25' Daytona setup and progress
 

I bought a 2001 25' Daytona last summer with a 496 HO and an XR drive. In that form it ran 72 mph with a 24p 4 blade bravo prop. Over the winter I added an Imco extension box and full hydraulic steering, and an IMCO -2 lower and sold the 496HO and put in my 540 that I had from another boat I sold. It made 800 hp at 6500 rpm. I've heard that the bravo xr drives don't like much about 6000 rpm. I finally got a chance to run it this past weekend. So far with a 28p 4 blade bravo prop 30 ish gallons of fuel and 2 guys it ran 95mph at 5800 rpm. From data logging my AFR was 12.8 at WOT at 5800 rpm. I could try a 26 blade prop I have to get it closer to peak power but I'm nervous about the drive. At 5800 I'm still making 740 hp. I don't see another 60 hp really hugely beneficial if it's going to nuke my drive just to get 2-3 more mph. I feel I'd have better luck getting a 28p prop labbed or maybe even a 30p labbed.

Any thoughts? I think I'm close, when I look at the slip with a 28p prop 1.5 gear ratio, and 5800 rpm I get 7 % slip. That sounds reasonably. I'm using a brand new Livorsi 10x GPS speedo for speed reference.

i may be wrong but i think spinning the drive faster with a smaller prop would be easier on the drive,less load on gear sets.

That's what I was thinking. Smaller wheel less stress on the drive

Lab the 28 and get a skinny passenger on board, 100mph!

I don't think it's the rpms that's going to kill the drive...7% slip is pretty darn good. Change gear lube and inspect frequently.

Sounds like a cool project, let's see some pictures.