Need help reducing understeer!!

boucherie

boucherie

New Member
Went for a drive at the weekend with a couple of mates (ones got a mk2 MR2 Turbo, the others got a GT4, and both are much lower than mine (not difficult!!)) and going round a fairly tight right hander the car just didnt feel confident going in, so now i need to seriously look at how to improve the handling. (i wasntt going into the corner particulary hard as the other side of the road was blocked by hedges!)
Below is a list of what ive currently got fitted/waiting to fit, what else does everyone recommend to help redress the balance?

Front & Rear upper Strut Braces (fitted)
Whiteline Lowering springs (waiting to go on)
17" MO's (waiting to go on & are have smaller diameter than my current wheels)
Whiteline rear ARB (waiting to go on)

Would i get away with fitting the antilift kit or do i need more to help improve the handling?

cheers
 
J

jiw

Guest
i'll agree with that, it totally transformed my car both in the wet and the dry :D
 
boucherie

boucherie

New Member
well i cant go down the 15's route as ive gota set of 310mm wilwood 4 pots on the front and 15's dont fit! The 17's are actually smaller in terms of diameter as ive got 205/50 profile tyres on at the minute and the 17's have got 40 profiles, so il be reducing the amount of sidewall movement straight away, which hopefully will improve the handling!
 
Fast Guy

Fast Guy

Moderators
Staff member
boucherie said:
The 17's are actually smaller in terms of diameter as ive got 205/50 profile tyres on at the minute and the 17's have got 40 profiles,
Click to expand...
The MOs weigh a ton, well about 22lbs. Try weighing a wheel and tyre together of the 15s and 17s to see how they compare. Let us know if you do :wink:
 
K

kyepan

New Member
lighter wheels made a good deal of difference to the chuckability on my set up... but if understeer is the problem.. bumpsteer kit is the answer. And i didn't see it listed as one of your bits.. I had the same problem on my car till i fitted it, after that, its welcome to the gti-r express.. on rails, no mid bend understeer, vastly better turn in, solid.. very confidence inspiring.. i would go as far as to say.. a different car to drive.
 
gtiroz

gtiroz

Administrator
Staff member
the whiteline rear ARB will help

the anti-lift kit will improve things further

the other whiteline bushes tighten everything up and help even more
- front and rear control arms (W0568 & W0567)
- rear trailing arms (W0566)
- rear subframe (KCA349)

and a little bit of neg camber at the front also helps
- whiteline camber bolts (KCA412)

and of course get a professional (not a generic tyre place) to do a 4 wheel alignment...


(the bumpsteer kit would also be nice, but its very expensive, especially down here)
 
timmy

timmy

New Member
Put 2 degrees of neg camber on the front of mine and made the world of dirfference. Make sure you get the camber adjust bolts straight from Whiteline in OZ though as it's a lot cheaper than getting them through a UK supplier.
 
W

wetpants

Guest
Dude,

Ditch them 17s and get some 15s. Surely an R that handles like a bag of s h i t is pointless.

Do you really want hairdressers in their MX-5s and Pumas beating you through the bends?

Joking apart though, the comp MOs are nice rims.
 
gtiroz

gtiroz

Administrator
Staff member
stoned,
the powerstation bumpsteer kit is only availble down here (oz) from whiteline - they sell it for ~$580au
(alternatively we could go direct to PS for ~$480au + shipping + import duties)

i was not aware of gordons more economically priced alternative
(would be ~$290au plus postage)

thank you for the link!
 
campbellju

campbellju

Moderators
Staff member
boucherie said:
going round a fairly tight right hander the car just didnt feel confident going in.....Below is a list of what ive currently got fitted/waiting to fit, what else does everyone recommend to help redress the balance?

Front & Rear upper Strut Braces (fitted)
Whiteline Lowering springs (waiting to go on)
17" MO's (waiting to go on & are have smaller diameter than my current wheels)
Whiteline rear ARB (waiting to go on)

Would i get away with fitting the antilift kit or do i need more to help improve the handling?
Click to expand...
Strut braces - good idea
Alloys - you've bought them so you are where you are
Rear ARB - Is it adjustable?
Whiteline springs - ok BUT no dampers????? :roll:


What you describe sounds more like instability than understeer.
Instability is often down to underperforming dampers. Putting on stiffer springs might make it enter a corner better but will make it more unstable on exit as you'll still have old dampers that are expected to control more force in less movement. Save your money on any bumpsteer/antilift kits for the moment and get some dampers, preferably adjustable. The other things are good but your setup has a huge problem in using the old dampers.

Look at the link I've posted in the handling sticky for more information on curing specific problems I've you're experiencing other issues too.

Jim
 
K

kyepan

New Member
The simple fact is, that the standard gti-r's wheels don't point in the correct direction when cornering, meaning you loose masses of turning potential, more IMHO than through anything else like body roll or higher center of gravity, etc.

If the wheels are tracking where they are supposed to then the suspension is working the best it can to begin with. why keep it broken and make it stiffer and lower, thats just crazy. ....

sorry.. But I still believe he should just get the bump steer kit then go from there... it really does transform the handling, and is very cheap in comparison to all the other stuff on his list. Its a hundred quid and a bit from the guy on the forum.

Sort the geometry out when cornering first, then make it stiffer and lower so it will run closer to the limit of grip without getting out of shape.
 
campbellju

campbellju

Moderators
Staff member
kyepan said:
The simple fact is, that the standard gti-r's wheels don't point in the correct direction when cornering, meaning you loose masses of turning potential, more IMHO than through anything else like body roll or higher center of gravity, etc.
Click to expand...
I hear what your saying and I was careful with my choice of words in the post. I'll be honest, I've not got the bumpsteer kit on my R but I do understand how they work and what they solve. The instability he's getting on turn in could be bumpsteer as well, I don't know enough details about his car to confirm either way.

If it wasn't for the fact he's already changing his springs then a bumpsteer kit would be a cheap fix. However, he's changing his springs already, IF his dampers are 6 or even 12 years old :shock: then he should change his dampers at the same time. It will save him money in the long run and could solve some of his problems.

I don't want to get into an argument over which suspension mods are better than others. I'm just talking basic car mainteance.

For bumpsteer, there are some great posts on the SR20 forum

Jim
 
K

kyepan

New Member
campbellju said:
kyepan said:
The simple fact is, that the standard gti-r's wheels don't point in the correct direction when cornering, meaning you loose masses of turning potential, more IMHO than through anything else like body roll or higher center of gravity, etc.
Click to expand...
I hear what your saying and I was careful with my choice of words in the post. I'll be honest, I've not got the bumpsteer kit on my R but I do understand how they work and what they solve. The instability he's getting on turn in could be bumpsteer as well, I don't know enough details about his car to confirm either way.

If it wasn't for the fact he's already changing his springs then a bumpsteer kit would be a cheap fix. However, he's changing his springs already, IF his dampers are 6 or even 12 years old :shock: then he should change his dampers at the same time. It will save him money in the long run and could solve some of his problems.

I don't want to get into an argument over which suspension mods are better than others. I'm just talking basic car mainteance.

For bumpsteer, there are some great posts on the SR20 forum

Jim
Click to expand...
yep some nice new dampers will help keep the tyres on the road longer so you will get grip more of the time.. agree totally, if he is getting them already then why stop, it can't hurt.

If you havn't got the bumpsteer, you would be surprised at the difference it makes, but i really can't stress that enought that you have to drive a car with one on, to really know what a difference it makes to the driving experience and confidence in the cars performance round bends.

When i fitted the bump steer kit, the car was already lowered on nismo shocks, with front and rear strut braces.. the handling went from ok.. to flipping brilliant.

no more vague front end, turn in was much improved, you point it... squirt and it goes, it comfortably held the road at nearly 1/4 greater speeds round a particular roundabout I know well, where it would have been drifting towards curbs and banks before.

:p
 
campbellju

campbellju

Moderators
Staff member
Some bump steer correction might be further down the line but I'm trying to be methodical about setting up the suspension.

I finally fitted my coilovers and various other upgrades on Tuesday night.

I've already got the whiteline anti-dandruff kit :wink: that will reduce bump steer a bit and increase castor. This was an obvious start as I was replacing my front arms at the same time as changing to the coilovers..

The coilovers were set on their lowest setting when I got them (60mm lower??? not checked, could be less, at least 40mm) and the arms/steering links were just short of parrallel to the ground. If I had some really stiff springs and drove on smooth roads this would be about perfect.... but I don't :(

On its lowest setting its also on its sofest so the ride quality is very good but when ever the suspension compresses I can see its going to do nasty things to the geometry (Bump steer, negative roll centres, reduced camber etc) So my plan is to raise up all four corners back up (Maybe 20mm) to give a bit more movement before you get these effects. It will also stiffen the springs up to give less overall movement too and give better control of the geometry.

The first balance for me is good geometry etc against the shi**y country roads where I live that are full of pot holes and ruts. If I have to go lower to soften the springs I might have to correct the increased bump steer.

It might make a difference on a standard car as Nissan intended their WRC cars to use stonger springs and limit the suspension movement. On the road car the softer springs give too much suspension movement causing bump steer etc. Just a wild idea.

Not ruling a bumpsteer kit in or out yet, just being methodical.

Jim
 
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