Grand National Thought

Discussion in 'U-shift em' started by someguy2112, Jun 29, 2007.

  1. Floydsbuick

    Floydsbuick Well-Known Member

    Yeah...it was fun. Although I never could get out of the 14s.

    I do miss shifting really bad:3gears:
     
  2. AbeWhat

    AbeWhat Member

    It was done by a car mag back in the day, made the TR a second slower in the quarter I think. Definitely was slower, with a good driver and all.
     
  3. MPRY1

    MPRY1 Gear Banger

    So I guess if it's been tried once 20 years ago no one should ever try it again? :puzzled:

    Back in the day they did not have whats available now computer wise for tuning, roller bearing turbos that spool up faster, etc.. Technology marches forward.

    I still think if a 3300 pound Subaru WRX STi (yea they are that heavy) can go incredibly fast with a six speed manual, a smaller engine and a smaller turbo, there is no reason why a Turbo Regal can't do the same if not better. It's not like Buicks are on some other plain of physics. :laugh:
     
  4. AbeWhat

    AbeWhat Member

    i dont think they exist on another plane of physics, no. hmm. But there is a good case for using a big turbo/big converter setup that is very popular for drag racing setups. 1. Building boost at the line 2. keeping it floored through gears... Not saying a manual is impossible at all, just going fast in a straight line in a turbo regal is easier/cheaper with an auto. Go to gnttype.org and search their forums, there are many posts proposing this idea, and a good amount of discussion. Some research on the TR's, not WRX's, will turn up a lot of info.
     
  5. Electrajim

    Electrajim Just another Jim

  6. CTX-SLPR

    CTX-SLPR Modern Technology User

    The way a manual is spooled on the line is to retard the timing so far that it burns in the headers creating the load you need for the turbo to spool. This does all sorts of weird things for the metalurgy of the headers and for the EGT's. The bigger problem with a stick is the instant a brutal torque. Not saying you couldn't build a tranny to handle it but in testing on the '89 Turbo Trans Am they tested it with the T5 and no only was it atleast 1s slower it also shredded the trans in only a few hours of testing. Granted a T5 is junk to holding that kind of power but still its a lesson not to be ignored. The import motors don't torque as hard as the Turbo6 since they are sometimes less than half the size. Smaller motors mean smaller turbos which have less systematic losses due to bearings, wheel interia, and tubing lengths. This also has the side effect of requiring a blowoff or bypass valve to keep the turbo from not only spooling down but reversing direction and trying to pressurize the exhauste due to the pressure going backwards across the compressor.

    Sorry but the cool factor on this is so outclassed by the practical issues that I personally don't think its a good idea for anything but a LSR car. A good shifter on a properly prepared and cooled TH200-4R will be all that even a AutoX car really could use without having a ON/OFF clutch and unubtainium internals on the trans.
     
  7. BadBrad

    BadBrad Got 4-speed?

    Turbos are well matched to automatic transmissions because they are both non-linear energy transfering devices. The turbo provides almost no power until it reaches a certain rpm - then power climbs rapidly. Essentially, the same thing happens in the torque converter - at a certain rpm the power transfer climbs rapidly. I read a description of torque converter operation once that indicated some crazy immense momentary multiplication on the order of 25 to one. Tune the turbo to approach peak somewhere around the converter stall speed and look out.
     
  8. sporty-to-GN

    sporty-to-GN Well-Known Member

    There's a thread re. manual conversions at turbobuick aswell. And it argued the same as it has here...until...some one mentioned the Buick V-6 lacks the thrust bearing/webbing strength to hold up as well as it would with an automatic.
    The cruising coolness factor would be there.
    In addition to the block, I don't think the body/frame would hold up very well to the torque shock of a manual trans for long. Although they weigh about the same a 68-72 GS, the sheet metal and frames are not as durable. The frame and 1/4 panel on my relatively stock GN have the cracks to prove it.
    With mileage these cars tend to become rattle traps. I can here it now, like a sledge hammer to the dash with every WOT dump shift!

    Do what you will and make it your own. Personally, if I had the inclination, I would go with a hyraulic pedal set up. Why use an antique pedal linkage design on ECM muscle?
     
  9. bob k. mando

    bob k. mando Guest

    The problem with a manual transmission in a Turbo car is between gears while shifting you would lose the boost that was built up, so the turbo would have to spool up all over again


    stick shift turbo's aren't very good unless you're driving them hard. if you scream the engine out to ~6,500rpm and then drop down to 4,000rpm for the next higher gear you'll still have the turbo 'on boost'.

    do you intend to drive that way on the street?

    the specifics will vary depending on how the turbo system was designed and set up but you shouldn't do this without researching very carefully where your expected shift points and minimum engine rpm for turbo boost are going to be.

    most of the modern cars get around this by using extensive computer controls and variable vane/inlet turbo systems.
     
  10. rdj59

    rdj59 It's like sex on ice

    When i turboed my b2200 with a 5 speed i didn't really have a problem with boost lag between gears. As long as you use a blow off valve to relive the intake pressure it should stay spooled. When you shift the turbo is still spinning very fast and takes a split second to shift and your back on the gas again enjoying the boost. It worked just fine for me. Sure an auto is ideal but what do you want, something you would enjoy driving everyday or something you only enjoy one day a week?

    Jeramie
     

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