As I mentioned already, backpressure does help smaller motors in their lower RPM's, but it does hurt them on their top end higher RPM's. You are right in the fact that it does rob some power, horsepower. This is what I was refering to on the top end. Now how does it help on the bottom/low end? Easy, it's called torque and that helps get the car going in the first place.

I'm going to try and keep this short and sweet as science debates such as this seem to go on forever.

Your talking about fluid dynamics, which can often times relate the same to gases, but in this case they do not. Here is a segment from using Bernoulli's principle to air/gases,"Next, we make the approximation that we can ignore non-mechanical forms of energy (such as chemical reactions or heat produced by friction), and that we are not adding energy to the air using pumps, pistons, or whatever." In the case of exhaust gases we are using both pistons and heat which change the airs energy making Bernoulli's principle not applicable.

If your statement were true, then the top fuel dragsters with their big open pipes would have ungodly amounts of backpressure robbing them of power and the millions of dollars put into them has been wasted with their backwards thinking and research. With them making over 8,000+ horsepower and going down the 1/4 mile in 4 seconds at over 330 MPH with those big power robbing pipes, I couldn't imagine how much better they could be with tiny crazy straws for their exhaust.

With almost every upgrade, power and performance increasing exhaust made, being larger than the stock exhaust and proven on the dyno, at the track and on the street, how could you ever think and believe that they're wrong and it's all BS? This is like saying there is no such thing as wind just because you cannot see it. You can go too large and have it hurt performance, but that doesn't happen very often as most fabricated exhausts are sized properly.

 

I'm not going to argue physics on an automotive forum anymore. I know you're not an idiot. Google David Vizard.

 

i think ill try a high flow first, i asked the question cause i had a 96 protege, i took the cat off it and it opened it up, my top speed in it was 157mph(thats why i dont have a licence) it made a big differance in it . but my burple has a bigger motor but the gears arent as tall as the protege but i like my burple a lil better, the cat on the protege was huge, i mean it made my muffler look like a ciggarette it was big,but i couldent see throught it the holes in it were so small and the stock exaust pipe was 1.25 inch very small, that went first, to 2.25 that made a big diff then i had a drunkenvision, take the cat off....WHACK.. out came the sawsall and boom it was gone. I was hoping on getting the gain out of my neon