Whats the difference between a conical and a non conical header?

I second that....need to know also....anyone know?

The pipe of a conical header is smaller on the engine end than on the pipe end. It gives more power but uses more fuel.

conical means cone shaped so that the easy part to your Question, but as far as performance and the science of why the conical is better I don't know that except to say the exhaust can escape faster with conical headers, possile more revs and quicker?

Whenever you have a cone shape tube through which fluid flows you create a "venturi effect". Depending on which way the flow is you either accelerate or decelerate the flow( increase or decrease pressure, respectively). In the conical headers’ the flow is from the smaller diameter to the bigger diameter, so it decelerates the flow(lowers pressure). It would be cool if an engine designer could explain why it creates more power.

In contrast to the conical header and to give a better idea, we have the venturis in the engine carbs. These venturis work opposite to the header, in the carb the air that is sucked through the venturi goes from the big diameter to the smaller diameter therefore accelerating the flow

Thanks a million guys this helps out a lot, and I'm sure TIX thanks you too.

I know people think that engines suck air in but the opposite is true, the engine creates lower pressure when the piston drops inside the motor then what is outside and the air is pushed into the motor

Nitro you deffinetly right about slowing the exhaust down, I was typing before completely thinking which way the pipes conical was,

In a valve type motor the valves close and the fuel is packed in the cylinder, but in these two strokes you need back pressure to help with the air packing of the cylinder

Well, thats right, but its a different way of saying that air is "sucked" into the engine. Semantycs?

I was sure that the bigger end of the pipe was on the engine side, but before I typed I got up and looked at a header and was surprised.

Perhaps a conical header generates more power(with more fuel consumption) because the header being smaller on the engine side helps scavenge(another word for suck) the mixture faster before slowing it down in the pipe? Just thinking.

I small restriction in the exhaust (Conical) helps to speed up the air flow, which helps to bring in more air through the carb (scavenging effect)

So, I was right. Not bad bad for shooting in the dark

As long as you hit something right

Just don't hit the boards!!!!!