4 speeds for 55-56 chevrolet superstockers

[bill dedman]

Here are some thoughts on the Powerglide issue...

As I understand it, if a car has a three speed automatic available as an option "from the factory,," it is legal to run a different "more mechanically advantageous" transmission with the same number of forward gear ratios as long as it will bolt up with no adapters, and is in the same "corporate family."

An example of that would be a smaller, lighter, 904 T-Flite replacng the O.E.M. 727 in a 1970 340 Duster.
Another would be a smaller, lighter, Ford C-4 replacing an O.E.M. C-6 in a 352 Ford (nevermind about the bell housing.)

In 1957, as most of you are aware, Chevrolet engineering introduced a new transmission that was a 3-speed automatic called Turboglide that used a pair of planetary gearsets that approximated first and second gear ratios in the later Turbo-Hydramatics... something like 2.5:1 and 1.5:1. These planetary gearsets were attached to individual torque converter elements that were a part of the main converter, but instead of being held for reaction by bands, or clutches, they were on sprags. This allowed them to overrun when they got to their rpm limit, thereby "shifting" into the next higher gear without actually applying or releasing any clutch/band apparatus.

For a more complete explanation of the mechancs of this operation, there's a well-written dissertation on the engineering that went into this short-lived aluminum transmission in Wikipedia http://en.wikipedia.org/wiki/Turboglide by someone who has a good grasp of the operation of this somewhat revolutionary torque converter automatic.

Since it is a little different in operation from other 3-speed automatics, it never caught on with the hard-core Stock and Super Stock racers, but there wouldn't seem to be any legitimate reason why it couldn't be used as a stepping-stone to allow it to be replaced by a different 3-speed automatic in say, a 1961, 245 HP 283 car running an automatic transmission class in Stock or Super Stock.

This might alleviate some the discomfort and wrenching of hands that seems to accompany the conception that the racers who have heretofore been limited to a 2-speed automatic are being "given something" by NHRA when allowed to use a 3-speed.automatic. Replacing a Turboglide with a Metric 200 is simply trading one 3-speed automatic for another, something that is the norm for most Ford and Mopar racers, already.

Disassemble a Turboglide, and you'll find the same sort of planetary gearsets (approximately 2.5:1 for first, and 1.5:1 for second) that exist in other 3-speed automatics. But, instead of clutch packs, and bands, you'll find sprags to deliver the power, or hold the elements of the planetaries in place for reaction.

The fact that there's no neck-snapping "tire squeal" wihen going from one ratio to another doesn't mean it's not happeneing;.. it is... I think they had reliability issues for awhile (I seem to remeber them earning the moniker "TroubleGlide",) and I believe that 1961 was the last year they were offered.

Food for thought on a rainy day...

[Ken Haase]

Good post Bill. Back in the day I drove a couple of Turdo-glides. A '59 El Camino 280/348 was one and as I recall, you couldn't even percieve when the gear change occurred. Kinda like stepping in wet cement when you mashed the gas too. And as Dwight mentioned, those trannys had the infamous 'GR' on the shift quadrant. When you pulled it into 'GR' the pitch of the engine changed a little, but I never felt any deceleration. I always thought they were single speed transmissions! Maybe it was just that particular car. Back then, no self-respecting hot rodder drove a slushbox anyway. Well, maybe the early Torque-flites and Hydro's.

[bill dedman]

Ken,
You don't "feel" the gear changes in a Turbogglide, but they are there.

That Wikipedia site explains it a lot better than I can, but the explanation that I have heard that makes the most sense is that the first, second and third (1:1) geared elements in the converter are ALL pulling as you leave from a dead stop. But, the one that's really MOVING the vehicle is the one with the "longest lever," the 1st gear element with its 2.5:1 gearng. When the vehicle speed reaches the point where it can no longer contribute (because of the rpm) the 2nd-gear (1.5:1) element, which has been pulling all along, continues to accelerate the vehicle more rapidly than the high gear (1:1) element can, but at some point, it, too, runs out of rpm and it "overruns" on its sprag, and is just along for the ride, and the 1:1 high gear element continues to pull, but with no gear reduction... you're in high gear, now.

The rpms stay pretty constant until the 2nd gear element starts to overrun; then, you're in "high gear" and as the vehicle accelerates, rpms will increase in a linear manner, since it's a 1:1 ratio, now.

Clear as mud??? Like I said, the Wikipedia explanation is much better than mine...


http://en.wikipedia.org/wiki/Turboglide

[Tony Janes]

I think that the 63 Ford in Div 1 is a K or L stick 390 ci 300/280 hp stocker

[Dick Butler]

The picture is blurring...... Reality cars produced versus expensive "sorta stockers" Wouldnt it be just easier to fast forward to where the plan is going instead of mind irritating one at a time what seem to be irrational changes? Maybe there is no "plan" to recreate S and SS as generic "sorta stockers" but it seems to be going that way.
Paper cars, sorta factored running with real cars tightly factored by the old days methods and now the new method which choses to factor based on body type, trans used, al***ude, ?
I think some people would rather see a spec motor,spec trans,spec chassis with a 10 year guarntee of no changes than this costly continual gradual move that direction. Just think thats SS/AH already. Its getting bigger all the time. Couldnt others be allowed this courtesy who dont chose to run Hemi or cant afford them today?

Better Disclaim this one.

[Chuck Norton]

Dick,

That suggestion seems to be a mirror of the NASCAR logic that led to the mandated '"Car of Tomorrow." (I just wish they had offed the Ricer Wing. Something about that irritates me.) But then, would NHRA feel comfortable ins***uting a policy that was initially concocted by NASCAR?

c

[Dick Butler]

Chuck, Maybe its the fact most racers know how it was intended when S and SS started. Most are just too stuborn to admit the 100s of motors and 100s of combination is out of NHRAs control. Not handled by current enough processes to factor, update parts and index all at one time. every new year brings a new group of headache motors not one.
My main feeling has always been the pain every year one at a time for each and every racer watching it happen is FAR greater than a one time declaration that would put us to the final product. Generic classes. Modified eliminator with spec carbs and lb per cubic inch not fake hp ratings which take forever to correct.
AH is there but VERY EXPENSIVE. How about the llittle guys. Do we want to keep gouging them in the pocket every year in the name of "fairness" 4 speed s in 55, 3 speed automatics, Aluminum heads for one brand this year. ANy size injectors.
Step back and watch what works...AH. No mystery factoring on another motor. They are all the same. As much as I know all brands would make a better show I recognize under current methods by the organization it can never work withing the NHRA or IHRA methods. It is too complex for their methods to handle today.