Very good reading! Like many people, I enjoy autocrossing as well as driving the car occasionally on the street.
I'm turning fast times and am giving some of the fastest competitors a run for their money in autocross (and they have lots of mods on their cars).
What would be a good entry level upgrade for a 2002 ZO6?
I have the following: Car is lowered all the way on stock bolts. Negative camber of -1.2, 7deg, 0 inches front with 0 total toe, 0 cross camber and -0.06 cross caster for the front and and -0.93, 1/8 inch on rear with 1/4 inch ctoe and 0.01 thrust angle for rear. race tires are Kuhmo V710s I'm considering upgrading the shocks to Bilstein Sport or 2004 ZO6 (sachs shocks?) upgrade from stock, negative camber settings to max possible.
opinions please.
any other easy mods that make a substantial improvement?
thanks in advance!
PS how harsh are bilstein sports????
Please make sure that you're not on the bump stops since you mentioned that the car is lowered all the way on the stock bolts.
I don't have any experience with the Bilstein Sports, so I can't comment. I have the 04 Z06 shocks (yes, they are supplied by Sachs) on my '03 presently, and have had decent results with the car.
Alignment specs look okay. You may want to experiment with toe out in the front. Since the car is aligned to zero toe, simply mark the links so that you can easily reset if you don't like toe out up front.
I doubt that you want maximum negative camber up front. Seems that most folks are in the -2.0 to -2.5 range. Max negative camber will be more than that. Lots of negative camber, of course, gives you more grip in sweeps, but is a detriment under braking.
You didn't mention if there's a particular sanctioning body you're running with (and their rules), and I'm making the assumption that you're running a stock-type category. You may want to consider a different front sway bar. Seems to be a split between those running the factory front bar and those running a bigger bar.
Thanks ACRACE.
How do I check to see if I'm on the bump stops? I've heard a loud thump occasionally when I'm deep into a corner under significant g-force load. The chasis didn't seem to get upset when I heard this noise. Could that be a bump stop?
for the Alignment, I'm thinking of increasing it to the -2 deg range to get better bite in the corners. Since I don't drive it long distances and on the street a whole lot, I'm hoping this will be acceptable.
I'd like to change sway bars, but I believe that Group II in NCCC, which I race, prohibits adjustable swaybars. If not I'm certainly game for it.
I'd like to be able to adjust the camber, toe, etc myself; but am a novice at doing that stuff and haven't done it on the Corvette. Plus I don't have a lift.
Thanks again for the advice.
(Is there a better place to post this thread? )
Happy Holidays!
Darren
The best way to determine what camber to use is by gathering empirical data in the form of tire temps taken across the tread. You will need a tire Pyrometer to do so accurately and the temps need to be taken immediately after coming off the track or course. Thus, another person is almost a necessity. You can also mark the tread/sidewall shoulders with white chalk and watch for excessive outside shoulder wear.
Much of this depends on the tires you are running of course; with Hoosiers for example preferring much more negative camber than street tires.
As far as determining whether or not your shocks are contacting the bump stops, the fact you are lowered all the way on the stock bolts and using the stock shocks, it's a virtual certainty they are at times. In order to prove this you could paint a telltale on the shock bump stop, but unfortunately, it's not visible on the stock shocks due to the protective sleeve. Hence, max lowering with the stock suspension should be no more than 12mm. Per Mike Neal, Corvette ride and handling engineer.
You don't have to have a lift to perform an alignment; in fact, you don't have to lift the car at all, although it obviously helps in many other ways. Using the string method, with a straight edge and a tape measure works fine. And although not required, a camber gauge makes it easier and faster with less calculation required.
You're right in that Group II NCCC doesn't allow for an adjustable sway bar, but you could always put on something like the Addco 32 mm bar and use the factory end links.
As far as getting on the bump stops, I would surmise that it would be most evident and disruptive if you were to hit a bump or expansion joint during hard cornering or under acceleration during corner exit. I took the protective sleeves off my shock assemblies, and simply used small balls of clay on top of the shock body to see if I had contact. Since you have the sleeves on your shocks, this isn't practical. As I understand it (but have not done it myself), there are folks that have checked shock travel by putting zip ties around the shaft. But, to be honest, I don't know the details.
Toe is relatively easy to do. Since you haven't done it on the Vette yet, I would suggest getting a baseline (of course, that baseline changes every time the camber is adjusted) and marking the tie rods so you know where the baseline is. I don't remember the exact value of how much turning the tie rods one "flat" relates to the numerical value. I'm sure that info is archived on some forum somewhere. I've used a trammell bar to adjust toe, but maybe I should just spend a little money and buy toe plates. Easier to use on a Vette.
If I go with Bilstein Sport shocks to replace the 2002 stock shocks and the car is lowered all the way, do I need to have the bilsteins modified to avoid hitting the bumpstops on them too?
thanks again!
D
If I go with Bilstein Sport shocks to replace the 2002 stock shocks and the car is lowered all the way, do I need to have the bilsteins modified to avoid hitting the bumpstops on them too?
thanks again!
Addco 32mm sway bar....how much better is it?
D
The bigger front bar will tend to make the car understeer more. But some people think that the car is faster/more stable in slaloms, and that power can be applied a touch earlier exiting sweepers. Really, it's going to come down to personal preference and you may want to borrow a bigger bar and test it back to back with the stock set up.
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