Quote:
Originally Posted by Bob Eyres
Semantics are important if you want your meaning to be clear.
I've never understood the semantics of the term "torque multiplication". I've seen it used, mostly, to describe the advantage the automatic transmission has, at launch, in the quarter mile. The torque converter allows enough slippage to let the engine come higher into it's power band before the car starts moving. So that you have more power available at launch. The automatic has other advantages, and disadvantages, but I don't see how torque is literally "multiplied" in any way. Semantics  |
Semantics in the actual number expressed as an ET being meaningless to me, while being a factor to you. In other words, I was willing to drop the subject of ET importance, based on semantics. Semantics being "the
meaning, or an interpretation of the meaning, of a
word, sign, sentence, etc.: Let's not argue about semantics."
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The torque multiplication of a torque converter is in play whenever there is a greater force applied to the torque torque converter, as like you described during a standing start, but also down range and during upshifts.
Torque converters have an STR or K value. STR means Stall Torque Ratio. Usual STR's for stock GM TC's are 1.8. SO if you input 100 lb/ft you get 180 lb/ft applied to the input shaft.
The only time the STR is taken out of the equation when applying an acceleration force is when the Torque Converter Clutch is applied, then the engine torque is applied to the input shaft of the trans in a 1:1 ratio.
As I stated torque multiplication occurs in a standard clutch as well, while it is slipping. Not advisable in a conventional clutch, but it's advantages can be seen in a slipper clutch design. Whenever 2 friction materials are forced together yet move at differnt speeds, torque is multiplied. The difference in a TC is that instead of 2 friction materials, when have "fans" of different pitches driving and being driven by an incompressible fluid, in effect, performing the same torque multiplication that that a ZF-6 performs, except by using a fluid instead of mechanical gear contact and the amount of torque multiplication is controlled by blade design in the TC and gear tooth counts in the ZF-6.
Torque Multiplication occurs through a manual clutched trans as well, input 100 lb/ft into the input shaft of a ZF6 in 1st gear, and 266 lb/ft will be seen on the trans output shaft(assuming zero loss).
At least that the way I understand it, using my personal base of semantics.
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Thanks X-Fire for the tire specs.