Exhaust H Pipe vs. X Pipe: Difference?
 

I know these go on the same portion of the exhaust system after the cats, that's not my question.

My question is given all other aspects of a cat back exhaust are the same (even the point at which the exhaust is merged) is there supposed to be a benefit of an X versus an H. Anything documented here or on the 350 forums?

X and H pipes merge the exhaust streams differently so the sound is different between the two as well as the performance characteristics. an X pipe allows full stream crossover while the H pipe on allows pressure eualization to occur. Traditionally the x pipe has been shown to produce more power but all X pipes are not made the same the amount of overlap and the changing cross sectional area of the pipe as well as the smoothness of the transition all effect flow and scavanging. the less overlap you have the higher the cross sectional area but there is less crossover to help scavanging. they have to be designed carefully.

I believe the H pipe will actually produce more low end torque and less of a high end gain, while the X pipe produces a little mid range torque with a higher top end.

what about a y pipe?


and someone said they connected a y pipe to their stock exhaust with hfcs... could you do this with an X or H pipe too?

If so out of all 3 which would be the best?

I am trying to retain stock catback for a quieter sound. So I want to go hfc + ypipe like someone did.. I will get most of the power out of the car, maybe only leaving about 5-9whp and I am ok with that to have the car quieter and saving money too

I don't know if you want to go with hfc if you're going for quiet...

for replacing the center section look into the HKS center pipes they are what you are looking for kinda. an x pipe can make low end as well as i said it is all about tuning the overlap of the two pipes.

To put it simply x flow provides a smoother flow. We were the first to bring the Xflow design into the 370z and we made a designated chamber for this. Other companies seem to have jumped on this by merging two pipes together forming a X.

http://i613.photobucket.com/albums/t...DSC_0084-2.jpg

Thanks all for the info so far.

ARK, I don't doubt that it's good but just curious during the testing did you have a prototype that had both an X and and H? If they were both tested what would have been the benefits as far as tq/hp gains in different areas of the curve? Or did you just go with the X right off the bat.

Also you are right some of the other systems (Berk, FI, ARK, Stillen) use and X. Seems like traditional Japanese tuners (HKS, Greddy ECT) use the H design.

From a 350z post. Honestly, I don't think some H-pipes contribute much to the flow.

http://i58.photobucket.com/albums/g2...0810091630.jpg

LOL that looks really cheese-ball. I don't think/hope most H-Pipes looks like that. I'd be willing to bet the HKS is the full I.D. of the pipe or close.

Stock is y-pipe, if you get x-pipe it wont fit. From what I understand, a well-designed x-pipe creates a current in the exhaust that suck the exhaust air out of the back. As for y-pipe, you can connect a single back exhaust which is the most lightweight and track-proven design. That is why my ideal catback is y-pipe with amuse r1000 single catback. Check Travisjb's exhaust