No way, If youre running an NA honda motor you wanna have backpressure. Sacicons posted an awesome writeup on it, and i really think if u did a search for "backpressure" you can learn a lot. The whole idea is to keep backpressure yet remove all exhaust gasses as quickly as possible........Unless youre running F/I, then backpressure is your enemy.

 

Sacs made a GREAT term for it:

If you take a garden hose and tunr it on, the water comes out. That would technically be lack or back pressure. However, when you put your thumb over most of it the water shoots out. You have created back pressure.

 

that^^^ isnt backpressure tho. thats just resistance. backpressure would be taking another smaller hose, feeding it up the end, and turning water on on both of the hoses.

you want resistance, not backpressure.

 

That post of sacs was the sticky I was refering to. He points out that "backpressure" is a misconstrued term that people often confuse for "velocity."

 

right, Kedawei has the right idea. backpressure would refer to the resistence of forward motion, and thats bad. you want as little resistence as possible, while keeping the pipe small enough that the gases have a lot of speed, to help pull the burnt exhaust out of the combustion chamber. try this, next time youre sitting in a turn lane (left), notice when a car goes by you, your car sways toward them, and it does it as they pass you, from the vacuum behind the car. (this works better when you are in a big vehicle with kinda soft springs, but you can feel it in about anything). well that same vacuum follows the exhaust pulses out of the cylinder, and if timed right with cam timing, it can be used to pull more fresh air in when the intake valve opens. so the faster that air is moving, the more vacuum is behind each pulse, and the more of the burnt exhaust is going to get pulled out, and the more fresh air is going to get pulled in. so a small exhaust will give you better low-end power, and a biger pipe will let the higher amounts of exhaust gases escape at high rpm, giving more power. thats why race cars have huge exhausts. they only need low-rpm power once per race.