H or X pipe

[dfrazz]

I have a '71 Challenger with straight dual exhausts. I heard a couple people suggest switching to an X or H pipe exhaust to increase the compression in the engine. Any thoughts?

 

[moparleo]

To increase compression in the engine?? Really?? Punch line please.

Help equalize exhaust pressure, exhaust sound yes. Increase compression, no.

 

[bobs73challenger]

Hi Leo,

Care to explain further?

I don't really know a thing about exhaust, but I do understand that it won't increase compression.

X vs H pipe vs straight back pipes, is there a preferred setup? I didn't really know there were options at all until I started looking at exhaust systems. I had previously thought they were all straight back.

I'm going to be making these decisions when I take the manifolds off my challenger and go for set of headers, of which TTI sounds like the clear winner.

Again, coming from someone who knows virtually nothing about exhaust systems.

Thanks in advance for the insight!

--Bob

 

[moparleo]

In my late teen years I worked for a muffler manufacturer and learned a lot about back pressure, exhaust scavenging, decibel levels with different muffler lengths, internal diameters, placement of the mufflers and resonators in relation to the head pipes, such as the further back the mufflers are placed, the better job they do lowering noise. How an H-pipe ( this was in the late 60's, early 70's) affected scavenging, lowering back pressures, equalizing back pressures and sound tone.

I currently run a TTI ceramic coated system with the X pipe in my wife's 5.9 Magnum 73 Challenger.
She loves the exhaust tone, but also like to hear her stereo tunes.

 

[burdar]

The basic principle is that with an H or an X, the flow of exhaust from one side of the engine can help pull the exhaust from the other side. This means the exhaust can escape faster.....more hp. This also changes the tone of the exhaust. An H will have a different sound then an X. There are probably some Youtube videos that compare the sound between the two systems. Listen to them and see which sound you like best.

 

[Locomotion]

It's my understanding that an H-pipe will balance the pressure while an X-pipe will balance as well as help scavenging. Both beneficial.
In my particular case, I added a 3" TTI X-pipe and DynoMax Ultraflo mufflers ending in front of the rear end housing on my 360 Dart Sport race car. After years of tuning with open headers, this system helped ET by almost a tenth in the 1/4 mile. (Your results may vary.) I figure the X-pipe helped and the mufflers didn't hurt. The only downside was the added 60-70 lbs of the system and having to drop it when removing the trans. I've gotten a lot of compliments on the sound from other racers and have gotten use to the quieter exhaust over open headers, and like it. But I don't know if or how the long duration cam compared to a streetable grind or adding tailpipes would alter the sound.

 

[burntorange70]

An H or X is prefered over straight especially for a performance build. On a stock motor with manifolds I would say it is not all that necessary. Just one of them things that may or may not gain much depending on the build but every little bit adds up.

 

[Chryco Psycho]

X pipes seem to be the top performers & definatly help flow using both mufflers when pressures rise inside the exhaust

 

[dfrazz]

I'm kind of in the same boat as Bob, so when I heard X or H and compression I wasn't quite sure. Thanks for clarifying. I'm curious where you installed the "X" on your wife's '73?

 

[70CUDA4SPEED]

Over her mouth, I used ducktape.

 

[Adrian Worman]

I spent most of my teenage years cutting up and modifying 2 stroke expansion chambers to learn more about the affect it has on an engines power band and output.
It's a very exacting science and one that takes a lot of research to properly comprehend.

Any modern header and free flowing system is going to help an engine realise its power potential, careful choice of header primary tubes, mandrel formed bends and good high flow mufflers will see the biggest gains.
The crossover of whatever type will help increase torque at low and midrange engine speeds but won't have much effect higher up.
In all honesty a fat healthy 440 or similar will hardly ever need more torque on the street and most serious track users will drop the pipes at the header flanges.
I must admit I don't bother with any crossover on my 440 Challenger cos I quite like the raspy bellow that comes out of the tailpipes