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  1. #1
    Site Admin Green Hulk's Avatar
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    Intake manifold modification and 60mm throttle body

    I started a little experiment today to see if there would be gains from opening up the bottle neck in the throttle body and intake manifold. I haven't hit the water yet but wanted to throw up some pictures and get input from you guys on if you think there will be gains or not.

    First, i started with a throttle body bored to 60mm. Stock is 54mm. As you can see the difference in size is huge

    CLICK PICTURES TO MAKE THEM BIGGER




    Next up is the intake manifold. There is a huge ridge where the stock ribbon or intake manifold upgrade would go for those that have done the upgrade.




    First, my local machine shop built a jig to hold the manifold and they proceeded to machine the intake manifold all the way thru removing the bottle neck



    Secondly, they machined a taper in the plate the throttle body bolts to to transition from the 60mm throttle body opening to the 72mm opening machined into the intake manifold.

    Sorry for the blurry pic here




    Here's a picture of the mounting plate against the stock throttle body to give you an idea of just how much bigger the bored throttle body is. You can see the huge ridge pointed to with the red arrow



    This picture shows the mounting plate against the 60mm bored throttle body.



    I can tell you guys now that this will NOT be a mod for those using a stock or reflashed ECU. When i cranked up my ski it idled at a very high 2800 RPM due to the larger volume of air coming in from the over sized throttle body. Motec Pete is working real hard with me tonight to make the necessary adjustments to the mapping to get the idle tamed down. Once he gets it nailed down I should be able to water test tomorrow.

    Another point of interest is 60mm is the max amount one of these stock throttle body's can be bored.

    So what do you guys think? I'd love to hear some predictions on whether or not all this effort will produce some gains






  2. #2
    X-Closed Course Racer xracer128's Avatar
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    Thumbs up

    I have always been a fan of more air and fuel, plus the intake track that will accept it equals more horsepower and mph!

    This looks great Jerry!

  3. #3
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
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    I think there will be good gains on top with the right AFR but i don't think there will be gains on bottom.

  4. #4
    It's not the destination, it's the journey!! Rip'nTear SHO's Avatar
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    Very smart actually.....tame down the low end as we can't hook now as it is......and give the motor more air in the mid-range and on top end....I like!!

    But yeah...I can see where you need a Vipec or Motec to run this mod so you can tune to get the idle down from the increased air flow......awesome Jerry!!!!!

    Be cool to see what the Stalker shows.....and what effect it has on ur RPM's, AFR's, and prop pitch......

  5. #5
    SpeedJunky's Avatar
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    Nice, I like it. Not sure whats going to happen but I,m sure we will find out once you test it. I hope its a positive report because its going to be hard to put it back if it doesnt work.

  6. #6
    speedskixp's Avatar
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    I think you will see some nice gains. Especialy in throttle responce and acceleration. Probably even a couple hundred rpm increase.

  7. #7
    Happily Self-Employed WFO's Avatar
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    IMO dont worry too much about the idle on the trailer... it should settle down once the engine is loaded

  8. #8
    Quote Originally Posted by Green Hulk View Post
    So what do you guys think? I'd love to hear some predictions on whether or not all this effort will produce some gains
    I don't see why it wouldn't produce any noticeable gains. Let that sucker breathe, it's amazing how choked down this motor is. I would think you could expect snappier acceleration and more top end power especially with your setup. Near stock motors probably not so much.

    **EDIT: And does it look like anything can be done with the manifold itself? Porting or potential gains from aftermarket manifolds?

  9. #9
    Site Admin Green Hulk's Avatar
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    Special thanks go out to Motec Pete tonight for helping me get everything dialed in and ready for water testing. Thank you very much Pete

    Not only did he have to solve the idle issues but mapping changes needed to be made due to the increase of air coming into the engine.

    Okay, so here are my predictions. No gains on top but noticeable gains on bottom end and all thru the midrange.

    Looks like some nice weather for testing tomorrow so we will see soon

    9 am
    57F
    Feels Like
    55F 12 pm
    66F
    Feels Like
    66F 3 pm
    67F
    Feels Like
    67F

  10. #10
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by RXP-REX View Post
    **EDIT: And does it look like anything can be done with the manifold itself? Porting or potential gains from aftermarket manifolds?
    There's definitely room for improvement here. JD 1 has sent his manifold off to be extrude honed so I'm anxious to see how that works out for him.

    He's also bored the intake manifold out like I've done above but he's been running the stock sized throttle body. He just got his TB back from being bored also so he will be able to give us some feed back as well.

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