The newest drag racer gears up!

[YENKO DEUCE REGISTRY]

Just like other drag cars, these Jr's will make you pull your hair out! [img]<<GRAEMLIN_URL>>/eek.gif[/img] Went to Maple Grove this past Sunday for TnT, and just couldn't seem to get the ET's we expected. Changed the rear gear to a 6.00:1, and did get better ET's and 60' times (1.89's!!) but this car should be flying. We now have a vibration issue to figure out along with the other headaches!

As Rob says, if it was easy - everyone would be doing it!

Still a fun day - no matter what happens. [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

[jeff morocco]

Hey Marlin,
what are your head temps leaving the line and at the end ? Those 8.90 motors LOVE the heat in the head. I like to make sure we are at about 150 degrees on the line. right around 350 or so at the other end.exhaust temps are 550 and 1300 at the end.33mm i run a 57 pilot , 185 main , .7,.8 air bleeds and mixture screw is 3/4 of the way out. Both cars are identical to make it easy on me except on Coles car i have 50 lbs of weight on it. i sometimes take weight off to stay in the 8.90 range but with two cars, i usually dont have time to mess around. what it runs on race day, it runs.
On your graph, does your rpm get up to 8000 and stay there or does it gradually lose rpm ? my 8.90 combo in the clutch is 15-28-22 ramps, 6 grams on each arm , 38degree helix and the yellow spring on the secondary in the 5th hole. If your losing rpm down track, try removing some weight off the arms. like 1 gram at a time until the rpms stay up in the 8000 range. I run a 12 tooth front and 72 tooth rear for a 6.00 to 1 gear ratio.
hope this helps you.