Shock / Spring Tech Discussion

[someonestolecc]

negative camber i run around -1.8 on the rear and around -2.2 on the front... I also think i have about 3mm toe in on the rear, none up front...

I only have a rudimentary knowledge about these things but isn't -1.8 rear camber a lot for the rear? Wouldn't 0 or -0.5 be where you'd want to be?

Sorry if I'm wrong but it may be something to confirm?

[dangerous_daveo]

I only have a rudimentary knowledge about these things but isn't -1.8 rear camber a lot for the rear? Wouldn't 0 or -0.5 be where you'd want to be?

Sorry if I'm wrong but it may be something to confirm?

Mines about 1.8- or 1.9- and I have near on perfect tyre wear.

From my understanding obviously like other things, UP TO A POINT rear camber is good for getting out of corners, as you boot it, the tyre grips, instead of the inside not being in contact with the road. Obviously too much as the other effect, and then starts wearing too much on straights.

[Sydneykid]

I only have a rudimentary knowledge about these things but isn't -1.8 rear camber a lot for the rear? Wouldn't 0 or -0.5 be where you'd want to be?

Sorry if I'm wrong but it may be something to confirm?

For circuit work, between 1 and 2 degrees negative is the range we usually work in. For street I would be looking at 0.5 to 0.75 negative. For drag work I usually start at 0.5 to 0.75 positive, then it squats to 0, maybe 0.5 negative if necessary.

[ferni]

Yeah as SK mentioned -1.8 isn't heaps, i use my car on track as well as street... i think the -1.8 matches the -2.2 up front... if its just a normal daily driver then less camber would be better for longer tyre life.

[TurboX]

You can get the springs rates measured, most good suspension shops have a coil rate tester.  Or if you tell me the wire diameter, the coil diameter and the number of coils I can work out the spring rate for you.  Just post the dimensions up.

Thanks SK, I will take it into Pedders to check them out.

If they cant make some sense of them I will take you up on the offer.

Can i just get the valving changed to make a difference to the ride or do I have to change just the springs, or both?

Might as well buy new fully adjustables the way prices are coming down if so.

[Roy]

Yeh Greg, was interested, did a bit of homework first before replying, but is seems GTS4 suspension is not compatible with GTST, so wont do the trick. Will see what times i get next week at Eastern Creek, then do some more susp work and see the difference.

Based on SK thoughts, the Bilsteins may be up to the job, so ill give it a go. Worst case they dont work and ill have to buy some new adjustable Bilstein or Koni shocks, fingers crossed wont need to.

[TurboX]

Yeah, now you mention it I seem to remember that they were to suit a GTR!

GTS4 being AWD and all:)

Your going to damn fast now as it is, and I will never be able to catch you!

Waiting till after the run on the 15th to pull the cams out and find my noise problem, then I will see you out at the track.

[Roy]

So the only question left is do i go for linear springs or do i go for progressive. Speaking to ppl and reading up on it all, well plenty of ppl contradict one another, and so did the reading:(

My thinkig is ill get some linear springs. They might be a bit twitchy on the street, but as long as they are on the money on the track im happy to live with the compromise.

I did however think about going for a higher spring rate again but getting pregressive springs, but meh...just make a decision and stick with it...lol i had done that with the Tein RAs until i found out they were no longer made:(

[Sydneykid]

So the only question left is do i go for linear springs or do i go for progressive. Speaking to ppl and reading up on it all, well plenty of ppl contradict one another, and so did the reading:(

My thinkig is ill get some linear springs.  They might be a bit twitchy on the street, but as long as they are on the money on the track im happy to live with the compromise.

I did however think about going for a higher spring rate again but getting pregressive springs, but meh...just make a decision and stick with it...lol i had done that with the Tein RAs until i found out they were no longer made:(

Simple stuff Roy, progressive on the front is a waste of time, the weight means you would have no "soft" rate when static anyway. I don't think anyone actually makes progressive front springs for Skylines, for that reason.

The rear progressive Skyline springs I have tested aren't really progressive. They sit at the full ("hard") rate. The "soft" rate is only there to ensure that the spring is trapped at full shock travel, which is a valid reason after all.

Similarly, on the race cars we run stacked springs on the rear, with a helper (tender spring) to keep the main spring trapped at full droop. This is not necessary on the front, as the main spring is always trapped.

[Roy]

Cool, thanks.

A few things have come to light with my car as the semis have started to wear, with the chassis charactersitics changing dramatically. In the wet at Sandown it was great, really happy with the balance.

In the dry at Winton it would oversteer on corner entry which was fun, but hopeless for trying to get the power down. Earlier with 34psi all round it was ok, with tyres hot when i dropped pressures to 32 front and 30 rear it was all over the shop but fun:)

So on Friday at Eastern Creek, i couldnt get over how oversteery the thing was. I had 32psi all round and the car was ok on turn in, any oversteer was the result of just carrying a bit too much speed on corner entry, but felt good, but as soon as i cracked the throttle, i mean 15-20% throttle she lept into oversteer:( Again fun but id catch cars on two good corners only to lose all that ground with oversteer on the 3rd:( That was with stiffest setting for front & rear swaybars.

So next time its wet ill put the rear swaybar on the softer setting and see the difference it makes. Will have to wait until the new gear goes in before trying to get my head around this oversteer thing.

That said it could be as simple as tyre pressures as my tyre pressure gauge is massively different to the servos electric tyre pump, so could be im changing the tyre pressures to 24psi when i think they are at 30psi.?!?! I have a strong inkling this may be the case as it has only started since i got this new tyre gauge:( You need the right tools:)

[dangerous_daveo]

....

In the dry at Winton it would oversteer on corner entry which was fun, but hopeless for tring to get the power down. Earlier with 34psi all round it was ok, with tyres hot when i dropped pressures to 32 front and 30 rear it was all over the shop but fun:)...

Could that slight oversteer partly be because of toe settings? I was told you run that slight bit of toe out to stop that, or counteract that turn in oversteer. Is that right or on the wrong track (pardon the pun).