Jellybean Posted April 29, 2013 Share Posted April 29, 2013 Hey Just trying to figure out a compromise between a road setup but a somewhat competent track setup; mainly illuminate as much body roll as possible for my friends GTST skyline. Background His current setup is comical on track Tein Springs , kyb rear shocks Tein Springs, OEM Nissan fromt shocks S tech Tein GTST TEIN part number : SKN64-AVB00 Ride Height Drop : -32 / - 30 mm Spring Rate: 2,9 / 3,5 kgf / mm Looking at buying Nismo S Tune setup Spring rate on these are 5.3 Front 4.8 Rear The Supra Question I have the TRD Bilstein setup , which is track focused and not too nice on public roads Front K=10 kgf /mm Rear K=9 kgf /mm Looking at BC BR Setup Front Coilovers : Rubber Top Mount. Front Spring Rate : 14kg/mm (782.2bs/in) Rear Coilovers : Rubber Top Mount. Rear Spring Rate : 10kg/mm (558.7lbs/in) Considering I read a lot of members consider the BC setup as comfortable on the road, just wondering does the dampener has such a drastic impact on the cars setup considering the BC setup is nearly twice the spring rate as the TRD setup ; if they were using the same dampers it would be twice as hard. Can somebody explain why the TRD is ridiculously stiff compared to the BC? Is it also correct to say the Spring rate also affects the ride height of the car? If anybody who is educated in Suspension theory, will the Nismo S Tune give us what we want for the GTST? Illuminate the body roll, increase corner speed Thanks Quote Link to comment Share on other sites More sharing options...
johnny g Posted April 29, 2013 Share Posted April 29, 2013 Can you add anything you find to here? http://www.mkivsupra.net/vbb/showthread.php?267488-Coilover-Spring-Rate-Register&highlight=spring+rates Quote Link to comment Share on other sites More sharing options...
Dan_Q Posted April 29, 2013 Share Posted April 29, 2013 BC's are fine for me on the road, i too looked into spring rates and was sceptical. If anything with the dampers set at zero (0-30 range) I find that they are a little under damped, so when i'm done at the track i back them down to 5. IMHO there isn't much difference in ride comfort from these to both the stock KYB NA and Toyota bilstein TT setups i've used previously. I'm no expert by the way so dont take any of this as gospel, but yes the rate of the damper effects the "stiffness" of the car very much- IE when talking about how you feel the bumps in the road etc. spring rate with coilovers does not effect the rideheight, as the spring stays at its correct preload and the rideheight is independantly adjustable, so you can set that to what you want. In the case with fixed spring platforms then i'd assume it does make a difference, as I tried tein TT springs on my NA (lighter engine) and the rideheight did not change. Must sell those thinking about it. no idea with the datsun, but if body roll is a problem why not look at uprated / adjustable anti roll bars? Please don't act on my comments as i'm a bit of a 'tard, i'm sure the likes of chris wilson or paul whiffin (plus the other experts i've not mentioned) will be able to properly help just wanted to share my thoughts of the BC's on the road. Quote Link to comment Share on other sites More sharing options...
Jellybean Posted April 30, 2013 Author Share Posted April 30, 2013 (edited) Thanks for the feedback The car has all whiteline uprated anti roll bars; interesting the Damper affects the ride comfort so much, I will see if I can find something to explain what is actually happening inside the damper when you adjust the dial. Taking a guess, I presume when you adjust the Damper setting to make the ride stiffer you are shifting the piston , in turn causing the damper to have a shorter stroke and the volume metric capacity of the cylinder is reduced causing the shock oil to compress or thicken, resulting in a more rigid platform. Just in comparison to whats on my car (TRD springs) I was surprised to see the BC setup with such stiff spring rates and looking at Johnnys link, the variance in spring rates available for the car. It has made me think, you really need the damper design matched to the spring rate. I presume the spring rate's on the BC setup are so stiff because you could not have such a wide range of Soft / Track orientated setup unless the springs are ridiculously stiff. At the lowest setting they would bottom out. Taking the above into account, BC are trying to cover a huge range of settings ;I am very skeptical if a Damper setup can be designed to effectively cover such a broad spectrum regardless of cost, some compromise needs to be taken Edited April 30, 2013 by Jellybean (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 1, 2013 Share Posted May 1, 2013 Convert them to proper English pounds inch and I'll tell you what they are like, they all sound pretty stiff, but no time to get the calculator out! Quote Link to comment Share on other sites More sharing options...
Jellybean Posted May 1, 2013 Author Share Posted May 1, 2013 Come on Chris, get with the Metric system 2.9/0.0178579673228346= 162.4 Lbs/In front 3.5/0.0178579673228346= 196 Lbs/In rear Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 1, 2013 Share Posted May 1, 2013 Sounds very arse about face, are you sure? I don't "do" metric Quote Link to comment Share on other sites More sharing options...
Jellybean Posted May 1, 2013 Author Share Posted May 1, 2013 Sounds very arse about face, are you sure? I don't "do" metric Well it is a Nissan ha ha Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 1, 2013 Share Posted May 1, 2013 What the fast lorry one, with the rear transaxle? Given their weight those springs sound reasonable then Quote Link to comment Share on other sites More sharing options...
Tyson Posted May 1, 2013 Share Posted May 1, 2013 What the fast lorry one, with the rear transaxle? Given their weight those springs sound reasonable then I love some of your replies Chris they do make me chuckle Say it how it is Quote Link to comment Share on other sites More sharing options...
Jellybean Posted May 1, 2013 Author Share Posted May 1, 2013 What the fast lorry one, with the rear transaxle? Given their weight those springs sound reasonable then Quote Link to comment Share on other sites More sharing options...
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