370 CUMMINS

buzzk · Post by **buzzk** » Wed Dec 24, 2008 4:19 am

I usually run my boat at 2100 to 2200. Which is fast enough for me. I could run her harder but I don't. That being said if I was going to repower I would go with the 370 Cummins. The reason being is that everyone wants more speed when you go to sale the boat. Buzz

Post by **dougl33** » Wed Dec 24, 2008 5:44 am

Hey John, Have you wrapped up your re-power yet? Any final numbers? Speeds, fuel burn, etc...?

Gonzalo · Post by **Gonzalo** » Tue Dec 30, 2008 10:23 am

Please delete this post.Appologies

Gonzalo · Post by **Gonzalo** » Tue Dec 30, 2008 10:27 am

Buzzk and Dougl, Thanks for all the data. I Dived down and found all prop data. I'm running 23x26 with 2.08 relationship. Based on the data you gave me and the fact that I'm not even close to your speeds is clear that I need new props or cups. I'll get the engines phototached next week that I'm doing a full service and once I'm sure I'm running at the right RPMs with no load measure again before deciding to get new blades. I'm thinking I need pitch closer to 29?

Post by **dougl33** » Tue Dec 30, 2008 10:53 am

Gonzalo, What are you getting for speeds? I'm not so sure you can add 3 inches of pitch to a prop. I've been told its very stressful to the prop to change the pitch, and my prop shop will not add/subtract more than 2 inches of pitch. Try going to boatdiesel.com. If you pay the $25 yearly fee you can use their prop calculator to get a starting point.

Gonzalo · Post by **Gonzalo** » Tue Jan 06, 2009 8:02 am

Thanks, That is what the calculator is telling me. I will need new props, adding 3 inches is too much for what I read too. I,m getting 4knots less than all of you. I'll speak with the service guy coming next week and check the engines first, then make a decision. Thanks to all, been extremely helpful.

JohnD · Post by **JohnD** » Tue Jan 06, 2009 7:24 pm

Doug, I don't have anything real concrete numbers I've been finishing the odds and ends and recovering from repower-hangover... For the most part I find that I cruise between 1900 and 2200 I could cruise faster, but I'm happy with the speed and the boat feels like it's loafing along. Here are some speed/rpm numbers take from my GPS. 19-20kts @ 1900rpms 20-21kts @ 2000rpms 21-22kts @ 2100rpms 22-23kts @ 2200rpms wot 31kts @ 2950-3000rpms (2800 is spec) So I clearly have room for some prop work to get some better numbers. Most importantly, the boat loafs along at speeds that had the gas motors gasping. Fuel consumption is cut in half for most of my normal short run trips, I'm guessing 1 to 1.5mpg depending on how easy I run her. Though I haven't made any real mesurements of economy. br

Gonzalo · Post by **Gonzalo** » Fri Oct 16, 2009 11:52 am

Anybody running 315 6bta with 2.08 relationship? One prop is gone so I decided to change both. Every "specialist" gives me different suggestions, from 23x27 (not enough in my mind) to 24x28 I was running 23x26 and was not getting out of the water at 2500 - 16knts. That is the most RPMs I want to run, at wot did get out and went faster. Thanks