Boomer111

I am experiencing bottoming out. I think it is the bump stops although it sounds and feels more like the tire hitting the wheel well liner.

This seems to be only on the driver side and in the rear.

Inspection of the tire and well as the liners shows no damage so I am assuming it is the bump stop shock travel problem.

My reading's from the center of the fender arc running through the center of the hub to the ground are as follows:

26 9/16" 26 6/16"

28 2/16" 28 1/16"

with the center of the air dam being 2 3/4"

These reading's are approx 3/4" front and 1/2" rear under the levels the car came with.

When the FSD's where installed I had the dealer, using their guage with the suspension components, lower it from stock by 1/4".

So it appears if this was done accordingly the FSD shocks do lower the car 1/4"-1/2".

So I am looking for the owners of the C6 coupe who have installed the FSD shocks to tell me their measurements and if you have had the lowering bolts adjusted at all. Also of course if you have experienced any shortened shock travel.

My tires have 9/16 center tread depth and they are oem sizes with 30 lbs cold psi. Fuel as always been at least 3/4 full.

The bottoming occurs occasionally but with my wife retiring I expect to be doubled up more often with more trips involved.

I appreciate your time and help with this endeavor in trying to access where I need to be for complete shock travel.

AORoads

Dave, have you looked at the posts/threads by "Gearhead Jim" on the height of his car? I know he's had several posts on it, even tho he doesn't have Koni FSDs. Mine are on a convertible but I've actually had the car slightly raised shortly thereafter.

Boomer111

Yes Bill I have read thru Gearhead Jim's threads more than once, thank you!

I want to narrow this down to guys with the FSD shock setup. Since there has been a suspicion of lowering with just this shock replacement alone.

Right now I am thinking of raising the front up 1/2" and the rear 1/4" This will still leave me with a 1" rake.

Still looking for some more input.

BTW Bill why did you raise after FSD installation? And by how much?

peter pan

I have had my Koni shocks on for over 40k, I do not experience what you do. I run Z/GS size tires so my measurements probably would not help. No rubbing or hitting the bump stops for me and we lowered a 1/2" when I did the change.

Boomer111

So the 1/2" was just with the shock install correct? No bolt adjustments.

hungryhippo

The fsd's lowered my car because they aren't under pressure. I remember the left and right air dam pieces would scrape when cornering on back roads. Coilovers fixed that, lol

peter pan

We did not do any adjustments at all.

Boomer111

Thanks

REVAK

Many moons ago , I installed Koni's on my 06 Z51 vert . Ride height dropped aprox. 1/2 ". [ due to original equip. shocks being high pressure and the Koni's being low pressure ] . I had to adj the ride height bolts at the four corners to get back to original height . I don't recall the exact measurements as this was done 7 years ago . After the adjustment , no more scraping or bottoming out .

Flame Red

I installed FSD on my vert last year. I found that the ride high was lowered, as after the install but I was scraping the air dam constantly. I had no way of measuring exactly how much lower it went but it must have been a lot since it did not scrape very much before the change. I moved the front ride height bolts two complete turns to raise and it stopped scraping just as before. I also had an alignment done as playing with the ride height effects the alignment.

I think that you lowered it too much.

GearHead Jim thread is the authoritative source.