torque question

[raffshore]

I want to use a cummins 12V 5,9 diesel engine to replace a blown chevy 540 BB. the diesel engine puts out 500 HP at 3000rpm with 945lbs at 2000 rmp.
If I would use a speed increaser gearbox of 1 to 2, I convert this to 1000HP at 6000 and 472ft lbs at 4000 wich actually lies close to my BB corrrect?

Questions:
Has anybody done this?
Any leads on a gearbox like this?

Thanks,

Raf

 

[Metalguy]

No. You cannot multiply HP with gears, like you can do with torque. HP is simply torque with the time (power) included.

You can get a million ft. lb. torque from a lawnmower engine but it will take a LONG time to make one full revolution.

 

[ivymike]

Metalguy is correct (in case anyone was wondering). You can't get more power out of a transmission than you put into it. The Cummins engine you described is putting out about 875ft.lbf @ 3000rpm. If you use a gearbox to double the speed, you halve the torque (ignoring losses), so you'd have the same power output (438ft.lbf @ 6000rpm gives about 500hp).

 

[raffshore]

You guys are right, any leads on gearboxes?

thanks,

Raf

 

[Rob45]

Why increase the speed?
Wouldn't it be cheaper to buy a different pitch prop?

Or are you using a jet pump?

 

[raffshore]

I want to increase speed to lower the torque. Years ago we had yanmar 350HP on bravo drives and I never saw one holding together longer then 30 hours.

The bravo's can handle power and RPM, not torque