what speeds to expect???
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what speeds to expect???

  1. #1
    lawnmower repair man
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    Default what speeds to expect???

    18' 1978 challenger hull.lightened hull. redone berk pump, cut A, polished bowl. No droop or snoot. motor pulled 675hp 640torque @6300. getting it all together figured id ask!
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  3. #2
    Senior Member skippers WFOT's Avatar
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    you can expect 45-60, you can always hope for more. i dont know just thought id toss in an answer for your thread
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    Senior Member zacho!'s Avatar
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    with my luck, it would get on plane!
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  6. #4
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    Quote Originally Posted by notathing View Post
    18' 1978 challenger hull.lightened hull. redone berk pump, cut A, polished bowl. No droop or snoot. motor pulled 675hp 640torque @6300. getting it all together figured id ask!

    dont think that A cut is gonna let you turn 6,300. might think about whackin it down to a B. i bet the A will knock you down to 5692 rpm. mph will be approx 71.7394
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  7. #5
    lawnmower repair man
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    Quote Originally Posted by nelson#109 View Post
    dont think that A cut is gonna let you turn 6,300. might think about whackin it down to a B. i bet the A will knock you down to 5692 rpm. mph will be approx 71.7394
    guess duane has the dyno #s and is going to cut it to what we need.. we had a mild motor home 454 same pump lumi B it did 74. The new impellar is just a bronze duane is going to cut to a/b ? going with a diff nozzle size as well. whats a guy gotta do to hit 85-90 mph?
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  8. #6
    Senior Member Filucky's Avatar
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    What is a "Challanger" hull? If its a tunnel or gull wing 675hp with a "B" cut should get you to 85-90. But i agree with Nelson109, that "A" cut will bog your motor down well under its peak hp level.
    Nice!
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  9. #7
    lawnmower repair man
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    the engine is pump gas,
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  10. #8
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    Quote Originally Posted by Filucky View Post
    What is a "Challanger" hull? If its a tunnel or gull wing 675hp with a "B" cut should get you to 85-90. But i agree with Nelson109, that "A" cut will bog your motor down well under its peak hp level.
    just an standard type hull. Qrtr stringer delio.
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  11. #9
    About 500' AGL MudPumper's Avatar
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    It's most likely a 18' Southwind splash. Mine did 78 MPH with 500 HP and some pump work.
    Last edited by MudPumper; 05-16-2010 at 10:08 AM.
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  12. #10
    Senior Member nosfomoco's Avatar
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    Well I would guess with a good pump and straight bottom somewhere in the high 80's to low 90's. My Kachina with 650hp spun an Aggressor bronze B impeller to 6000rpm with a best top speed of 93.3 mph on gps! The bottom of the boat was straighted and I has a rideplate and shoe with a Berk Droop. Oh Ya the Kachina looks just like a Challenger.
    Last edited by nosfomoco; 05-16-2010 at 11:49 AM.
    1978 Eliminator Sport Cruiser 20.5ft BBF 460!
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  13. #11
    lawnmower repair man
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    the impeller is a B, so maybe that makes a difference. the boat was lightened by 3oo lbs. the whole inside was redone, little lumi tanks were built for it. Has a nice intake, and diverter. just trying to get a true 85-90mph. motor made great power/torque for having a moderate cam.
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  14. #12
    Senior Member sleekvino's Avatar
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    it really depends on the boat and its hardware, take notes of set up on your boat is before you make changes on it and then make small steps to see where it takes ya.
    PORNO RACING INC WHERE ITS "HARD" TO WIN
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