Prop help please!
 

I have a 1988 Chris Craft Stinger 312/w 500 hp 454s/bravo 1s.I am currently running 26 pitch bravo 1s and turning them inward at 4500 to 4600 with a true blue tach reading on the top end.The mid range speed and handling is great but the top end seems to suffer.4000 to 4100 =60 mph,4500 to 4600 =67 mph.Is there a better choice?? :(

Re: Prop help please!
 

ratsinger,

Do you know werer the peak HP is produced on your motors as stock 454 carborated motors run at 4600 RPM at WOT.

Post your performance numbers and we can look at your efficency and set-up.

Julie

Re: Prop help please!
 

Your current WOT numbers show slip % in the 8 range. This is great for your boat! Unless your g.r. is different from 1.5, you have something other than 500hp x 2 under the hood.

How fast do you feel this boat should run? Do you know the fully loaded wet weight of the boat?

Re: Prop help please!
 

I had a chance to run the boat and get some numbers.

The boat was fully loaded, 5/8 tank of fuel, waves 1 ft or less, water temp 79 Deg F, Air Temp 80 Deg F and humidity 60%. Here are the numbers we got:

RPM MPH
3000 44
3200 47
3400 52
3600 54
3800 57
4000 59
4200 62
4400 65
4500 67.3

At the bottom we did hit anywhere from upper 67 to 68MPH on GPS. The result RPM was 4500, don't believe it was anything over 4600.

We did try a lab finished 25 Bravo I last summer. I got over 5000RPM with them but that was with incorrect reading tachs.

I'm really happy with our cruising speed but we're lacking RPM compared to last year. The humidity is very high and the lake water temperature is way up due to the very hot summer we're having. May or may not be a factor.

What would be recommended. Rework the 26 Bravo I that we have or is there a better alternative?

We're trying to be realistic. This isn't a race boat and never will be, but we're trying to get it dialed in the best that it can.

Re: Prop help please!
 

At what RPM is your peak HP produced. This is of course were you need to run your motor at WOT.

Julie

Re: Prop help please!
 

The engine builder recommended 5000 during the hot time of summer and 5200 in the fall when the temp cools off.

Re: Prop help please!
 

It was great talking to you today. I am sure that with a little work we can get you dialed in a little better. Verify the data we talked about and try the props we talked about.

Julie