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  1. #1
    98gsxl951's Avatar
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    whats the consensus on running et137+4 with 48s only for fuel and 12.3-12.5 WOT afr?

    so last year i ran a black et137+3 wheel for 35 hours with only 50lb riva injectors, this season moved up to the et137+4 and with the 50s my afrs at wot were as low as 10.6/7 but usually around 10.9 to 11.2 depends on heat and humidity. Ran the +4 like this for 20 hours this season. i decided to throw in some 48 deka injectors as i was dumping to much fuel at idle and low rpms. my afrs now at idle ar 12.5, mid is at around 13.5-13.7 and wot between 12.2 but ive seen as high as 12.4 12.5 ... i ordered a new o2 sensor and will re calibrate it and try to do some more pulls. spark plugs look ok, but hard to tell as they only have a hour or 2 on them.

    i have no fuel control, running stock fpr, stock ecu, riva through hull, and kani flex is really my only other mods as well as custom pitched prop by slow91(chris)

    I know that im not doing things correctly but am on budget and cant swing the rrfpr at the moment.

    is low to mid 12s ok to run the ski with the 48s or should i put the 50s back in till i can scrounge the money up for the rrfpr?


  2. #2
    R88ory RXP's Avatar
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    hmm tough one that, It probably mostly rides on your riding style... If you like long WOT topspeed runs then that is too lean for my liking, it needs to be under 12.

    If you like short burst "bouy to bouy" type riding then it will live OK, There are plenty of CC race boats running leaner then that WOT, the big problem you have is it will kill your pistons/rings, the stock units can only put up with so much, some of the 08's were very prone to failure.. For the racers this is not an issue as winning is the goal and running leaner to a point will make the motor sharper. A rebuild at the end of the season is good practice...

    I would, do some reading, you can make your own RRFPR setup for not much cash, im talking about 1 weekend off of the water and not buying a tank of fuel cash...

    It takes some work but the 08+ setup is quite easy as you dont have to use a tank adaptor.

    There are quite a few options for regulators out there.

    Having the RRFPR set to 58 will help clean the idle up as the vac will pull the fuel pressure down a touch and then you will have the fuel up-top.

    I really would advise missing a weekends riding and spend the fuel cash on getting it right, a re-build is going to see you off the water for a long time if getting cash together can be an issue... I know this well...

    Too rich at the bottom is bad too, it can wash the cyl walls of oil = worn rings = low comp = re-build..

    Keep it off the limiter!!!!!

    R88

  3. #3
    shrabber's Avatar
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    To lean scrounge the money or buy a piggy bank and save up for a motor in the future.

  4. #4
    skigolfnut's Avatar
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    you can make a rrfpr for cheap, get the tank adapter, then a regulator off e-bay and your set,
    I race with my afrs at about 12.2 to 12.8 at WOT mid range is 11.9 to 12 idle is about 13-14+
    I have the et-137 wheel with 3mm spacer, never run for very long with it rich, it will wash the oil off the piston walls and fill your crankcase with fuel,

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  6. #5
    98gsxl951's Avatar
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    what should afrs be at like 7000-7500 rpms? 12- 12.5 ?

  7. #6
    Mod less, ride more! troyheb's Avatar
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    Quote Originally Posted by 98gsxl951 View Post
    what should afrs be at like 7000-7500 rpms? 12- 12.5 ?
    yes

  8. #7
    Eric Ocman's Avatar
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    Quote Originally Posted by 98gsxl951 View Post
    so last year i ran a black et137+3 wheel for 35 hours with only 50lb riva injectors, this season moved up to the et137+4 and with the 50s my afrs at wot were as low as 10.6/7 but usually around 10.9 to 11.2 depends on heat and humidity. Ran the +4 like this for 20 hours this season. i decided to throw in some 48 deka injectors as i was dumping to much fuel at idle and low rpms. my afrs now at idle ar 12.5, mid is at around 13.5-13.7 and wot between 12.2 but ive seen as high as 12.4 12.5 ... i ordered a new o2 sensor and will re calibrate it and try to do some more pulls. spark plugs look ok, but hard to tell as they only have a hour or 2 on them.

    i have no fuel control, running stock fpr, stock ecu, riva through hull, and kani flex is really my only other mods as well as custom pitched prop by slow91(chris)

    I know that im not doing things correctly but am on budget and cant swing the rrfpr at the moment.

    is low to mid 12s ok to run the ski with the 48s or should i put the 50s back in till i can scrounge the money up for the rrfpr?
    At those rpms you're perfectly fine.


  9. #8
    98gsxl951's Avatar
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    im going to throw in a new o2 sensor for my wide band re calibrate it and do some pulls , might datalog my afrs if i can find a smaller laptop, and pull my plugs after doing a half throttle pull, 3/4 and wot. my idle to boost afrs seem on point but wot was on the leaner side then again... my 2 back to back pulls at wot were way off first one at 12.3 12.4 2nd single digits low....

    if my afrs continue to be lean i will leave the ski till i add a rrfpr.

    thanks for the replys

  10. #9
    shrabber's Avatar
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    If 12.5 is perfectly Fine at WOT I might Need to adjust My tune

    You need a rrfpr Period. Its like fighting a killer whale on a hand spool with no gloves, your all over the place.

  11. #10
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by shrabber View Post
    If 12.5 is perfectly Fine at WOT I might Need to adjust My tune

    You need a rrfpr Period. Its like fighting a killer whale on a hand spool with no gloves, your all over the place.
    If you're gonna run it for only an 1/8 mile at a time you might want to make it leaner still! Got my best speed at 12.6

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