Roger Renfrow, Driver
Bobby Vyne, Crew Chief
Click for
~Tech Page Glossary~

Kevin $laby
kdslaby@yahoo.com


Before

Kevin,
I am involved with a 67 camaro with too much engine. The suspension is factory with adjustable drag shocks up front with limiting straps. The rear is a 4 link using a mickey Thompson ET street 31x 14.5 tire. We are running in a tire limited heads up class and are struggling with our 60 foot times. The car is running a blown alcohol 522 ci chevy with a 1471 blower. The engine produced 1400 hp at 7500 rpm with a very conservative tuneup. The problem lies in a 3200 pound car with 1250 horsepower and 1300 plus foot pounds of torque at 4800 rpm running through a powerglide. We have managed to get an 8.41 at 172mph so far on a Friday night track in Arizona. The best 60 foot so far is 1.372 with a 5.50 1/8 at 136mph. The car, when it leaves it is violent, it hits the wheelie bars hard and hazes the tires. It seems to be unloading the tires when it hits the wheelie bars and it hops about 3 times before it settles down and runs. So far we have tried one 4 link adjustment to no avail, (moved the top bar up to take some bite out of it (mov e IC forward) and it just hazed the tires about 200ft) 1.4 60 ft. Any suggestions would be greatly appreciated.
Bobby.

After

Kevin,
Thanks a lot for your time, everything went better than expected. We went for condition 3 because we knew we had a limited number of passes at super chevy. It responded with a 1.320 60 ft (best ever) and a 8.42 at 169.4 m ph. The car did nothing stupid but struggled a little to bump the wheelie bars. So it added a little more bite by moving the instant center to 90% antisquat and 51 inches o u t. Also, I adjusted the front limiters to allow 2 inches more travel and raised the wheelie bars another inch. I put the timing back in the engine and the car went 8.02 at 176.85 on a bad track!! The 60 ft time was 1.300, 330 was 3.42, 1/8 5.241, 1/8 mph 1 40.5. The next pass, it looked like it could take more power out of the hole. I added 2 degrees more timing out of the hole, roger forgot about it (he wants a 7 real bad) and hit the timing advance button with the front end up in the air. The car smoked t he tires with the front tires about 12 inches off the ground and didn't stop hazing the tires for about 150ft and still went 8.14 and 1.310 60 ft. A great weekend .
Thanks Kevin,
Bobby V.
Roger Renfrow

Update
2/18/04

Kevin,
We just ran at Speed World here in phoenix and took second place.  We ran 8.11 at 180mph but are still struggling with the tire.  The reason I say the tire is because we bolted on a Mickey Thompson 10.5 w (33 inch tall) and the car went 7.80 at 180mph three times with no problem. We won the Outlaw class at a memorial race at speedworld with a 7.80 @180. We made big power changes, out of the hole and top end and the car seemed non critical.  Everything worked all three runs were in the 7.80's.  It also went 1.22 60ft on the rear tire. Humm. With this (suspension) setting the leave is fairly aggressive but the back body line stays the same distance from the ground on the leave.  I think this is very close to your first recommendation to us a long long time ago.

Bobby

kdslaby@yahoo.com