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-   -   4-link/swing-arm dragster burnout (https://www.racingjunk.com/forums/showthread.php?t=27910)

johnracer 05-24-2010 11:19 AM

Yes we race in Denver and in Grand Junction Co a lot. In Denver with the Goodyears he ran 8.02 @ 169 with 1.18 60's in 7800' air. About the same in GJ with the Goodyears. The Hoosiers picked up the 60 a solid .03 and pushed the et to a 7.96@169 best. Only runs in Denver with the Hoosiers have been on the stop, so really can't compare.

If all he did was bracket race it, the delay wouldn't be a problem. He's one of the most consistent leavers I know. I've personally witnessed the guy go .000 3 times in a row in eliminations, and go between .001 and .009 all day, race after race in his Superstreet Chevelle, but he want's to run Supercomp on a .4 pro tree and the best he can do there is .050 or so. Gonna be tough to go many rounds that way...

Hooked the practice tree to his car yesterday, to experiment. With the same delay, same button in his car, he go .030-.040 on the tree and I'd go -.003-.008 on a .4 pro tree. We tried a few different release methods and got him down to consistent .015's so hopefully he can do the same on the track...I'm sure he'll send the converter in this winter or buy a new one built for the car.
Johnny

shawnp 05-24-2010 11:34 AM

What's the launch RPM when running Super Comp?

johnracer 05-24-2010 02:39 PM

5600 rpm

shawnp 05-24-2010 03:26 PM

One thing I caught in reading is the PSI at 5 lbs. My guess is the thing is wadding that tire up horribly. I would recommend going up in air pressure. I ran 6.0-6.25 in the Hoosier 33.5x17x16. That may help. The other thing you may look at doing when running super comp is stiffening up the suspension to make the car react harder.

johnracer 05-24-2010 05:27 PM

We tried them at 6.5 in an attempt to help the shake and the 60's fell off to 1.19-1.20. 5-5 1/2 psi produced the best 60' times with the Hoosiers and the curent 4-link/shock/ballast combo. Any idea of what IC combinations work on a dragster? The current setting doesn't appear to have been changed since the chassis was built. The powdercoat on the brackets isn't marked at any other holes.....I can measure is up and figure the IC if it'll help.
Johnny

shawnp 05-25-2010 02:32 AM

A lot depends on the total set up of the car for IC. I would spend some time on the phone with the chassis builder. I would think that a little more tire hit would be wanted when super comp racing.

Also, have you checked the pinion angle of the dragster?

johnracer 05-25-2010 03:53 PM

No, haven't checked the pinion angle. We talked about it but never checked it. Should it be the same as any other 4-link car? 1-1.5 degrees negative?

shawnp 05-26-2010 02:22 AM

Yes it should be the same.

hammertime 05-26-2010 06:25 AM


Originally Posted by johnracer
No, haven't checked the pinion angle. We talked about it but never checked it. Should it be the same as any other 4-link car? 1-1.5 degrees negative?

yes ...

johnracer 06-08-2010 03:48 PM

Finally got around to checking the pinion angle. It was at .8 degrees negative. We reset it to 1.5 negative.......planning on testing Thursday night.
Johnny


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