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I watched a few vids of cars at some Goodguys events doing their mini autocross track for fastest time. This interests me a bit planning on the upcoming Goodguys at Kansas City Speedway. On a tri-5, what would be the most bang for the buck upgrades to making one handle the orange cone hiway? I don't mean spending oodles of money on an Art Morrison chassis, but just some basic upgrades. I already have disc brakes.
 

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Swaybars- if you don't have them already. Are you going to run the '56 or the '55? There was a post about Newman's green wagon (bosses son) running autocross a while back. He mentioned that they increased the tire pressure when they got to the track. That doesn't make sense to me- wouldn't that decrease the tread in contact with the road?
Sounds like fun, Jesse
 

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Tire Pressure increase

I think they raise air pressure to keep- tires from rolling under and off the rim.:)
 

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Anti-roll bars front and rear with polyurethane bushings.
Good shocks
Lower profile tires
Add negative camber and reduce positive caster(maybe even toe-it out a small amount for race day)
Lower the suspension (increase the spring rate some at the same time)
Increase tire pressure to reduce sidewall flex

Controlling body roll and having good tires will likely give you the best bang for your buck.

Have fun,
Andy
 

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I always used Hooiser auto cross tires, 8 inch wheels on front and 10 inch on back with about 26 lbs. pressure on a trailered car. the guys who drove their street cars usually had someone in another vehicle bring another set of tires for racing other than their street tires if their class allowed it. You are right , it is fun but can get very costly with no return except for fun and recognition.
 

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I would think a steering box swap would be good???? Turning the heck out of a stock steering box with that slow ratio would be funny to see.
 

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C4 suspension and steering.:D

Or: QA1 shocks set to full stiff, sway bars front and rear, and lower profile tires.
 

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We have an autocross event at many of our Corvair get togethers. They are a lot of fun. They require us to have an approved helmet and do a basic safety check. Check on the rules before you get there. The Corvair inspection involves hitting the brake pedal pretty hard and it's supriseing how many rusted brake lines bust open. If a swing axle, Corvair van can run, a tri-5 and do it. :)
 

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We have an autocross event at many of our Corvair get togethers. They are a lot of fun. They require us to have an approved helmet and do a basic safety check. Check on the rules before you get there. The Corvair inspection involves hitting the brake pedal pretty hard and it's supriseing how many rusted brake lines bust open. If a swing axle, Corvair van can run, a tri-5 and do it. :)
needs an outrigger
 

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I think they raise air pressure to keep- tires from rolling under and off the rim.:)
Increase tire pressure to reduce sidewall flex.
Well, I didn't expect my first post here to be about autocrossing and tire pressures, but here goes! :D

I autocross my '86 BMW 535i extensively. While I do have stiffer and lower springs (20%/40% F/R, 1" lower overall), stiffer sway bars, stiffer shocks, and adjustable metal/bearing camber plates up front (no rubber isolation), I still get a good bit of body roll. I can't go more than 1° negative up front unless I go with coil-overs (spring hits the inner fender), so with the body rolling, both front and rear tires camber out relative to the ground.

Thus, to keep the tire from cornering on the sidewall, I jack the pressures up to about 44/42psi F/R, depending on the track. I measure how much I need by marking the sidewall with "window chalk" and making sure that the mark isn't rubbed off past the shoulder. Yes, this does reduce contact area when going straight, but grip when going straight isn't usually a problem (folks who run 3° or more negative camber usually see reduced braking grip, though). I adjust the pressures between runs to allow for heat, where the mark is rubbing, and if I want to change the balance (too much understeer = put more pressure up front or reduce the pressure in rear; too much oversteer, do the opposite).

BTW, the tires are 225/50-16 all around and the car weighs about 3400 pounds.

Hope this helps with the pressure question!
 
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