682gold

I will go ahead a say this might be a stupid question but if I don't know well....

If you have two motors that are both 800hp. One is supercharged (any style) vs a naturally aspirated motor. Does it boil down to torque to determine which is stronger or a more powerful motor?

endeavor1

I believe the SC motor will have more longevity and make the power easier than NA. TQ should also be higher

phughes69

Blower motor_ torque curve is flatter, lower RPMs (unless you are comparing a blown 454 vs a 732 NA)

SB

Really depends how your asking because this can get quite intricate. And beware, even when get down to the nit picky, many will disagree with each other. Read on and you'll see why.

1st, torque is measured by the dyno. Torque is the force, and again, that's what the dyno can measure. But it does not involve time, Since we need to find out how much work the force can do, we need to involve time. So, rpm is figured in. And the term for work done, is Horsepower. Why ? BAck in the day, we used horses to get work done. Yup...believe it.

Now.....we can have two motors, one with a lot more torque than the other, but the other has more horsepower. So, which is stronger ? IMHO, it depends to me what it's going to be put in. One will be 'stronger', actually 'better', for one application while the other will be better for another application.

682Gold, maybe, if you mention an application maybe we can discuss that.

682gold

Not really an application in mind. I was on the Corretti racing engines site and he has a monster 700 ci motor producing 900hp at 5800 rpm's. Also has a blower motor 565i making 850 hp . I know the cu is smaller in the blower and the hp is not the same but for this lesson lets say they are both 875 hp which will push the same boat faster?

SB

Probably be damn close. We would need dyno graphs to see what may have the edge.

Mr Maine

How about a blown 502 making 750 horse at 5200 vs a NA 350 Nascar making the same at 9500. Even though they make the same power, the 502 could turn say a 28 pitch prop and the 350 a 16 pitch.

The 502 cruises at 3k, the 350 at 6k.

phughes69

if boat A makes 850 hp at 5800 and can spin a 30" prop and boat B makes 850 hp at 5800 and can spin a 34" prop, then shouldn't boat B be faster? If it is then boat B is making more torque near 5800 than boat A?

Mr Maine

If it's making more torque at 5800 then it is making more horsepower at 5800.
Hp=torque x rpm /5250

SB

You can take that to the bank. Something none of us will disagree on because it's fact.