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  1. #1
    Old School Never Dies! codemanrose's Avatar
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    180 PSI too much?

    I am about to buy new heads for the Raider and the guy said it runs about 180 compression. Is that too much? What should I run for octane? 93 or more?


  2. #2

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    180psi is too much for 93 octane. You are looking at mid 100 octane to run that head. 41cc domes will give you about 150psi which is safe for 93. Anything about that is pushing it. For 180psi its probably a head with 36cc domes. I have a pro-tec head with 38cc domes that will give you 165psi but still recomends 100 octane for sale...

  3. #3
    Greenhulk Grasshopah (DRC) HallPass's Avatar
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    Quote Originally Posted by johnson7454 View Post
    150psi which is safe for 93.
    I have a 150psi... those are 91 safe

  4. #4
    Old School Never Dies! codemanrose's Avatar
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    Quote Originally Posted by HallPass View Post
    I have a 150psi... those are 91 safe
    for sale?

    And the ones I was looking at have 37cc domes.

  5. #5

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    Quote Originally Posted by HallPass View Post
    I have a 150psi... those are 91 safe
    yeah 91 or 93...we only have 89 and 93 here in texas..

  6. #6
    Old School Never Dies! codemanrose's Avatar
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    Well shouldn't I be able to place different domes in it so I can run 93?

  7. #7
    Don't know if it applies, but on dirtbikes and old two-stroke quads they routinely run 180 psi on premium no problem. It's not until they go to 200-210 is usually 100 octane required and 215+ requires 110 octane.


    Perhaps the timing is different such that PWC engines can't do this.

  8. #8

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    Quote Originally Posted by ChewyR View Post
    Don't know if it applies, but on dirtbikes and old two-stroke quads they routinely run 180 psi on premium no problem. It's not until they go to 200-210 is usually 100 octane required and 215+ requires 110 octane.


    Perhaps the timing is different such that PWC engines can't do this.

    yeah not sure what makes the difference but there is one on the pwc's.

    Depends on what head it is. Only some heads have changeable domes. The only head protec still makes for the waveraider has changeable domes. Not sure on any other ones. Why dont you just get your stock head cut for around 150 dollars. They will just need to know what your psi is stock so they can cut it for 150psi

  9. #9
    Old School Never Dies! codemanrose's Avatar
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    I guess. But I can get these heads for 100. Thats Why. according to Protec's website, 37cc domes for the 1100 are 170 psi. Thats what they have...93 octane and some good octane booster? I have some from lucus that isn't even street legal.

  10. #10
    Old School Never Dies! codemanrose's Avatar
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    just found out the domes are changable...so would I be able to get ones from protec?

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