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  1. #1

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    Talking How much boost can a Sho motor take?

    " Stock oem motor" I see a lot of post on the forum about higher boost SC wheels comming out for these motors 18 lbs even 20 lbs. I have noticed several lower boost aftermarket SC wheels on the classifieds on the forum for sale lately due to guys wanting to up the boost even more! As soon as these wheels hit the water I supect we will see some guys crying the blues when there motor starts pushing oil out the breather , head gaskets leaking, bolts pulling out the block or even worse piston and rods hanging out the block. I know Yamaha builds some good motors but watch what I am predecting. I use to be a fortune teller in my previous life! Tommy Jordan


  2. #2
    cigarlust's Avatar
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    You can only get blown so hard...

  3. #3
    Site Admin Green Hulk's Avatar
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    Good topic Tommy!

    I feel that my ski is at it's limits right now at 15.5 psi at 8700 RPM. In fact, i really think I'm beyond my limits. I'm adding pitch to get the RPM's down to 8500 to 8600 RPM until I can put forged pistons into the engine.

    I think you will find that when the big companies introduce their 18+ psi supercharger upgrades they are also going to recommend upgrading the pistons.

  4. #4
    GOT BOOST? Dockside's Avatar
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    Quote Originally Posted by Green Hulk View Post
    Good topic Tommy!

    I feel that my ski is at it's limits right now at 15.5 psi at 8700 RPM. In fact, i really think I'm beyond my limits. I'm adding pitch to get the RPM's down to 8500 to 8600 RPM until I can put forged pistons into the engine.

    I think you will find that when the big companies introduce their 18+ psi supercharger upgrades they are also going to recommend upgrading the pistons.
    logs dont have forged pistions learned something new today....

  5. #5
    SHOBiz's Avatar
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    I am thinking ~15-20psi on stock internals. After that, get some rods and slugs.

    At around 20psi forged pistons should be REQUIRED IMO.

    Where's that order form

  6. #6

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    Quote Originally Posted by Green Hulk View Post
    Good topic Tommy!

    I feel that my ski is at it's limits right now at 15.5 psi at 8700 RPM. In fact, i really think I'm beyond my limits. I'm adding pitch to get the RPM's down to 8500 to 8600 RPM until I can put forged pistons into the engine.

    I think you will find that when the big companies introduce their 18+ psi supercharger upgrades they are also going to recommend upgrading the pistons.
    When you start boosting a motor that much you need a purpose built motor bottom to top complete. Been there done that! Tommy Jordan

  7. #7
    RUSH.'s Avatar
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    Quote Originally Posted by 2fast4u View Post
    When you start boosting a motor that much you need a purpose built motor bottom to top complete. Been there done that! Tommy Jordan

    I think there is alot of hp to be found in these engine outside of just going with more boost. I have been talking alot with Bill and Glen at r&d and I can tell you that there are alot of options coming for big hp without going high boost. I will be testing some of these options soon.

  8. #8
    SHOBiz's Avatar
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    Quote Originally Posted by RUSH. View Post
    I think there is alot of hp to be found in these engine outside of just going with more boost. I have been talking alot with Bill and Glen at r&d and I can tell you that there are alot of options coming for big hp without going high boost. I will be testing some of these options soon.

    Indeed, actually been thinking of doing a prototype turbo setup.
    If the $$ don't scare the shyte out of me who knows...

  9. #9
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by RUSH. View Post
    I think there is alot of hp to be found in these engine outside of just going with more boost. I have been talking alot with Bill and Glen at r&d and I can tell you that there are alot of options coming for big hp without going high boost. I will be testing some of these options soon.

    +1

    Higher compression with lower boost will achieve same results with better bottom end.

    Cams will work wonders too

  10. #10
    *Quiet Storm* #22gpr's Avatar
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    Quote Originally Posted by Green Hulk View Post
    +1

    Higher compression with lower boost will achieve same results with better bottom end.

    Cams will work wonders too
    +1 on the cams

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