Lower a C4

Lowering the
ride height on your 84-96 Corvette
by Bill Rauch
Whenever I
think about lowering a car, the old Cheech & Chong movie pops to mind that
begins with Chong strutting around his “Chebby” dusting it off
to the tune of “Low, Low, Low – Low Rider”. Well, to quote
famous engine builder Myron Cottrell, “Lower is better”. I
often wondered about the lowering options available to C-4 owners, and
just completing the job on our ’90 Polo Green convertible I though I
better jot it down before it’s forgotten.
Besides better
looks, a lowered Corvette has reduced wind drag and enhanced cornering
ability. Translation: higher top speed, quicker 1/4 mile ET’s,
better gas mileage and lower lap times. Just be careful entering and
exiting driveways with different grades or you’ll be replacing front
spoilers. I’m on my third one, how about you? The specifications
for the C-4 Corvette in your service manual call for a higher trim height
in the rear than in the front, and us drop-top folks riding even higher
than the coupe-group. I like a car to sit level. I’m not
suggesting that you drop the bumpers to the ground and make showers of
sparks, just lower your car an inch or so. I used to be able to stick my
whole arm above the tires to clean the inside fenders, now I can barely
get my fingers in there -it’s great. Since you can’t see in
there anymore, I no longer have to clean in there. And it LOOKS much
better! Just remember that if your want to race your Corvette, check
your NCCC competition Rule Book first – most suspension modifications will
put you in a different (faster) class – which should tell you something
about the performance benefits!
Lowering the rear of your Vette
is easy, just be careful and follow the instructions in your service
manual. C-4’s use a lightweight transverse spring on both ends of the
car. Just move some spacers from the top of the rear spring to the
bottom. Another way to lower the rear of your car is to buy a lowering
kit (under 30 bucks) from Mid-America Designs. Included are longer spring
bolts that’ll do the same thing and are infinitely adjustable. Here
we go again, on the creeper. Sometimes I think I spend more time UNDER
our Vette than actually driving it…
Lowering the front of a
C-4 Corvette is where things begin to get nasty. The rubber bumpers need
to be cut off the top of the transverse spring and replaced with smaller
urethane wedges included in the lowering kit. The only problem is that
you gotta take the car half apart to lower it �”-1”. Is it worth
it? I think so – I can’t stand to see gobs of wheel well above the
tires. Once the car is up to the moon on (very high) jack stands, the
wheels are removed. Then the lower ball joint, sway bar end links and
shocks are unbolted from the lower control arms on both sides of the car.
The lower control arm on one side of the car is then removed. After
removing the spring protectors and spring retainers, the spring can be
pulled out. You then cut the rubber bumpers off from the top of the
spring and glue the urethane wedges in their place. I used my hackmaster
(SawZall) to cut the rubber. Friends stopped by our house one Saturday
afternoon in their ’62 and watched in horror as I used this very
tool to cut a big hole in the radiator shroud of our Vette for a cold air
intake system. It seems ironic that such a crude tool would have a use on
a precision automobile like a Corvette.
Yet another way to lower
your C-4 Corvette is to install “coil-overs”. These are shock
absorbers surrounded by a coil spring and a threaded collar for ride
height adjustment. This system replaces the transverse springs and shocks
in your car. Each wheel is truly independent, so there’s no
“crosstalk” from side-to-side like the stock setup.
They’re the racers choice. The downside is cost (about $1300) and
they take a very long time to install (just ask my wife), requiring
modifications to the front and rear frame in the shock mounting area. The
front sway bar must also be moved forward 5/8”. I would guess the
weight difference is about the same between the two systems. Those
transverse springs are really light, but there’s lots of mounting
hardware associated with them.
Heck, now that your Corvette is in
a bazillion pieces all over the garage floor, now is the perfect time to
install those BIGGER ANTI-SWAY BARS you’ve been thinking about! The
front bar on our car was surprisingly wimpy – it was hollow and weighed
practically nothing. No wonder our car had so much body roll. I fixed
that pronto with a solid 30mm (Z51) bar and new urethane bushings. In the
rear I went with a solid 24mm bar and new urethane bushings. The stock
setup was 26mm hollow front and a solid 22mm rear, with rubber bushings.
If you change bars, try to approximate the stock front-to-rear size ratio
or your car will have oversteer (back end likes to lead the way into and
through the cones), or understeer (car plows into the cones without
turning). Stock, the car had understeer – a safer, more forgiving
alternative.
Now go get an ALL WHEEL alignment. It only takes
about an hour and runs around $75. Sometimes I pick a sunny day and call
for a while-you-wait appointment. Usually though, I’ll drop it off
the evening before and have them park it inside – nice and secure. Enjoy
cruising in your LOW RIDER
-Bill Rauch 2/3/1998