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Thread: Only 77mph

  1. #1
    rxp1972's Avatar
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    Only 77mph

    I'm installing my new ET 68-140EXTREME with 60lb injectors walbro fuel pump fuel regulator Les coke 8650 ECU 15/22r open loop Riva ride plate pump wedge ,4" air filter
    Pump cone and 82 ring head porting riva valve train upgrade trottle body 61mm xs intercooler.The fuel ratio is 11,8-12,3 (full throttle).
    The boost pressure is 14,5psi (7920rpm)
    The water in the sea is very hot 30'celcius.
    I use to the pump cone the two bigger spacers.
    The problem is that i see on GPS only 77MPH at 7900rpm.
    I thing i should be at the 82MPH minimum.
    Do you guys imagine the problem?
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  2. #2
    Remove the pump cone spacers and open up the ventury to 83-84mm or install a 15/20 Solas, you are overproped for salt water and hot weather.

  3. #3
    rxp1972's Avatar
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    You thing i should remove all the spacers?

  4. #4
    Vern's Avatar
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    Quote Originally Posted by RXP6 View Post
    Remove the pump cone spacers and open up the ventury to 83-84mm or install a 15/20 Solas, you are overproped for salt water and hot weather.
    +1 ... Your speed is about right for the rpms you are turning ... but you have a combination of a big impeller, tight nozzle ring, and the cone and spacers ... ALL of these work to knock your rpms down. Since you really need to gain 600+ rpms, RXP6 is right ... first try the biggest nozzle ring you have (or stock nozzle), with NO cone spacers. That will get your rpms up some ... if you are still low, you may want to try a stock cone or switch to a 15/20 and tune with nozzle rings. Once you get your rpms up to 8500+, your speed will come way up too ... I think 82 for sure, maybe more, depends on heat/humidity/weather too.

  5. #5
    rxp1972's Avatar
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    Ok thank you vern i will try to remove the spacers first and after that the nozzel.

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