Exhaust H-Pipe leading into a X-Pipe

Sean SS68

New Member
Hi All,
I know that this topic has been discussed many a time (Exhaust H-Pipe X-Pipe) in great length and with many different views and theories but, after doing a lot a research I have been unable to get a clear answer to my question.

My question is, is there any advantage to running a H-pipe leading then leading into an X-pipe or X-pipe leading into a H-pipe. Is there a performance advantage or a sound difference ???

H pipe X pipe.JPG


The Grumpy Grease Monkey mechanical engineer.
Staff member
first , thanks for posting a great quality diagram
H pipe X pipe (2).JPG


h-pipes are no where near as efficient or effective at equalizing or reducing individual, bank to bank exhaust pulse strength,or reducing the restriction to exhaust flow, as a similarly placed (X-pipe )
if you have the room two (X-PIPES in sequence have been repeatedly been tested,
and repeatedly found to provide a minor but measurably better result in increasing cylinder scavenging and a mellower exhaust sound
your not going to see any huge gains from either configuration, but a single (X-pipe generally produces a bit better and a wider torque curve ,
and two x-pipes in series is not all that rare recently even on the higher end performance cars



that adding just two, 3" x-pipes in close series does make a significant difference in noise levels , is well proven, if you could fit 3 3" x-pipes in close series that would certainly not hurt.


Last edited:

Sean SS68

New Member
Hi Grumpy and thank you for the quick reply.

I see that Akrapovic are using X-pipe H-pipe combinations on some of their systems ( interesting ) . Looking at motorcycle exhaust ie; four cylinder machine, the exhaust headers have crossover pipes linking all four headers then 4>2>1 for torque and 4>1 for top end power. sure I totally understand pulse, cam, engine size, etc etc etc....

I also see that you have an image of a H-pipe located after the mufflers for drone noise....

All in all it is an interesting conversation with not many people having any great understanding of this concept of running two X-pipes. I will arrange another X-pipe and give your advise ago.... Thanks Mate, Cheers