Lock up Turbo 400?

Discussion in 'Transmission & Driveline Topics' started by bbc nova, Feb 23, 2010.

  1. bbc nova

    bbc nova Veteran Member

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    Is there such a thing? If so are they as good as the old school 400's?

    Ive been thinking lately even if I took gear out of the rear or put a gear vendors od on the back of my tranny the 4000 stall converter is going to generate heat like a B.

    Just locking up the converter in 3rd would more than likely act just as much as a 4th gear?

    couldent you lock it up like half way through 3rd at the track and have a wicked top end?

    Just thoughts

    but is there such a thing?
     
  2. bbc nova

    bbc nova Veteran Member

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    one question answered MAYBE
    Not that I think this is bs but my 496 @ 2500 rpm 55 mph is a heat generating machine. I have a tranny temp gauge and 2 coolers.

    Can I run a high stall converter in overdrive with a 3.42 axle?

    Yes, this is one of the most often confused questions (even when you ask people you would think would be knowledgeable). Here is the detail. Our example could be this 3.42 Chevy guy. In overdrive he is going to be a 2.67 final drive ratio. He is a Cutlass body with 27 inch tire and so at 75mph in overdrive the motor will be turning 2484 rpm and he has a 3500 stall speed on the back of a pretty nicely built 350ci motor making close to 400hp. 95% of the people you would ask (even tranny guys) would say no-way and yet we know this is an awesome package (drives wonderful, no high temps in the trans etc) why does it work? When his converter was made it was set up to stall at 3500 with 400hp. However if you put 600hp to it it would stall at something like 4500. Conversely if you only put 125hp to it (as when you are just crusing at 75mph not accelerating) then the stall is way down at 2,000 rpm. So his stall with a 3500 converter is not 3500 at cruise because he is not making 400hp. Car drives wonderful. If he romps on it while cruising then the trans is going to downshift to a lower gear and get him into the powerband. (note: read gear vendors passing gear in this section) So, this is why you never lie to you converter builder (because if you overstate your hp you will not get the stall you wanted).
     
  3. jakeshoe

    jakeshoe Veteran Member Lifetime Gold Member

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    Are you asking a question or answering one?
     
  4. bbc nova

    bbc nova Veteran Member

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    Sorry

    Asking / thinking out loud.

    then I found gear vendors answer about converters.
     
  5. ZS10

    ZS10 Moderator Staff Member Lifetime Gold Member

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    I'f you're thinking about spending $2k+ on a G/V, consider a 4L80. Then you get o/d and lock up.
     
  6. tom3

    tom3 Veteran Member

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    I think you have to have an internal fluid passage to lock up the converter with a solenoid valve in the tranny to control it. I suppose anything is possible though.
     
  7. jakeshoe

    jakeshoe Veteran Member Lifetime Gold Member

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    It is possible to make a TH400 a lockup transmission. It has been done in the past and is still done on a very limited and expensive basis.

    The GV information on stall converters is mostly correct.
     
  8. jakeshoe

    jakeshoe Veteran Member Lifetime Gold Member

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    Switch pitch is still available but getting pretty hard to find.

    I have two complete TH400 switch pitch setups, pumps, inputs, converters, switches, etc.
    I would love to get rid of them. I used them for testing.

    Pretty neat setups.

    One has a Pro-Torque 1400/3000 converter, the other is a PAE 4000 setup.

    Both converters have 1-2 hrs run time, one pump and parts setup has 3-4 hrs time, the other setup is unused from PAE.

    I also have a pretty trick setup for engaging the high stall in manual low and it goes to low stall when shifted to 2nd gear :)
     
  9. bbc nova

    bbc nova Veteran Member

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    Cant believe im even going to ask

    $$$$$$
     
  10. bigdav160

    bigdav160 Veteran Member

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    Not sure about TH400 but you can buy a lock-up Powerglide!
     

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