For example, exhaust on turbo cars is far more beneficial than and NA car. Id assume it is the same for SC cars. What about NOS cars? In addition to the whatever gains you got intiially, would there be more when you were physically running the bottle??? does that make sense?

 

Yes, you're right. get 3" for nos, turbo, or s/c it'll help out.

 

yeah - i saw sum sites on shopping.yahoo.com and they label the 2.5 as regular application and 3.0 as turbo application (SC and nos falls under that category as well also)

 

then could you experience a loss of hp with say 3" piping?

 

No it doesn't

 

There is a good a article on nos on Maximadriver.com, and it discusses exhuast size. I also talked with Dallas at WSP a while back when I got my y pipe put on, and he seemed to think the 3" exhuast did not help out on NA cars, maybe even decreased power (less back pressure), he also stated that a lot of SC cars may not even need it....

 

If you are not running NO2, SC or Turbo 3" piping will hurt you in the area of low end torque due to the exhaust systems inability to provide enough back pressure.

If you are running NO2, SC or Turbo then 3" piping will help you achieve better HP on the mid to high end level due to the ability of the gases to exit more quickly.

For NA applications it is best to keep the 2.5" piping.

 

Guys, guys, it's not "backpressure" it's more related to exhaust velocity and exhaust pulses. Try blowing into a straw and then into a paper towel tube. Then imagine 6 little "breathes" all going along in a row down the small tube and big tube.

 

I mean, i have also heard that too big of piping can hurt your performance because of the above mentioned reasons. I dont plan on refilling a bottle every week. So... If I just plan to use this at the track, what size piping would be the best? 2.5?

 

"best" for what?

 

it was tested and dynoed by an SC guy and no it didn't show any gains. Not a bad guess though becase on other cars it has helped people

 

Its more about power out put & exhaust gas volume than weather you are running SC, nitrous or turbo. If your running a 30hp shot of nitrous stock size should be just fine. If your running a 125hp shot 3" full should help some.

WSP's experiance with a 3" Y pipe comes from a member who used a 3" Y with a 2.5" greddy exhause system. He lost 1hp.

IMHO a full 3" system would show gains, but $ per HP its one of the last things on my list.

 

If your car is mainly a daily driver, I would suggest sticking to 2.5, unless you plan on putting an s/c on in the near future. You dont want to be losing low-end torque in city driving. Unless you always drive hard

 

When in doubt, let you wallet decide.

 

precisely! ever take one of those lung volume tests? They make ya blow in this big ole tube thing, its like trying to fill an empty room with air, they keep tellin you to exhale more, yeah right...all my air was long gone seconds ago and ya just stand there turning blue. Same principal with engines, it allows the air to flow better with less swirling effects and what not. 2 stroke engines have tuned exhausts that take advantage of thif, they are much more critical then a typical 4 stroke application.