380 Racer

Last weekend went down to Cedar Falls to race 2 days. We just had installed a 4.56 ring and pinion instead of the 4.88s that were in there. Kept everything the same, 2600-2800 launch, foot braking instead of the trans brake (no difference). I have had 5.13, 4.88 and now 4.56s in the 12 bolt. 1.30 sixty foot times for all of them. I figured it should have changed somewhere......any ideas?

coppercutlass

Same with me i went from 3.42 to a 3.73 and no real change. the biggest change i ever saw e.t. wise was the x pipe it shaved 2 tenths

MDchanic

Any chance you guys were essentially at your traction limit already with the taller gears, so got no 60' benefit form the additional torque?

- Eric

J-(Chicago)

Fresh slicks for all 3 ratios? If yes, you are probably at your limit for the race track conditions. I remember Steve-o had an older pair of slicks on, and blew the tires off of the track every time. He thought it was the old tires. Him & I swapped a new pair onto his car and....same thing.

I hate to say it, Nick, but if you don't lose the wheelies, and 4 link it, you've probably peaked& plateau'd with the ol' gal.

Best bet to test the theory is to show up to byron wheelstanders. Track will def. be prepped to the max for that event.

oldcutlass

What rpm are you shifting at? Whats the rev limiter set to?

380 Racer

The 4.56s I figured would help the car go more forward rather than up. Which it does. It only comes up about a foot now but carries the wheels about 45-50' out. Don't get me wrong........I do love the wheelies and the 1.30 times are very good in my book especially as consistant as they are.

Ladder bars are always more violent than 4-links but......they are much more confusing. Can't afford to do that anyway. If the slicks start to go away, we know it CFR has one of the best starting lines I have ever been on.

I guess I'm kinda thinking that the torque coverter flashes right @ 5600 and my peak torque came also @ 5600 (579.5 ft lbs). Maybe it is all ideal? LOL

380 Racer

It is shifting @ 6700 and yes it shifts mid wheel stand. With an rpm switch & air shifter. Upper limit is set at 8000.

oldcutlass

It takes more hp to turn the 4.56 vs 488's, I would have though that possibly your 60' times would have changed.

J-(Chicago)

I think your car is right on the button. 1.3 is GREAT.

ah64pilot

Considering a dragster runs 1.10's 60' I'm thinking you're asking a lot out of a full body car, no matter how light it is. What are other guys in your class running?

380 Racer

Actually I'm not complaining at all . I feel it does very well for a 3250 lb tank with the aerodynamics of a brick ......LOL. I really thought it would slow down to maybe a 1.33. Color me "surprised", the combo is close to being perfect in my eyes .

380 Racer

We tamed the launch down yesterday, still pulls the wheels but not so severe. We have a stripe taker under the front bumper to make sure it's the same spot on the car that trips the finish line lights. Used to be that if the brakes were pounded it would trip the beams with the bumper. Anyway it was clicking the 60s with the stripe taker when the front bounced on coming down. I was right, 1.33 60s now

380 Racer

You can see the stripe taker in this photo.

61reoldsman

Hey do you ever get up here to Canada to run ?specifically Ontario ??I'm close to Grand Bend Raceway and St.Thomas ,in an hour I can be in Port Huron Michigan.Love the sound of an Oldsmobile at full honk!!