Horsepower vrs. Torque
 

When building a marine motor for a larger hull like a Scarab or Cigarette do you want horsepower or torque and at what rpms is best?

Thanks

Do you want a honda engine with 500hp and 200tq or would you want a hp500 with 500hp and 500tq.

Get as big CID as you can afford and build it for 1.2hp and tq per CID. Moving up the cost ladder with a mild supercharger and 1.5-1.6 hp and tq per CID. Some of the best combos I have seen have equal hp and tq. If hp>tq= too much cam, if tq>hp=not enough carb, intake, heads, cam. Go for a proven balance package.

with all due respect, that's the wrong question. the question is " what do you want to do with the boat?" . a race motor is a completely different animal than a recreational cruising motor which is diffrent from the guy that wants to go 91 mph for 2 mins once a month etc...

you define the requirement , the configuration becomes self evident. bigger low reving motors will tend to make a lot of torque which will get you good top speeds and good fuel economy and last a long time. supercharged motors and higher reving packages tend to move the torque much higher in the rev range to make much bigger HP numbers a result of which is higher top speeds etc along with massively higher fuel consumption and exponentially lower service hours. so... if you are taking your stewardess babe to lunch once a month and need a blast to 70 to get her wet ( so to speak) you need a big low reving motor.. but if you are poker running for big money and racing and trading your G5 once a year because you don't like the color, then you get higher reving high HP supercharged motors...

what you want to accomplish defines the hardware. not the other way around.

Wow, never heard it spelled out like that, well said. I thought my next upgrade envolved boost but now I'm second guessing that. Just to clarify a boosted motor will burn more fuel vs a bigger motor w/ the same power? Sorry for the hyjack.

in broad terms, yes . now... talking about cars is easier for a minute so you understand... when the motor is making boost, it is also making a lot of heat. more often than not, that involves extra fuel both for proper air fuel ratio and for keeping the combustion chamber cool. also... boosted motors traditionall need lower static compression ratios because the dynamic compression ratio at speed can , and often does, get critical if you aren't careful. on your turbo or supercharged car, you can keep the fuel economy within surviveable limits if you stay off the throttle. but thats not why you did boost in the first place so that's one of those things thats easy to say and hard to do.

boost is like heroin except heroin is better because it will kill you before all your money is gone. boost will just make you go faster and faster and spend and spend until you run out of cash.

the only real downside to supercharged motors is getting them built properly and set up properly on day one. a good boosted motor is not just a normally aspirated motor that someone glommed a procharger on. there is a price to be paid for that both in components and expertise. in my opinion... and i stress that it is my opinion, unless you have a genuine need for supercharging then a big normally aspirated motor is always the smarter play. you can go almost as fast for a lot and i mean a LOT less money for what would be easily twice as long with no hassles or magic what so ever. you get eddie to build you some 550 or 600 HP 9 to 1 injected 540 or something and you can run that thing until you grow old and not spend lunch money on it. you start putting superchargers on it and the price doubles and the service life is cut in half.

but... if you need to make the big numbers because you can't live if you don't then supercharging is the only path...

believe me... your girlfriend will never know the difference. if you can't scare her clothes off with a 550 hp 540, then another 250 hp isn't going to do it either.

OK, in addition to being damn good advice IMO, that is just funny as H3ll

I love it, but how do you do the math on,...what was that..... " scaring the clothes off " of her, is there different formulas for different females based on age or build ???

My last drag car motor was a 615 with north of 1100 and I miss it, I think another like it but tamed down to 7-800 for the boat will cover any of my needs as I have been married to the same one for ever and 15 years and she scares pretty easy still......

lmao +1 :drink:

Uh, with all due respect, could you please refrain from mixing hobbies into your explanation. I was following along just fine, until well.... uh.. what were we talking about? Also, In your last statement, were you talking about the motor or the babe?
I am confused now.:drink:

it's like coefficients in math... dimensionless.... women, boats, cars, airplanes... doesn't matter. the objective defines the hardware.