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  1. #1
    David 1 FAST VE's Avatar
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    New SC Mod to go to 13 P.S.I.

    Well a lot of you know about this it may be news to others.

    There are a few places doing this now that we can get done, they are all overseas for now

    I have a question for some of you guys to ponder. @ 13psi will adding fuel do enough to make up for the added boost or will you have to have control over timming as well?

    The cost of this mod will be around $1200 so it is reassonable to get this much boost I think. Someone on the board here has this setup and runs Niles fuel controller but needed even bigger injectors than what he supplied.

    So my question is this, maybe Niles can give some insight, when adding this much boost what else do we need to be looking into to make it reliable and have you found any limitations with added boost and pump gas? I do not want to change computers as it starts making the cost really high so what if anything do we do other than add fuel.


  2. #2
    captain obvious Lurker's Avatar
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    The problem is that nobody knows exactly how the stock computer works. We need to add boost while having a scope hooked to the engine. Normally you want to add fuel to keep the a/f ratio good and you also want to trim back timing as the boost increases. But you trim back timing to keep just under detonation. In leu of timing adjustments you can run higher octane gas, but this can be expensive and race gas isn't usually avilable on the lake.

    So yes when adding more boost you want less timing advance.

  3. #3
    Site Admin Green Hulk's Avatar
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    You need control of both fuel and timing.

    Right now the only way to do this is with a stand alone ECU. Nils has been working on a fuel/timing controller that would work great with this application.

  4. #4
    David 1 FAST VE's Avatar
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    Some other guys told me that about 10psi would be pushing pump gas.

    With enough fuel do you think you could overcome detonation problems?

  5. #5
    Site Admin Green Hulk's Avatar
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    I personally wouldn't risk it without having a data logging/programmable type of engine management system on it.

  6. #6
    Vern's Avatar
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    What is done to get the boost that high, and can you control it, or lower it slightly?

    Following is a quote from Procharger, but it is about cars, our PWC motors are used in a whole different manner than car engines, but it is interesting from a theoretical viewpoint. I think our compression ratio is 8.5:1, someone correct me if I am wrong.

    "The primary issues that determine the type of fuel needed are whether the engine is fuel-injected or carbureted, the compression ratio of the engine, and whether or not the supercharger system is intercooled.

    For Intercooled ProCharger EFI/TPI applications with compression ratios less than 9.5:1, boost levels of 14-17 psi can be safely run with full timing on pump gas, and will produce horsepower gains of 75-100% (depending upon the boost level and the motor specifications). For 9.5:1 EFI/TPI applications running without an intercooler, boost levels above 5 psi will require the use of ignition/timing retard on pump gas, and will produce horsepower gains of 35-45%. Boost levels above 12 psi should generally be avoided even with racing fuel on a 9.5:1 motor. Of course, lower compression motors will be able to run more boost, and higher compression motors should run less boost, everything else being equal. All Intercooled ProCharger systems for street applications are designed to allow the use of pump gas with full timing and will not affect daily drivability."

    Personally I like Procharger and wish they would go after the PWC supercharger market ...

  7. #7
    David 1 FAST VE's Avatar
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    Vern Procharger is in the PWC game and hopefully will have something out this summer.

    Therefore, by their theory our engines could run 13psi (w/ic).

    I wonder if you put that much boost in why the knock sensor would not back timing out in the event that something did happen.

    What compression do our motors run?

    I know the stand-alone ecu would be killer but you open a completely new area of tuning when you do this. Now it is more of a full-blown race ski. I could never convince the wife anything different but come on "These are just bolt on parts"

    That was our deal if I got another ski, only bolt on parts and I cannot take the motor out.

  8. #8
    David 1 FAST VE's Avatar
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    Vern it is a SC impeller and cover mod, like on the Japenese site.

  9. #9
    Nonstop, all day, everyday. 01xdime's Avatar
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    Has anyone been able to contact Quattro motorsports, the japanese site i belive we're talking about? I sent them an email but i guess the language barrier is a problem. I'd like to find out about the mods they have. I like the looks of their exhaust manifold as well. I saw another manifold on that Yellow site but the price is outrageous.

  10. #10
    David 1 FAST VE's Avatar
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    I got throught to Quatro but it did not do any good all they could do is say hello.
    This is Les Cook in AU. He is doing the same thing as Quatro.
    He is also using something differant for the clutch.

    I spoke with Niles and he thinks it will work with his fuel controller @ 13psi.

    He thinks they are using 75lb injectors to make it run

    He suggested adding a O2 sensor and checking it with that to be sure.
    Maybe like Jerry suggested and do a Data Logger to verify everything.

    I think I am going to pull some parts and get them ready to go to Les.

    13PSI would be Bad A**

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