what are power valves

[dustin420]

ya this is a newb question but what is a power valve and what do they do, i looked on google but most of the links just made me more confused.

[BigG]

I know by answering this I'm setting myself up to be scrutinized by one of the E2S Scientists as I like to call them.

Power Valves do multiple things such as increase low end/torque, smooth out power band, reduce emissions, and more. This is all accomplished by restricting and/or controlling the exhaust flow. The "valve" usually starts out at idle in a near closed position and as rpms increase the "valve" begins to open.

Ok everyone else go into more detail here cuz I'm sure I missed a few things! HAHA!

[MX86]

With the power valve system, there is a "crossover point". This is the RPM whereby the engine produces the same amount of power, whether the power valve is open or closed. By opening the valve, it allows the engine to produce more power at higher RPM; however, if it is open at low RPM, the engine will produce less power (if it is below the crossover point) than when it is closed. To get the most power out of the engine, the power valve must be open just as the crossover point is reached.

The advantage of these systems over an engine that has a large exhaust port is that at low RPM, the power valve engines will make more power and use less fuel. It will also produce more power at high RPM than an engine with a small exhaust port.

pretty much sums it up

[MX86]

designed to give ya the most horsepower possible by contracting and expanding the exhaust port at certain RPM

[dustin420]

are they avaliable for all 2 strokes? like could i get one for my blaster.

[BigG]

Originally Posted by MX86

With the power valve system, there is a "crossover point". This is the RPM whereby the engine produces the same amount of power, whether the power valve is open or closed. By opening the valve, it allows the engine to produce more power at higher RPM; however, if it is open at low RPM, the engine will produce less power (if it is below the crossover point) than when it is closed. To get the most power out of the engine, the power valve must be open just as the crossover point is reached.

The advantage of these systems over an engine that has a large exhaust port is that at low RPM, the power valve engines will make more power and use less fuel. It will also produce more power at high RPM than an engine with a small exhaust port.

pretty much sums it up

Yeah what he said!

[BigG]

Originally Posted by dustin420

are they avaliable for all 2 strokes? like could i get one for my blaster.

Gotta get an aftermarket cylinder that's power valveD!

[MX86]

Originally Posted by dustin420

are they avaliable for all 2 strokes? like could i get one for my blaster.

your engine must come with a powervalve, it is nothing you can just add on.. sorry. most comonly found on race bikes, and newer two stroke bikes

[MX86]

Originally Posted by BigG

Gotta get an aftermarket cylinder that's power valveD!

you'd need a new lower end as well, the PV is run from inside the cases off the crank i believe or a switch off the crank... it's hard to explain haha.

[BlueDiablo]

If you can find a DT200 top end they are PV but liquided cooled so youd need to make rad mounts. a great mod if you can find one but they are far and few.