Back-in-the-day....when the "thang" was twin engines, what gear ratio did they run? Was it a taller gear to take advantage of double the power(no really!) OR...... the same gear ratio as single engine dragsters with the hope of more HP would equal more speed? Taller gears would just blast the slicks into 'smokes-ville' wouldn't it?!(so double the tire print too!) Just wondered if you fellas had any first hand knowledge............ 6sally6
Same as any other race car... Target mph Target rpm Tire diameter All that works into gear ratio selection. The rest you sort out thru tuning, clutch/convertor and tire width to make it hook up.
All but doubling the HP is going to have a significant impact on gearing. Of the top of my head probably going from something like a 4:10 to a low 3. You'd use total HP, total weight, max rpm, tire diameter to solve for gear. I'm not where I can do that math right now. It won't work out just figuring like you doubled the HP in an existing car because a twin will be significantly heavier. So I figured 1000hp @1500lbs & 1900hp(100hp coupling loss) @2000lbs. The change in gear ratio wasn't as dramatic as I would have guessed. Betting lower hp would see a larger change in gear ratio.
Doesn't make any difference how many engines, horsepower, whatever if you can't get it to the ground.
the duallies weren't the most desireable design. They were made necessary due to an NHRA ban on nitromethane (too dangerous) that lasted from 1958 to 1964. Gasoline was the only permitted fuel. Racers resorted to dual engines to get some of the HP back. thus the rise of rebel races like the March Meet at Famoso drag strip in Bakersfield.
Famous words, "I know a Guy" that built and ran one. I owe him a phone call so I'll use this for an excuse and find out his program and why. Wasn't his first go at Twin Engine dragsters. This is his last one. It's H.A.M.B. friendly, ran hard, was fun while it lasted.
I still have my 1961 HotRod Yearbook that my dad bought, and it features the infamous twin-Pontiac and dual whitewall slicks beastie of Eddie Hill, with the report that the car spun the slicks so fast that it melted holes in the starting line. I was lucky enough to meet Eddie, Ercie and Fuzzy at the boat drags in Chowchilla in '84, as our friends' Blown Gas Flatbottom (Arias power) was sponsored by the same company, and we also stayed at the same hotel in Fresno. It was discovered that the hot tub was right outside of our room, so the window screen disappeared, and the crews were doing cannonballs out of the window into the tub. He gave me a t-shirt and signed it, and I wore that shirt to the NHRA Nationals at Sears Point in '94, and walked up to his area when they were prepping the car. He caught sight of the shirt, kept looking at it, finally walked over and said "I know you, don't I?" Yep, and he started grinning, remembering about the hot tub thing, and signed the shirt again with the new date. He and Ercie, some of the nicest people you'd ever meet https://www.motortrend.com/news/vintage-twin-engine-dragsters-from-the-1960s/
True, but in this instance, it would have to be programmed into a desktop drag racing program. I rather doubt it was. Things like aerodynamics and traction don't appear to be variables that the user can manipulate in this simulator, leaving me to wonder about about the validity of the outcome presented.
First, just by using 2 engines does not mean that the Horsepower is doubled, each engine is different and the 2 will seek a HP balance. Will it be more than a single sure, but the addition of the second engine adds a lot of weight which so happens to take more HP to accelerate which eats up a lot of benefit of the second engine
I'm back and very glad I made that phone call. It ended up him asking more about what I'm doing and him coming over for a little Bench Race and B.S. time about 3 hours worth. It was all good. So to the basic questions on the first post. The tires are 30" tall and roll out is 92". The rear gear is a 2.90. That's right 2.90. Our conversation took a life of it's own and he had a ton of questions. What I didn't get was what he ran M.P.H or E.T. I just know it turned in some pretty good numbers.
It's the usual trial and error X 10. Your instinct that gearing and traction are the keys is correct. But that's always the case with BIG POWER. Don't worry about the best formula on day 1. Just have fun getting quicker if you can the next time out. That's a feeling you can take to the bank, psychologically speaking.
My thoughts: Probably not a big change in rear ratio, since I would guess the target RPM at the top end would be very similar to a single engine machine. I expect they maybe played a little lighter on the throttle until the tires hooked up some, and then put the wood to it once they were hooked. But then again I've been called clueless by some over the years, so could be way off base.
Motors times 2 or 4, you have to give the Guys that do that stuff a Ton of respect when they make it work at all. Our basic single motor TechKnowledge just goes out the window and you're on your own until you find your specific formula. I have been so Blessed to have been in the shadows of several projects in my life that just didn't conform to the rules and worked well.
Most do not understand how things where done back then unless you where involved in around this hobby / sport, So many had there own ideals and thanking befor late 60s , all across USA Mags did not cover it all (information and thinking ). Alot of trial and error an experiment, This was a response to me from the Swamp Rat in early 2008ish ~~~~~ Ed, Back then we ran lock-up clutches, hard tires on dry tracks that were NOT Sprayed with glue! When you spin the old tires on the new surface that is "glued" with some sort of traction compound, it is very dangerous, as the car can instantly go out of control. I know, I have done it several times just doing a simple burnout for the fans! We had anywhere from 1250 HP to 2000 HP back then and used 3.08 to 3.42 gears with short 30" tires about 9" to 10" wide. We got 25 to 30 runs from a set of tires and I campaigned a fuel car for an entire year for less than 100K! This is why the "Cackle" cars have become a draw, they are relatively safe and fun to watch, plus they don't break parts very often. I hope I have answered some of your questions> Thanks, Don Garlits CEO Don Garlits Museum of Drag Racing Inc.
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