hooty301

"I think it’s pretty safe to say anyone that buys a Jett engine specifically to put onto an airboat is in it for the long run. .'


No doubt, i did do some mods like cowling in the engine for better aerodynamics and added some thin runner pads on the bottom of the sponsons but didnt really test it after that. Maybe a little more speed left in it. I tuned on the motor to find the best header length and also tried another pipe, i ran it for 4 or five years. It was a blast hearing it stage up on the pipe Maybe Dub could change the port timing for more power.

1QwkSport2.5r

If you have a 90LX, you already have pipe timing. If you didn’t get the pipe from Dub, then you might be able squeeze a little more out of it depending on the brand of pipe and manifold. Where you can make a little more power is lightening the prop load and getting more rpm going. If you were doing 16k on an 11x7, I’d take the 11x7 and cut it down to 10.5” diameter. I don’t know if APC did a 10.5x7, but anywhere you can reduce diameter a little while maintaining pitch will usually eek a little more out of it.. Maybe go 10x8 or 10x9, or a 9x10. My buddy suggested a pylon prop - maybe 8.8x8 or 9.5x7 on my 56LX.

Lowering the head and/or adding nitro can make a difference, too. It takes a little fiddling to get it just right.

hooty301

Sweet carbon pipe!
The motor and both pipes came from Dub, he knew what i was ttrying to achieve when he built it. I ran it on 30% nitro. 4 years of running. Tried 10 inch diameter props and lost speed. 11 inch was needed for the thrust. 84mph is where its at, may can squek a little more speed with aerodynamics but
this electric combo can turn the same 11/7 apc at 23,000.or more.

1QwkSport2.5r

Scott (Pylonracr) makes them. A really neat sound, and stupidly light. I don’t think my .56 pipe weighs more than half an ounce if even that. It’s pretty light. I’m expecting a carbon pipe this spring for my BSE .35.

Be careful with over-speeding props. It’s no fun when a blade gets chucked.

hooty301

What do you run that .56 on. Would like to see it.

1QwkSport2.5r

I have the pipe tuned for a 10x6 APC, which turns 18,200 or better on my 15/20 fuel. My buddy suggested a Pylon APC prop - maybe 9.5x8 or something close. The pylon props have a thicker hub and wider blades than the regular 9” props do.

I put my .56 on Kurt’s SI3 .60 after I ran it in mine. His ran 10mph faster than mine (his ran 55 IIRC). This was only the second time the engine had been on the water. It’s still tight as a frogs butt, so I was running it a bit fat. It was peaking just barely on the pipe.

I need to run the .56 on the rigger, but I gotta get another set of hands to launch it for me. Life has had it on hold for some time. I’ll have to reconnect with Kurt sometime.

hooty301

Cool, i would like to get my SI 3 point back on the water so my boy can run it.

1QwkSport2.5r

Me too. My oldest boys are 10 & 6. I built my 10yr old an SI Tapered Flat Bottom several years ago. It’s a good kid-friendly boat with a .25 or .30 on it. It’s a bit of a handful with a .46 and tuned exhaust. I had to revamp the rudders because the rudders made from the plans don’t work very well. If you double the rudder size, it steers like it’s on rails.