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Automatic gear ratios

Discussion in 'The Garage' started by neverendingproject, Aug 24, 2006.

  1. neverendingproject

    neverendingproject 1/2 ton status

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    Does the torque converter multiply gear ratios as well at torque before it reaches lock up?

    At low rpm, would the 2.48 ratio be more like 4 something, or does it not work that way?
     
  2. sweetk30

    sweetk30 professional hooker Premium Member

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    the basic concept of a convertor is put a fan in front of a nother face to face. plug one in. watch how it will spin the other fan over time. this is how a convertor works.

    so to answer your question no it wont.
     
  3. neverendingproject

    neverendingproject 1/2 ton status

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    So I only get more torque because its not a direct connection? I guess if you get more torque, then you dont need the lower gears huh?
     
  4. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    The torque converter will in fact multiply torque, most converters will almost double the torque at full stall, the less the converter slips the less torque multiplication takes place. It's hard to explain how this happens without pictures but basicly (and very oversimplified) there is a third set of blades between the turbine and the pump inside the converter that redirects the fluid and keeps the fluid from bouncing off the pump blades and and hitting the turbine blades in the opposite direction and causing drag. Instead it bounces off the the stator blades which redirects the fluid the correct direction and gives it a second push and this is where the torque multiplication effect comes from. So long story short stator turns a fluid coupling (very inefficient) into a torque converter that multiplies torque during slippage.
    I'm sure I lost you a by the second line, just run a google and learn all you want.
     
  5. neverendingproject

    neverendingproject 1/2 ton status

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    No, I read up on it a bit, but if I plug my 2.48 first gear into the mix, I have a sucky crawl ratio, but i know that there isnt a direct connection, so I didnt know if somehow it got a little when it stalls or slush boxes just are gonna suck period.
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    The crawl ratio on paper looks sucky , but I have video of wheeling with 33's and 3.08 gears that contradicts it .

    The converter works great at low rpm for crawling .
     
  7. DEMON44

    DEMON44 Low-Tech Redneck

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    This all true. A converter does multiply torque.

    for instance, some of the converters on heavy equipment, such as articulating wheel loaders and scrapers. often have multiple turbines and stators for increased multiplication. with these types of power shift transmissions there is no lockup on the converter and the stators are fixed.


     
  8. 85-m1028

    85-m1028 1/2 ton status

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    I think the general rule for autos is about half the final crawl ratio than what you would want for a stick.
     

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