different impellers versus speed

[Jungle Boy]

Has anybody done some real same day / same condition testing of impellers. I would be interested in hearing some results. No aluminum impellers please, they tend to be eaten by rpm and rocks. We have a local guy who is building steel ones that work real good and are very durable. But a couple of MPH is a couple of MPH. Thanks.

[jet496]

My 2001 Ultra 21 Stealth was delivered with a "B" & loader impeller with the new 496HO. The 496 was new to the jets & nobody was sure how it would respond. It hit the rev limiter too soon (not sure if the loader impeller had anything to do with it). Ultra immediatly put the "AA" imppeller on. My current specs at sea level are: 4800 rpm @ 61 mph. I'm thinking I'll buy an "A" impeller. Why? Besides the low RPM's, which actually will save wear & tear on the motor plus get better gas mileage, is I run at a 4600 feet altitude regularly. At 4600 feet I turn barely 4200 rpm @ 53 mph. I also need more info on the 496. Was told by an auto mechanic (actually the guy who bought my old jet boat) the computer chip was designed to adjust to the altitude. It reacted the same as my old 454 did. No big deal. I don't have any reason to cruise at high speeds there anyway. Just curious. SORRY ABOUT THIS BEING LONG WINDED.
This message has been edited by jet496 (edited July 29, 2001).]
[This message has been edited by jet496 (edited July 29, 2001).]

[Jungle Boy]

I am wondering what the HP rating on the new 496 motor is and type of pump came with your new boat. I don´t believe that an electronic ignition can by chipped to adjust altitute. But I may be wrong on that. You may be better off having 2 impellers and changing them depending on the altitude that you are running in. We run regularly in about 3900 ft and if I go to sea level in will put a 'A' in my boat, from a 'B'. I am running a stroked small block and pull a 'B' at 5200 rpm in 3900 ft altitute.

[Rod]

Hey Jungle boy, I got a sbc in my boat but i think that im giving up some hp because I didnt know how much you could spin a sbc 350 . I like to hear more about your combo thats it your boat. enigne spec and hp and cam etc . thanks Rod NC

[Jungle Boy]

The motor in the boat is a 383 ci small block chev with AFR heads with stage 3 porting, victor jr intake, forged pistons (9.8:1 compression), 1.6:1 roller rockers, roller camshaft (sorry,don´t know the grind), steel crank, and 750 holly double pumper carb. It was built and dynoed at AMS in Edmonton Alberta by a guy how builds some real nasty cascar, sprintcar, river raceboat motors. It was dynoed at 467 hp @ 5400 rpm, 449 hp @ 4900 rpm with imco power flow exhaust manifolds. Torque is great, from 3450 rpm to 5400 rpm it does not drop below 435 ft/lbs and peaks at 465 ft/lbs at 4925 rpm. It runs on pump gas and is very reliable. I have run it all day long at 5100 rpm and have about 45 hrs on it so far. It pushes an 19 ft Eagle Marine aluminum boat at 86 mph in the crappy air and altitude we have here.

[jet496]

The 496Ho is rated at 415 hp. The standard 496 is something like 385 hp. The HO version has a forged crank.

[hoolign]

the 496 in my chev4x4 is rated at 340 hp and it doesnt make that until 4500 rpm .approx

[smash]

Jungle Boy
Give Outlaw Marine a call in Red Deer they can help you out.We run a small block with a C impeller at 7700rpm in a hull similar to yours. At sea level it will bump the rev limiter at 8400

[smash]

BTW AMS does some great motors