jmiller

This is my buddy's car...

2003 z06 Lingenfelter Supercharged car. We experienced an issue where the car was under hard acceleration at the top of 3rd gear going into 4th over some bumps, the car was getting light in the front and floating and searching around (sorry, I can't really explain it any better). So much so I quickly got out of the gas.

My car is a stock c5 coupe, and it absorbs the bumps with no issues. Even at speeds 30 mph faster, my car is much more stable over the same part of the course.

(the z06 cruising down a smooth interstate has no issues. It appears to have its issues at higher rates of speed and bumps. No floating at normal speeds. Suspension feels tight.)

Car is lowered on stock bolts and it was aligned at the same time (it's not slammed, just eliminated some of the wheel well gap)

The supercharger adds close to 100lbs on the front. Could this extra weight be what is causing the car to be unsettled at speed? Is 100lbs an issue?

How do we resolve this issue? New Shocks? New springs? I guess my main question is should we compensate spring rates for the added weight of the supercharger? All he needs is to have the stability and trust that the car can be safe at speed.

look forward to your thoughts and advice...

rustyguns

cheapest test to is raise it back to stock height and see if it is still bad but it sounds like bad shocks to me...i use Koni FDS...excellent for lowered vettes!

gkmccready

100# is less than 3% of the cars total weight. Sure, it could make a difference, but not as dramatic as you're describing.

I'd check alignment, ride height, rake, and shocks before I ever looked at springs here. Others may have more direct applicable experience, though.

varkwso

Did the supercharger installation change the airflow at the front of the car? I have seen some "interesting" aero mods to get intercooler, etc into the airstream. They may have taken away some downforce the car was designed with.

davidfarmer

that 100lbs is right over the front tires, and the increased power would certainly unload the front much more under hard acceleration, but I agree with the others that the weight is the main problem. I wouldn't expect Aero to be the issue, as the cars have lift from the factory anyway, and I can't imagine they could have made it that much worse.

I would recheck the front alignment, and make sure the toe isn't excessive. Shocks could certainly be an issue, and a fresh set might be worth the small investment.

The increased power certainly changes the car under acceleration, but I doubt it is that much more powerful than a C6Z06/ZR1, and those cars have virtually the same suspension as yours (yes with stiffer springs).

jmiller

Thanks for your info, keep it coming.

I'm pretty sure the alignment is good, but who knows how bad it gets on hard acceleration. 500hp to the wheels with no wheel spin pulls the nose up. Not sure how much, but it's noticeable.

How do you keep the nose down?

gkmccready

Call Randy@DRM. Shock valving will be key.