believe me wtz........ stiffer rear springs increase OVERSTEER, stiffer front springs increase UNDERSTEER (all other things remaining the same)

 

The EVO8 rates are the same for japan, understeer is inherent in almost all cars, it's a safety factor for the average driver.

Adding spring to the front of the car will reduce mechanical grip and increase understeer, assuming no other changes to the car.

This of course depends on what kind of tire you are running, the amount of downforce, the sprung weight of the car. This is why racers run different rates than street cars, of course the race cars are setup much differently too.

FWIW, some local guys here in california have had some good track times with the EVO with just stock suspension.

How does 2.13 min.sec at Thunderhill sound? Or how about 1.58 min.sec at Sears point?

Steve

 

OK you guys, I'm not going to disagree with what you have said about the effects of individual components on the Evo's handling when certain other components remain stock. This is not the case with my car. My car has been lowered and corner balanced. I am running 9kg springs in front and 8kg rear with coilovers. I run an adjustable 25mm rear swaybar with adjustable endlinks. I have a Torsen-type front LSD. I run -3 degrees of camber up front, -1.5 rear with 0 toe all the way around. Lighter race wheels with a wider front track, Hoosiers, lighter rotors etc, etc. I ran the car at Limerock in this configuration. The rear bar was set in the middle holes. Tire pressures were 41 degrees hot on all corners. The track is bumpy and I found that I could only use something less than half of the available damping on the shocks. This leads me to believe that these spring rates are higher than neccesary on most tracks in the Northeast. The car turned in crisply and kept its tires on the ground. Mid-corner balance was almost neutural with some understeer on corner exit. I believe this could be tuned out with the rear bar. Even though I am running a softer rear spring vs front, the addition of the bigger rear bar ups the rear wheel rate. Maybe someone could work out the combined effect of spring and bar on wheel rate? The first thing I noticed in the stock Evo was that most of the understeer is caused by excessive body roll. The stiffer rear bar helps immensely and I believe it to be the best first handling mod. Since I believe the rear bar change to be a mandatory starting point to improving the car, this lead to my original question regarding slightly more spring in front vs rear.
Cheers,

 

First of all, it is very difficult to judge what if anything could be wrong with your car. Also, handling is subjective to the driver, meaning someone may think your car handles fine when they drive it, but you may think it needs tuning. Also what type of coilovers are you running? Does the car have more/less weight taken off?

In general, a swaybar depending on where it is located, it's size and diameter will add more torsional rigidity than a spring will. It is a good tuning tool to dial the car in at a specific track or if you want to change the transient handling nature of the car.

Body roll does not cause understeer. Even with really stiff springs/swaybar, a car will still transfer it's weight in a turn, it's just the rate at which it will transfer it's weight that is affected.

Steve

 

There is nothing wrong with my car. Sorry I got involved in this thread. Will find answers elsewhere.

 

Getting back to Ohlins, they make the best motorcycle forks and shocks. Absolutely top-notch. For $2k+ I'd want independent rebound and compression damping tho...

 

wtz.... I appreciate your input and it is certianly valid, keep it coming



redvolution... true double adjustability cannot be had for less than $3-4K per set....

 

Thanks OGVW,
Nice chatting with you yesterday. If you want to know more about my diff, do a search for "Front LSD installed". Maybe Steve is right, body roll does'nt cause understeer. But it sure as hell accentuates it.
Cheers,