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502 prop help

Posted: Mon Dec 09, 2019 5:09 pm
by dcm5899
I'm in the process of putting an airboat together, it's a 15x8 aluminum/stainless rigged panther ( built for South Florida water management) I've put a Crusader 502xl Marine engine on it with a 2.37 gearbox. I bought ( Warp Drive Replacement) blades 82" 6 blade for a hub I already had, dealer said they would be plenty of prop, and they will hold the engine back.
But I have two problems 1st it will not push on ground and 2nd it does have a rev limiter unsure what rpm. What rpm should the aftermarket blades be spun to preform I'm at 2000/2100 now, which should be right in the performance range?
I started at 18 degrees @4800rpm, went to 22 degrees@4400, now at 15 degrees@4900- maybe hitting rev limiter. This thing doesn't even act like it wants to take off and go, hooked my buggy to and moved it around to make sure it wasn't stuck to the ground

Re: 502 prop help

Posted: Mon Dec 09, 2019 8:22 pm
by Aeon
To much weight, not enough hp to pich and spin that warp drive. That motor is only 380hp and that's not a lot when you start talking about running dry. Might cost less to sell that motor and build one that will make enough power 550+ hp

Re: 502 prop help

Posted: Tue Dec 10, 2019 5:44 am
by CarMotorBarge
A warp drive is pretty much the worst prop for pushing on the hill. An 82 inch 3 blade wide or super wide prop will push better on the hill.

Re: 502 prop help

Posted: Tue Dec 10, 2019 2:56 pm
by SWAMPHUNTER45
3 problems

big commercial hull, low power engine & skinny blades

Run the data by Darrin at Sensenich see what blades may work but it will NEVER be a good ground boat with that power combo.

The 390hp big block is making less power than most well built stroked small blocks with apx. 150lbs more weight.

Re: 502 prop help

Posted: Mon Jan 20, 2020 8:24 pm
by dcm5899
Darrin @ Sensenich thought I was a little low on power for the JR or JX, but suggested if I have any disire to increase power close to 500hp + that the JR 3 blade would not hold it and to go with the JX. So JX 3 blade 82" is what I bought, still have rev limiter on engine @ 4,900rpm (2070 prop rpm), but pitched @ 18 on pitch sticker it'll push this barge.

Re: 502 prop help

Posted: Tue Jan 21, 2020 5:57 am
by CarMotorBarge
Can't beat the push of wide or super wide blades on the hill. 8)

Re: 502 prop help

Posted: Tue Jan 21, 2020 7:15 am
by SWAMPHUNTER45
So what is your opinion of the new JX blades?

Did you find them to have a good mid-range push ?

I have run both the "S" and "JX" and love them both for my application.

Going from that WARP to the new JX is like putting that boat into 4Wheel drive.