iliveonanisland

I would have backed you on this sooner joe, but i dont have solid internet signal on my island.
Just lòok at the two engines side by side, then look at the heart of the engine, the cranks. Look at inline cummins and 7.3 IH or duramax... everything about the cummins is beefier. The v8 crank is no match for the inline cummins when it comes to strenth rigidity. , the shared throws are so much weaker on a v8 and there is so much more bearing area supporting the I6 crank. You dont need to be an engineer to see all the benefits of the 6. If v8 diesels are so great why are junkyards littered with GM 6.2 and 6.5 engines that are actually best suited for use as mooring anchors.

iliveonanisland

I have a question for you joe, on running a diesel boat like say a 41 saber/apachce with a pair of cummins diesels in it with arnesons.
When you leave the water coming off big waves the diesels dont throttle up and down quickly , correct?, like a gas engine coming on and off of the throttles. ld think would let the turbo spool down enough for it to take a little while to be back to where it was when you chopped the throttles.
That being the case, Whats the best way to run a fast diesel powered boat in big water.
Have you ever tried a jake brake or driveline brake to unload the drive when youre air born.
i would think you do not want to over speed the engines or land with the throttles wfo
Ĺike when the posche turbo cars race, the diver stays on the gas and slows the car using the brakes but never fully coming off the gas so the turbo is always spooled up.
It would seem the instant on/off of a jake brake would have the engines at max power quicker.
Thx for sharing all your hard earned diesel knowledge with us. Rm

paul buckner

There,s a fountain called Blast off here in the uk that races with twin 440 yanmars which can hit about 80 mph and hit 84 mph at speed record week on the Lake .
You can get more imfo at Blast off racing .

hoodoo

Duramax VGT's spool up at very low boost but may not support really big power

iliveonanisland

The point i was trying to make is turbo diesels i dont think respond well to coming on and off the gas

Bobthebuilder

You are exactly right. That was our biggest challenge on the Key West to Cancun run once we got into the really big water in the Yucatan Straits beyond Cuba. It was a lot of work constantly on and off the throttles and we found we had to back off and keep the drives in the water as much as possible and it cost us MPH. We found we could get spooled back up quicker by trimming the drives up but that of course would want to launch us again so it was back and forth or back off.

Bob

Bob

sutphen 30

and then the crank will break.Happens in trucks,gonna happen quicker in a boat,especially a heavy boat.

hoodoo

[QUOTE=sutphen 30;4398539]and then the crank will break.Happens in trucks,gonna happen quicker in a boat,especially a heavy boat.[/QUOTE

Guess Waglers really screwed then

BigSilverCat

[QUOTE=hoodoo;4398685]My engines don't have stock parts.

hoodoo

I know, that was my point, your not stuck with a crank built for 300hp