H pipe necessary?

[gopokes]

I am starting to work on my exhaust and was thinking about running each side straight back into a muffler and dumping in front of the axle. I started doing a little research on what mufflers sound best on the 5.3 and found that there are alot of people out there that say you should have an H or X pipe. From what I have read it will lower the tone a little and take away any popping on deceleration. So my question is how much of a difference are we talking here? Does anyone have any experience with the sound of one vs. the other?

[67C10BUB]

I am planning on straight piping mine as well, so I am also interested.

[gopokes]

Originally Posted by 67C10BUB

I am planning on straight piping mine as well, so I am also interested.

I checked out your build, looking good! From everything I've read, they all say do it if at all possible. It will not only help with lowering the tone and popping, but will give you more low end torque as well. I'm not really going for massive power in this truck, just the factory 5.3 is enough, but I do want it to sound good. I went ahead a fashioned one in to my exhaust last night. It's not much to look at yet, so don't laugh, still have some grinding to do. I stuck an extra piece of exhaust pipe up there to simulate the driveshaft. It clears that and is a little lower than the middle crossmember so it should work out ok.

[BR3W CITY]

and h or x pipe helps with exhaust scavenging and harmonics i.e. balancing the exhaust. I have 100% true duals on my 66 right now (on an sbc) and it sounds mean as hell.

Here is excerpt sniped from the 350z forums

"he H-Pipe does balance out the pressures and slightly helps start the scavange effect on the next exhaust pulse. But it's most effective use when properly placed and sized is for it's tuning function. Sound waves enter the tube changing to a specific frequency that was found to be a problem. Prehaps a droaning noise at highway speeds. With the correct placement in the system and correct inside diameter, sound waves entering the tub shift to the problem frequency. When like frequencies collide, they cancel.

The power comes from opening up the exhaust. A slight add comes from the scavenge effect but ultimately the H-pipe is to counter the noise from opening up the exhaust.

The X-Pipe on the other hand is more effective in sound cancellation. By forcing the exhaust streams to collide, some sound frequencies are cancelled. (In a much larger range than the H-Pipe.) You would think the two exhaust paths colliding would cause more backpressure. In reality, the exhaust flow mass follows the path down the same side. (Bending around the inside of the X.)

The sound frequencies cross paths of the exhaust. Cancellation of like frequencies occur even though the mass of the exhaust flow hits and deflects into the same side pipe.

This is all assuming WOT condition or near full mass flow rate. At lower flow rate, the X-pipe does make the low frequency idle sound a little irratic. Something desireable in a Mustang or Corvette. But a Cadillac wouldn't care for it.

This is used as a band aid in tuning high performance vehicles to meet the legal pass-by requirements. Something that is difficult to do on a car like the Viper Roadster or Corvette.

The X-pipe idea was tried on the Viper roadster but ultimately they used the H-pipe design. If you've ever seen the OE system on a Viper Roadster, the exhaust exits the headers, enters an un-Godly hot converter that I have seen damage body panels and melt basalt packing back into a crystal solid. It runs down the side of the car into the main muffler and then to the rear axle. Then it turns to the opposite side and hits the H-pipe which is over the axle and exits out before the axle on the opposite side of the car. If it were not for the Pass-By requirements, this would be an easy design. "

Kind of long winded but somewhat interesting.

[gopokes]

Originally Posted by BR3W CITY

"he H-Pipe does balance out the pressures and slightly helps start the scavange effect on the next exhaust pulse. But it's most effective use when properly placed and sized is for it's tuning function.

I hope I got mine properly placed and sized. This is a little disconcerning for me since I basically just moved it back and forth till I thought it was about in the right spot and welded it in. I guess I will find out in a few weeks when I get her fired up.

[Oilbrnr]

By my calculations, you should have placed the H pipe 1.75" further towards the rear of the chassis.

j/k

[67C10BUB]

Originally Posted by Oilbrnr

By my calculations, you should have placed the H pipe 1.75" further towards the rear of the chassis.

j/k

Thanks for the heads up. I will put in the same pipe, but be sure it is exactly 1.75" back.

[BR3W CITY]

lol hey I didn't write it, like I said it was taken from another site.
But: An h or xpipe of a smaller or larger diameter than the rest of the system is likely less effective. I think the same would go for putting it at the way rear of the vehicle, as it won't do nearly as much for the "drone" that dual'd vehicles can get.

[Shon]

I dont run one and once you get everything in there you might decide you dont want to make it work...just depends on how the exhaust is ran.

I do not think there is MAJOR improvement to go thru the effort, if you are racing and want every millisecond then you might want to but just to drive around and beat on...

[gopokes]

Originally Posted by Shon

I dont run one and once you get everything in there you might decide you dont want to make it work...just depends on how the exhaust is ran.

I do not think there is MAJOR improvement to go thru the effort, if you are racing and want every millisecond then you might want to but just to drive around and beat on...

I did get it in there, we will see if it ends up staying. I figured while I have the cab and bed off, this would be the time to try to see if I could make it work. Plus I'm not really out anything if it doesn't end up working. I got the pipe I'm using from my dad's shop, no telling how long it has been hanging on the wall, you can tell by the surface rust on it. I am definately not looking for extra seconds or anything, this truck will just be to cruise in. I guess I have a problem with seeing something done on another truck and saying "I can do that".

[JPCY72]

I just redid my exhaust two days ago and I can tell you going from true duals then adding a h pipe after the tcase I have a 4x4 woke it up and seemed to make it a little more responsive and toned down the rumble a tad but I think it sounds better at wot smoother for sure.. If you want that tuned sound then go for it... oh and It doesnt drone in the cab at lower rpms anymore...

[Big Port Jimmy 6]

I have been considering one of these.
http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
Jay