Spring Recommendations Please

[Steve]

Hi Guys,

Just wondering what springs people use out there?

My car isnt a cruise around town setup, I like a car that handles well, ie, hard suspensions go kart style:) Having said that, I dont want rock hard shake the car to pieces.

I have heard alot of recommendations for around 400lbs front and 250-300 rear. I just dont think that would be hard enough, as I have been in silvias with 12/10 and 10/8kg combinations and they handled very well (well, the way I liked).

So, if anybody has played with spring rates, or has a combination that they like, please post up. I am currently running ohlins height adj shocks, that take stock sized springs, so items such as the Tein S-Tech.

If you could include spring brand and rates, that would be awesome. Also, if you have had any bad experiences, let me know also

Thanks heaps for all comments/thoughts.

Steve

[Sydneykid]

Hi Steve, you already know what we run on GTST's, 400 to 450 lbs on the front and 190 to 250 lbs on the rear. You can't really compare the spring rates for a Silvia and a Skyline at the front, as the Silvia is a MacPherson Strut and the Skyline is double wish bone. There are motion and leverage ratios to be taken into account when looking at the spring rate at the tyre which is the only place that matters. We use a lot of anti roll (big adjustable, stabiliser bars) plus anti dive and anti squat geometry. The shocks have a lot of low frequency compression valving which limits the dive, squat and roll as well.

We don't run that sort of spring rate for comfort, we run them because it is faster on R tyres.

[Steve]

Thanks for the reply SK. So what brands have you tried and which are your favourites and why?

I dont have the top of the range ohlins fitted, just basic damp (and rebound) adjust (both on the same adjust knob). I have them set pretty firm. I have fitted just about everything else I can think of, but the car still doesnt handle the way I would like. I havent timed it around a track, I can only go by feel - but thats what its all about for me, the pleasure of driving.

The springs are still a bit too bouncy (for want of a better word) for my liking. I have just fitted some 8kg springs on the back, and it feels alot better than the front, which is also around the 8kg mark from what I can tell. At the moment the rear feels alot tighter than the front.

Also, some springs work better than others, esp with progressives. So any info on brands would be good. It gets a bit confusing when so many different shops recommend different setups, its a bit hard to know if they have actually tried many different types, rates, heights etc. So the recommendations can be a bit biased if you know what I mean.

thanks again

Steve

[Sydneykid]

Hi Steve, I don't use progressive springs on the race cars, we use stacked coils. The rear main springs are 250 lbs (4.5) and the flat wire helpers are 125 lbs (2.25). It is not necessary to run stacked coils on the front. If you find the 8's (450 lbs) are OK on the rear then 11's (620 lbs) or 12's (675 lbs) would be the go on the front, as that suites the GTST weight distribution.

I don't understand your expression of "tight" though. A 27 mm adjustable stabiliser bar on the front of a GTST gives almost zero roll on the hardest setting. Ditto a 24 mm adjustable stabiliser bar at the rear on the hardest setting. The only roll you feel is the compression in the sidewalls of the outside tyres.

With 8 mm of anti dive on the front radius rods there is very little dive under brakes. In fact any less weight transfer and the braking distances increase. This is pretty much the same for the rear anti squat, any more than 12 mm of sub frame angle and the rear tyres lack traction due to the lower weight transfer.

We run a static 100 mm ground clearance under the front splitter and it never touches the track (well OK, over the ripple strips it does). As previously posted, that is with 450 lbs in the front and 250 lbs in the rear. That is not very much suspension travel for a road car, where I would usually aim at 150 mm to 180 mm as a minimum. Otherwise you are severely compromising the life of the chassis, with torsional stress fractures and cracks at suspension mounting points.

On one of the smoothest circuits around (Philip Island) any more spring rate than that and we have braking, power down and turn in problems. I simply can not see how a road GTST would be faster (ie; handle better) with higher spring rates than that using R tyres.

As for brands, we use Whiteline, if I order a 450 lb spring then I get a 450 lb spring, as confirmed on my spring rate tester. They are parrallel, top & bottom and sides. They are designed for 40 million, full travel cycles so their lifing is what I would expect. I don't know that there is anything else I could want for the price. Maybe they aren't as shiny as some other brands, but that is of no concern to me. Whiteline don't carry every size in stock and, if for some reason I can't wait for them to be made, I pay twice the price and buy a pair of Eibachs.

Hope that makes some sense

PS; Other readers should note that these rates are for a GTST (2wd) at 1,245 kgs and not a GTR (4wd) at 1,610 kgs. Plus this is using R type (street legal radial) tyres, not (crossply or radial) slicks.

[benjiman74]

SK - What spring rates would you recommend for the gtr running R type rubber?

[Sydneykid]

SK - What spring rates would you recommend for the gtr running R type rubber?

It really depends on what other stuff you are runing (anti roll bars, roll cage, dampers, braces etc). Even the brand and compound of the R tyre makes a difference eg; we find Yoko A032R's like a slightly lower spring rate than Bridgestones or Dunlops. Plus whether they are buffed or unbuffed (full tread) makes a difference as well.

The philospohy we have found that works for GTR's is based on the fact that they don't need as much weight transfer to the rear, being 4wd. So you can run more rear spring rate and still get the power down. Our GTR is 1610 kgs (with driver) and the GTST is 1245 kgs with driver, so we have to compensate for the extra weight with a higher rate spring. Otherwise we end up with too much travel under compression. Plus the GTR trends to understeer more that the GTST, so we have to run a softer (24 mm adj) front stabiliser bar.

The end result on A032R's is around 600 lbs (13 kg/mm) in the front spring rate, although we have used up to 800 lbs (16 kg/mm). The rear spring rate is in the 450 lbs (9 kg/mm) with the 24 mm adj rear stabiliser bar to 600 lbs (12 kg/mm) with the 22 mm adj rear stabiliser bar. For Bridgestones or Dunlops we would probably end up with a bit more.

All the race team cars use the same diameter & length springs and we have pairs in 50 lb increments from 100 lbs to 1100 lbs, and even some in 25 lb increments, so we can, and do, juggle them around heaps. As well as adjustable stabiliser bars, we also have adjustable torque split, so setting up a GTR can be a bit mind numbing at times. The data logger is an expensive necessity.

Hope that helps

[B-Man]

Hi SK,

Are these the Whiteline coilovers or the standard 'Works Kit' springs and dampers (which I understand are whiteline springs and bilstein shocks) ?

[Steve]

Thanks for the detailed reply SK. It sort of confirms what I am thinking with regard to spring rates. I run a slightly heavier car, stock they are 1380kg, so with me in it, I am guesstamating around 1450-1470kg all up. This combined with the fact that I have bridgestone, not yoko r tyres, may explain why it feels like it needs harder springs.

By 'tight' I was referring to how well the car sits on the road. The back seems to be better planted than the front with the 8kg springs, think its time to try and find some 12kgs for the front

Thanks for your help.

[Sydneykid]

Hi SK,

 

Are these the Whiteline coilovers or the standard 'Works Kit' springs and dampers (which I understand are whiteline springs and bilstein shocks) ?

Hi B-man, Whiteline make all sorts of springs. We use race coils, ground flat top and bottom, parrallel sides. They look like this

http://www.whiteline.com.au/images/feature...feature0310.jpg

Their "Works kit" has way more than springs and shocks in it, but the springs are Skyline configuration, tapered (not parrallel) coils to fit the standard spring seat configuration. They look like this

http://www.whiteline.com.au/images/product...s/kca348_02.jpg

Some "Works Kits" have Bilsteins shocks, some have Konis, some have others. Whiteline choose the one that best suites the application and then revalves them to suite the spring and stabiliser bar rates in the kit.

Hope that answered your questions

[benm]

I think SK should charge a "forum appearance" fee

[B-Man]

Yep SK - I know what you mean -

Thanks heaps

Hi B-man, Whiteline make all sorts of springs. We use race coils, ground flat top and bottom, parrallel sides. They look like this

http://www.whiteline.com.au/images/feature...feature0310.jpg

Their "Works kit" has way more than springs and shocks in it, but the springs are Skyline configuration, tapered (not parrallel) coils to fit the standard spring seat configuration. They look like this

http://www.whiteline.com.au/images/product...s/kca348_02.jpg

Some "Works Kits" have Bilsteins shocks, some have Konis, some have others. Whiteline choose the one the best suites the application and then revalves them to suite the spring and stabiliser bar rates in the kit.

Hope that answered your questions

[Maxx]

R*SR Ti2000, becoz the light weight