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Adjustbable Strut Tops


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Hey ppls.

Not knowing a MASSIVE amount about suspension, I just need to know the following.

Can you fit adjustable strut tops to the front end of an R34 GTT and have it effect camber?

I'm getting feathering on the front wheels as I only have about 0.5 degrees of camber and I'd like to be able to dial in more, easily, before a track day, and then dial that out again afterwards......

So, can I do it, or do I need to get the adjustable linkages?

Cheers

BASS OUT

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Adjustable strut tops only work on Macpherson strut style suspension, where the stub axle is (effectively) connected directly to the strut top.

If the R34 is anything like the 32, then it uses double wishbones, and the strut top only holds the shock absorber in place. You need to be able to adjust the wishbones (usually the upper one) to affect camber. Easiest done (but not easily done) with something like the Whiteline camber kit (set of eccentric bushes for the upper wishbone).

Simplest to compromise with about 1 deg neg for both track and street.

Edited by blind_elk
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If you are using street rubber on the track then you can get away with 1.5 neg on the front, which combined with plenty of castor will give you good wear and grip/performance.

But if you are going to go to sticky rubber then start looking for adjustable inner and outer bushes as you will need 2.5-3.0 neg if your car is anything like mine...

And as Greg said...:P

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Hey ppls.

Not knowing a MASSIVE amount about suspension, I just need to know the following.

Can you fit adjustable strut tops to the front end of an R34 GTT and have it effect camber?

I'm getting feathering on the front wheels as I only have about 0.5 degrees of camber and I'd like to be able to dial in more, easily, before a track day, and then dial that out again afterwards......

So, can I do it, or do I need to get the adjustable linkages?

Cheers

BASS OUT

AS you can see from the attached the strut tops are simply there to hold the shock/springs in place.  The alignment settings are controlled by the upper and lower control arms and the radius rods;

R34_GT_R_Front_Suspension.jpg

The yellow dots mark the camber adjustment points and the red dots the caster adjustment points.

:P cheers :P

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Okay, so I've done some reading around and Whiteline don't seam to have an adjustable Camber kit for skylnes, not screw adjustable anyway. I have the offset bushes, but can only get a small amount of adjustment out of them.

I would like to be able to fit semi-comps, and I can't do that with the camber I've got at the moment, there simply isn't enough.

So, SK. How do you do the camber on the race cars?

Do you have a custom made part, or a bought one?

spanks

BASS OUT

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You can get aftermarket upper arms which are rose jointed and the lenght can be adjusted. Cusco plus plenty of others make them. Locally www.nismo.com.au probably has them, dido www.noltec.com.au

Shorten the arm, the top of the tyre sits in closer to the shock giving you more camber. Longer equals less camber.

You can use adjustable bushes to get up to -3.5 camber. On my R32 i use to have adjustable inner and outer bushes which gives you twice the adjustability and on an R32 an easy -3.5 deg on the front.

When i had to get my eccentric bushes replaced (After 3 years) i only got adjustable outer so stuck with not being able to get more then -2.0 camber.

Im stuck between two minds of going adjustable rose jointed upper arms, or just getting another set of eccentric bushes for the inner...

Such as

uasbbtoparms.jpg

r32upperctrlarm.jpg

These are for the R32, but cant see the R34 being a problem to source

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Okay, so I've done some reading around and Whiteline don't seam to have an adjustable Camber kit for skylnes, not screw adjustable anyway.  I have the offset bushes, but can only get a small amount of adjustment out of them.

I would like to be able to fit semi-comps, and I can't do that with the camber I've got at the moment, there simply isn't enough.

So, SK.  How do you do the camber on the race cars?

Do you have a custom made part, or a bought one?

spanks

BASS OUT

Hi Bass, on the race cars (both Production and Improved Production) we are not allowed by the regulations to replace the upper arms. We are allowed to replace the rubber bushes, with say polyurethane. So we do basically what Roy has described, run offset bushes in the inner and outer pivot points.

With 7+ degrees of positive caster and the ride height set at around 345-350 mm (centre of wheel to guard) we can achieve around 4.5 degrees negative camber. Which is more than we ever use, mostly it’s around 2.5 degrees. The higher duro (hardness) of the polyurethane means the negative camber is not lost by compression of the rubber bushes. This means we can run less static negative camber.

That’s OK for R32’s, as the inner and outer bushes are the same dimensions. On R33/34’s the outer bush has readily available offset bushes, but not the inners which are different sizes. To date I have been unable to convince the polyurethane moulders that there is sufficient demand. So they have been reluctant to manufacture the unique tooling for R33/34’s. The front inner upper control arm bush is the same as the rear (inner and outer) upper control arm bush. But the rear inner upper control arm bush is larger, so this is the one that unique tooling would need to be made for.

You could try Noltec (Greg or David), they make off the shelf polyurethane bushes for lots of race cars. So they have the capability of moulding low volume parts.

Please let me know how you get on.

:D cheers :)

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I do like the look of those nice shiny silver ones that brisby posted...

But I think you will find that the front end will rattle it's brains out on the street, because there is absolutely no give at all in the pivot points (even the polyurethane have some give). ie massive increase in NVH.
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