Horsepower help

[mms140]

Hello everybody,
I am looking to upgrade my 6.5 hp greyhound to a higher horsepower engine. My question is will a higher horsepower really make a difference and what will it do. Do I need to gear higher or lower for more speed, and what should my wheel sizes be, bigger or smaller.
This is a normal homeade kart, not a shifter kart.

 

[r_chez_08]

HP=torque x rpm/5252.

Therefore a higher HP engine will usually have an increase in torque or rpm.
Most 'industrial' general purpose engines like your greyhound are limited by a governor to ~3600rpm. Therefore if you got another higher HP industrial engine the increase in HP is probably from a higher torque reading, but the rpm limit would be the same.

Torque is a measurement of turning force. The higher the torque the more force is applied to turn the wheels. Therefore an engine with more torque will have better acceleration and would handle hills and rough ground more easily, however the maximum theoretical speed would stay the same.

However, the additional torque allows for steeper gearing, which therefore equals a higher theoretical top speed.

You could increase the rear tire diameter, or decrease the number of teeth on your axle sprocket. See http://www.diygokarts.com/speed-calculator.html

Please bear in mind- you can increase the speed of your kart by increasing the rpm of your engine. This can be done by removing the governor. From there you can install aftermarket parts which increase the torque and rpm of your engine, and therefore HP.

For under $50 you can make your greyhound have 8-9hp and 4800+rpm.

 

[Jcotz]

I agree with everything said by Rchez, however if you plan to remove the governor the please read this...http://www.diygokarts.com/vb/showthread.php?t=16518