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  1. #1
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    The custom piston question

    Alright guys Im setting up my ski to be a big bore monster and the zx piston route ended up being way more than just getting custom pistons made so thats what im going to do. I am planning on an 86mm bore which should put me right at 1600ccs and some change, now I need to set the ski up to run on pump gas and am not sure of the compression ratio that I need. I am thinking 9.5 to 1 but I talked to macc racing and their big bore kit is 9.5 to 1 and they said that you should use 100 octane av gas but im not sure if that is just insurance or if its needed. I have done a full head job for those of you not following my nasty 15f build. any advice is appreciated.

    Sean


  2. #2
    dawson's Avatar
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    need more info
    how much boost are you going to run ...

  3. #3
    I'M BAAAAAAAACK wrenchedexcess's Avatar
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    Lol, you are putting too much into this ski...

  4. #4
    pete71's Avatar
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    YOUR WIFE HAS SPOKEN

  5. #5
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    thats not my wife! hes my ski noob that I took under my wing! lol
    Its going to be naturally asperated so no boost, all motor. and some how I still have less into it that you dave!

    Sean

  6. #6
    Team N2L #112 *Monster 15FKawi*'s Avatar
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    Smokey.. im keeping an eye on this build. but ive looked at all the routes and there seems to be no way of BigBoring without running race gas.

    But Maybe,Just Maybe.. It can be done.

  7. #7
    dawson's Avatar
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    make up your own mind off the following info:
    i run more than 9.5 :1 comp
    h trim super charger
    with motec ecu (bag's of timming)
    on aussie pump fuel 98 octane RON.

    did you tell chris that it was a N/A ski he may have thought it was a blown boat?

    a 15f is more than 9.5 :1 comp standard right ??

    what cams and ecu you looking at running?

  8. #8
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    My goal for this is to keep the stock ecu and run a boondocker fuel controller with a wideband gauge and just up the amount of fuel alot then slowly back it down to set the afr. I hit a snag today though, i went down to re install the valves on the worked head and they were in really sorry shape.. so i am going to order a set of stainless valves as seen here
    http://www.schnitzracingstore.com/ca...showprevnext=1
    so thats going to put the big bore on hold.
    I am on the trail of a set of stock zx 12 r cams but i ran across this
    http://www.schnitzracingstore.com/ca...showprevnext=1
    these are a set of aftermarket cams for the zx and other than the fact that i need this to be a somewhat normal ski they look great and are half the price of the factory cams
    The stock compression on the 12f is somewhere around 11 and the 15f is 10 flat if i remember correctly.

    Sean

  9. #9
    dawson's Avatar
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    mate i will tell you now your ski will not even start run make it off the trailer with zx 12r cams and stock ecu
    they have more than 30 deg more timming that the stock cams
    you will need a full after market ecu to get those boys to run...

    sorry if i come across negative i just dont want to see you buy stuff that you wont be able to get to work with in you current build scope....

    Ferra valves will be the way to go just buy direct www.ferrea.com
    i can highly recomend them

  10. #10
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    So should I look for a endurance kit ecu? I appreciate all the help.

    Sean

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