1toDV8

I appoligize if this has been covered before here, I never bothered to search on it being that it was the strangest thing I've ever heard.

A few weeks ago I was talking with a buddy of mine that used to do alot of circle track racing.

He told me a story about a local guy (trans builder) who had built a trans for a circle car where they completely eliminated the torque converter from the trans, I have no idea how they did it. But this guy built this trans with some sort of coupling which was more like a direct drive type system, he used a hand control valve to control the clutch pressures and aparently it was quite "interesting" to drive. So much so that when you let off the throttle in a corner it would through the car sideways trying to stop the tires.

I'm not sure what trans it was or if its even possible to do without alot of machining.

From my knowledge of heavy equipment I'm very familiar with "charge pump type" transmissions. So its no impossible I my mind to do. This is what it sounds like they created, but from something like a powerglide or a TH400.

In affect they turned the pump into a "charge pump" and rerouted the fluid through a valve, which they could control by hand and apply variable pressure to all available gears.

I thought Hey? what a concept, no need for a trans brake, or a stall coverter. Choose your RPM to launch the car and go! With todays hydraulic techknowledgy, I'm thinking this is very possible! You could program the PCM to control it.

ANY THOUGHTS? You trans guys ever heard of anything like this?

01ssreda4

iTrader: (96)

i believe i have heard of this also for circle track cars....dont remember any details though.

twinturbo496

iTrader: (2)

This was a common conversion for powerglides & TH350's

go to www.speedwaymotors.com for the parts needed. Note that this is not a practical street car setup.

In the 60's it was fairly common to eliminate the converter on a 727 mopar transmission, but again, this is obsolete stuff.

tptransmission

This a good explanation of the direct drive converter.


http://www.circletrack.com/techartic...ech/index.html

Circle-D

iTrader: (21)

Sonnax makes a kit for the PG. My dad did this stuff years ago when he raced dirt track. Not sure how they did the hydrolics though, before my time.

Here is a visual though:



Link to Sonnax's page"
http://www.powerglide.com/part_summary.php?id=2604&pl=1

Chris

forcd ind

iTrader: (7)

i have heard of it on p/g's-back in the 60's i ran a clutch turbo, a 400 with a bellhousing held on with the pump bolts, diff input shaft, kind of a bastard clutch spline-i think it was from Fairbanks(they were going to bring out a newer version, cnc'ed, but was pushed back)
it was pretty cool, def some brutal shifts-i ran a 58 vette, b/b on the street with it-prob nowadays, a vacume mod setup could soften the shifts some

CarsandWomen

iTrader: (19)

betcha wish you still had that vette

veee8

iTrader: (40)

Not practical at all for a street car. I dynoed a circle track car a few years ago with that setup. Pain in the *** to say the least. It had a clutch pedal, when pushed in, it dumps pressure, when let out, you are locked up in low. There is no slipping like a clutch, it all or nothing. It will buck and hop until you are rolling, then you bang it up and you are rockin. Very unique.

382ssz28

iTrader: (24)

Those trannies were called Clutch-Flites or Clutch-Turbos, made by Fairbanks, ATCO and a few others. I built a few back in the late 70's and early 80's. You're right Chris. They are very harsh, and not recommended on the street.

Chrome355z

iTrader: (1)

I like my torque converter.

mike13

iTrader: (27)

I'm missing something, when your sitting in gear not moving is it the clutchs that are allowing slip? Is that controlled by oil pressure?

9000th01ss

iTrader: (10)

Theres a cable or other device that activates a valve in the trans that dumps line pressure. No line pressure=no motion.

Many of these are set up to have this line pressure controller activated by a lever or clutch pedal.

When you want to move activate the line pressure control and it engages the first gear clutch. (forward clutch)

Imagine when you're driving down the road and you chirp second (in a th350 or th400) thats a clutch applying.

Activating the line pressure control on a circle track car is like that clutch that creates the chirping shift.

tptransmission

It is similar to dumping the clutch on a manual transmission. The band and or clutch in an automatic must apply quickly or it will fail very fast. On a dirt track the surface us slick so it is not as severe but on pavement it is rather abrupt.

Vortech Converters

have to run glides and torque converters is make a dummy converter (basicaly a drive hub that is welded to the cover of the converter, then the hollowed out pump is welded to the hub and cover) and drill and tap holley carb jets as bleed off holes in the direct, reverse, and band apply circuits of the valve body.

When your at idle, the holley jets are bleeding off the pressure/volume creating a neutral, then just stab the gas, the trans engages, and your off to the races. We do it for the th350 guys as well.

1toDV8

Hey thanks guys for the feed back on this. Guess I gotta catch up on these inovations lol!

Here I was thinking this was something so new. Boy am I behind lol. I will dig around on this for a while til I learn something more about it. Its very interesting to learn some of these old school tricks though. The more I learn, the more respect I have for my old man's ways lol! He was a builder in the early '60's. I learned alot of tricks from him, but most don't apply to todays cars anymore. What really does apply though is the "thinking outside the box".

1toDV8

Anybody ever tried this on a 4L60E?

I was looking into this idea as a different approach to stalling the trans, and well to educate myself more on transmissions in general. I've found nothing on the 4L60E though.

Thanks for the tips guys!

tptransmission

Direct drive would most likely hurt your performance on the street since it would bog the engine down. Stall converters are designed to keep your engine rpms at a level were the engine start making decent power.

9000th01ss

iTrader: (10)

The fwd clutches aren't designed to apply up from a dead stop, but you'd get rolling and when it hits second, watch your neck. And soon I'd imagine the input shaft would break out of the drum.