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  1. #1
    FallinOffHurts's Avatar
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    VTech 8900 Tune without logging please BEWARE

    This thread is based on facts, not to bash. The head was pulled on a 2014 RXTX with 39 hours due to a blown head gasket. Coolant overflowing out of the overflow tube under boost. The ski has a 137+4 with all supporting mods. Fuel pressure was set and tuned via wideband to run a conservative 11.8 afr under WOT. Here's pictures of what was found after the head was removed. The #2 and #3 cylinder were detonating which blew the head gasket out on the exhaust side on both of these cylinders. The intake valves were also getting VERY hot as you can tell by the pic of the head. Continuing to run this tune as is will lead to necessary piston replacement and valve replacement.
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  2. #2
    Sanfish's Avatar
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    Quote Originally Posted by FallinOffHurts View Post
    Fuel pressure was set and tuned via wideband to run a conservative 11.8 afr under WOT.
    Are you saying you tuned motor by adjusting your fuel pressure or were you actually "tuning" with a data logger and adjusting fuel/ignition tables?

    If you are adjusting via only fuel pressure, we've all seen how this movie plays out.

    This topic should read "BEWARE if you tune only with fuel pressure."

    -Guns don't kill people, people kill people.

    BTW: What RPM's were you turning?

  3. #3
    FallinOffHurts's Avatar
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    By the number of times VTech is bold in your signature Sanfish, I get it. You feel the need to defend the product. This thread was made for a ski that I help my buddy work on. I run an Athena stand a lone ecu. Here's my head after 90 hours of abuse with a 68-140 and bigger cam. Based on the advertising I've seen from Vtech, many assume they can just reflash and go. This is apparently NOT the case with the VTech reflash. I'm just stating facts to try and help others save motors.
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  4. #4
    Branden's Avatar
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    Ive told several people this, the 8900 tune has way to much timing in it for a 137 wheel and likely on the ragged edge for a stock wheel, the tune itself with a little tweaking is a good tune, but 39 degrees is way to much. i run that tune in my ski, but i also have 31 degrees of timing in it......

  5. #5
    We have MANY versions of 8900 tunes, from "normal" to aggressive.
    What file did he use, what is his skin vin so i can check ?

  6. #6
    GRF + DashPac:) seadoo02xp's Avatar
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    39 degrees is just nuts on our pump gas. For those guys out there chasing big speeds you are better off to just get a bigger charger and keep timing down. You are less likely to break shit this way! The 4tec can take some big boost but deto will kill it quick even at stock boost levels .
    Some of the crazy speeds people are seeing aren't gonna last long .....

  7. #7
    Sanfish's Avatar
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    Quote Originally Posted by FallinOffHurts View Post
    By the number of times VTech is bold in your signature Sanfish, I get it.
    Not sure how my signature means anything in regards to my comments. Only thing I will defend is to properly tune a ski and that does NOT mean via the fuel pressure regulator. If someone runs a tune with 8900 limiter, they are far from stock and supporting mods are vital.

    I'm sorry this happened to you but if you are so concerned about "facts" and trying to help others, you need to be honest with yourself first. Gus was honest enough with himself (and publicly) to fully admit he failed to properly tune.

    FYI: I payed for all my vtech stuff.

  8. +1 by:

    JPR

  9. #8
    Gus13letter's Avatar
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    Well damn, that is two down with less than 40 hours with similar problems.... Good info and hope this saves others from similar issues.

    Mine motor went with only 47 hours but only ran that 8900 Jesus tune for about 15 hours and had similar issues. Detonation was the biggest contributor to my problems, pitting damaged rings causing excessive blow by, pitting on valves and valve seats caused visual gaps, spark plug ground strap, etc. The oil was also washed out and also looked like soot. Unfortunately I had to sell off all of my mods to allow me to raise enough money to fix my ski. I was so disgusted with the situation and since my ski had to be put back to stock I just decided to go with a SeaDoo re-manufactured engine and just ride and enjoy the ski for what it is, but still stuck with the VTech credit....

    When I saw the condition of the spark plugs, I decided to get the datalogger to see what was going on and confirmed I had BAD detonation above about 7800-7900 rpm mainly on cyl 2 and 3, but also occurring on cyl 1 too, just not as bad. The 8900 401/8900 Jesus tune has 38 degrees of timing, but even with less aggressive tune with 36 degrees of timing I was still detonating. This tells me that I really should have been running closer to maybe about 33 - 34 degrees timing, but I never got to confirm this.

    In my opinion, to say that once the ski is modified it must be data logged just doesn't seem right and means that the tune is to aggressive and must be modified to make it less aggressive and safe. My 2006 RXT ran ET Rude upgrade wheel Riva ECU 8600 rpm and 82 mph, my GPRXP with Rude 1 and Riva ECU at 8600 RPM ran 89 mph, my FZR along with hundreds are running the R3 or R4 flash, ET18 or ET19 but are pushing upwards of 23 - 24Lbs of boost at or above 9000 RPM, aftermarket cam or cam gears, etc, and are all tuning with an AFR gauge and rising rate regulator, still on 93 Octane pump fuel. Which is why I say in my opinion it doesn't make sense to say that with an X charger running 12-13 Lbs of boost at 8800 - 8900 rpm and recreational cam (my setup that had issues) requires data logging and tuning. I feel that the available tunes are not like the other tunes we are accustom to and are too aggressive for recreational riding on 93 Octane pump fuel.
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  10. #9
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    people been using FPR regs for years without issues like this & the DECENT TUNES they get from them so I think people might wanna find a NEW CAUSE as in AGRESSIVE TUNES & suspect GAS cause these things more then FPR's do...............u can tune insufficiently with an FPR and they r not a FULL MAP TUNE but that is NOT the root cause of this problem......these issues were not as common until certain people came to town with race tunes in rec users hands and if u don't pay ATTNTION TO DETAIL with certain tunes they have u get this............FPR tuning is not the ROOT cause of this problem.....FACT!!!!!!!!!


  11. #10
    GRF + DashPac:) seadoo02xp's Avatar
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    Quote Originally Posted by REID2168 View Post
    people been using FPR regs for years without issues like this & the DECENT TUNES they get from them so I think people might wanna find a NEW CAUSE as in AGRESSIVE TUNES & suspect GAS cause these things more then FPR's do...............u can tune insufficiently with an FPR and they r not a FULL MAP TUNE but that is NOT the root cause of this problem......these issues were not as common until certain people came to town with race tunes in rec users hands and if u don't pay ATTNTION TO DETAIL with certain tunes they have u get this............FPR tuning is not the ROOT cause of this problem.....FACT!!!!!!!!!
    Tru dat!!

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