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  1. #1

    plastic intake manifold flexing?

    is this what I`m seeing ?
    when flushing the ski on the hose, I was watching the engine and saw the intake manifold expand when giving it more rpm`s and letting go
    nothing is loose, I can see the block-off/clamp end of the intake grow when reving, I think I read this somewhere before but never noticed it. this is with a stock sc wheel ...any comments?..PR...


  2. #2
    Aren't our IM's plastic? I've been concerned about this for awhile now, especially when increasing boost and such. Hopefully the external IC's are doing a good job. The guys that concern me are the ones still running the stock IC and green SC wheels or higher. I haven't heard of any failures though. The reason why I'm concerned is because I've heard of people increasing boost and such on SC Pontiac Grand Prix and melting the intake manifold which is also plastic. I've even heard of these problems being quite common on stock SC Grand Prix. For this reason my friend did not purchase the SC Grand Prix.

  3. #3
    Moderator Franko's Avatar
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    Yes, they do expand and contract. It is normal with these plastic manifolds. Now I don't know what effect this has on performance, but I would think a sturdier manifold would move air more efficiently.

  4. #4
    HORSEPOWER JUNKIE 9secZO6's Avatar
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    I gotta jump in here.....think COMPOSITE--not plastic. This same material is use on autos everywhere, would take the heat of a flame to hurt it. Besides the weight savings, it refuses to retain heat. It will not get heat-soaked from the head and as a result not over-heat the incoming air. Put a bag of ice on the LT-1 b4 a pass when the motor is warm a .2sec or better will result. (aluminium intake) Do the same w/ LS-1 (composite), lucky to see any measurable gain. I think the 155hp non-s/c benefits more from this, but the cooler u keep the intake charge the more timing u can run and the more power u can make. It may swell a little when pressurized, but its construction is like fiberglass in that it has resins and tiny strands of material. Diff. from standard injection-molded proccess. U think u could get that swelling to show up on high-res. video? I am glad the intake is "plastic"!

  5. #5
    Quote Originally Posted by 9secZO6 View Post
    think COMPOSITE--not plastic. It may swell a little when pressurized, but its construction is like fiberglass in that it has resins and tiny strands of material.
    laymens terms: plastic
    I`m all to familar with the 4.6 composite intakes at the thermostate housing on the Fords... ...
    and the GM 3.8 composite intakes leaking coolant into the intake runners .

    anyways, I can see that expand about 1/4in at the block-off end...PR...

  6. #6
    Moderator Franko's Avatar
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    Quote Originally Posted by 9secZO6 View Post
    I gotta jump in here.....think COMPOSITE--not plastic. This same material is use on autos everywhere, would take the heat of a flame to hurt it. Besides the weight savings, it refuses to retain heat. It will not get heat-soaked from the head and as a result not over-heat the incoming air. Put a bag of ice on the LT-1 b4 a pass when the motor is warm a .2sec or better will result. (aluminium intake) Do the same w/ LS-1 (composite), lucky to see any measurable gain. I think the 155hp non-s/c benefits more from this, but the cooler u keep the intake charge the more timing u can run and the more power u can make. It may swell a little when pressurized, but its construction is like fiberglass in that it has resins and tiny strands of material. Diff. from standard injection-molded proccess. U think u could get that swelling to show up on high-res. video? I am glad the intake is "plastic"!
    Dude, ease up. Sorry we didn't use precise enough terms for you. But I assume you knew what we meant.

  7. #7
    HORSEPOWER JUNKIE 9secZO6's Avatar
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    sorry, been on the corvette forum again, got to be anal to get along w/ anal

  8. #8
    PIRANHA's Avatar
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    Quote Originally Posted by Pale Rider View Post
    is this what I`m seeing ?
    when flushing the ski on the hose, I was watching the engine and saw the intake manifold expand when giving it more rpm`s and letting go
    nothing is loose, I can see the block-off/clamp end of the intake grow when reving, I think I read this somewhere before but never noticed it. this is with a stock sc wheel ...any comments?..PR...
    If you want to rectify this problem, keep an eye on the Piranha-Parts website in about 6-8 weeks!!

  9. #9
    Quote Originally Posted by PIRANHA View Post
    If you want to rectify this problem, keep an eye on the Piranha-Parts website in about 6-8 weeks!!
    swell! ...PR...

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