R33 Drag Suspension Setup

[r33cruiser]

hey guys. getting back into the straight line stuff.

atm i have heavy duty billstein suspension.

they are nice and stiff and have a bit of squat in them when launching. is this good? mates have told me that this squat actually helps traction.

i only ask because i was thinking of grabbing some drag suspension...but they are hard muthers that do not squat.

so. is my billstien stuff good...or is the rock hard drag suspension the go?

cheers

*this is purely a suspension question. not a tyre/traction question

Edited April 7, 2008 by r33cruiser

[br3ndan]

squatting is the way to go! =D

I read in Imports Mag (skyline special edition), they actually had an article on achieving 11seond time slips. That actually the original suspension provides the best "squatting' for drag racing.

stiff suspension (like mine! HKS Hipermax D). Not the way to go, due to excess wheel spin.

Hope it helps!

[Sandeep]

hks make hipermax-drag

http://www.piaa.com.au/prod535.htm

low spring rates

high front compression and rear rebound damping, stops car from nose-diving when you change gears

low rear compression and front rebound damping helps car squat

[r33cruiser]

beauty thanks for that. so soft rears and hard fronts are the go

Edited April 8, 2008 by r33cruiser

[Sydneykid]

beauty thanks for that. so soft rears and hard fronts are the go :thumsup:

Not quite.

You want no more then 3 kg/mm rear springs, around 2.5 kg/, is better. You want rear shocks with very little low frequency bump valving but a large amount of low frequency rebound damping. If the shocks are a decent brand then you can leave the high frequency valving alone. The soft spring rate allows the rear to squat and absorb the torque hit, the large amount of low frequency rebound damping holds the rear down for maximum weight transfer onto the rear tyres. The problem is you get a lot of dynamic negative camber when you get enough squat, so you need to set the static rear camber slightly positive (around 0.5 deggres). A rear subframe alignment kit installed in the "Maximum Traction" positions is also a must.

Around 3.5 to 4.0 kg/mm front springs are OK (hardly "hard"). You want front shocks with a large amount of low frequency bump valving but with very little low frequency rebound damping. Similarly to the rear, if the shocks are a decent brand then you can leave the high frequency valving alone. The limited amount of low frequency rebound damping allows the front suspension to extend therebye reducing the weight over the front and hence more effective weight transfer to the rear. The reasonable front spring rate helps to hold the front tyres onto the track, you may need to steer at some point. The front suspension geometry is pretty much irrelevant, just make sure the wheels are pointed straight ahead (zero toe) so they don't provide too much drag.

In a general sense the average Japanese aftermarket coil over kits are not suitable for drag racing and the standard suspension is better. But (there is always a "but") the problem with the rear standard shocks is that they don't have anywhere near enough rebound damping. That's when they are new, let alone 15 or so years old. So you get bad axle tramp, the kind that breaks drive shafts. The more power the car has, the worse this problem becomes. In a standard'ish Skyline (boost up, FMIC, exhaust etc) you might just get away with it (standard shocks) on street tyres. But drag radials or slicks and decent power don't mix well with poor rebound control. You will spend more money/time replacing drive shafts than you will spending the extra on buying the right shock spring combo.

Cheers

Gary

[r33cruiser]

thanks heaps guys.

well in that case. im happy with my bilsteins. they offer enough squat, minimising wheelspin.

thanks alot.