I was noticing that a supplier advertizes a pump drive that eliminates the torque converter in an automatic transmission. Anybody ever done such a thing? How does the tranny shift? I'm just having a tough time imagining this. Wondering if this might work on our bellytank project. It would save about 35 pounds of rotating weight.
Circle track guys have been doing this for years on powerglides,go to tci or any major trans web site for info.
Yeah, I've had several in circle-track cars but I wouldn't recommend it for the street, however. It's really easy to burn up the clutches by slipping in and out of gear. Basically, you have to use something from the crank to turn the pump and a bypass line from the pump to the pan with a valve to make it go. I think I've got one on the shelf from an old Modified. It looks like it was made from a cut up converter. Close the valve (creates pressure) and it goes. Open it (relieves pressure) and it doesn't. To avoid hurting the clutches, we'd often start in gear, especially on dirt. Shifting from low to high is just on the fly. In order to stop and put it in reverse or park, you have to open the valve first or the engine will die when the wheels stop moving. I can't imagine one on the street, unless you really want to work hard.
Yes, if you are using it to run the flats with it I think you could use one. I've run them many times in prostocks, limited and late model dirt stock cars. I still have a hub and stub pump drive hanging on the shop wall. TCI is a great place to go for info on this setup. They have a trans I think it is called "circlematic" you can buy or they have parts to build you own with. By far one of the lightest drive units available. If you prefere to run a manual trans....there is a dog clutch set-up that is just as small/light you could use.....
I ran this in a power glide on asphalt circle tracks for several years. It is not for the faint of heart. It is either on or off and no in between and absolutely no slipping the clutches. One slip and it is toast. I probably went through 4 or 5 in two years of racing. I have never ran on the salt but I would think that one downside to this setup on dirt is that without a torque converter there is very little flywheel weight and when you just touch the throttle the motor zings up real quick and when you let off the throttle it is just like slamming on the brakes. I would think this would really piss off a salt car? Scott...
I read about a clutched automatic being run years ago. I think the torque converter was removed and a clutch put in its place or the converter was modified to work with the clutch. That memory is a bit unclear.
Scott, on dirt that was not a downside but a huge plus!!! You could drive the car solely with the gas pedal. There were few guys that tried them when they found out I was running them, but they didn't like them. You have to be able to "feel" your car and be smooth on the throttle otherwise you cannot control them for sure. It makes for instant acceleration and instant deceleration... Not sure why you burned up soo many transmissions, I ran this setup for 6 seasons and only lost 1 tranny that was due to a deep pan that needed to be baffled or have the filter extended down to stay in the fluid.... How was yours "plumbed" for the control/shut-off valve? Mine was done by controlling fluid within the pump, not through the trans.
10/4 the old Clutch-Flite! back in the day they were used in 1/4 drags, had a clutch and when it was engaged it was go time! You had the benefit of a clutch like a stick for launch then the auto.
The drive that this original post is about is not a cluth set-up. It is a "direct drive" for an automatic that eliminates the convertor WITHOUT the use of a clutch set-up. It is just a drive flange and a stub shaft that goes into the drive flange and into the pump.
why is this a concern in a car like that? if you're doing LSR and you have a powerful engine, weight is usually helpful (for traction), and at the speeds where you're fighting the wind the engine is not revving fast enough that you'd need to worry about wasting power by spinning rotating mass.
I've seen guys use the 'Glides in dirt modifieds using a hydraulic clutch pedal to actuate the valve. You push the pedal down to close the valve, let go and it opens the valve. The trans is set up to be locked in high gear, so no need for the pump once you get it going. You push in the "clutch" and get the thing rolling, then jam it in high gear and go race. They're pretty light, and have a lot lower rotating mass than a standard or even a gutted three/four speed, but they're not real strong. The advent and cheap entry price of aluminum cased Bert/Brinn style "clutchless" manual transmissions coupled with their near bulletproof nature has more or less made the 'Glide obsolete. I don't see how either of them would be useful on the street though. You had to spin the tires to start a 'Glide car rolling, or you'd burn them up in no time. The Bert/Brinn doesn't need to spin the tires, but their low gear only works while you're holding the clutch down, and those burn up pretty fast too if you're on them too much. Low gear in a short track car is only for loping around the pits, and to get the thing rolling so you can shift into high gear.
I doubt it's a big deal with LSR stuff, but on a short track dirt oval car, 35 lbs of rotating mass is a bunch. You would not believe how much difference in acceleration you can feel when switching from a flexplate/triple disk clutch/three speed trans set up to a flexplate/Bert trans set up. It was like night and day as far as throttle response and wind-up off the corner. Nevermind that I got to replace a 145 LB trans, 10.5 lb clutch, and 29 lb bellhousing with a 45 lb trans and 4.5 lb bellhousing. That's 135 lbs off the car, about half of which was rotating mass. Like night and day.
A 40 pound 10" converter spinning at 6000 rpm has about 1.5% of the kinetic energy of a 2000 pound car moving at 150 mph. 1.5% seems pretty insignificant, and land speed cars don't really have problems with kinetic energy anyway. To put it another way, a 250 hp motor would have to work for 0.15 seconds to spin it to 6000 rpm. Substantial on a small time scale, insignificant on a long one. The advantage I would see is the removal of a less than 100% efficient part in the path of the engine power. But, quality converters these days are pretty efficient so it would be hard to justify on that basis.
I had one with a shut off valve that went into valve body through modulator hole had it hooked to a clutch petal never failed but they were start w deep gears mostly like 6.00 something I did run a aluminum flywheel on that one so locking the brakes up on coming into corner engines would stall out and be hard to relight, which was common on running a flex plate i run one with flex plate and the turn off valve and that one was a little slower on the take off, they just slam into drive when shifted, very fast into a corner on low gear restarts, I loved them on circle track, very cheep to run compared to burning out stick clutches
ok let's get this right yes there is a valve hand or foot operated went open would dump the oil from the pump directly back into the pan no pressure to the clutches, the pump is reduced (machined) by 2/3 as you don't an oil supply for the torque.using only a flex plate the motor responds faster as you don't have a mass of a flywheel or torque to slow it down and shifting from low to drive was just like any modified automatic trans and it runs cooler.The only problem was that we had to use a winch to load the car in the truck.
I can see a big advantage on a car that's slowing and accelerating over and over again. LSR is a whole different game.
There are a number of cars at Bonneville that use automatics without torque converters and without the valve. They simply use the coupler to drive the front pump and input shaft. Start the motor on the start line. Push the car off to about 25-30 mph and drop it in gear. It then shifts as a normal automatic. My car had a clutchflite in it years ago. More trouble than it was worth I think.
Rich, how do the gear ratios work out with an automatic? any problem keeping speed with the relatively large rpm drop when it shifts to high?
Apparently not. The car that I was mostly thinking of was the Bryant family comp coup. Which unfortunitly crashed this year. Tom ran a Powerglide for years and the car was always fast. Not sure what he had in it for first gear. There may be more information on the Bryant web page http://www.bryantauto.com/ or you could contact Tom and ask for information. Be aware he must still be mourning Barry, his son.
When I wrote my first post on this thread, I forgot that I'd run one in a big block sportsman dirt car. Didn't have a problem with it until toward the end of the season when at the start of a main event I spun the tires in water left on the track from the water truck that wet the top of the track during intermission. (The water ran down the track surface in one spot.) I lit up the tires but before I could get out of the throttle, the tires grabbed hold of the track and there it went. That said, in the Modifieds, dirt and asphalt both, it seemed like I couldn't keep one in the car. The last few years I ran I used a Falcon, which worked much like the Bert/Brinn mentioned above. Once you get used to it, it's a much better deal but you still have to be mindful of what you're doing driving through the pits at low speeds.
Indeed. I agree. I very much like my Berts, you just gotta get them out of high gear before you decide you want to slow down and come into the pits. Once the motor starts to lug in high, it's a bitch to get them back into neutral.
I wouldn't think so because it's a set up designed more for benefit once you are rolling, not to get started. Maybe with the clutch pedal setup but probably not. Also, in a dragster don't you want a little clutch slippage off the line so you don't loose traction? <input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">
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