dragster drivetrain

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miniv8
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dragster drivetrain

Post by miniv8 » Thu Dec 07, 2006 3:18 pm

Hi guys

Is it possible to run a dragster with only a torque converter..
no transmission, just a converter mated to the pinion?

has anyone tried this? What should I need?

Is this feasible in a low power application 9-8sec rear engine bracket dragster?


Thanks

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John Wallace
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Post by John Wallace » Fri Dec 08, 2006 11:14 am

I'm not sure I understand your question.

You want a direct drive set-up?
Just the actual torque converter hooked up to the pinion with no transmission?

The torque converter would need a pump to circulate the fluid.

If you're wanting a direct drive set up with a torque converter, you could use a Powerglide and use the high gear only.
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Ed-vancedEngines

Post by Ed-vancedEngines » Fri Dec 08, 2006 2:21 pm

At the risk of seeming negative, May I just suggest that it won't work. Even if you did not need the pump, you need the torque multiplication of the gear ratios unless you have an engine with tons and tons of torque.

I was around in the old days before the slipper clutches, when dragsters and roadsters used only a CAE In and Out box with only high gear in the baddest cars with big blown engines and light weight. The only way high gear only worked for them was they immediately got the wheel and tire speed up so the rpm went up and they smoked the tires half way down the track or further but did keep the rpm up.

The lower class cars that were running speeds and Et like you are talking about still needed at the least a 2 speed and that was a manual shifted affair usually was the 2nd and 3rd gears in a 3 speed tranny.

Several companies do make what is called a Shorty Version of a PowerGlide that does use a convertor and would be maybe what you would need to use. There may be some more economical ways to do this too but I don't know them. I know that there are a lot of economy dragsters that are using powerglides of some sort. Maybe they are regular powerglides that are just beefed with a shorty shaft. Not sure.

There is a way to not use any torque convertor or fluid coupling device by modifying the valve body in a ppowerglide and routing the pressure lines between the pump and the trany through a manual operated switch or valve that would give a direct drive connection immediately. They have used that on some circle track asphalt cars years ago. For dragstrip use it results in eithe engine bogging of in tire spin though.

That is all the alternatives I can think of for now.

Ed

Cobra

Post by Cobra » Fri Dec 08, 2006 3:14 pm

Ed- I break out in a cold sweat when thinking of in-and-out boxes. No tach, just an oil pressure gauge and a foolish, young driver with more guts than brains.

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Post by miniv8 » Fri Dec 08, 2006 3:49 pm

Thank you for your replys guys,,

Yes you got it right, I want to use the converter similar to a centrifugal clutch.

I am wondering what equipment I might need to make this possible.

How does the converter behave when mated to a gearbox like the Lenco or Liberty?

what about regulating the amount of fluid inside the converter during a run?


Thank you Wallace for your website, it has been of great use over the years

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Post by gimmemud » Fri Dec 08, 2006 4:12 pm

You need a Bruno unit with a Lenco or Liberty, works great for high horsepower. They are fairly expensive though.
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Post by BillyShope » Fri Dec 08, 2006 7:25 pm

I would say that which you're contemplating is quite reasonable and, if you're bracket racing, should be very consistent. You can use a power steering pump to provide the pressure. (Yes, I know the power steering pump normally delivers very low flow at very high pressure, but, when flow increases, pressure drops. The power output of a pump is proportional to the product of flow and pressure load.)

This calls for a story from my youth: Back in about '58, a fellow showed up at Chrysler Central Engineering with his own car, in which he claimed he had installed an infinitely variable automatic transmission. He provided prints and a schematic for the very complicated planetary gearing involved. At the time, there was great interest in such a transmission. (Chrysler was very active in investigating the feasibility of a hydrostatic transmission which would provide this same feature.) I had the opportunity to ride in the car and I came away impressed. It was, indeed, very smooth. But, when the gearing schematic was analyzed, it was discovered that the final gearing was always 1:1! In other words, all those planetary gears were accomplishing nothing and the total torque multiplication was achieved with the torque converter. Granted, we didn't take it over to Woodward Avenue and look for a drag race, but, for normal driving, it seemed to have adequate performance. Well, I suppose that should come as no surprise, since this was the normal operating mode for the early Powerglides (unless the driver manually shifted into "Low.")

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Post by Engguy » Sat Dec 09, 2006 4:01 am

Why not? As long as all you need for a reduction ratio is some where in the 2:1 - 2.5:1 area it would work just fine. You would either have to build a case for it or use a transmission case modified and could use the normal front pump arrangement. Or even consider an electric pump if allowed. Remember it will need a stator support arrangement, and support for the turbine shaft, which will be your output shaft. If I was going to do something like that I would use a bolt together torque converter, it would give you options for changing stall speeds and ratios.

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Post by Baprace » Sat Dec 09, 2006 4:09 am

Engguy, old bolt together torque converters date backto the 1950's and i remember fixing plenty of them when guys tried neutral starts and all of the bolts broke and the converter was in two pieces, now how about the funny car ( nitro ) with the torco label on the side of the car , I understand that is a direct drive with slippage in a converter assembly ?

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Dragster Drivetrain

Post by Haywood » Sat Dec 09, 2006 11:26 pm

A few years ago B&M experimented with a high gear only powerglide. It was consistant but had two major drawbacks. It built a ton of heat and the roadster they tested it in ran a couple tenths slower. This project spawned the B&M Envrocanister cooler. If your just looking for consistancy by doing away with the gear change this may be something to look at. If you want to go after low time slips forget it.

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Post by C Stevens » Tue Dec 12, 2006 10:57 pm

And there was the old B&M Torquemaster of the late '60's, it didn't work as they hoped. It's a catchy idea but NHRA requires a neutral and reverse.
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