Originally Posted by vince1611

I've decided to get new springs+revalve for my FLT-A2's. The current setup at 10front/12rear is ofcoarse very oversteery and makes the car handle like a muscle car on the autocross. Despite my current sidewalls being too stiff, the A2's sit into turns fairly well. Many companys seem to like using a 10/8 setup and I'm trying to figure out exactly why. I'll be switching to RE-01R's in the future for the softer sidewalls so that I get more grip, but I suspect that it still won't help much. I know some of you have LOTS of experience with different spring rates, so any advice appreciated.

Originally Posted by vince1611

Excellent! That was the explanation I was looking for!

Fiddling with the tire pressure diddn't do enough. I wasn't clear about this earlier, but my main problem was controlling oversteer in the middle and exit of the turn while powering out. I've tried softening the rear shocks but that mostly only effected the entry of the corner. I suppose tire size and sway bars will help, but I'm thinking that it would be better to get the springs right in the first place, instead of having to compensate for it.

If I did my multiplication correctly truechoice uses a 9/7.5 set up. In that case, I think I'll either go with a 10/9 or 9/8 setup to counter the understeer caused by my nismo LSD. What do you guys think?

Originally Posted by WA2GOOD

Keep in mind, just because JIC (or any company for that matter) says their spring rates are xxK doesn't mean that they actually are. I have tested MANY coilovers for various companies for track and street use for these cars and have found out the hard way that you need to personally rate test each spring yourself. For example...... I personally tested a set of JIC FLT2 springs that the coilovers came with. They claim that they are 10K front 12K rear. I personally tested them to actually be 541LBS or 9.68K for the fronts and found the rears to be 395LBS. or 6.44K. Pretty big descrepincy, huh? So, from personally experience and from my race car chassis background, I rate every spring personally before installing it, so I know what it is exactly I am installing.

Originally Posted by Gsedan35

Are you sure you didn't have part #Z33FLTA2S in hand vs Z33FLTA2H? That would explain the rear rate

http://www.jic-magic.com/ViewProduct...art=1#AppChart

Originally Posted by FritzMan

I ran the JIC in a hybrid setup with 10 kg (560 lbs) front and 9 kg (502 lbs) rear. I then switched to 12kg (672 lbs) front and kept 9 kg rear when using the stock sways. The JIC package is supposed to be configured with a 10 kg front and 12 kg rear. I have no idea why they chose such a stiff rear but I suspect their setup is tuned for stock sways and stagger tires. For my setup of 245/40 all round and Hotchkis sways med f & r, I think 10(f) and 9(r) was the perfect street/track mix with a JIC package.

Originally Posted by FritzMan

Their selected spring rate bias is very similar to what I'm now running with my JIC FLT setup. Instead of the standard kit of 10kg front and 12 kg rear (560/672 lbs), I'm running 10 kg up front and 9 kg rear (560/502).

The softer rear provides a lot more corner exit traction while the stiffer front allows agressive turn-in and sharper steering response. Not only has handling improved, but I found that a softer rear really improves the street ride. It seems as though the rear is more sensitive to spring rates than the front.

Originally Posted by FritzMan

I ran the 560/672 all last season in Solo2 and felt the rear was too snappy. It was good for rotation but bad for weight transfer/traction when exiting corners. Also, any kind of bump would upset the tire's traction because the rear was just too stiff.

Throughout the '04 season I played with sway bar rates and the JIC's adjustable compression and noticed that a softer rear allowed more traction without ill effects to handling. The car certainly felt different, but the clock (and butt) said it was a good move.

This season I'm setting up the car for Solo1 so an even softer rear is ideal (some understeer). Initial testing with the current setup has been quite favorable.

Note that I'm running 245/40/18 Kumho MXs front AND rear so understeer has been substantially tamed with that setup alone.

Originally Posted by FritzMan

I'm quite pleased with how the car is riding ride now. Frankly, it depends a lot on road conditions in your area but in Canada we can get some pretty rough stuff due to frost upheaving etc.. Because this is a year-round daily driver I refuse to compromise driveability for the sake of performance.

The best thing about this setup is that the shocks can be noticably stiffened up when you want to play so to a certain extent you can get the best of both worlds.

I wouldn't worry so much about softening the front rate as the rear. For example, I autocrossed this weekend and ran the front dampers full stiff and kept the rear full soft (handling was fantastic). I had to drive off the lot (to the john) and was surprised how decent the ride still was with the front full stiff. IMO, softening the front much more would result in brake dive and loss of steering precision.

I guess what I've saying is that 10/8 setup should work well and save you the cash of having to separately purchase the front springs ($120 for both).