You want to lower your
Vette, go for it.
I should have done that
on the first day I bought the car. Some owner
could not lower because of the angle of their driveway or the usual
road condition.
I drive 80% to 90% on
highway. I do not go on regional road too much.
The front air dam touches the ground sometimes, but at the same places
it was scraping before I lower. It is mounted with springs so, it is
design to scrape anyway. I will buy an other one if it wears out, but I
would doubt it. The front fascia or frame guard never scrapes. I enter
big gap drive way in an angle. The only time the rocker panel scrape
was at the dealer on the alignment machine.
They should have put piece of wood. Next time I make sure the put some.
It is not a problem at all.
I’m kind of sorry for the ones who cannot lower. 
In summary, Measure the
stock height on a level surface. Measure from
the frame. In front of the hole where we put the jacking puck. Always
measure at the same spot. You can put tape on your garage floor to put
the car at the same place. Use a full tank of gas to measure. Some guys
put the equivalent on their weight on the driver seat to simulate the
driver weight.
Jack the car
Remove the clip on rear bolt. Unscrew the rear bolts. Leave two thread.
Re-insall the clip.
Remove
the clip on front bolts. Release spring pressure by putting a jack
under the end of spring leaf. Unscrew the front 10 mm bolts. That will
raise them. They are counter threaded. Re-install the clip.
Before:
After :
Be careful not to strip to front bolt head. Drive for a couples of
hundreds miles and get it aligned.
See the difference:
Additionnal notes:
How
can I turn the front bolt without stripping the head?
I have the car on 4 jack stand. I putted an hydraulic jack
with 2 hokey
pucks under the spring to remove the pressure between spring leaf
& A-arm & bolt bushing. I use a 6 point socket. I put
wd40 yesterday and still no movement.
Since the leaf is fiber glass I cannot heat with the gas welding
torches without damaging it.
Any idea?
note 1: The driver bolt turned without removing the pressure
from the
spring at first attempt.
Eureka ! I
got it. 
I went in the garage and spray wd40 all
over the spring and rubber bushing. Normally, I
heat jammed bolts with gas welding torches. Since I cannot do it on the
composite leaf spring, I started to heat the spring with my heat gun. I
heated the bolt and leaf spring for about 2 minutes just enough to burn
my finger when I touch it, but not enough to damage the spring. I also
put shield to make sure I was not heating the wheel sensor and wire,
shock and plastic end-link sway bar. Then I removed the spring pressure
from the bolt. The bolt & rubber was not touching anything.
Well, except the leaf spring that it was jam to. I took my 10
millimeter socket and the ¼ ratchet and the bolt turned
without
excessive force. I moved it from left to right a few times and it is
turning freely now. Fantastic!
I hope I will be able to get her down by 1 inch and hopefully see some
gain on the handling.
Lower
and impact on alignment. I drove 4600 miles between both
alignment.
Before lowering (Oct 20, 2005)
_________LF __ RF __ LR __ RR
Caster____4.76 4.66
Camber__-0.34 -0.26 -0.14
-0.16
Toe______0.06 0.05 0.01
0.01
After Lowering (Feb 10, 2006)
Caster____5.48 5.61
Camber__-0.62 -0.56 -0.20
-0.24
Toe_____-0.07 -0.13 -0.13
0.17
As expected, lowering gives negative camber. It also gives tow out. I
read somewhere that lowering we resulting in toe in. That was wrong.
The surprise came as a change on caster. The GM tech told me that I
could have lowered the rear more than the front causing a change to the
angle.
I decided to come to GM
spec caster setting. I do not know why previous
owner had it at 4.6 & 4.7.
new specs (after today's alignment)
_________LF __ RF __ LR
__ RR
Caster____6.35 6.43
Camber__-0.35 -0.34 -0.21
-0.29
Toe______0.04 0.07 0.00
0.00
I
do not feel any suspension or handling difference at all after
lowering. I have not tested on road race thought. Also, since the tires
have little traction because it is cold I could not really test on
curves or turns.
The only difference is the look. I guess I’m the only one who
can tell. I’m happy with it….
For now…. I’m not saying that I will never lower
it some more.
Is it worth it? Technically? No. Look wise? Yes for me. No for the
other people because they will not even notice the difference unless
they are C5 expert.
Jan 2006. It
has not been raining or snowing here for the past 4-5 days. It is cold
(5-10 F) so the roads are clean and dry. I drove about 600 miles over
the past three days (400 today). It does not scrape more than it was
before.
Note: someone on the CAC forum said that GM set up the Vette with like
that for bumper height regulation. This is why I believe they made the
lowering job that easy for us. I see it as the 1-4 shift (CAG). GM gave
us the option to easily bypass some rules. So why not lowering?
Cannot plow snow yet. Not
low enough! Maybe next winter if I decide to
cut the busing....
