R32 Gtst Understeer

[NZM.031]

hey guys..

now that ive made my decision to buy a gtr... i dont want to spend any more money on my gtst but it will still be my daily for a while..

it understeers like a pig and has lots of body roll, and the stock seats do nothing.. i had planned to give it the works... but now id rather save the money so i want to know what is the cheapest/best upgrade to reduce the understeer..

only mods so far are Cusco Coilovers with 8kg fr and 6kg rr springs and dampening set to 3 or 4 (out of 5) depending on comfort required, rear cradle bushes (alloy type) and slight toe out at rear to encourage oversteer and thats it.

it has standard wheels 16x6.5, with Kuhmo 205/55/16s with a very large and weak sidewall which i think is the problem, i cant get enough pressure in the tyres to make them nice and stiff

so whats my best bang for buck option??

castor rods for more castor + some camber??

lower profile, used semi slicks (215 or 205/45/16s) for less sidewall flex + more grip??

bolt on spacers to improve current wheel track??

R32 gtr wheels with current tyres meaning tighter sidewall due to 8" rim??

rear swaybar to encourage oversteer??

17" rims?? (i have some 215/45/17s toyos at home)

cheers

Linton

[MrStabby]

Rear swaybar for sure. Cheap and easy to fit.

[Bullet32]

Going to a lower profile tyre in the same width will probably increase the understeer, stick with the original size but get a better quality tyre with a grippier tread pattern/compound and a stronger casing.

The cheapest and easiest way to reduce understeer would probably be to get adjustable caster / camber arms and set it up for cornering.

[djr81]

It has been said time without number that the first, best & cheapest handling upgrade is a set of swaybars.

If you have aftermarket springs, particularly ones with such a high rate and standard swaybars then it is pretty self evident that the bars need to be stiffer to work in conjunction with stiffer springs.....

Of the rest of the list:

castor rods for more castor + some camber??

Castor will help only a little. Camber will help more.

lower profile, used semi slicks (215 or 205/45/16s) for less sidewall flex + more grip??

Grip and handling are two different things. More grip won't promote better handling. You will still get understeer, albeit at a slightly greater speed.

bolt on spacers to improve current wheel track??

Only if you increase one end & don't chamge the other. Which will just look silly. In anycase it is only a small gain.

R32 gtr wheels with current tyres meaning tighter sidewall due to 8" rim??

Again, grip and handling are two different things. More grip won't promote better handling. Please don't think stretching a road tyre will improve a car other than to make it fully sik. Do the job properly.

rear swaybar to encourage oversteer??

Yes.

17" rims?? (i have some 215/45/17s toyos at home)

No.

[NZM.031]

thanks for your responses..

it feels like, and excuse my lack of proper terms, that through a corner, the front end is being pulled by the weight of the body rolling over the top of the wheel, and the large sidewall of the tyre lets its get up momentum, and overcomes the grip of the tyre.. its not like any understeer that ive felt before where the weight of the car is pushing from behind the front wheel and pushing the car wide.

hence why i was wondering about increasing the castor angle, to make the weight push from behind the wheel instead of over the top of it.

also the same about the wheel track.. if i increase the wheel track, that will change the roll centre.. and the body will roll about within the wheel track and try and push the wheels... not over the top of them and trying to pull the wheels.

and if i get lower profile tyres/wider or bigger rims, that will lessen the sidewall flex should make it more responsive

cheers

Linton

[djr81]

thanks for your responses..

it feels like, and excuse my lack of proper terms, that through a corner, the front end is being pulled by the weight of the body rolling over the top of the wheel, and the large sidewall of the tyre lets its get up momentum, and overcomes the grip of the tyre.. its not like any understeer that ive felt before where the weight of the car is pushing from behind the front wheel and pushing the car wide.

hence why i was wondering about increasing the castor angle, to make the weight push from behind the wheel instead of over the top of it.

also the same about the wheel track.. if i increase the wheel track, that will change the roll centre.. and the body will roll about within the wheel track and try and push the wheels... not over the top of them and trying to pull the wheels.

and if i get lower profile tyres/wider or bigger rims, that will lessen the sidewall flex should make it more responsive

cheers

Linton

If the car is rolling too much then upgrade the anti roll bars. Simple.

Castor is less of an influence than camber.

But do the anti roll thing first.

Any change in track width in percentage terms will be minimal. So it is not worth bothering with at this stage.

If you fix the cause of the problem ie the body roll then you either will not need to address its affects ie changing tyres etc or if you do the changes will be more effective.

[NZM.031]

you have made sense sir... anti roll bars it is.

thanks

[SLEEPR85]

+1 for sway bars.

Had the same problem as yourself, had fairly stiff coilovers and standard sway bars and used to get a LOT of understeer. Upgraded sway bars, fixed problem instantly! Thats your best bet mate.

[GTS4WD]

I found a good quality strut bar helped emensly.

So did loosing some weight over the front wheels via GTR bonnet.

[battery]

personally i have noticed the biggest improvement is attained with good quality tires....

[blind_elk]

I got this info a few years ago now. To reduce understeer:

At the front -

Increase tyre pressure

Reduce tyre profile

More -ve camber

Softer springs

Softer / thinner sway bar

Reduce weight

At the rear -

Reduce tyre pressure

Larger tyre profile

Less -ve camber

Stiffer springs

Stronger / thicker sway bar

Add weight

[NZM.031]

are gtr swaybars bigger than gtst bars??

im also a fan of decent tyres so ill get some 17s and semi slicks asap just for shits and giggles... grip and handling may be different things, but no amount of stiffening and suspension tuning can make up for balloons attatched to my skinny rims.

paid a bit more attention on the way home yesterday and it wobbles when the weight changes.. but feels flat not tilted which points at tyres.. had the same on my 31 years ago, it had 215/65/r14 on 14x5.5" rims... not hard to see why it was wobbling around.

[Bennett]

Castor rods would be a good investment after the swaybars. Then front upper control arms (camber) although this will chew through tyres so depends what the car is used for. Relocating battery to the boot is another way of taking some weight out of the front of the car and adding some to the back. Makes things a bit more balanced. Also you can get a rear strut brace just to stiffen up the rear end a bit more.

[Taso84]

+1 for sway bars.

Had the same problem as yourself, had fairly stiff coilovers and standard sway bars and used to get a LOT of understeer. Upgraded sway bars, fixed problem instantly! Thats your best bet mate.

Did u upgrade both front and back? And with what spec swaybars... whitelines?

[Roy]

Ride height, the only time i have ever suffered from understeer was when the front of my car was too low. Just have a look at the ride heights and get the front lifted, i am betting your front is too low. LOL though of course that is a guess having never seen you car so...caveat emptor, though i aint selling anything

[battery]

bit off topic but i noticed my front swaybar is alot thicker than the rear one is this normal?

[pipster11]

bit off topic but i noticed my front swaybar is alot thicker than the rear one is this normal?

yes

sort of off topic but what are the recommended heights for an r32

i was suggested 350 front (from wheel center to guard) and 340 rear

i have a gtst and wound up the coilovers to this and it looks rediculous now

can someone recommend some suspension heights to me please? (gtst)

or confirm that gtst and gtr are slightly different (different guards/ susp set up)

Thanks

on topic, swaybars are the way to go

countless threads on how good ppl found their swaybars

just do it!