well getting duals put on monday, and the question is whether the H pipe will do anything much. no mufflers and highflow cats. I know the H pipe balences the exhaust pressure, but does it really make a difference that you notice? Does it change the sound?

 

Put the H pipe in. Your left header pipe is going to be considerably longer than the right side, that is, if you have chosen to do your exhaust as previously discussed and not disturb the 02 sensor in it's stock location. You will need the H pipe to compensate for the diff. in length. As far as sound goes, again the H pipe will not make it significantly quieter but it will make it less crackly and not as obnoxious.

 

H-pipe use in Ford vehicles is half a century old. X-pipes have replaced typical H-pipe uses. Both are to be placed in a specific area of the exhaust with equal lengths of pipe BEFORE them, making them inefficient on F-150s. Here is an expert opinion on the difference:

Quote 1- "Why is an "X" pipe better than an "H"? The reason an X-Pipe crossover works better than an H-pipe crossover isn't more flow because of volume, but more effective use of exhaust gas velocity. Exhaust gas (or air) has surface tension, and flows much like liquid would through the same pipe system. As the cylinders of each bank on a "V" style motor fire, they create a pulse in the system. The pulses will alternate back and forth from bank to bank as the motor runs. With multiple cylinders, such as a V-8, the eight cylinders alternately fire creates lots of pulses in the system. If you put your hand behind the tailpipe, it would feel like a constant flow of air, but what it really is a lot of singular pulses giving the impression of constant flow. The idea behind the H and X style crossover is to unite the two banks of cylinders for better exhaust gas scavenging. Instead of two separate banks of four cylinders doing their own work, the crossover uses the pulse created by a firing cylinder of one bank to create a vacuum in the other bank because of surface tension. When a cylinder of the other bank is ready to fire, instead of the piston having to force the exhaust gas out of the cylinder, the vacuum that was created by the other cylinder bank helps suck the exhaust gas out of the cylinder, hence the term "scavenging." Whenever you can reduce the load on an internal combustion engine, you are likely going to see performance and efficiency benefits. The difference between an H and X crossover is a smoother path for the exhaust gas to follow. Exhaust gas, like a liquid, will follow a path with the least amount of resistance. An H crossover has a path with two sharp 90-degree angles that are close together. An X crossover has a path with a much more gradual bend to allow the exhaust gases to continue their path back out to the ends of the tailpipes, rather then turning sideways for a short distance, then turn again to head out the tailpipes. Smooth flow with high velocity means more power by use of scavenging. Using an exhaust system with too large of piping diameter work against scavenging in the same way that running an exhaust with too small of tubing chokes the motor and forces it to work harder to expel the exhaust gases."

Quote 2- "For any performance exhaust system, some type of crossover connecting the two sides of a dual exhaust system is important because it acts to balance the two banks of the engine. The common H-style crossover is good at balancing sound pulses between the two halves, but does little to promote scavenging because the exhaust gases tend to follow the path of least resistance, which is straight through each pipe rather than taking the 90-degree turn through the H-pipe into the other half of the system. In an X-pipe system, however, where the two sides of the system intersect, the gasses have no choice but to intermingle as they pass through the junction. This promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engine’s firing order. It also helps quiet down the exhaust, resulting in a mellower, less raspy tone. The faster acceleration of the gasses through an X-pipe causes them to flow in a linear fashion parallel to the walls of the tubing rather than tumbling. This “laminar” flowing gas is much quieter than tumbling gas, resulting in an exhaust tone up to 8 decibels quieter than a traditional H-pipe."

 

thanks for the post max, but im just going to go with a standard H pipe. But the thing is will it make much of a difference from no H pipe power wise and whatnot? I know it will make it less cackly, which is good, thats one of the main reasons. but will it make a seat of the pants difference on low end or anything

 

You're Welcome ! I don't recommend duals. If someone prefers duals, I recommend equal length pipes in front of the H/X-pipe. That being said, an improperly placed H/X-pipe in a dual exhaust system won't hurt performance. I wouldn't expect enough difference to feel it in the seat of your pants.

 

i see what your getting at.So the H pipe will get rid of some of the cackle/rap/popping sound?

 

Yes. Hopefully, a few other members will give you more opinions.

 

were can you get f150 H-pipes for a decent price

 

im getting mine custom made at an exhaust shop, they should be able to do it cheap

 

On F-150s, they're generally modified universal kits or made from scratch.

 

ohh alright