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exhaust balance tube/ "H" pipe

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californiajohnny View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Topic: exhaust balance tube/ "H" pipe
    Posted: 14-January-2014 at 7:07PM
ok guys, give me your opinions good or bad , pros and cons about using a balance tube aka " H" pipe. is there any benefit performance wise?  is there any difference in sound/exhaust tone? has anyone tried it with and without the balance tube- and noted any difference? if so what were the results and your opinions???
JOHN
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kychevyguy Quote  Post ReplyReply Direct Link To This Post Posted: 15-January-2014 at 3:15AM
I have always been told (by people I feel were smarter than me) that an "H" or "X" pipe should always be used in a dual exhaust for equalizing pressure from both sides.  Supposedly, this doesn't really effect the sound but can actually increase horespower a little and maybe even better throttle response.  Just my two cents.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 15-January-2014 at 6:10AM
Synchronicity By Wayne Scraba

----------------------------------------------------------------------
from Dr. Gas.com (this article is currently not available on line)

An upside-down car at Daytona helps solve a Winston Cup riddle.

Here's a clue. Bobby Labonte got upside-down at Daytona during his 125-mile qualifier and showed the world how his guys mate the exhaust from the right and left side of the engine. This system is similar to the one created by Dr. Gas. (Sam Cranston, Daytona Beach News-Journal)

The early-season upside-down adventure at Daytona of one Bobby Labonte provided onlookers with a worm's eye view of one of Winston Cup's best kept secrets - and solved the mystery of the unusual sound of two-time Daytona 500 winner Sterling Marlin's car. In 1995, most technically astute patrons at the NASCAR® season opener, including pit road reporter Mike Joy for CBS, perceived a different sound to Marlin's car, as if it were fitted with 180° headers. The next hypothesis - that the Morgan-McClure team was using a "flat" crank - was simple, logical and dead wrong. Turns out it was the exhaust system past the headers that accounted for the change in engine note.

With Labonte's timely escapade, most observers figured they had a handle on the deal, The exhaust pipes were joined in an "X" pattern under the car. Close, but no cigar. That's when SCR decided to poke around. As luck (skill?) would have it, we discovered the real answer. And it wasn't even close to NASCAR®-land. The equipment responsible for the exhaust note originates from the sleepy confines of Sandy, Utah.

There, Boyd Butler, the owner of Pro Motorsports Engineering, has made an exact science out of exhaust system tuning. One of his products is the Dr. Gas crossover - the piece that has turned Winston Cup upside-down (figuratively.) Here's how it works.

All V-8 engines with 90-degree cranks have an imbalance in the firing order between the right and left cylinder banks. The firing order imbalance is a necessary sacrifice so that a dynamic balance of the rotating and reciprocating assembly (crank, rods and pistons) can be maintained. Each time the firing order is complete (two full revolutions of the crank), two cylinders within each bank fire and exhaust within 90 degrees of each other. Because of this, this pair of cylinders will be exhausting into the header collector (on one bank) almost simultaneously. This overlap creates a back pressure. Meanwhile, the header on the opposite bank has no activity (or pressure) in it at all. Conventional full-length four-tube headers help separate the exhaust in the cylinders until it reaches the collector. After the header primary tubes dump into the collectors, the two cylinders close to each other in the firing sequence again are fighting for space in both the collector and exhaust pipe. This results in reflected pressure waves traveling backwards though the exhaust system. What you get is more backpressure, diminished power and fuel economy, and the V-8's characteristic growl.

Wouldn't a traditional H-pipe crossover, or equalizer, allow some of this excess pressure to bleed over to the "quiet side" of the exhaust system? Jere Stahl ran 330 gallons of fuel through a pair of street engines in part throttle dyno testing to find out. One was a 350 small block, the other a 400 small block. Testing at 2550 RPM and 3050 RPM, primarily at part throttle, in HP ranges from 35 to 125, Stahl found that a balance tube actually hurt fuel distribution on every manifold/header combination he tested. It never helped at full-throttle power, either.
The heart of the Dr. Gas system is this crossover junction. At this point, the crossover is unwelded. As you can see, it's not a simple "X." instead, the separate halves of the exhaust system are effectively merged. (Wayne Scraba)

As many observers at Daytona suggested, the engine exhaust not is changed with this system as well. The deep growl common to V-8s is replaced by a smoother, higher-pitched sound, almost like a high-RPM Japanese motorcycle engine or the shriek of an Indy car. Typical sound reductions of 4 to 6 DBA (a 75% decrease) are realized, with an overall increase in power.

Just now much power are we talking about? This is one of those "it depends" things. Every combination sees different gains, but in testing, the power increase range runs from 5-20 HP at wide-open throttle (with corresponding increases in torque output). Your typical Cup car can see something in the neighborhood of at least 5-10 HP in restrictor trim with this combination. Incremental gains are seen through the entire RPM range.

In practice, the crossover tubing is kept the same size as the collector up to the crossover, the crossover should be located after the transmission and cross member have been cleared. This will usually be 12'-36' after the collector flanges. After the crossover, smaller tubing may be used since the flow is very smooth and pulsations are gone. Butler offers the system in many tubing sized, shapes and materials. Oval section tubing is available for low ground-clearance application (e.g., a Winston Cup car). The Dr. Gas crossover can also be built in carbon steel or 304 stainless Nickel plating and high-temp coatings are readily available too.

The crossover system approaches the same efficiency (and sound) as a true 180-degree header system without the nightmare of the tubes going everywhere. The riddle is solved.


Edited by Rockatansky - 15-January-2014 at 6:10AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 15-January-2014 at 6:29AM
I don't believe that exhaust pressure pulses can, much less want to,
make a 90* turn through a small diameter pipe as in an H balance tube?

I was looking at a single 2 in / 2 out muffler

Dynomax Ultra-Flo X-Pipe Mufflers

that has a perforated X pipe built into it, like a cross-over pipe plenum










Edited by Rockatansky - 15-January-2014 at 7:04AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote robot9000 Quote  Post ReplyReply Direct Link To This Post Posted: 15-January-2014 at 10:39AM
Think of the pulses acting on hundreds of tennis balls in your exhaust tube. The air doesn't really make bend to push into the other exhaust, it just pushes the existing air in the tube that way.  

If you google it, there was a guy that did a comparo on stock duals, H and X pipe.  X pipe is hands down the winner with the H second.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Big Bird Quote  Post ReplyReply Direct Link To This Post Posted: 15-January-2014 at 1:43PM
The exhaust pulses don't really go "thru" the h-pipe. Very little exhaust goes back and forth. What the H-pipe does is damps the pulses, by changing the effective volume of the exhaust system, and the frequency of the pulses.
Essentially, each side uses the other as a resonator.
If you are building your own exhaust, you will need to find the sweet spot for maximum effect. A crossover stuck on in the wrong spot can be worse than useless.
The above post should be read in a "Grumpy Old Man" voice.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 16-January-2014 at 6:15PM
thanks guys for the input, after reading all of this i'm still just as much "on the fence" about it as before. i suppose in nascar where they are turning 6,000 rpm's + there may be an advantage, but IMO for our street cars any advantage may be so minor. and what works on one guy's car may be different on another guys car with same engine , due to variables like different carb jetting,headers different, colder spark plugs, total timing, and even different ambiant air temp, elevation, etc. so "the riddle is solved" i think not! i believe that the addition of a cross over pipe would alter the sound more than anything. i for one like a good exhaust sound "load pipes save lives"! Wink  but all a good read none the less, thanks
JOHN
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aquartlow Quote  Post ReplyReply Direct Link To This Post Posted: 16-January-2014 at 11:20PM
When I installed my exhaust I wanted an X-pipe installed, due to every article I had read and/or heard of stated that the x-piped exhaust had better sound control and more power over a standard true individually piped dual exhaust. After a bit of research, I went with a Pypes XVF-13 X-pipe kit that runs down the trans tunnel to aid in ground clearance. I realize I'm not running a small block and have the larger diameter pipe than you may need/want but the F40-ish evil exhaust tone (due mostly to the X-pipe) on acceleration was/is an added bonus. I went with fully welded Dynomax Ultraflo #17221 mufflers, nice rumble when at idle, no droning like Flowmasters while at cruise RPM and sound really wicked paired with the X-pipe @ WOT. For having the exhaust dump before the rear axle and having 3" tubing, my system isn't at all obnoxious (at least not to me )and is surprisingly docile sounding while at cruise RPM. After a little cutting/welding this is what I installed behind the headers




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Post Options Post Options   Thanks (0) Thanks(0)   Quote BackInBlack Quote  Post ReplyReply Direct Link To This Post Posted: 22-September-2017 at 6:43AM
I'm redoing my exhaust and have been digging into some of the research...so I thought it would be good to share.

Quick summary:  H-pipe or Xpipe does help but not drastic as some might think.  The tests I found showed about 5-6ft torque increase below 3k rpm for both.   Over 4K the X-pipe made 1-2 HP more than H-pipe.   This particular test was 360hp v8.  Obviously if your running 600+ hp the gains would be larger. 

For street...either is fine and almost equal in performance.   Both helped quiet the exhaust with less droning.   H-pipe would very likely be easier to install with less bends.   Both dropped the noise a couple dBs.  The X-pipe was 1 dB quieter than the H-pipe.

This is an interesting video; showing a simulation of the scavenging effects of both options.
https://www.youtube.com/watch?v=2crCWF5cmLk

I'm putting in an X-pipe...similar configuration to the picture previously posted.   I'm using Borla XS mufflers because they were one of the quietest with good CFM.   There are some mufflers that are better for performance but do little to quiet the noise.   Hooker Max flow, Magnaflow, and Dynomax Ultra Turbos were all pretty good options.   I'm also using 304 stainless builder kit from Speedway.   Good prices for a complete kit.

I couldn't find much in the way of test data or flow numbers for mufflers but what I found showed Hooker Max Flow was near the top with the others close behind.   I think Basini or gibson mufflers did flow very well but were definitely louder.


Edited by BackInBlack - 22-September-2017 at 7:09AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BackInBlack Quote  Post ReplyReply Direct Link To This Post Posted: 22-September-2017 at 7:08AM
Originally posted by californiajohnny californiajohnny wrote:

thanks guys for the input, after reading all of this i'm still just as much "on the fence" about it as before. i suppose in nascar where they are turning 6,000 rpm's + there may be an advantage, but IMO for our street cars any advantage may be so minor. and what works on one guy's car may be different on another guys car with same engine , due to variables like different carb jetting,headers different, colder spark plugs, total timing, and even different ambiant air temp, elevation, etc. so "the riddle is solved" i think not! i believe that the addition of a cross over pipe would alter the sound more than anything. i for one like a good exhaust sound "load pipes save lives"! Wink  but all a good read none the less, thanks


What I found is that it does help a little.   The amount will basically scale with the HP you're running.   The more air you move through your engine the more it will help.  When your racing and your trying to get 5 hp or 5 ftlbs torque then it makes a difference.   For me...Street car.... I'm doing it to help control the noise.   I dont like too loud an exhaust...at least not on a street car.   That is why Im using an xpipe to boost the torque in the low-end for my 351C (running 4v heads) and to quiet it a little more.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 22-September-2017 at 2:32PM
I've been looking for this thread Hug
 
 
pack of hornets in the tailpipes
 
 
 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Big Bird Quote  Post ReplyReply Direct Link To This Post Posted: 22-September-2017 at 2:48PM
I used to run factory H pipes on Crown Vics. It didn't seem to affect the power, but it definitely made the exhaust sound more mellow, it took the rasp out of the glasspacks.
The above post should be read in a "Grumpy Old Man" voice.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Don V. Quote  Post ReplyReply Direct Link To This Post Posted: 22-September-2017 at 5:44PM
https://www.youtube.com/watch?v=fCio5K0WfHU

This is a dyno test of H, X and straight pipes from Engine Masters. The same people that did the parasitic power loss from various radiator fans.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BackInBlack Quote  Post ReplyReply Direct Link To This Post Posted: 23-September-2017 at 7:28AM
Those are some of the references I found as well. Good info and it coorelates with other reference material as well. There is also a 2.5 vs 3 inch pipe test

https://m.youtube.com/watch?v=_PVXvHkr-Vs



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