I have a 2000 nsx with approx 550 hp, 1.36 gears, and a 24 pitch 4 blade bravo. The boat turns 5500rpm at 76 mph on gps. Does this sound reasonable? It seems like I have the slowest nsx in history. I do have a B&M 250 I'll try to get on this weekend. I've had the boat for a couple years and I'm not sure I could live without it but I need to get serious and start pushing 100. What's it going to take?

An NXS with a 502/502 runs in the neighborhood of 78mph... what exactly is your engine. what rpm are getting and what is the powerrange of the package. With 550 hp you should be running mid 80's. A 525efi runs 84 or a little better.

Don

secondly ... a 502/502 with 1.36 gear generally uses a 26 prop.. with an additional 50 hp i would think you would be running a 28.

Don

It was a 502 mag EFI. I put on a carb, intake, new hydraulic roller blower cam,roller rockers, ignition, and did the heads(shaved and stock valves). The motor runs great at 32 degrees timing, planes pretty well and runs up to 5500-5600 rpms. Maybe my prop is junk? Its a bravo 24 and you can tell its been worked at some point. I've tried a 27 3 blade mirage and couldn't even get on a plane. I have a hydromotive quad IV 26 but it runs worse. I don't think the boat likes or needs the stern-lifting prop.

I also put HP 500 exhaust (gil) on the motor.

The boats definately like the bravo 4 blade prop... if your prop has been reworked multiple times it could have lost some diameter and have lots of slip.....
Have the motors been dynoed ? where did you get 550 hp ?.... if the cam is for a blower application.. it is possible that you are not making even 450 hp...

Don

your numbers show about 15% prop slip... thats higher than it should be in my opinion..

Don

I would dyno the motor for sure.

Sounds a little slow. I am still dialing in my new 2600 AO that has a 525EFI, 1:36 gears and 15 1/4 26 Bravo 4 blade. I have seen 82 @4900 this past weekend, still have some more work, but boat should be in mid 80's when done. Ed really builds a great cat. PS it is my third 2600 in nine years...

What elevation do you run this boat