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TBI adapter?

Discussion in 'The Injection Section' started by HammaK5, Aug 14, 2006.

  1. HammaK5

    HammaK5 Registered Member

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    Ive got a 87 R30 w/454 tbi TH400, my question is there is an adapter between the throttle body and the intake, it appears that it has coolant hose attached to it. What is the deal w/ this? Is it needed? Also it looks like the knock sensor is unpluged and the sensor plug is broken off. How much will this affect the performance? Thanks in advance for the help.
     
  2. k20

    k20 3/4 ton status

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    GM didnt design a big block TBI manifold, so they used that adapter, to mate a TBI unit to a 4bbl manifold. So it is needed, unless you want to pony up for a big block TBI manifold from edelbrock, which really doesnt help performance much.

    The knock sensor being unplugged isnt going to hurt performance, it just wont retard the timing if there is knock, so there is potential for engine damage.
     
  3. HammaK5

    HammaK5 Registered Member

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    Thanks for the info on the adapter, I just thought that the hot coolant wouldnt help performance any. I saw an adapter plate in summit made by trans dapt I think that was flat plate, just htought if I swaped them it might cool the intake charge some, just an idea
     
  4. yoshisv

    yoshisv 1/2 ton status

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    The hot coolant is for emmisions. It actually may not run right without it.
     
  5. k20

    k20 3/4 ton status

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    Shouldnt hurt driveability, I havent seen an aftermarket adapter, I sold my old one on here bout a year ago, cause the guy couldnt find one. Anyway, you could probably get creative with the heater core routing, and a few pipe plugs, and just unhook the lines going to the adapter. It has one line run in the back, and one out the front. This wouldnt run the coolant through it, and it would only cost you a few bucks in heater hose and pipe plugs.

    I probably wouldnt worry with it though, cause you are only talkin 2-3hp loss here in all likelihood.
     
  6. HammaK5

    HammaK5 Registered Member

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    Thanks for all the info I think Ill propably leave the adapter alone and just replace the knock sensor for now and pull the codes and see what I get.
     
  7. sled_dog

    sled_dog 1 ton status

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    the newer TBI 454s had real tbi manifolds.
     
  8. bowtiepower00

    bowtiepower00 1/2 ton status

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    Holley makes one ( I know they used to, anyway) for TBI- 4BBL, the part number used to be on their site, it may still be. I remember seeing it in the Jegs catalog, but it's been a couple of years since I've looked though one though.
     
  9. Thunder

    Thunder 3/4 ton status

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    The heated TB adapter plate is not for emissions. It is heated to stop icing of the throttle plates and bore. Without it the TB can ice up causing driveability issues and possibly the throttle sticking open. 454 dont have the exhaust crossover in the manifold to heat the TB like 350s do so they need the heated adapter plate.
    Also you should get a new knock sensor. The ECM does look for its proper operation. With it dosconnected or broken the ECM wont allow full timing advance to protect the engine from detonation. ECM also uses the knock sensor to trim fuel and timing at cruise for best fuel MPG.
     
  10. k20

    k20 3/4 ton status

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    Yeh I thought I had said on the Mark IV's, guess I didnt lol, on the Gen V & VI, I believe they did have a tbi manifold.
     

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