stall torque ratio?

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inkjunkie

inkjunkie

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What be it? I am looking at a companies web site that sells torque convertors and seen it mentioned. Just kinda wondering....:happy1:
 
I believe it is the ratio between the impeller (drive) and the turbine (driven) units. Maybe this will help. The two do not travel at the same speed. The converter is a torque multiplier and the ratio is the difference between the speed of the impeller and turbine. I am sure there are different ratios available.

Of course all of this is subject to a forum know it all coming in and saying I am completely wrong. Which could actually be the case.
 

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The stator fin angle has a big role in it as well. 1.8-2.5 is the range the smaller the number, the wider the effect on the power band will be, the effect only works when the impeller and turbine are at different speeds. That's the essence of what I take out of the whole topic.
 
Both are correct. Rusty, a great job,on actually defining the actual operation. 74,nailed the multiplications.Demands(combinations?), change this criteria. N20/turbo/ transbrake,all heavily involved. How deep,you wanna get ,Doug?
 
How about the old variable converters from GM years ago called the Switch Pitch? Bet yall never heard of those.
 
RustyRatRod said:
I believe it is the ratio between the impeller (drive) and the turbine (driven) units. Maybe this will help. The two do not travel at the same speed. The converter is a torque multiplier and the ratio is the difference between the speed of the impeller and turbine. I am sure there are different ratios available.

Of course all of this is subject to a forum know it all coming in and saying I am completely wrong. Which could actually be the case.
Click to expand...

Thanks...

PoisonDart74 said:
The stator fin angle has a big role in it as well. 1.8-2.5 the smaller the number, the wider the effect on the powerband will be.
Click to expand...

Can you clarify "the wider the effect on the powerband will be" please?


Abodybomber said:
Both are correct. Rusty, a great job,on actually defining the actual operation. 74,nailed the multiplications.Demands(combinations?), change this criteria. N20/turbo/ transbrake,all heavily involved. How deep,you wanna get ,Doug?
Click to expand...

Just trying to understand what it is and how much it effects getting a vehicle moving. A few years back my trans guy built an a4ld for a Ranger I had. He was building his own convertors at the time and I seem to remember him telling me the converter was 4:1, but I may be wrong. The convertor was in a 4x4. It was a very low stall unit, I kinda remember him explaining to me how you could tell by looking at the fins but it was a while ago and I was not really paying much attention...:banghead:
 
cool...had to Google this...

"From 1964-1967, Buick and Oldsmobile versions of this transmission used a torque converter with a variable-pitch stator called Switch-Pitch by Buick and Variable Vane by Olds. The stator blades moved from high to low position by an electrical solenoid and a stator valve, controlled by a switch on the throttle linkage. At light to medium throttle, the stator blades were at 32°, providing a torque multiplication of 1.8:1 and a converter stall speed of approximately 1800 rpm. At ⅔ to full throttle, the blades switched to the 51° high position, giving torque multiplication of 2.45:1 and a stall speed of approximately 2300 rpm. The blades were also set to the high position at idle to limit creep when stopped in Drive. The variable-pitch stator was eliminated after 1967. This feature was not used on the Pontiac versions of this transmission."
 
The higher the ratio,the more torque multiplication. (As a general rule....). You can loosen a converter for a higher multiplication,lose trans life being lost.(Too much heat, My personal experience).
 
Nope. They came in the turbo 400s.

They actually started out in the 300 series transmissions first, but the ones I am familiar with ......a little came in the 400.
 
Just to be trivial, lol.. sometimes I wish I didn't remember this stuff,, sheesh,, talk about old..

In 1953, Buick redesigned the Dynaflow, calling it the "Twin Turbine Dynaflow". The converter now incorporated two turbines and a planetary gear set, with a single stator. The first turbine was linked to the ring gear and the second to the planets, which gave a 2.5:1 torque multiplication which was now partly mechanical. This resulted in better efficiency, especially at highway speeds, and a higher level of performance and no penalty regarding the trademark smoothness. Buick also incorporated a variable-pitch stator in 1955 for greater flexibility. While these changes improved the transmission's overall performance and efficiency, the Dynaflow still was no match for other designs that utilized three element converters with automatic shifting.
 
That's really cool. It's amazing some of the stuff the automakers were onto back then that has practical application even today. Thanks for the info.
 
RustyRatRod said:
That's really cool. It's amazing some of the stuff the automakers were onto back then that has practical application even today. Thanks for the info.
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Does anybody remember "Fluid Drive"?

My mom learned to drive in a 49 Chrysler w/Fluid Drive.

It said on the clutch pedal: Safety Clutch!
 
But I don't think the fluid drives had a true torque converter, just a fluid coupling. So there was no torque multiplication, just slip below the stall RPM.
 
Regetably I remember them too,, IIRC the only time you stepped on the cluth was at a stop sign.. Once you let it out,, you shifted without the clutch,, ..49 -53 ish..
 
inertia said:
Regetably I remember them too,, IIRC the only time you stepped on the cluth was at a stop sign.. Once you let it out,, you shifted without the clutch,, ..49 -53 ish..
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Old fart....
 
RustyRatRod said:
How about the old variable converters from GM years ago called the Switch Pitch? Bet yall never heard of those.
Click to expand...
had one in my 55 chev.dad was mr goodwrench forever...it worked but they needed more stall.replaced it with a vega converter it stalled 3200. tore up that 400 turbo....to be young....
 
RustyRatRod said:
How about the old variable converters from GM years ago called the Switch Pitch? Bet yall never heard of those.
Click to expand...

Had one in my second car. An old beater 66 Buick Lesabre. Mine had the superturbine 300 trans (buick's version of the powerglide) and a switch pitch.
 
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