X-pipe? Yes or No? And what's the deal with E-test

LXSC

Registered User
I'm still pondering my exhaust options. One of my biggest things is I want to be able to balance each side. My plan is to have them come straight from the headers to the cats (stock as they are), then balance them before they each go through a glasspack and then to the back of the car. I'm thinking of gettin' a X-pipe off ebay because they're cheap but I hear a lot about them. Why is it that they are so often refered to as "off-road"? Why aren't they legal with emissions? Is it still possible to use one and have an emissions passible vehicle?
And another thing, what's the deal with emissions? Maybe i should make this another post but maybe later. What are they looking for? Backpressure??? If my engine is beltchin' out the same smoke, why do I get the impression they care if it gets out a little faster and more efficiently? Thanks to all who care to explain, rant, rave, and give me a hand understandin' this.
 
"True Duals vs. H-Pipe vs. X-pipe vs. 2-1-2

The H-pipe was used in the late '60's. It's purpose was to give each exhaust pulse 2 paths to the back of the car. That way in stead of 4 high pressure pulses (V8 True Duals) per side, you get 8 low pressure pulses per side. The H-pipe has phasing problems, due to the long path through the "H" that the exhaust pulse must travel. Also with the H-pipe you have exhaust pulses trying to pass both ways through the "H", at almost the same time.

The X-pipe does the same thing, but much more effeciently. There are no phasing problems with the X-pipe. All the gasses come together & are split equally down each pipe. 50% of the exhaust gasses still have to change direction 90 degrees to flow through the opposite leg of the X.

Of course, the ULTIMATE "X-pipe", is the 2-1-2 style exhaust that originally came on our cars. All the exhaust pulses flow & combine in the same direction.

The problem with the OEM 2-1-2 exhaust, is that the center section wasn't big enough! Even on the Supercoupe, the exhausts were dual 2.25" into a single 2.5"!!!! That's 8 sq. inches flowing into 5 sq. inches. (actually 7.952175" into 4.90875" for you math-nics). The problem is obvious!!!!

"True Duals" came about back in the early 60's when typical OEM exhaust systems were pushing 390 CID engines through a single 1.75" pipe (2.4 sq. in.) With an engine choked off like that, of Course true duals would out perform the single exhaust!

The truth be told, a properly sized 2-1-2 exhaust will outperform (so called) "True Duals".

BTW: It's not a "True Dual" system if you have any sort of a cross-over in the system.

68COUGAR
 
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