H pipe X pipe What do I need?

[Dmichels]

I need to replace the header to muffler pipes. Should I just keep my duel set up or go with the x, h type. What advantages  if any? Do either the x or h pipe work better for any engine, cam , trans type?
 I am planning on welding them up form a kit. Looking for ideas
Thanks Dave

[myk]

I just had an X pipe installed along with the rest of my new exhaust system.  X pipes are supposed to be the most efficient setup for exhausts, although many people don't like the way they sound.  Personally, I care more about the performance than the sound so I went with it.  Besides, with 2 inch primaries on Doug's headers into a 2.5" based exhaust system I assure you the car sounds mean and loud enough...

[Dmichels]

Have you noticed any performance or drivability changes? I am not just interested in top end power but also standard driving conditions. How did the sound change?
Thanks

[c00nhunterjoe]

The exact change varies from car to car since they are all built a little different, but generally, the pitch will deepen and the overall volume will decrease a small amount. Performance goes up slightly with the h pipe and a little more with an x pipe. The x pipe is the most efficient at enhancing cylinder scavenging

[myk]

Have you noticed any performance or drivability changes? I am not just interested in top end power but also standard driving conditions. How did the sound change?
Thanks

I have a stock 440.  I was told that with 2" primaries on the headers I would lose low end torque but in my case it boosted power throughout the entire RPM range.  Now, maybe my previous exhaust was just really choking out my engine but in MY application the 2" Dougs, X pipe and Dynomax Ultraflos boosted power, throttle response, sound, gas mileage, the whole thing.  I should've done this 20 years ago and I advise other muscle car people to seriously consider these mods....

[Dmichels]

I have a  med hot cam for street use my low end is in question  am I better offer with the old school duels?

[tan top]

 when I put a tti 3 inch system on mine  ,   went for the H pipe      preferred  the look over a X   ,   although if TTI were selling true duel exhaust set up , would have gone for that 

[myk]

I have a  med hot cam for street use my low end is in question  am I better offer with the old school duels?

Can't go wrong with 1-7/8" primaries on headers and a 2.5" exhaust...

[Dmichels]

I have a  med hot cam for street use my low end is in question  am I better offer with the old school duels?

Can't go wrong with 1-7/8" primaries on headers and a 2.5" exhaust...

That's what I have now just wondering if an h or x pipe is going to help me anyhow
Thanks for all the input
Dave

[68CoronetRT]

I have a mild built 440, I went with the H pipe and 2.5" exhaust. I was explained it like this. A river is going down stream and if there is an H in the stream what happens? It equalizes side to side. With an X at some point the two rivers cross and casue turbulence/cross flow. I was all about the X pipe until I read that they can be raspy. Also an H gives you that muscle car growl at idle. The X will give you that European high end sound at upper RPMs. To each their own though.

Here is a clip of my car with the H pipe and 2.5" on Dynomax Ultrarflow 14's.
https://www.youtube.com/watch?v=tdeZ_sCbFTk

[myk]

Yeah my Charger does have a hint of Mustang/Euro/raspiness but....that's what flows and performs better.  That's what I was after, the sound was a distant 2nd priority...

[don duick]

watched a you tube clip a few years ago where they compared a H to an X on the dyno and the X produced an extra 7 hp on a small block chev

[Chargerguy74]

An average increase of 12hp and 15ftlbs from H to X pipe here:

http://www.hotrod.com/how-to/engine/mopp-0301-dodge-challenger-x-pipe-exhaust/

[myk]

Every application is different.  The only way to know for sure is to mount it and test it.  Again, I don't know about you guys but I'll take the 12 HP over the noise an H pipe makes.  Just my preference...

[Chargerguy74]

Every application is different.  The only way to know for sure is to mount it and test it.  Again, I don't know about you guys but I'll take the 12 HP over the noise an H pipe makes.  Just my preference...

Seems like the right choice. I would too.

[Ghoste]

But for sure go with one of the two crossover types.

[firefighter3931]

The X-pipe is the best choice....hands down ! 

The basic function of the exhaust system is to get the spent gasses from the exhaust port to the end of the tailpipe as efficiently as possible. Several conditions come into play here, most notably reversion. Reversion occurs when the exhaust system cannot properly scavenge the spent gasses. In this scenario dirty exhaust gets pulled back into the combustion chamber and dilutes the mixture...reducing power and efficiency. This is a problem with restrictive exhaust and is aggravated when using a cam profile with tight lobe separation. There's a reason the stock Chrysler camshafts are all wide (112*+) LSA grinds. The wide LSA is there to compensate for a flow restriction and poor exhaust port relative to the intake port.

The old school grinds are split pattern with extra duration on the exhaust lobe to compensate for this issue. This is why the Crower HDP271 & HDP282 cams work so well with factory heads and HP manifolds. 

Getting back to the question at hand ; with any exhaust the idea is to reduce restriction and increase efficiency. The X-pipe creates a venturi effect because the design pulls spent gases from the engine rather than making the engine work to push them. This results in a cleaner intake charge and increased power. Think of exhaust as pulses....not continuous flow through a pipe. As the exhaust flows through one head pipe and reaches the X it creates a suction (venturi effect) on the other pipe pulling the spent gasses away from the engine. This goes back and forth between both banks of the engine so that they are working in tandem with each other. With an H pipe the pressures are equalized but you won't get the same scavenging effect as you would with an X-pipe.....making the X more efficient and hence the increased power & torque.


Hopefully this helps clear up some of the questions regarding X vs H pipe discussions. 



Ron