glackore

What will I gain by keeping or removing my rear sway bar? I've heard that handling will improve on autocross and road courses by removing it. I am not a chassis guru. The car feels like the front & rear are not in sync. I have the following:
Front - Borgeson steering box, traditional vette front suspension w/550lb springs, Koni, heavy sway bar and poly bushings
Rear: composite 420lb spring, solid adjustable strut rods, traction bar, stock trailing arms


Comments? Thx.

diehrd

What do you mean not in sync ?

glackore

The rear end feels very tight when in the middle and exiting a road course corner while the front end gives the feeling it is looser. Not scientific I know. What would I gain or lose related to the having / not having a rear sway bar? I am sure some guys have experimented here on the CF.


Thx,

glackore

Diehard - I also only drive it on a road course once or twice a year so I'm not an experienced driver by any means either. Maybe my experience level needs to be heightened! Autocross on the other hand is something I'm getting a good feel for.

larrywalk

From where you're at now, adding a rear sway bar, or increasing its size will make the car looser and will tend to make the back end break loose first at the limit.

Removing the rear sway bar will make the car more prone to under steer and may make the front tires plow at the limit without the rear braking loose.

The optimal solution is to make the car neutral by balancing the forces at front and rear for best cornering. YMMV!

gcusmano74

A 420 lb/in rear spring is VERY stiff. The factory F41/FE3 package, IIRC, had 550 lb/in front springs matched to a 300 lb/in rear spring. So your 420 lb/in rear spring is 40% stiffer!

gkull

It all depends on your rear traction. a 420# mono is a wimpy spring if you have power and good tires. I can't even run my 420 on a track I have to use a 500+

even when I had a little 355 ci I had to go to bigger rear. It is the amount of rear squat and body roll.

To the poster. your small front tires will push and wash out while the rear is planted. I use 295 slicks on the front like all the c-6 road racing vettes.

Rear sways are a balancing act. I've tried 3/4 5/8th 9/16th and none. As your rear spring rate goes up and the compression resitance of your shock goes up the less bar you need

jerome1979

what about your wheel alignment ?
You can add a spreader bar on front to stiffen the front a little bit

Traction bar for autocross ?

glackore

Thx gkull. I do have wimpy tires on the front which could be the real issue. I have a fairly stiff front end with spreader bar, stiff springs, some negative camber but street compound tires that don't stick so the front does slide. Heck, I really need more brake too! The back is stiff and gets good traction w/o much lean. The hp on my 355 if 362 at the rear wheels so I'm probably not over powering the back of the car. I have been looking at BFG g-Force Rival tires with a 200 wear rating. My Nitto 555s are really street driving tires. I am probably at a crossroads where I decide do I want my car to perform better on the track or the street.


Gary

glackore

Spreader bar check.
Wheel alignment check.
Traction bar check (stiffens up the back tom reduce squat and wheel hop)

FKING1

IMO the smallest diameter rear available would be best, believe it is 7/16".
I run a 300 rear composite spring and 550 front in my 70 autocrosser.

gkull

You have to think about what the car is doing. You need to do some testing. Just out driving I will come into a turn way to fast with my foot off the gas and no brakes. on a nice warm day the front end will push or understeer until it scrubs off enough speed and the front tires hook back. I can go through that same turn on the way home at the same speed on a cold day and my big 335 rear tires instantly come around beside me in the classic oversteer.

I have a 3/4 rear sway bar and my Vette is tire temp sensitive as to what it will do.

A vague feeling coming out of a turn can be caused by several things and one of them is not enough rear spring to resist weight x-fer and the front tires are so light that they don't hold the road. The rack of the car, like the front end lower than the rear also resists lifting the front end

http://www.drivingfast.net/car-control/oversteer.htm