F36 underpropped?

prowlersfish · Post by **prowlersfish** » Thu Sep 22, 2011 8:39 am

Ross it is you that picked up the bait

. can you awnser the smiple questions ?

this is not gas vs diesel . It is torque we are talking about . don't side step it with the fuel type .

prowlersfish · Post by **prowlersfish** » Thu Sep 22, 2011 1:19 pm

rossjo wrote:

I'll pose back a more interesting question:

Given a 36', 16,000# semi-planing hull, which pair of 300hp rated engines would be the best choice for cruising on plane and top speed, assuming each was equipped with its optimum gear ratio and propellers:
1) Pair 7.4L, 300hp, 4,500rpm, V8 gas engines
2) Pair 5.9L, 300hp, 2,500rpm, L6 turbodiesels
3) Pair 5.7L, 300hp, 5,000rpm, V8 gas engines
4) Pair 2.6L, 300hp, 8,000rpm, L4 "tuner" gas engines
?

Why?

Semi planing ?

Are you in politics ? you awnsered a question with a question

Top speed all the same , Best choice for cruising ? 3 out of 4 will be OK . The 8000 rpm chain saw hot rod most likely be a short lived engine .
that leaves the gas vs diesel . For me the 5.9 diesel would be the right choice , close to what I have ( mine are 300 hp @ 2800 ) . But for Mr. T and his wife its the wrong choice she hates the diesel aroma and the only cruse 100 hours a year or less . so its the 7.4 vs the 5.7 top speed is the same cruse maybe the same so what is the best choice ? the 7.4 may have the edge , but what if the 5.7 is EFI ? now you have fuel savings ?

No simple answer is there ? and not enough info on each engine

I will give you My thoughts on the gas vs diesel acl. later got to get back to work

alexander38 · Post by **alexander38** » Fri Sep 23, 2011 4:10 pm

Allen Sr wrote:My answer is the boat with 500lbs torque@2500rpm. It would require the bigger shaft and wheel and ultimately have the higher horsepower! Now how dumb am I? Tony PLEASE keep your comments held off til later, at least til 0615!

never kick a man when he's doing it on his own

alexander38 · Post by **alexander38** » Fri Sep 23, 2011 4:24 pm

and my gassers will out pull Paul's oilburners there hmc..but given time he will match me, and at wot with a clean bottom
I'm as fast or faster but his oilburners will cruise faster than my gassers

prowlersfish · Post by **prowlersfish** » Fri Sep 23, 2011 5:06 pm

Tony is correct in a dead stop drag race his boat will beat me . Why ? you would think the diesel with more torque would do better . on paper maybe but in the case of a turbo diesel you have to wait until the turbo builds boost , so the gas has a advantage . This is called turbo lag . The newer engines with variable turbos the case maybe different but you don't see that much in marine use . and a Volvo diesel that uses a blower for low end ( instant ) boost will do much better ( turbo takes over at higher rpm )

Tony , now chain the boats together in a tug of war things maybe different
or give me a 10 yard head start and I will put out so much black smoke you will turn right and run LOL

alexander38 · Post by **alexander38** » Fri Sep 23, 2011 5:52 pm

Allen Sr · Post by **Allen Sr** » Sat Sep 24, 2011 8:12 am

prowlersfish wrote:Tony is correct in a dead stop drag race his boat will beat me . Why ? you would think the diesel with more torque would do better . on paper maybe but in the case of a turbo diesel you have to wait until the turbo builds boost , so the gas has a advantage . This is called turbo lag . The newer engines with variable turbos the case maybe different but you don't see that much in marine use . and a Volvo diesel that uses a blower for low end ( instant ) boost will do much better ( turbo takes over at higher rpm )

Tony , now chain the boats together in a tug of war things maybe different
or give me a 10 yard head start and I will put out so much black smoke you will turn right and run LOL

Tony won't turn and run he will turn on his radar and hope for the best!!!!!!

He wont back down, might veer off but wont back down!

alexander38 · Post by **alexander38** » Sat Sep 24, 2011 1:20 pm

and why wastes good gas .... I know where you work...And I can just put you on the down wind side..