arm spacers help or what do I need to do to make it a good car again. I have read lot of info on here and can't make heads or tales of it the theory of suspension is out of my league, I really just need to be told what will work if possible I would like it lower than factory

Some help would be great

[GTSBoy]

Lower control arms want to be horizontal the the worst. Preferably not sloping upwards from the inner pivots out to the ball joint. Preferably sloping down a tiny bit from the inners out to the balljoints.

As such the lowest height (as measured from the centre of the wheel cap to the underside of the guard lip) is about 350-355mm at the front, 340-345mm at the rear. And no lower. This is around 40mm lower than factory (generally, it varies a bit from car to car).

[nismo6]

Ok thanks for that what about the roll center spacers

[Duncan]

Luke what is your ride height, wheel alignment, which tyres, and what is wrong with the handling that you are trying to fix?

[nismo6]

The alignment specs I don't have tyres are 245 17 and it under steers and the tires skip on tight turns

[nismo6]

And it bump steers

[GTSBoy]

Roll centre spacers are an unnecessary bandaid.

Along with what Duncan is asking, we probably need to have a handle on your spring rates and damper type, anti-roll bar setup, etc.

[nismo6]

As in sway bar? It's standed

It has new blitz coil overs but unshore of spring rate I'll have a look at the paper work and I'll measure the ride hight and put that up to

[nismo6]

355mm on the front and 350 on the rear and no spring rates for the coil overs they are zzr blitz

[niZmO_Man]

Probably 8kg/6kg f/r

Get the castor increased to +5 or more, gives good steering feel. Front upper arm bushes will get flogged hard (Nismo mounts helps apparently).

Wind some negative camber in there, -1° rear, -2° front. It'll chew the tyres but you'll turn like a machine.

What tyres do you have? Also, they aren't sway bars (they don't cause your car to sway), they're anti-roll bars (increase roll stiffness, reduces body roll) .

[MrStabby]

Get sway bars (Are you positively annoyed friend? nismo_man?) - they're usually the best place to start, in particular getting a stiffer rear bar will reduce the understeer. You can get adjustable bars - i have whitelines on mine with the front full soft and the rear full hard. Still understeers, but its a lot better.

[niZmO_Man]

I removed my sway bars, the car swayed too much. Now it turns like an F1 car.

[GTSBoy]

Depending on what springs he actually has, he might be better off pissing them all off in favour of a set of 5kg/mm* springs at each end. After all, the stock springs on a GTR are much firmer at the rear (relative to the front ones) than on RWD Skylines.

Just as an example of a spring rate that is quite a bit firmer than stock but not as ridiculous as the typical 8/6 shenanigans on cheapy coilovers.

[nismo6]

The tyres on there are just cheap ones i have some new rims coming I'll get some good ones for them lift it up a little get a wheel alignment done with the specs you have put up and give that a try thanks for you help guys should I get better anti roll bars for it ?

[blind_elk]

245 17 tyres. That's about as useful as "rubber tyres"!

There are tyres, and then there are tyres. Manufacturer? Model? Profile? Pressure?

And which model Blitz coilover? Are they height adjustable? If so, you will have to have the car corner weighted if you want the best outcome.

This what I'm told works to reduce understeer (or increase oversteer):

- increase front tyre pressure (higher than rear)

- reduce rear tyre pressure

- softer front spring

- stiffer rear spring

- softer front roll bar

- stiffer rear roll bar

- higher front tyre profile

- lower rear tyre profile

- increase -ve camber on front

- reduce -ve camber on rear

[niZmO_Man]

I would look at replacing the tyres first. Think Hankook R-S3 if it's not a daily. Tyres are the only thing connecting you to the ground, so they have a big impact on handling.

[GTSBoy]

I would look at replacing the tyres first. Think Hankook R-S3 if it's not a daily. Tyres are the only thing connecting you to the ground, so they have a big impact on handling.

Actually, that's not really true. Tyres do obviously have a direct effect on grip and therefore roadholding behaviour, but you really have to differentiate between raw grip and the balance of grip at each end and the way that changes under the effect of the various car controls.

"Handling" really does mean how the car handles - ie, how it responds to the controls (the hand). If you have some poorish tyres on with low grip levels and the car is a committed understeerer, then putting sticky tyres on will still leave it a committed understeerer, it's just that the tendency to wander off into the weeds won't become apparent until higher speeds. So you can mask poor handling with better tyres to some extent, but you can't realy change the handling. Well, you could....you could put different tyres on at each end. I've actually run a car that way deliberately for a while because I couldn't afford to fix its real problems.

I would actually have a car with low grip tyres and good handling balance than something with really sticky tyres and a severe problem in the handling.

[niZmO_Man]

If you have some poorish tyres on with low grip levels and the car is a committed understeerer, then putting sticky tyres on will still leave it a committed understeerer, it's just that the tendency to wander off into the weeds won't become apparent until higher speeds. So you can mask poor handling with better tyres to some extent

That's what I was aiming at. Take a corner @ 60 km/h on shit tyres = poor handling. Take the same corner at the same speed on stickier tyres = better handling. But you still need to look at the other aspects.

On the flip side, you can have an awesome suspension etc. and have crap tyres, and still get poor grip. But it depends on what you want from your car though (seeing it's a GT-R, I would say, the higher the grip level, the better).

To me, it sounds like the OP's suspension is too stiff and low, with standard-style wheel alignment settings/stuffed up alignment.

What wheels do you run Luke?

[GTSBoy]

That's what I was aiming at. Take a corner @ 60 km/h on shit tyres = poor handling. Take the same corner at the same speed on stickier tyres = better handling. But you still need to look at the other aspects.

I disagree. Both your cases are poor handling. One has better roadholding, but they both have the same lack of handling balance. Handling <> roadholding. Different concepts.

[niZmO_Man]

Dude, you're an engineer, nitpicking and talking about specifics and higher level driving! Average user, roadholding tends to be handling.