Ideal spring rates for autocross (1st gen)
 

Autocrossers, what is the ideal spring rates for autocrossing, given the following: ZX2 struts and Suspension Techniques sway bars (front and rear)?

I currently have Progress springs - 240 front and 140 rear.
It seems to me that the rear is too soft. The rear sway bar easily picks up the inside rear wheel around corners. Will increasing the stiffness in the rear reduce this?

I'm thinking about replacing just the rear springs. What is the stiffest spring I can get for the rear (non coilover). My guess is H&R Sport for the MX-3, but H&R won't reveal the rate. Does anybody know it?

I'm not a big expert on G1 suspension setup, but here's a few things to consider...

(1) The March issue of GRM has an article about David Avard's car, which was the top-finishing Protege at the SCCA Nationals last year. He reveals his spring rates in the article; I don't remember what they are, but I KNOW the rears are stiffer than 140 lbs/in. :)

(2) Lifting the inside rear tire in tight corners on a FWD car is not necessarily a bad thing; it's normal behavior. Don't worry about it. You should worry about the car's handling balance.

(3) Speaking of handling balance, I would remove the front S/T bar and run a stock bar. I haven't heard of many G1 autocrossers running a larger front bar. The car should rotate better with the stock bar.

(4) H&R won't release rates to the public. They are a "trade secret." :( However, I would discourage you from screwing around with mixing and matching different brands of F&R springs; it may mess up your ride height. The right way to go is to GET COILOVERS. That way, you KNOW what your front and rear rates are, and a different spring rate is only an inexpensive spring swap away. :)

Barry runs in STS on Falkens

the MX3 H&Rs i have IIRC, are 240 front and 180 rear (but was told more like 165rear)

the Eibachs i had before (like you have now) were too soft in the rear, it would snap around very easily. With the stiffer H&Rs the rear started to work rather than spin. But i don't have the ST front bar, just the rear.

David and Will run 250 front / 200 rear on coilovers.

I'm the guy who started the thread (btaira). I run in STS and I have Azenis 205/50/15.

Carguycw, I'm actually not too concerned about the inside rear tire coming off the ground. I'm just trying to dial out a little more understeer. That the inside rear comes off the ground suggests to me, however, that rear sway bar is already overpowering the rear springs. Hence, I think getting stiffer rear springs will do more for reducing understeer than getting a thicker rear bar.

Since David has 200 lb springs and the CMS bar in the rear, should I go with something even stiffer than 200? Will the ZX2 struts handle 200 in the rear?

Finally, I realize that coilovers would be the best way to go, but I would like to go a less expensive route of possible. Has anyone ever put coilover springs on the stock struts (i.e., without the sleeves and hat)?

if your getting that much wheel lift, maybe the front is not as stiff as you think...as a softer front end, will kick that wheel up with the stiffer rear sway bar.

I get massive wheel lift going into driveways and such, but hardly even notice it out on course.

hehehe, Jesse, Barry runs in the San Diego region, but never comes to LA :(

Even those companies who publish spring rates are usually full of --it when it comes to reality. I found the rates for my MX-3 H&Rs through a friend (also how I knew they were stiffer than Protege springs), and when we actually tested the rears (the fronts are too large in diameter to fit most spring testers), they came up short of what H&R said (165lbs/in vs 180). So, the fronts were likely the same. And I wouldn't put too much stock in what Progress says, since they don't make their own springs.

And at this past weekend's practice, I watched my car lifting the inside rear tire several times on course (Julie was driving :) ). It usually takes a pretty tight turn to do it, though. And hitting a driveway cross-ways was how I ripped the rear swaybar mounts off the car (with a resounding "POP!").

The progressive part of the rear H&Rs is so soft that is little more than a tender spring, and can be compressed with very little effort.