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  1. #1
    Lbaronio's Avatar
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    TARGET AFR with 17psi boost at 8800RPM?

    Ive been reading all the AFR threads almost for a couple of hours...
    Last weekend finally i change my injectors (60s) and all become clear....
    Now im planning to get my AFR on the spot this large weekend...

    So the question..., 8650rpm, almost 17psi of boost, at open sea... all the times i saw the rpm going to 9000 or 9500 on the air while im at WOT on open sea...
    My Target AFR will be...... 11.7 ?....or


  2. #2
    Mod less, ride more! troyheb's Avatar
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    You may want to go maybe a little richer, just to be safe.
    I am sure someone with more experience will post up what would be safe.

  3. #3
    Eastside Powersports Slow 91's Avatar
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    If your on stock pistons run 11.5

  4. #4
    Lbaronio's Avatar
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    Thanks....

  5. #5

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    Race gas

  6. #6
    Having Fun jp1300r's Avatar
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    Quote Originally Posted by rxpstan View Post
    Race gas
    +1, I worry about the stock pistons after seeing so many go bye-bye. I run 100 octane, 11-11.2:1 WOT, XXX SCer at 8900 on my stock piston engine. And I still worry about them stock pistons. The way I am running seems to be okay, but no guarantee.

  7. #7
    Eric Ocman's Avatar
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    I know i may be an exception but the stock pistons are forged just like the aftermarket ones so what actually makes them weaker?? Won't any piston have issues if you run it lean/hot?

  8. #8
    richrxp's Avatar
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    Quote Originally Posted by jp1300r View Post
    +1, I worry about the stock pistons after seeing so many go bye-bye. I run 100 octane, 11-11.2:1 WOT, XXX SCer at 8900 on my stock piston engine. And I still worry about them stock pistons. The way I am running seems to be okay, but no guarantee.
    Afr 11.2 is a bit to safe,you'r losing performance.
    11.7 will work,but you want some extra cooling for your pistons , is that the reason your' running that rich?

  9. #9
    formerly Gold06RXP Turbo Nick's Avatar
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    Better to lose a little performance and know your safe than melt pistons IMO. I keep mine at 10.5AFR. But thats with methanol injection and the tuning for it is different than just gas only
    Quote Originally Posted by richrxp View Post
    Afr 11.2 is a bit to safe,you'r losing performance.
    11.7 will work,but you want some extra cooling for your pistons , is that the reason your' running that rich?

  10. #10
    Having Fun jp1300r's Avatar
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    Quote Originally Posted by richrxp View Post
    Afr 11.2 is a bit to safe,you'r losing performance.
    11.7 will work,but you want some extra cooling for your pistons , is that the reason your' running that rich?
    Yeah, maybe losing 5-10 hp at 9K. As much as these 4-tec engine parts costs, I am going to run mine at 11-11.2:1. Saves headgaskets, too by the way.

    I run rich like this on stock pistons. You can run CP, RIVA leaner and not damage them. Just a little detonation and you will more than likely blow a headgasket, too.

    They are all forged, yes. But they are not all made from the same type of aluminum. So the OEM stock pistons are weaker than CP, RIVA, etc.

    Also, some reason Eric your ski is slower. I don't know if its the ecu flash you have or what. Maybe your timing on your ecu is lower than mine.

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