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too much horsepower take II

Discussion in 'Early CJ5 and CJ6 Tech' started by dunl, Jan 25, 2010.

  1. dunl

    dunl Member

    They're discussing the option of turbo'ing this engine. And Patrick, I totally understand.

    However, the forum I am looking at is one dedicated to these engines....maybe they know something we don't about this engine. I do know that it was problematic in certain ways, and only run for about 4 years....but if used properly it is supposed to be a great engine.

    As I'm not totally immersed in these, turbo or not, I can't say he's wrong.
     
  2. Patrick

    Patrick Super Moderator Staff Member

    A blow off valve on the transmission? Really?
     
  3. dunl

    dunl Member

    Yup...let me find it:

     
  4. Patrick

    Patrick Super Moderator Staff Member

    They mean the turbo would need a blow off valve on an engine mated to a manual transmission.
     
  5. dunl

    dunl Member

    Doesn't look that way....and if it did mean that, why couldn't one just be hooked up for it?
     
  6. Warloch

    Warloch Did you say Flattie??? Staff Member

    That has to do with the turbo spooling up. Depending on the turbo, will determine how many RPMs it takes to spool and make boost. Turbos for these motors are high RPM, not something for a jeep normally. I don't remember the turbos comming with Manual trans, as that would require a quicker spool to produce boost vs the ability to maintain spool with an auto.
     
  7. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    D'oh. Nevermind... I'm way behind on this thread.
     
  8. Warloch

    Warloch Did you say Flattie??? Staff Member

    FWIW - I would go with an FI and run it that way.

    A quick scan and I am pretty sure you would need a custom turbo setup to run a manual with that motor as it never came manual with a turbo.
     
  9. dunl

    dunl Member

    Weeeeeeeelllllllllllllllllllllllllllllllllll........the one I am looking at it a non-turbo.

    Any reason I shouldn't run it, instead of modifying it to be turboed?
     
  10. Patrick

    Patrick Super Moderator Staff Member

    How/ where do you put a blow off valve on a manual transmission? What're we blowing off?
     
  11. Patrick

    Patrick Super Moderator Staff Member

    Not sure why you'd want a turbo on a Jeep.
     
  12. dunl

    dunl Member

    So there's no reason why I shouldn't run the natural aspirated version?
     
  13. Patrick

    Patrick Super Moderator Staff Member

    As long as it wasn't a turbo motor, as the compression would be lower..
     
  14. dunl

    dunl Member

    Non-aspirated version of the turbo 4.1 V6.
     
  15. duffer

    duffer Rodent Power

    The Dave Williams stats are about all you can pull up on the web-same list for just about every site. The Jeep data are about non-existant. I might have to weigh a few of these this summer. Have complete L and F heads, 226, and 230 and a 2000# calibrated platform scale good to plus or minus 1#. Might have to throw in a few versions of sbc, 225, and 360 for comparison. Science project 101:) How far can we digress from the OP? My apologies.
     
  16. A Mandery

    A Mandery Member

    Well, I turbo'ed my jeep because I thought it would be a fun project - and it was. None of the turbo engines were mated to a manual trans. However, good old GM still machined the crank to accept a pilot bearing. Jeep 55 lb flywheel and bop bell fit right up. Your flywheel and harmonic must be balanced to the crank. Other than above, the mechanical part of the swap was easy. She bolts right up. I had some custom exhaust plumbing made. Making the electronics happy was more of a chore. Without seeing the thread, I think the blow off valve relates to the turbo. I did lots of lurking on turbobuick web site during the build - it helped. I was told that the turbo might surge with a manual behind it so I bought a custom burned chip for the stock computer. I have the boost limited to about 15 lbs. Stock setting is 6 lbs. I have never dinoed the jeep but estimate it might make 300 horse at 15 lb boost. Rule of thumb is 10 horses per 1lb boost. Revs limited to 600 by computer. It runs great.
     
  17. dunl

    dunl Member

    Thanks Mandery. The one I am looking at is a 4.1 from an 81 Cadillac, naturally aspirated. I'm thinking that it most likely has the 2bbl carb, so going to a 4bbl and opening the intake like this:

    http://www.turbobuick.com/forums/be.../281474-modification-4-1-4-barrel-intake.html

    ....should free it up a bit. The exhaust from the 3.8 was routed along both sides of the jeep, but it'd be nice to go to headers too. As I had a 3.8 in there, mechanically it should bolt again just fine. I don't think there are any computer controls, but then again, you never know with Caddy. I know for their V8 they had emissions computer controls to let it run on 4, 6, or 8 cylinders depending on need.

    I have a chance to get a 4.1 V6 engine block, still crated....is it worth picking up?
     
  18. A Mandery

    A Mandery Member

    If the price is right, you never know what might come in handy. Ican't believe there are many 81 crate motors lying around. My best advice is to get the service manual for that engine/car. AM
     
  19. (0llllll0)

    (0llllll0) Mr. Willys or Wonty

    I think most of the 4.1 were 4bbl (quadrajet) carbs, the 2bbl were on the 3.8's.
    Mine came with the 4bbl manifold.

    Cam
     
  20. dunl

    dunl Member

    Well, the crate motor is mine. I simply am going to trade the Chev 4.3 that I picked up for $100 for the 4.1 crate motor. The mechanic who has it really has no use for it, and not really that many guys in the area who are interested in that type of engine. So I get a nice deal for $100 worth of stuff, and he gets a nice deal for what is probably only worth about $100 to him too. (maybe more, but no one here is going to pay for it).

    I do think most 4.1's were 4bbl, but for some reason I seem to think that the Caddy V6's were choked off with a 2bbl. Not sure why, but maybe I read it somewhere.