Quote Originally Posted by Ghost View Post
(Curious Bill, when the Dee used to hit the wall in the low 60s, did the revs seem to climb up without adding speed, suggesting a loss of bite? Or did the drag just seem huge and the motor just wouldn’t make more RPM?)
Interesting question. I tried 4 wildly different props. I remember the Ultra 26, Solas 23, a Spinelli 25, and don't remember what the 4th was.

All 4 were within .8 mph of each other right around 65 GPS mph. The rpms were within a 400 range. On the Spinelli prop, you could tell it was loosing bite as rpms climbed without the appropriate increase in speed.

The Volvo Ultra 26 would bite, also like a pitbull, and you could trim it to the moon, but the slip was nuts, like 19%.

The Solas 23 was the fastest at 65.3, and most stable. Good slip numbers, and trim made almost no difference to speed. You could lift the bow a little, but with that prop the boat really preferred to run flat.

I would say the hydrodynamic limit to that Volvo 290 to about 65 mph. I had 430 hp, and 495 ft lbs of torque, and 65 was all I could get with that combination.

All a fun learning experience.

As opposed to my most recent "learning experience." I burned 3 pistons in the Criterion, running WOT AFR of 10.3 (WAY TOO RICH), with a 29% methanol injection that lowered the intake temp to 110 degrees, at 8 lbs of boost. Best I can figure is that the valves were relashed incorrectly.

Anyone want to buy a BBC Wieand 174 Blower?