Speed with new blower
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Speed with new blower
I posted pics a week or so ago. Boat is a 24 Lightening tunnel built by Wyatts Performance Boats. It ran 77 on GPS with two aboard and about half fuel at around 4700 RPM (I never look real close). Engine was a stock 454 Mag spinning a 28 pitch bravo 1 four blade. Now it has the same 454 Mag with a B@M 250 EFI blower. I am starting with a 30 pitch Bravo 1 four blade. I also added external steering and some other stuff. I will also try a 32 pitch Bravo if this wheel isn't big enough. I want to keep the RPM's down if possible. How fast will it go? B@M said 8 to 15 mph gain. It seems like I saw someone on this board a couple of years ago who picked up 17mph on a 22 foot tunnel. Mine is actually barely less than 23 in fiberglass. I think it is going to see 90 at least. What do you think?
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You should be spinning that motor up to 5000 rpm. That is where the H.P. peak is. I picked up 14 mph on a heavy V hull at 6 psi boost so I would think 90 is not going to be a problem.
Do you have a GPS unit for speed? If not I would get one and have your passenger call out the speed numbers that way you can drive and trim up or down to get max speed.
Do you have a GPS unit for speed? If not I would get one and have your passenger call out the speed numbers that way you can drive and trim up or down to get max speed.
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I have a hand held GPS. Also, at 77 my liquid filled Gaffrig and the GPS read the same (actually the speedo is a few tenths less). I have a tattletale on the speedo and the GPS will recall the highest MPH reached. On this hull I need a lot of positive trim to reach 77 but have been told into the eighties and nineties I will not need near as much positive trim. I just haven't had enough HP to air it out right. By the way, my boat is one of two with a stock 454. All the others built have had blowers, big stroker motors, or twin outboards.
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