93Rubie

I have a C4 I just started auto-x with and I am wondering is it better to run with the targa top on or off. I would assume that off it would give quite a bit more chassis flex but I would not run the risk of cracking my acrylic targa top. Your thoughts?

Carolina C4 Racer

Leave it on. It will not crack.

bdanyluk

Most places require it on...unless you have roll bar.

jaa1992

ON, your car becomes a flexible flyer when it is removed - even with a roll bar!

93Rubie

I'll leave it on then, if fit (barely, 6') with my helmet on so I'm ok.

rfn026

Years ago Roger Johnson did a lot of testing with GM. There was no question that the C4 Corvette flexes more with the roof off. What was interesting was that it made no difference in his timed runs. It made no difference whether the top was on or off in the real world.

For all of you younger types Roger was SCCA national champion numerous times during the 80's.

btw - I run track events with the roof in place. It's just easier since I tow on an open trailer.

Richard Newton
Newton's Law

Z07coupe

http://r-dracing.com/targa-truss.htm


This may be an option. Check with your sanctioning body's rules and see if this complies with the rules. I thought SCCA had approved this, but others with SCCA experience will correct me if I'm wrong. I don't know if NCCC has approvrd this unit.

Glad to see you autoxing your Ruby.

Bill Dearborn

Yes, this is NCCC approved. It is no different than having the targa in place but allows tall people to drive the car in an autocross without being forced to bend their head down to fit in the seat. We have a club member who uses this bar since he is 6'3". With a helmet on, the top of his head is a couple of inches higher than the roof halo.

Bill

Biancone

That truss bar could technically bump you from B Stock to B Street Prepared if that's a concern.

93Rubie

I thought about getting the targa truss, but I fit in the car with the top on, barely. I'm 6' and with my helmet on I have maybe an 1 inch or so tops. Therefore, I think I'll just leave well enough alone. I don't need car mods, I need a driver mod...

I am running with a SCCA chapter and they are not too particular about things so I don't think I need to worry about bumping a class if I did choose to run the targa truss. I run in A Stock.

The only thing I don't like about Auto-x: A: I'm still learning and I am very slow, (the driver not the car). B: Car gets dirty takes a lot of time to get her cleaned up again. Then again when I got to shows and stuff I always get compliments on how the car looks, then I tell them I race it. Always gets a reaction.

My recent event I was very slow but had lots of run and learned a lot. After the timed runs my best was a 76 and change. FTD was 61 and change. I asked the club president who has a 98 and 93 (full race) Corvettes, if he would like to drive my car and show me what a real driver can do with it. He said yes, first run he ran a 71, he was stunned it was so slow as it felt fast. He turned it up a notch then ran a 66 on the second. All on Kumho Escta SPT's on all four corners. I then made a fun run and ran a 72, so I knocked off 4 seconds just by doing a ride along in my own car.

Next event is next weekend at a new venue a private airport. Should be fun, the last event was at a airport too, lots of speed. Auto-x is so much fun...

Biancone

The ride along was a great idea obviously, and you may want to consider doing it again or look at a school. There is also a great book by Henry Watts called [I]The Secrets of Solo Racing[I]. I've been autocrossing for 6 years and regularly refer to it. Lot's of good info.

A Stock? Hmmm....Here the C4's got bumped to B Stock this year. Interesting.

Showing cars is nice, but even nicer when there's a time slip in the console.

Z07coupe

Rubie,
You did it right to ask a more experienced driver to assist you. Keep riding with good drivers and you will learn more. I'm 64 and I am slow --even in a fast car.
What are your tire pressures?
Are you sure your Ruby should be in A stock?? Doesn'r sound right to me, but I do nothing under SCCA rules.

Is there a NCCC club in your area?

vettehardt

The Targa truss actually bumps you up to group 2 in NCCC. So 93ruby would be in 2G.

Solofast

Rich is right the testing that Roger and John Carrier did there was no time gained with the top on or off. The lower weight probably was traded off in chassis stiffness.

What I did find with C4's is that if you take the top out of Z07 car (with the stiff springs and bigger bars) you can really feel the chassis twist. It feels like you are riding on the rear suspension and the front is twisting every time you load the car to high G (like with DOT tires). The flexibility was disconcerting to me so I always left it in.

Also I noticed that the with my cars if I took the top out the car developed a lot of interior squeaks and rattles and noise that wasn't there before I took the top out and they never went away. All that flexing resulted in more plastic on plastic noise. Since I was cycling through two or three cars a year, I got to the point where I never ever took the top out of cars that I wanted to keep. They were a lot more quiet if I never took the top out.

JMHO, and with our BSP car Larry always took the top out.

93Rubie

No NCCC clubs around to my knowledge, their site does not show any nearby.

I will have to find a way to get more ride alongs with more experienced drivers but seat time is very valuable too.

I run 40psi at all four corners, even when the club president drove my car hard it never rolled over onto the side walls. Up to the edge of the tread yes sidewalls no.

Actually your right on the class, I am in B Stock, oops...I'll make sure I make this known to them. Only C5 and C5 are in AS and SS. AS is what they put me in, I had no idea. Now I know.

http://scca.org/documents/2011%20Tec...lo%20Rules.pdf Page 162

Here is a link to the chapters website, small group but really nice people. Very helpful and always a good time. http://ah-scca.org/Schedule.html

Z07coupe

I also checked the NCCC web site and find it hard to believe that there appears to be no NCCC clubs in western PA. The up side of NCCC events is that you will not only compete with only Corvettes, but your class will probably be restricted to your model. NCCC events are opened up more than SCCA, in that the courses are usually faster. SCCA courses are usually tighter, which is better for a light weight rice burner.

Bear in mind that since you are new to autox, I would learn to do the best I could with what I've got before buying the extras. Tires are the first improvement.

If you do get a truss, you may as well install a camber brace, also. That item will also bump you up to group 2.

Is your Ruby a Z07? SIx speed?

93Rubie

I agree with no mods until I can drive it stock. That has always been my idea, why mod, when you cannot drive the car to its potential wither it be drag strip or auto-x or whatever. Driver mod...still working on that one.

I'll stick to the street tires for now until I learn how to drive the car well with them on.

FX3, and ZF6. I'll just stick with the targa top for now.

Z07coupe

You're doing everything in a logical manner. You're doing well. Have fun with it.

Who is conducting the autox you attend, and where? In the late 60's and 70's I was a member of the Homer City Motor Club. We mostly held time/speed/distance ralleys and some autox. The club disolved around 80-81. The closest clubs were SCCA in Pittsburgh back then.

93Rubie

http://ah-scca.org/

Only formed a couple years ago. Nice group of folks.

Biancone

Rubie, if you want some more seat time, check out the events at the Cumberland, Maryland airport (technically in West Virginia) http://www.nationalroadrally.com/info.html. The Harvest Moon Autocross is next weekend. $40 a day, Saturday & Sunday events. Instructors available at no charge. It would be less than 2 hours from Indiana to Cumberland. We usually get some very nice participation from The Steel City Corvettes at our events along with the crew from Mid State.