| Author | Message | ||
     Isham |
I'd like to know the diameter of both outlets and the part where they come together. | ||
| Duff24 |
the outlets are the same after the two come together...not sure about the inlets coming from the manifolds, I'm guessing about 1/4" bigger than the 9. | ||
| Glitch |
The exit from the heads are the same size, the collector exit is the same size as well. Meaning you can use either XB header on either XB engine, and use either XB muffler on either XB header. Is that what you were needing to know? | ||
| Rr_eater |
Glitch, the pipe is a larger diameter on the 12. While the port is the same size, this difference does change scavenging characteristics and flow volume, exhaust velocity, etc. . Just my .02 Bruce | ||
| Glitch |
Risking sounding like a smart ass, but not trying to be. We all know the tubes are larger on the 12, but that wasn't the question. Isham has a 984 engine punched to 1200, my guess is that he still runs a 9 header, and wanted to know if a 12 header would fit. | ||
| Isham |
Well im convinced I have 12 headers I just wanted to know the size of both header pipes. Need a sure way to check, plus it would be nice to know the diameter of both headers since I heard they were different. Sorry my question was unclear. | ||
| Dragonbuell12r |
12 pipes = 1.75 9 pipes = 1.50 | ||
| Isham |
Good to know thanks. | ||
| Duff24 |
Didn't think installing 12 headers would make any difference in power cause the outlet is still the same size as the 9, making it just as restrictive. Compare it to a funnel...same principal. | ||
| Diablobrian |
actually it will affect the scavenging of the cylinder because of sound wave and pressure wave dynamics. These pipes are very carefully designed. It would have been cheaper for them to make only one diameter of pipe. They changed it to make it more efficient with the different motor characteristics. They did a very good job. | ||
| Pwnzor |
Why, then, are the headers different lengths? | ||
| Diablobrian |
3 reasons. 1) packaging 2) uneven engine pulses 3) trade-offs to balance out the above 2 |
