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Parasitic Loss

Discussion in 'The Garage' started by BIGEARL, Dec 9, 2005.

  1. BIGEARL

    BIGEARL Registered Member

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    We're all well aware of the increased parasitic loss when going from a TH350 or 700R4 up to a TH400 or 4l80e. Does anyone know if manual valve bodies recoup some of this horsepower by eliminating clutch slippage or is the TC the main source of power drain? I heard of vehicles getting more HP to the ground with manual valve bodies but that may just be BS. Anybody have experience with this topic?

    thanks in advance,

    Earl
     
  2. sled_dog

    sled_dog 1 ton status

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    I know with a 4l80E the TC is the main loss. The thing is a beast and heavy.

    I'd bet the vavle bodies boost line pressure, increasing holding power and thats where the gain in power comes from.
     
  3. BIGEARL

    BIGEARL Registered Member

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    Aint that the truth!!! I've got the drivetain out of a '94 3/4 ton Suburban and I can't decide whether or not to put it in my K5. The 4l80 is a freaking pig! I'm kinda leaning towards a BT 700r4, I'm just curious about the horsepower loss/gain issue regarding manual valve bodies.

    Eal
     
  4. perp

    perp 1/2 ton status

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    I was under the impression the parasitic losses were due to larger pumps in the trans, not the TC. just what i heard
     
  5. ryan22re

    ryan22re 1/2 ton status

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    the total rotating mass is what creates drag. the 400 and 4l80 have alot heavier rotating parts. ive heard that a 400 takes about 20-40 hp more to spin than a 350. im sure the same holds true for a 4l80. the 700's internal parts are about the same mass as the 350, the only difference would be the torque converter (lock up clutches and all). same goes for the 4l80. i dont think that a manual valvebody would make a difference. unless the manual valve body prevents slippage in a high horsepower application, i would say that that would be the only way it could put more hp to the ground.

    700's require a broader powerband due to the rpm drop associated with the split between 1st and 2nd gear. which is why they may have been blamed for bad e.t.'s, and having alot of parasitic power loss.


    ryan
     
  6. sweetk30

    sweetk30 professional hooker Premium Member

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    4l80-e have 3 planetares in them . lots of power loss. but 1 great tranny in my book. i have them in all of my rigs old and new style trucks.
     

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