where is your back preassure though?

 

Backpressure? What is that?

Actually, X-pipes dont need much backpressure. You wont notice much of a drop in low end power due to equalization effects. It will actually increase low end and top end power across the whole powerband if you size it right.

 

i did not know that. Kool though

 

This is from Bret at Bauer Racing Engines...let's just say these guys dont "assume" anything when posting...heres what he had to say...

"The inside area of a 4 inch outside dia. tube is about 91% of the inside area of 2 tubes 3 inch outside dia. Flow depends primarily on cross-section area and amount of wall surface. The 4 in. tube has only about 2/3 of the surface area of 2 3 inch tubes, so effectively, the flow of 2 3 inch tubes would be close to that of one 4 inch tube." ~Advanced Tech forum

Heres the math I did to go along with his numbers that he simply states:

He got the 2/3 from doing Pi*d + Pi*d..where d is 3" and we double it for dual exhaust. This is 18.85 square inches
A single 4" pipe is simply 12.57 square inches with the similar computation.

As we can see the 4" has (12.57/18.85~2/3) the surface area of dual 3"....*statement affirmed*

Friction, etc. all comes into play with this figure. So surface area is important, not just regular cross sectional area is. Don't look at one without the other....


Conclusion: Anything less than dual 3's and I might as well keep my single 3" catback...
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And as far as Pacesetters go, does anyone know how the company handles the flanges? are they included, but are a slip on style? I heard some things about that and I do not know which one is true...Hooker for example, there flanges are part of the header, very traditional style.. is this why Pacesetters are so much easier to install?!?! *supposedly*