62 Chevrolet, STILL No Traction

[Dick Butler]

On a good track by someone elses performance changing tire pressure UP 3 or 4 lbs stabilizes tire wall. This fights distortion or wrapping up the surface of the slick. With no one to observe for you the 60 ft time change if present can give hints about whether you are TOO high on instant center or ..... Sounds too High off hand for me. I think it would like more like 6 or 8 inchs. Get an observer to watch or film the rear tire on dropping clutch. My money is on TOO much attempted % rise. Dick

[Oldtimer]

http://aolsearch.aol.com/aol/search?...lover&ie=UTF-8

Here is a link that will give you a page of choices on Instant Center for free.

[Leif Andersson]

Maybe you find something usefull here.
http://home.earthlink.net/~whshope/

Leffe

[Bob Mulry]

Originally Posted by NHRAstocker409

DAMN !

What I failed to mention, is that I am releasing the clutch at about 5000 ( 7000 RPM engine ).

I don't know what you mean by 5000 (7000 RPM engine)??

Do you use a 2 step to set your leave RPM??

Do use a very light weight flywheel to cut down on inertia??

Maybe at a 7000 RPM leave you have all of your centrifugal assist in??

Bob

[Aubrey N Bruneau]

Oldtimer, that DID go to a list of links. None of them seem to address the what is desireable as a drag racing application.

Not bad there, Leif... but again, no practical diagrams indicating the desired geometry.

As mentioned earlier, Bob... aluminum flywheel ( 11 pound ), aluminum McLeod 10.5" "hat"
What do I mean ?
exactly THAT !
It's a 7000 RPM engine, that makes NO power below 3000, with horsepower peak at around 6700-6800.
With this 7000 RPM engine, I can release the clutch as low as 3500, and still blow the tires right off.
Two step ?
that's a dance, isn't it ? !
Need my "shoes" on the ground before I'll bother to try dancing !

oh... the centrifugal weight that I added.... 8 grams, on each of the 3 release fingers.

Here's a link to a VERY rough sketch that I did up, after I took a whole series of very acturate dimensions:
http://www.bruneauperformance.ca/62b...eometry900.jpg

Bottom picture is exactly as the car is right now.
Upper picture is after my proposed lowering the rear 1 1/2 inches.
The 63" dimension, is a result of lowering the front loer control arm mount at the frame ( not permitted ).

[Bruce Fulper]

If you got no help use a tripod for the camera. Must be able to see what's going on.

[Jeff Lee]

"A person can feel the slippage on engagement... the "torue converter" philosophy "

What do you mean " a person can feel the slippage on engagement" ?

[Aubrey N Bruneau]

Here's that clutch slipping, Jeff:
http://www.bruneauperformance.ca/wat...tstock409.html
can't explain the tires though ? ? ?
and p l e a s e... no more about the "track is God's ground"... time and TIME again, it aint.
but seriously...

Low RPM, high RPM... ?
If this thing planted the tires AT ALL, it would shut the engine off if I tried to dump it at 3000.
Like I mentioned earlier, there is absolutely NO slippage in high gear.
Yes, I do use the clutch to shift ( doesn't the rule book say you have to ! )

The video above, is an old one, with the old tires ( they were relatively new at the time ).
Isn't quite THAT bad anymore. Like I mentioned, rather than bouncing off the rev limiter, and having to "back pedal"... at least now, the limited traction I have, keeps the engine from flaring up like the car's on ice.

You're right, I doubt the lower 1st gear is the miracle cure ( like... not )...
I just wish somebody could tell me where this rear control arm geometry should fall ?

[Mike Pearson]

Make sure the lower link connecting the rear end to the frame is running down in the front at least 2 degrees. Park the car on a level surface and step back and look at it visually first. the bottom bar must run at a down angle ( lower in the front ) in relationship to the rocker panel. If it is running up it will not hook up even on the best track with new tires. You may need to adjust the ride height to correct this problem if it exists. Had the same problem with my super stocker.

Mike

[Aubrey N Bruneau]

Originally Posted by Mike Pearson

Make sure the lower link connecting the rear end to the frame is running down in the front at least 2 degrees.the bottom bar must run at a down angle ( lower in the front ) in relationship to the rocker panel. If it is running up it will not hook up even on the best track with new tires. You may need to adjust the ride height to correct this problem if it exists.

Mike

that bears repeating
all said
THAT is exactly what I am experiencing... no traction, no matter WHERE the tire pressure is !

Mike, it would be basically impossible to make the lower control arm rake "down", while even remotely staying within the rules.
By lowering the car though, I can get a lot closer... and the upper arms will provide that snap down ( up on the body ) on the axle housing when it tries to rotate back under engagement.

Thank YOU, Mike !