oh and people, this is the year 2002... statements like "A Car Need Backpressure" is FALSE!!! What people commonly confuse for backpressure is actually Exhaust Velocity. This idea is that a proper sized exhaust will maintain a high exhaust velocity and this produces a vacuum effect to aid in removal of exhaust gasses. When you go too big in piping, you lose velocity. This is the "Venturi effect" at work. An example of this is a garden hose. You turn on the water without a nozzle on it and the water comes out nice and slow, but by placing your finger over the exit or by pinching the hose, the water suddenly moves at a higher speed and you are able to blast your girl, getting her all soaking wet in her white t-shirt, from a distance. That is the basic idea of an exhaust. HOWEVER, as previously mentioned. A turbo doesnt rely on this principle. Its a different world altogether.

 

THANK YOU!!!!! now this is what posting is all about i won the argument and i gained an understanding THANX!!!

 

ok that makes sense csufweed. the water hose part...doesn't. the reason why water flows with more speed is because you are pressurizing it. you're not letting more out, just pressuring the water at a faster rate. if you fill a bucket with and without a nozzle, the hose with no nozzle will fill faster. thank you very much and come again.

 

themi6group:

no offense, but you were talking about how honda's need back pressure.

however, i will justify your response with an answer. i was using that point to illustrate how it works with exhaust gasses... i did point out the fact that the high speed equals vacuum effect to suck more exhaust out. so in the case of an na motor, you will have a more efficient exhaust and more power since this efficient exhaust removes a lot more exhaust and allows for more fresh air to be sucked into the engine.

 

in response to the water hose theory: If you restrict a firehose down to a garden hose without a drop in pressure from the original pressure will you get an increase in volume or pressure? You will only get an increase in pressure without an increase in volume since the smaller diameter hose will not be able to flow as much as the larger diameter hose.

 

Very true. I found this out when it came time to replace my fuel pump. Everyone said that a stock intank with 550 injectors would be fine. Well in my case it wasnt. Since I have ss line throughout my fuel system, the larger ID of the hose didnt let the stock pump flow more gas with the same velocity. The walbro is doing the trick now.

 

Csufweed hit it on the head.

There's no such thing as an exhaust to big on ANY Forced Induction car, Supercharger and Nitrous too.

And if you think n/a honda's need backpressure why don't you guys try running a a header with 1 3/4 inch primaries and open exhaust and see what happens. honda's don't like backpressure. We tested the **** out of it already.

Take a look at the stock S2000 header.
High reving motors don't seem to like backpressure instead they need to breathe.



[Modified by pny, 4:34 PM 6/8/2002]