TMyers

Last year was my first attempt at autocross and I had a blast. Ran 2 events just for fun and still have alot of room for improvement. My car is an 08 C6 with the F55 suspension. I plan on running a bit more serious this year but I am still going to stay in the stock class. This is still my everything car.

The first upgrade will be a harness bar and pilot harness. I entend to keep the stock seats at least for this year. It seems to me staying in the seat will decrease my times.

In the events I run in stock means no comp tires. What would be a good set of tires that are not comp in nature. Anything has to be better than the stock runflats.

The last thing I will do is get a good alignment. I have not had it checked since I bought the car. I am just trying to make sure alignment is within spec but would like to favor what would be good for track days.


Any advice or suggestion would be appriciated.

LehmanZ06

I believe you can cinch the lap belt. Maybe wear a knee pad on your left knee. Personally I never liked the harness route, when I ran SS in my C5Z06. Still don't have a harness, but now I run ASP with a Sparco Evo Seat-----

Alignment Yes !

Michelin Pilot Sports PS2.....go to tirerack.com and look at your choices.

Do a search for "track day/ street alignment"---a dedicated autox alignment---could be a bit twitchy at high speed.

DonF

I run Street class, have for years, just putting in a harness, did without for at least 10 years but find myself on high speed events using the steering wheel to hold me in place.
Kuhmo now makes an excellent street/track tire now but don't know if your size is ava. yet.
Your alignment will be the prob. if this is your daily driver. A true Auto X alignment will chew up your tires if you are on the road all of the time. Vette Brakes always has alignment specs in their catalog for various uses check it out.
Race on!

Pylons

You can have a pretty aggressive autox-oriented alignment that is not a killer for a daily-driven car. Negative camber is not necassirly a big deal as long as you don't pair it with toe out. I've had multiple daily-driver autox cars with about -2 deg front camber and zero toe without tire wear issues...I don't have a ton of miles on my DD Vette with the autox alignment (-2.2 up front with zero toe, -1.2 in the rear with a touch of toe-in), but so far so good.

Pylons

I'm also not a harness fan...more of a PITA than it benefits for me...would be a different story if I were on track I suppose, but for autox, I just get the seat belt a few inches from buckling and give it a quick tug to lock it...then buckle it and move the seat forward and up a bit to really be in there snugly.

AverageVetteNut

+1 on the the tire issue... toe is what really does a number on tires. Camber alone won't chew them up. I had 1.2 in the front of my Cobalt after nationals, and drove 18K miles on the car before I really noitced any inside wear on the tires.

I would say hold off on the harness and get used to the car as-is for now... you'll be able to feel how the car is getting pushed around IMO, and the $ can be better spent on tires / alignment.

next I'd get some decent brake pads that have good bite, but don't 'stick' once you let off.

Good luck and let us know how things are going

racerjon1

I agree with everyone else on the alignments (slightly aggressive is ok for the road) and tires (PS2). So I won't rehash that.


I will kind of clarify the belt issue though.

The belt won't make you magically faster, but in my experience being more solid in the seat helps with consistancy, slide recovery, etc. Personally, I like having a harness in an autocross car, but I will also use the "tug and lock" trick, twisting the belt to make it tighter, and I have seen good results with a device called a "CG Lock."

Like I said, don't magically expect to gain a second per run, jsut expect to be able to be more consistant where you are.


Jon

AverageVetteNut

I LOVED my CG Lock, but in the C5 that won't work since the stock belt design doesn't have the sliding connection. That helped me a ton to feel more planted in the seat, but I like having my shoulders freee to move, so it worked really well.

Z06Fix

I think my next investment is going to be a harness for mine. I feel like I'm fighting to stay in place then fighting the car on top of it. I drove a C6Z during the runs at the last event and it was a huge help being able to lock the shoulder belt. I really wish the C5's had the same belt in them

Aardwolf

Just a quick comment on the harness, I don't autox but do go to many track events. I didn't see any decrease in lap times going to a harness but I got much much less tired. One track day would wear me out, switching to the harness and after two days felt less tired then I did before with just one day and no harness.

racerjon1

Ah.. that's right.. I had forgotten what the GM design was on that.. (the last Z06 I was in had harnesses)

Back to the "pull-and-lock" or the twisting method for inexpensive but better driver-holding methods.



Jon

Bill Dearborn

Not sure why you would ever twist the belt when you can just use the cinch mode. With cinch mode you can get the lap belt tight enough it feels like it is going to cut you in two. Then the shoulder belt locks as soon as you start fast. Almost as good as a 4 point.

Even with 5/6 point harnesses in the car you still move around a lot due to the stock seat's lack of leg support.

Bill

EvilBoffin

Cinch mode on a C6 means pulling the belt ALL the way out until it stops, then it will make a mild 'ratcheting' sound as it retracts and tightens against you (there's no 'cinch' button like on a C4). It will not release again until the belt retracts back to it's fully-relaxed storage length.

I actually use my memory seat function to automatically tighten the belt against me for autocrosses --> while the seat is in the 'Exit' position (all the way back), get seated, buckle the belt and extend the belt all the way to activate Cinch Mode. Tighten the belt manually to a reasonable level and then press the '2' seat memory button, which is set for my pre-defined (much closer) racing position. As the seat moves forward, it also cinches me into a much tighter belt.

This ensures that my seat is in the optimal position for performance driving without having to fiddle with the adjusters every time, there's no need to twist the belt material, and it gets the belt really tight all at once.

Also be aware - SOME sanctioning bodies may consider a harness bar as grounds to move you out of a stock or street tire class, since it could be seen as a chassis stiffener. So, check your group's rule book before spending big bucks on one.

One alternative to a full harness & harness bar would be a lap belt bar, which attaches to the rear seat mounts - like this one (click the pic to visit HardBarUSA) :



Obviously, this device doesn't accommodate shoulder harnesses. But it keeps your butt stuck in the stock seats with a dedicated lap harness, while leaving your upper body free to make the big steering motions you need for autocrossing. And it can remain installed in the car all the time - just clip in the belts when you arrive at the event and you're ready to go...

.

meldog21

If you can do it, a harness will make driving easier. You may not realize how much effort you use to keep yourself in the seat while driving with regular seat belts. AutoX is different since the time is so short, but I have an example of how hard staying in the seat is without a harness on the track. Before I got my belts, I actually wore the skin off both elbows by the middle of a trackday. That is after 3-4 twenty minute sessions running on sticky tires, but you get the point. If you're not working at holding yourself upright you can spend the energy driving.

Dog

R Mackow

2000 C5;
1.Tires for AX- 17' front/18" rear BFG KDs 245/295 and are step better than the kumho MXs.
2.Ride height - lower the car a little.
1.&2. gave me about .7 sec. faster on a 60 second AX course.

Alignment - 1/16" toe out front, 1/16" in on rear. Caster 6-7 deg.
camber: -1.5 frt; and -1.0 rear...that's all you can squeeze out of a stock C5. KDs have lasted over two years now.

B-K harness bar - w/Crow 6 pt. harness. Use the B-K waist "clip-ins" which take the lap belt + the crotch belt (which you sit on). Therefore no belts are connected to floor infront of driver seat or no holes are drilled through seat to hold the crotch belt in a 5 pt. harnesss.

Seat - sit closer (and more erect) to the wheel than you would on a road course.

TMyers

Thanks everyone I really appriciate the input. After last year I decided that a harness was a must. But it was just to much work trying to stay in the seat.

What do you all think about the Kuhmo XS? I still have to check with the sactioning body but I think I can use them in the stock class.

avizandum

Kuhmo now makes a new tire - Ecsta XS in C6 sizes. I ran them in the back last year and was very pleased. I expect the fronts would be pretty bad in the rain for daily driving.

If your tires are F1 Supercars, use them up before you buy new tires, They're not that bad forAutoX.

Edit - There's no reason they would be illegal in a street or stock class.