H-Pipe costs HP
- Thread starter jesserose17
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skywalker
Member
chris: you should run an x-pipe, might help with that ****ty drone.
hack: the fact that the gases exhaust in pulses still doesn't help the fact that there is insane collisions at the X. the gases are coming out in pulses and there for having collisions that increase and decrease in velocity as a function of the acceleration (which is a given basically IF you know classical mechanics.) I can see this causing lots of back pressure at high RPMs which might just be what gives it the extra high RPM HP though I'm not much of an expert on the effects of backpressure.
hack: the fact that the gases exhaust in pulses still doesn't help the fact that there is insane collisions at the X. the gases are coming out in pulses and there for having collisions that increase and decrease in velocity as a function of the acceleration (which is a given basically IF you know classical mechanics.) I can see this causing lots of back pressure at high RPMs which might just be what gives it the extra high RPM HP though I'm not much of an expert on the effects of backpressure.
The x is not a true x, it is basically two 90 degree bends in the pipe that are mated by a hole in both pipes that is smaller than the size of the pipes....so the majority of the exhaust flow continues in the same pipe it was travelling in before and the when the pulse wave in one tube is at a point lower than the pulse wave in the other tube it allows excess pressure to enter that pipe to enhance flow. I don't know if that made sense........
Hack
15 Year Member
skywalker said:
Yes, the effect of x or h will vary by the engine RPMs. So the geometry would be tuned for the maximum benefit at a certain preferred range of RPM.
No, I don't agree that an x or h in your exhaust will increase backpressure. If it did that, it would reduce the engine horsepower. If the change reduced engine power, no one would run either x or h.
skywalker
Member
Actually it makes perfect sense. It goes along with the things I was saying about sound. Essentially, when the pulses come 90 degrees out of phases (thus why the sound is 90 degrees out of phase) a pulse can enter the empty space in the other pipe to enhance flow. Okay, now that I know the hole is smaller it all makes alot of sense. I was thinking it was a true X - apologies for my ignorance.
skywalker
Member
ronstang: Glad to see someone thinks I'm right about something! 
I'm thinking a true X might help out ont he torque side of the upper RPMs, but...That's not what you really want in that range. It makes me wonder if I could find a way to mix the 2.
85: Negative. Essentially what will happen is that a true dual exhaust will effect your performance BASICALLY evenly across the RPM range (I say basically cause in engineering, NOTHING is EVER 100% true. There is always an exception or 50.) An H-pipe will flatten the torque curve particularly and partially in the HP curve, Not really helping your upper RPMS all that much, but giving a boost to the low-end torque and a slight one to low end HP. Now an X-pipe will not effect your lower-RPMS that much, but will cause a sharper slope in the upper RPM area of the curves, particularly ont he HP side.
As for sound, an X-pipe will give you a quieter sound of true dual, and an H-pipe will increase sound over true dual - at least in theory.
I am ALMOST in the mood to explain how the larger pipe effects the frequency (pitch) of the exhaust's sound but well...I'm not THAT sadistic. Plus 65shlbycln was telling me a little while ago that int he morning when everyone wakes up they and their hangovers are going to hate me. hahaha
I'm thinking a true X might help out ont he torque side of the upper RPMs, but...That's not what you really want in that range. It makes me wonder if I could find a way to mix the 2.85: Negative. Essentially what will happen is that a true dual exhaust will effect your performance BASICALLY evenly across the RPM range (I say basically cause in engineering, NOTHING is EVER 100% true. There is always an exception or 50.) An H-pipe will flatten the torque curve particularly and partially in the HP curve, Not really helping your upper RPMS all that much, but giving a boost to the low-end torque and a slight one to low end HP. Now an X-pipe will not effect your lower-RPMS that much, but will cause a sharper slope in the upper RPM area of the curves, particularly ont he HP side.
As for sound, an X-pipe will give you a quieter sound of true dual, and an H-pipe will increase sound over true dual - at least in theory.
I am ALMOST in the mood to explain how the larger pipe effects the frequency (pitch) of the exhaust's sound but well...I'm not THAT sadistic.
Plus 65shlbycln was telling me a little while ago that int he morning when everyone wakes up they and their hangovers are going to hate me. hahahaSimilar threads
