Pure Energy

It is intercooled

Magic Medicine

If $$$ is no object that Quad rotor would be sweet!

JIMG

There comes a point where it takes so much horsepower to turn the little blower you are almost throwing away all of your gains. A 540 should not have a 2.3.

Pure Energy

I found out this is a kit for a 500 hp. I made no pulley changes. At 5700 rpm it is making 5lbs of boost.

If the blower is too small wouldn't it make less boost??

tomcat

The blower is a positive displacement pump, so without changing pulleys it's going to move about the same amount of air as it would on an HP500, but at less boost since you likely have more head and cam. Whatever the 2.3 was supposed to make on an HP500, is about what you should be getting (700 HP?). Any chance you're way too rich?

Why 100 HP only gave you 5 mph I don't know, but the prop numbers don't make sense. How can the same prop and RPM produce an additional 5 mph this year? If the boat is lighter and the hull is cleaner I could believe more speed, but it would be produced by an increase in RPM. This makes me wonder about the measurements. It's hard to do an experiment when you can't believe your instruments.

Looks like a smaller pulley is in your future. MAT or EGTs would be nice too have.

Good luck,

Tom

Pure Energy

Thanks Tom,

Sorry, I posted the wrong rpm for the 28p prop for last yr. Last yr it turned 5400 rpm, after the Whipple it is turning 5700 rpm.

monstaaa

you didnt post wrong numbers ken.

tomcat

OK, those RPM make sense. Speed increase is directly proportional to the higher RPM, so nothing has changed with the hull and drive. You just need to find the HP. An oversimplified estimate of the new HP would be:

[600 X pressure ratio (1.34) X density ratio (0.96)] - comp HP (50) = 720

You are moving enough air to gain 120 HP. But your speed increase says you're only getting half of that. Jetting and timing?

stevesxm

your math isn't bad. rough hp vs drag calculation to go another 5 mph at 81.5 suggests he needs about another 112 hp to do it. you think he is making about another 120 with his blower as is... allowing for losses, seems reasonable to me...

can't forget that mph gain not linear w/ power... drag is the cube of the speed... 5 mph at 81 is a serious hill to climb.

HP350SC

If this is a carbureted (radial) entry 2.3, the max. is about 675 hp. The axial entry (injected) is good to 700hp.
You should be feeding engine oil through the s/c at higher s/c speeds too.