thats only with the stock springs out of the car, remember they are preloaded stock

 

Pre-load does NOT affect spring rate unless you do something extreme, not in linear springs anyway, and the stock and the race springs are both linear rate springs.

 

After doing even more looking and researching, I may be doing a slightly different setup, but if so I need to order springs for the setup, which would be Hyperco springs; 2.5" ID and probably 9kg/7kg rates (or 500/400). My question is, what is the length of springs I need to make it work correctly. I've been told 7" front and 8" rear is a good way to go, but I'd like to see if that's correct, as I don't really want to have to exchange springs once I order them. Again, information is appreciated.

Behind my reasoning for the increase in spring rates yet again. If I go with this setup that requires springs be ordered separately, I will be spending in the neighborhood of 2200-2400$ after shipping for the entire setup ($1012 + shipping for Bilstein dampers, ~320 + shipping for springs, and ~$950 + shipping for camber/caster plates, front strut tubes for 2.5" coilovers, and the 2.5" rear coilover kit. The front strut tubes, camber/caster plates and rear coilover kit are the ones that AWR offers. If I am going to end up spending what a low end set of Zeal coilovers is going to cost, I'd rather start at a higher spring rate level so I do not have to buy new springs and have the Bilsteins revalved when doing so.

 

The AWR stuff was made before Bilstein had an FC specific application AFAIK. If you want it done cheaper you can go with FC specific Bilsteins for $450, revalve for $320, GC coilovers (any spring rate) for $420 and GC camber plates for $300. That adds up to $1420, so MUCH less.

Especially as you're on street tires, I think you'd be making a mistake going that stiff. You'll probably be slower because of the lessened compliance. It'll probably be years before you're good enough and have the car set up in such a way to actually make use of a stiffer suspension, and by that time it might be a good idea to get the shocks rebuilt anyway to refresh them, so a re-valve wouldn't be a big deal, and springs aren't that expensive. I've honestly never once felt a need or desire to go any stiffer than 7/5, and if you're not racing competetively, it really doesn't matter too much anyway, since those last few thousandths of a second you might gain from being stiffer really don't matter, whereas the increased street civility of a softer setup will matter.

On the spring length front, the length needed is somewhat variable based on weight (more = longer), spring rate (more = shorter) and desired ride height (lower = shorter). Also, if you go too short then you might not have enough stroke and they could coil bind (bad) before you hit the bump stops, that can cause you to suddenly loose control.

 

Street driving will be a maximum of 10% of the use this car sees, I'm not worried about being too stiff on the street. Also, I believe that I will be going with a set of R compounds (another research time that I hope is shorter than suspension) for track rubber, and the little bit of street driving it does see will be on the 16" TII wheels its got on it now with just some Falken Ziex ZE912's or something. Well, the AWR site says in the description, The tubes are threaded for easy fitment of Koni and Bilstein race cartridges (0000-04-7211-KN). So I'm not sure if this makes them compatible with the Bilsteins I was going to use or not. With my car being at 2200 with 8 gallons of gas, I may go with 6" front and 7" rear, but I'll decide after a bit more looking, I still have quite a while to research before I can actually buy them so it'll be an ongoing thing. As always, appreciate your thoughts and input

I'll give AWR a call on monday and talk to them about the Bilstein fitment.

 

I priced the Bilstein / GC setup at $1380, with a revalve.

It's in one of these threads in the Suspension section written by me.

 

That's good to know. It looks like AWR's are for older ones, when I searched for the part number they list for the fitment it comes up with some quite old results. So ground controls may be the way I have to go for now.

 

I have a awr ep strut and koni yellow setup with gc camber plates. I run 10in long springs at 8kg/mm front 7kg/mm rear spring rates, an RB front bar and a modified TII rear bar for a little more stiffness. On 225/45/17 azenis, this setup is very neutral and turns in extremely well. Any lift mid turn will get the back to jump out, the speed of the rotation depends on the speed of the lift. Its insanely fun to drive and very controllable. If i stay on the gas its rock solid. With 255/40/17 r888 it understeers more than the perfect balance found on the azenis, i think this is because of chassis flex in the front caused by a lot more grip. I run -2.5 camber all around with zero front toe and a touch of toe in at the back. For handling bumps, its not a mercedes but its not bouncy at all. Just one fast reaction to each bump I encounter.

 

The EP strut tubes have the upright attachment tabs welded on higher up than the ITS/street ones, so that could cause them to need longer springs. Something to keep in mind.

ALL Bilsteins use the same basic valving (maybe different sizes), so there shouldn't be any significant difference between them. That said, the AWR setup is probably a bunch stronger, so if you're going to be curb hopping a lot then it might be worth it.

How smooth are the tracks around your area? I know the ones around me aren't all smooth, some of the tracks are a bit rougher, where more compliance is needed. A freind who had lived in Calgary some 15 years ago and lives around here now recently sold his race car to someone in Calgary, and despite a lot of development (suspension, brakes, engine, etc), it's not as fast as it used to be, but it's been stiffened up a bunch for the smoother track at Spokane. Using those rates you'll be fine, it'll be quick and all, but it's just that it may be past the optimum.

As for track tires, what you'll see on 90% or R compound equipped cars at open track days are Toyo R888 and Nitto NT-01 (essentially the same tire). They've got a good combination of grip, long life and reasonable price. Unless you're going for all out fastest lap times, those are the best choice.

 

with 10 inch springs, the highest i can get the front is barely enough to clear the fender. I would do some more research before buying 7in springs.My friend bought the gc advance design dampers and they recommended 7in and he had to reorder 10in springs cause his car was on the floor when set as high as possible. I went with ten because iscracing.net sells 2nd gen springs at 10in for their its bilstien setup for ITS cars which use a stock damper location. http://iscracing.net/2nd_Gen_Parts.htm

The tracks around me are pretty smooth. I drive at Laguna Seca and Buttonwillow, but Ive also driven backroads and its still pretty good. I can ride on reflectors and the car will absorb them and still grip. On some really cracked pavement, things will get interesting though.

 

More great information. I'll have to decide which I'd like to do, it's probably going to be the AWR EP front strut tubes with the rear coilover kit and either their own or ground control camber/caster plates. Good to know about the spring lengths as well. Reason for debating on AWR or GC camber/caster plates, is that the GC ones use that bearing setup to place the weight there, so I'll see if I can get info on both setups.

 

Also on tires which I forgot to add in my previous post. Nitto NT-01's were going to be what I looked at initially because I had heard lots of good things about them, it was a choice between those and Toyo RA-1's, and since I haven't looked at tires in a while I'm gonna take a wild guess and say the R888's you mentioned may have replaced the RA-1's.

 

Yes, they're the replacement, although you can still get RA-1's, but they really need to be shaved for track use, where the R888 and the NT-01 can both be used from full tread.