[QUOTE]Originally posted by 02silversuby
[B]It depends on your definition of increased flow. When you increase the volume of the pipes, you then normally decrease exhaust gas velocity. I'm not sure if you know what the inside of a turbo looks like, but there is an injector like opening that 'spits' the exhaust gases right into the turbine blades which get it to spin. On smaller turbos, this 'injector' is pretty small to gain fast spool up. This fast spool up in caused by the opening being small which causes the gas velocity to pretty fast. On larger turbos, this 'injector' is larger which allows more volume of gas to enter. While this is good at high rpm's where you are shooting out a lot of exhaust gas from the engine, it doesn't do quite well at low rpm's which is why you have a lot of lag with these. THe same principle goes with exhaust piping such as headers. With the dyno charts, you have to read the fine print. There are so many variables that can change what the output on the car is. Such as, what other mods the car has, the ambient temp., octane of fuel, the tuning of the car, etc. Personally, I never take what a dyno chart says to heart. Just because something worked on one person's car, doesn't mean it will work on another. No two cars are the same. Even if two identical cars stock were to race one another with as many conditions kept the same as you could...one would be faster then the other.

 

That is true about hte heat loss, but the volume is changed also. The header pipes are a larger diameter, so this equals a larger volume of space that must be filled and therefore slows everything down. I'm talking if you compared two of the same engines, one with the headers and one without and compared flow rates at the same rpm's. What you are talking about is one of the factors which I didn't talk about. The only way I can think of discribing it is if you took two straws, one of which is twice the diameter of the other and were to blow through them with the same force. The smaller diameter straw will have your exhaled air flowing out at a faster velocity. And yes, what you said about heat loss does come into play. These are equations with many many variables. What you said is one of the many reasons why headers are not always good to get. Engines lose so much energy from the combustion stage to heat that escapes the engine, it isn't even funny...such a loss.

 

But is does increase peformance right? i see now how it would benifit a bigger turbo but with a stocker can i tell a difference?

-Adam