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Full Version: Split second oh sh!t moment during rotation.....
F-Body Road Racing and Autocross Forums > Community > General Discussion
FASTFATBOY
I havent been to an HPDE with this car, but I am trying to sort it a little playing on the street(on/off ramps).

Here is what the car has....

Strano Springs

Koni Da's on front foll soft

Koni Sa's on rear full soft

1 LE front bar

Stock rear bar

Spohn poly LCA's in rear, I know I need some roto-joints

Spohn Panhard bar, I know I need some roto-joints

Does Not have LCA relocation brackets on the rear.

Poly bushings throughout, totally new suspension.....all rebuilt.

New alignment, no driver in car.

Camber -.8 left, -.9 right

Caster 4 something

Total toe -.1


The car on turn in when it starts to rotate the rear end feels loose-disconnected for a split second, almost like it rises up a foot or two(thats an exaggeration, it does feel weird) then it finishes loading and bites down.

That split second will scare the crap out of you. Will lowering the panhard rod fix this?

Its very un nerving.
trackbird
First dump the poly LCA's.

Second, add some rebound to the shocks on both ends of the car. I find between 1/2 and 3/4 to full stiff is in the ballpark (tune to taste). And when I ran DA's, I ran 3-5 clicks of compression damping on mine too (3-4 front and 4-5 rear). Your results will vary, but our setups are similar enough that you can experiment from there (the compression is optional, but I found the car to be quick and stable with it, your results may vary).

I'd also seriously consider a 35 or 36mm front sway bar (and then a 21-22mm rear would be the next step). It's worlds better than the 32mm bar. You'll be amazed at the change it makes in the car.
Blainefab
QUOTE (FASTFATBOY @ Jan 28 2011, 04:50 AM) *
Poly bushings throughout, totally new suspension.....all rebuilt.

The car on turn in when it starts to rotate the rear end feels loose-disconnected for a split second, almost like it rises up a foot or two(thats an exaggeration, it does feel weird) then it finishes loading and bites down.

That split second will scare the crap out of you. Will lowering the panhard rod fix this?

Its very un nerving.


What rear bump stops? What tires? Tires same model front vs rear? What pressure?
FASTFATBOY
QUOTE (Blainefab @ Jan 28 2011, 07:34 PM) *
QUOTE (FASTFATBOY @ Jan 28 2011, 04:50 AM) *
Poly bushings throughout, totally new suspension.....all rebuilt.

The car on turn in when it starts to rotate the rear end feels loose-disconnected for a split second, almost like it rises up a foot or two(thats an exaggeration, it does feel weird) then it finishes loading and bites down.

That split second will scare the crap out of you. Will lowering the panhard rod fix this?

Its very un nerving.


What rear bump stops? What tires? Tires same model front vs rear? What pressure?



Stock replacement bumpstops(Moog). 275-40-17 tires that match 35 psi.

Heres the car, has some pics of the suspension stuff on the car

http://www.ls1tech.com/forums/vehicle-clas...trano-more.html
00 SS
You might want to drop a bit of pressure. I run 32 front 28 rear on my 275 street tires. Anything more in the back makes it slick back there.
Blainefab
I agree that getting the poly out of the rear end is the first place to spend money, but there are a few free things you can try. With those shocks/springs the car should be noticeably responsive to small changes in settings, unless the suspension bind is totally dominating the feel f the car:

-try dropping the rear tire pressure 3 to 5psi less than the front.

-try different settings on the shocks

-try swapping in the OEM rear control arms. The car may have a generally sloppier feel to it, but see if the transient response improves

-try loosening the swaybar end link nuts a turn or 2.

-try temporarily removing the rear bump stops. If the Moogs are too hard then get some of the OEM soft ones. If nothing changes then put the Moogs back on. Without bump stops there is a possibility that a large transient will cause snap oversteer, so be careful experimenting here.

-check the last alignment sheet for the rear toe measurement. If you have any rear toe out it will make the car squirrely.
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