Question on shocks

[e30shmobberr]

I want to get the Ground control valved koni shocks for the ground control coilover conversion kit that i have. i was wondering if there would be a difference to use normal sport koni's in the rear instead of the GC koni's. Any one have 2 cents to put in?

[e30shmobberr]

Anyone?

[Danny]

Gc's are specially valved.

[Wh33lhop]

Would there be a difference? Yes. Will regular Sports work fine? Yes--I've been running them with 600# rear springs for about 10000 miles.

[e30shmobberr]

Would there be a difference? Yes. Will regular Sports work fine? Yes--I've been running them with 600# rear springs for about 10000 miles.

how much of a difference for the rear will the gc konis be. or am i better off using normal koni sports in the rear. I will be running 750 rear.

[Danny]

Just give gc a call, talk to them. They aren't going to push you to buy something you really font want to buy. Besides, you wouldn't be "better off" running a shock that isn't optimized for your spring rate. Also I hope you understand 750 is really stiff.

[e30shmobberr]

Would there be a difference? Yes. Will regular Sports work fine? Yes--I've been running them with 600# rear springs for about 10000 miles.

how much of a difference for the rear will the gc konis be. or am i better off using normal koni sports in the rear. I will be running 750 rear.

[Hellabad]

Here are some quick info straight from the guy who designed the GC rear Konis for the e30:

First off there are three factory Koni rear shocks, plus The Mustang shocks that are used sometimes.

So I will compare the GC shocks to the Koni e30M3 shock, which is the best and closest comparison.

Things in common:
Both the GC Koni shock and the M3 Koni are yelow. They each have a bushing for 12mm on the bottom eye.

Things that are different:
The GC shock is shorter overall, (less "droop") to help avoid shorter stiffer springs from being loose when the car is jacked up.

The GC body length is shorter, so the car can use a full length bumpstop to avoid sudden bottoming out. (aka more suspension travel)

The GC rear shock is adjustable from up inside the car, the regular Koni needs to be removed from the car to adjust the rebound damping.

The GC has a 12mm top pin instad of 10mm, because 10mm is not strong enough when it is hollowed out for the adjuster to go up into the trunk. This requires new rear mounts or modified stock mounts.

So that's just the physical differences. The real big deal, and what takes the most time and testing are the internal (valving) differences. These changes are decided on by a combination of testing, measuring, retesting, and plain old experimentation.

Valving differences:
There is a greater range of damping adjustment on the GC compared to the standard Koni.

The GC rear shock has a higher max rebound damping, in order to handle stiffer than stock spring rates.

The "curves" are different. This is the black art of shock tuning. The GC has damping curves that we feel are more suitable for the sporty, occasional track day or autocross, rather than the pure street oriented damping of the standard Koni. This is not the same as "more or less" damping, this is a 3 dimensional change in "style" which is hard to define, almost like changing all the crossovers in your stereo systesm as opposed to just changing the volume.

I hope that explains most of it. Custom valved shocks from any company are a big commitment in time and money, and the people that are truly doing it, spend an incredible amount of time to make sure the shocks come out right.


Jay










(Note: at least two companies sell the Mustang shocks and say they are "custom valved" which is BS).