I've had some Z51 sways in my garage for a couple of years. Thinking about putting them on since the vette is on stands. Any tips? The new sways have poly bushings. I don't want them to squeek. Also, I heard somewhere you are supposed to tighten the bolts when the car is on the ground. Not sure how you would do that since the car sits so low.

 

Although poly bushings have a reputation for squeeking, OEM rubber
components can do this as well.

I've long used grease on the sway bar bushings to quiet them. Initially,
I used petroleum-based wheel bearing grease, petroleum is supposed
to attack rubber but I can't say I have noticed any difficulties. Just
the same, when I discovered synthetic grease like Redline CV-2
Synthetic, I switched to using this for bushings.

As for tightening the brackets on the ground. If you have Rhino ramps
or an equivalent, even if these are stacked pairs of 2 x 6 planks, it
should be possible to create enough clearance to reach the front
brackets. I don't remember whether there is anything that prevents
access to the rear brackets when the spare tire and the carrier are
out of the way.

My vote is that there are more than a few installations that have been
completed in the air. I expect that within a few hundred miles, the
bars have found their natural home within the bushings, esp if
lubrication is present.

.

 

remember, stiffer front equals more weight carried by the front tires, stiffer rear equals the same there. personally i would do the front one first, drive it, see how it handles and only do the rear if the car pushes in corners.

 

a small "push'' will safely scrub off speed if the car is driven with slight "excess enthusiasm", a "loose" car , esp on radial tires, may "swap ends" in the same situation.

ez way to remem sway bar and also spring requirements is to time-travel back to c3's...small block engined cars came with NO (the ultimate "small") rear anti-roll bar, big block cars got a rear bar to compensate for the extra front weight and associated "push" if no rear bar was used.

 

My understanding that with my 275s in front and 315s in the rear, that creats more push. I feel like it pushes too much right now. I am running Z51 shocks with std FE1 (base) springs. The ride is just about perfect, just leans a little too much.

 

The default characteristic on the '89 FE1 with 275/275 all around is
understeer (push).

Changing to asymmetric rubber (275/315) tends in the direction of
more understeer because the rears have greater grip. Under these
circumstances, increasing the roll stiffness at the front is counter
-productive because this also leads to more understeer.

Increased rear roll stiffness through a higher spring rate or a larger
rear sway bar will reduce understeer/increase oversteer.

The '89 FE1 front spring is quite stiff, the rear spring is soft in relation.
Would you agree that the rear of the car travels through a substantial
range of motion over moderate to medium sized dips - like it is doing
deep knee bends?

Study the '89 rates and compare these to the Z51/Z07 fr/rr rates that
evolved in later years.

One approach is for you to seek out a Z51 rear spring from someone
like member IndiannaVette or an aftermarket one from Pattie at VB&P
having a rate of 330-350 lbs/in (along with a set of their rear lowering
spring bolts for adjustability.) This will provide a rate more in balance
with the FE1 front spring and eliminate the knee bends with little
compromise in ride comfort. (My vote is to stay away from rear rates
of 400 lbs/in(+) unless prepared to do further work and endure greater
ride harshness.)

The spring change will reduce the understeer. If later you wish to
further reduce understeer/add oversteer, you have the option of
increasing rear sway bar size from the OEM 22mm to 24mm or 26mm.

Be aware that the rear toe setting changes in the direction of toe-out
upon braking, ie: 0º static toe will become toe-out. This is helpful in
rotating the car at low speeds in an autocross. But for higher speed
events and on the road 0º static toe WILL lead to the rear stepping
out (oversteer) during directional changes under deceleration/braking
maneuvers. The behavior can make an emergency lane change on
a wet freeway very troublesome. For road use and higher speed
events, follow the HPDE/Track alignment guidelines that call for toe-in
at the rear, rather than the AutoX and FSM ones that specify little
or no rear toe-in.

.

 

I totally agree with what just was posted above me, great advice. i had no idea the rear spring was so soft on those, in the OP's case using the z51 rear since he already has it would be a great first step. Leave the front alone, drive and see if you need more spring in the rear. Sounds like you might actually.

 

wow, thanks guys for the great explaination. I may just try the rear sway and see what it does. All I lose in trying is jacking time!