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BBC swap from TBI to TPI

Discussion in 'The Injection Section' started by SubYuman, Jun 12, 2006.

  1. SubYuman

    SubYuman 1/2 ton status

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    Always looking for more power/mileage. Anyone have ideas where I can get parts/plans?? Or do I just get a 54mm TBI body, a reflash and run premium fuel and live with it?
    I alread have tbi spacer, injector spacer, K&N FIPK setup... waiting on my headers and looking for Flexalite 280 fans....
     
  2. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Minor nitpick detail here: your system would be called an MPFI, not TPI. TPI is infact an MPFI system, but it has the runners tuned to the harmonic frequency of the air rushing through the runners, then being stopped by the intake valves, sent back up as a result, then being sucked down again once it opens. Hense, being tuned port :)

    Now, onto something a bit more helpful, lol

    The stock TBI ECM doesn't have the capability to run 8 injectors like the TPI ECMs are capable of. So you'll probally wind up needing to switch to a TPI ECM like the `7730, and do a whole ton of tuning to get the setup to run well.

    The aftermarket holds tons of ECM possiblities as well, such as the megasquirt controller, Holley Commander etc. They are all very powerful ECMs that will have no problems getting your BBC running very well on multi-port. The Megasquirt is exceptionally easy to tune yourself as well as being one of the cheapest. I'd personally recommend it over the rest :)
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    Multiport Systems for BBC's aren't cheap. Alot of people who don't have emissions in there area are getting MPFI systems off of Mercury boats that have BBC's. Holley has an MPFI system, Arizona Speed & Marine has a system, and many others I am sure but none of them are cheap.

    Harley
     
  4. SubYuman

    SubYuman 1/2 ton status

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    Can it...

    Be done for under $2k?
    If I can save 10% on fuel, that's 4.2 gallons a week. That's about $700 a year....3 year payback is pretty good.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    I *think* as mentioned the marine takeoffs would be a way to go.

    There are/were ramjet 7.4L's, correct? The injection setup off of that would work if so, although they *really* need to be converted to an O2 sensor setup to get driveability/economy as good as it can be.

    S10wildsides(?) over on thirdgen.org converted ramjet 350 setups with closed loop harnesses, so I suspect as long as there are ramjet 7.4 setups, the same is possible.

    The plenums and fuel rails are what make the cost outrageous on non-small block MPFI conversions, which is why you see almost no older Buicks, Olds, Pontiacs and Cadillacs with MPFI.
     
  6. eagle mark

    eagle mark 1/2 ton status

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