Why does everyone, according to the other thread on bilsteins shoxs, Use higher weight springs in the rear than the front? All of the japanese made suspension have higher weights in the front than rear, but in the U.S...

What would the average R owner get if they where to upgrade the stock suspension? -Higer weights in the front or Higher weights in the rear? Please explain to me the reasons for the setups.

 

First I wouldn't "upgrade" because theres really no such thing on a ITR. If I did, I would copy the realtime setup.

As far as changing the springrates, higher in the front will create understear, higher in the rear will create overstear(I think, unless I have it backwards).

 

The tendency for any front engined, front wheel drive car is to understeer. This understeering tendency is due to the forward weight bias.

The stock Type R uses linear rate springs in the front (~246 lb/in) and progressive rate springs in the rear of the same spring rate. This is a safe, understeering handling setup that is suitable for the general public.

The key to being faster at the track (I'm talking road course here) is to straighten out your car as soon as possible, immediately after you hit the apex. The reason is so that you can accelerate out of the turn a.s.a.p. What you really need is for the car to "rotate" so that the back end swings out so that the rear tires are directly behind the front tires.

In an understeering car - it will tend to plow into the turn (or go straight) and because of this you have to wait for the front tires to grip and turn the car around. The key to driving faster (or 'looser') is to have an slightly oversteering car. Oversteer is much easier to induce in a rear wheel drive car - but harder to control because the rear tires are also the tires that are putting the power to the ground. So you again have to wait until the back end swings around before you can get on the gas (or else you will spin the car).

To create oversteer in a FF car you need to reduce the grip of the rear tires sooner than the front tires, so that it rotates. In other words, you want the rear tires to reach their limit of adhesion faster than the fronts.

This can be done in two ways:
1) stiffen up the rear end with high rear spring rates and a heavy rear anti-roll bar or 2) use narrower tires in the rear

The Japanese racers are using lower rates in the rear because they often use smaller (narrower) tires in the rear. I use the same tire size all around and instead use higher rear spring rates.

Much of this has to do with driver preference BTW. I've never tried the Japanese setup at the track.

 

Upgrading a ITR suspension is easy enough to do. A mugen lowdown is a clear upgrade. There's plenty of others as well. Granted you can mess it up, but you can mess up a civic too. The ITR isn't the best setup car in the world.

Yes, higher rate springs in the back will cause more oversteer in an otherwise equally setup car.