R32 Gt-r Front Camber

[djr81]

Gents,

Am presently running my R32 R with the Whiteline package. Setup is as follows

Front:

Ride height 350mm

Camber -2 degrees

Castor +3 (Rods are done right up)

Toe 0

Rear

Ride height 345mm (As low as it will go because the tyres are now fouling the guard when in compression & turning hard)

Toe 1mm

Camber -1 degree

I am still getting a temperature differential across the tread face of the front tyres (About 5 degrees) & have too much mid corner understeer. Turn in & power on is now fine. I have fitted up the adjustment bushes fron Whiteline, but now find I need more. Question is where to from here. I have see the stuff on Nengun & Greenline & to be honest don't much like them. The Noltec gear is much the same.

Area there shorter (non adjustable) upper arms available that the Whiteline bush kit will fit?

[Beer Baron]

i believe nismo make shorter non adjustable upper arms. cusco do too from memory. so i'm guessing you are getting hotter on the outer edge of the tyre? definately sounds like more camber is what you need. what is turn in like? you could certainly go more castor if you want to.

[Sydneykid]

Gents,

Am presently running my R32 R with the Whiteline package. Setup is as follows

Front:

Ride height 350mm

Camber -2 degrees

Castor +3 (Rods are done right up)

Toe 0

Rear

Ride height 345mm (As low as it will go because the tyres are now fouling the guard when in compression & turning hard)

Toe 1mm

Camber -1 degree

I am still getting a temperature differential across the tread face of the front tyres (About 5 degrees) & have too much mid corner understeer. Turn in & power on is now fine. I have fitted up the adjustment bushes fron Whiteline, but now find I need more. Question is where to from here. I have see the stuff on Nengun & Greenline & to be honest don't much like them. The Noltec gear is much the same.

Area there shorter (non adjustable) upper arms available that the Whiteline bush kit will fit?

The caster at +3 degrees is way less than we can achieve, using the Whiteline adjustable radius rod bushes we get close to 6 degrees. Are you using GTST or GTR aftermarket radius rods? If they are GTST aftermarket radius rods then that is the problem, the GTR ones are shorter. This is required as the GTR (engine) subframe is closer to the front subframe to fit the diff and drive shafts in.

For more camber what we do is to fit adjustable (offset) crush tubes in the inner mount of the upper control arm. The same bushes and crush tubes as are used on the outer mount of the upper control arm. PM me for more details.

I would look at fixing the caster problem first as you may find that with an additional 3 degree of caster you don't need the extra camber.

Cheers

[djr81]

The rods are Cuscos and are supposed to be GT-R rods. They adjust (guessing a little because I can't read Japanese) from 339mm to 353mm around a stock length of 348mm. Not sure how many mm the Whitleline offset kit does nor approximately how many mm roughly equals how many degrees. The problem is that because the top link of the front suspension is slightly trailing the more -ve camber you add the less caster you get (Caster moves the bottom of the hub forward aswell) The rim is now noticeably forward in the arch. Don't know how to make a gain here without either losing adjustability (ie using bushes) or remachining the rods to make them shorter.

Anyway - to answer the first reply first - the turn in is really good - it feels better than the midcorner grip - but that may be a bit of running wide into the marbles - not 100% sure. The good book identifies caster as being the issue for this. Outside of the tyre is hotter than the inside. For the record I can still get that horrible shuddering (basically stalling the tyre with the lateral force being generated falling off as lock increases) from the front end that you can get from R compound tyres.

Nonetheless I suppose I should be thinking through how to address both issues. If there is a Nismo upper front arm then great - a 5mm shorter one could be about right. Matched with a Whiteline kit & that should give a +/- one degree range centred around 2 and a bit degrees, instead of one. Has anyone ever done this?

Maybe two Whitleline kits with both ends of the upper arm made adjustable to decrease the effective length - has anyone done this? (I am a little worried about clearance with two sets of bushes) - also how many mm does the Whiteline kit give you (As opposed to degrees)

On the upside - since I fitted the Whiteline gear I can carry noticeably more speed across the apex of the turn, generate more grip & found more lap speed - so things are on the up.

[Sydneykid]

The rods are Cuscos and are supposed to be GT-R rods. They adjust (guessing a little because I can't read Japanese) from 339mm to 353mm around a stock length of 348mm. Not sure how many mm the Whitleline offset kit does nor approximately how many mm roughly equals how many degrees. The problem is that because the top link of the front suspension is slightly trailing the more -ve camber you add the less caster you get (Caster moves the bottom of the hub forward aswell) The rim is now noticeably forward in the arch. Don't know how to make a gain here without either losing adjustability (ie using bushes) or remachining the rods to make them shorter.

Anyway - to answer the first reply first - the turn in is really good - it feels better than the midcorner grip - but that may be a bit of running wide into the marbles - not 100% sure. The good book identifies caster as being the issue for this. Outside of the tyre is hotter than the inside. For the record I can still get that horrible shuddering (basically stalling the tyre with the lateral force being generated falling off as lock increases) from the front end that you can get from R compound tyres.

Nonetheless I suppose I should be thinking through how to address both issues. If there is a Nismo upper front arm then great - a 5mm shorter one could be about right. Matched with a Whiteline kit & that should give a +/- one degree range centred around 2 and a bit degrees, instead of one. Has anyone ever done this?

Maybe two Whitleline kits with both ends of the upper arm made adjustable to decrease the effective length - has anyone done this? (I am a little worried about clearance with two sets of bushes) - also how many mm does the Whiteline kit give you (As opposed to degrees)

On the upside - since I fitted the Whiteline gear I can carry noticeably more speed across the apex of the turn, generate more grip & found more lap speed - so things are on the up.

Lots of questions, I will try and number them for easy reference;

1. I have a set of R32 Nismo front upper control arms, they are no shorter than the standard arms, just painted silver with Nismo stickers instead of plain black. The Nismo's achieve the camber with offset bushes.

2. The Whiteline offset camber bushes move the arm ~5 mm with full adjustment. You have to do a tiny bit of clearancing around the rear of the arm when you fit offset bushes. No big deal.

3. You may not have to use the full amount of adjustment, at some tracks we set the bush so the offset is downwards, which doesn't increase the static negative camber but gives more dynamic negative camber change.

4. If you have the Cusco radius rods set at 339 mm to get 3 degrees of caster then you must have had almost zero caster before you fitted them. Maybe check the caster readings again, just to be sure.

Glad to hear that it's getting faster, I find that it's a journey not a destination, I never actually reach "fast", I always know that there is a "faster".

cheers

[djr81]

Atached are a couple of plots which should be pretty self explanatory.

Gary, sorry about all the questions - just trying to get my head around how to fix the problem. Sort of leaning towards shortening up some spare rods I have & maybe going for the extra adjustor kit for the camber. How many mm does the whiteline kit adjust the caster rod?

Caster before the camber kit was added was 3.5 degrees & it only reduced slightly to 3 when the camber went fron -1 to -2, so to be honest I am a bit mystified as to what is going on. Do know that the local tyre shop has been making good money off the number of wheel alignments I have had with all the suspension upgrades.

As for offsetting the camber bushes up/down I assume you want the outside of the upper link to be as high as possible to gain the geometric (dynamic) camber when the suspension is under compression. Is that correct?

And you are right about the journey etc. I find learning about the suspension & the car in general to be as interesting as pedalling it around the track. There is always someone faster, just wish it wasn't by so much...

Edited April 27, 2006 by djr81