H pipe vs. X pipe exhaust
02-18-2008, 01:14 AM
#21
Le Mans Master
You keep mentioning a tune in the article. I was just kidding with ya anyways.
well where did he say they tuned the car? I asked you before because i missed it in the reading.
Mods do not work by adding up their gains one on top of the other.
They work together and usually better when combined with other mods.
The x-pipe did not give gains of 10hp it assisted the catback gain that are usually 8-10hp alone.
I have one and personally would rather have the hpipe sound. The gain is probably not enough to care about regardless however if you are trying to make your car as efficient as possible then perhaps you might?
well where did he say they tuned the car? I asked you before because i missed it in the reading.
Mods do not work by adding up their gains one on top of the other.
They work together and usually better when combined with other mods.
The x-pipe did not give gains of 10hp it assisted the catback gain that are usually 8-10hp alone.
I have one and personally would rather have the hpipe sound. The gain is probably not enough to care about regardless however if you are trying to make your car as efficient as possible then perhaps you might?
02-18-2008, 10:40 AM
#22
Le Mans Master
You keep mentioning a tune in the article. I was just kidding with ya anyways.
well where did he say they tuned the car? I asked you before because i missed it in the reading.
Mods do not work by adding up their gains one on top of the other.
They work together and usually better when combined with other mods.
The x-pipe did not give gains of 10hp it assisted the catback gain that are usually 8-10hp alone.
I have one and personally would rather have the hpipe sound. The gain is probably not enough to care about regardless however if you are trying to make your car as efficient as possible then perhaps you might?
well where did he say they tuned the car? I asked you before because i missed it in the reading.
Mods do not work by adding up their gains one on top of the other.
They work together and usually better when combined with other mods.
The x-pipe did not give gains of 10hp it assisted the catback gain that are usually 8-10hp alone.
I have one and personally would rather have the hpipe sound. The gain is probably not enough to care about regardless however if you are trying to make your car as efficient as possible then perhaps you might?
Many mods work better when used in conjunction with others such as Xpipe AND catback/headers. But even in the combo catback-Xpipe scenario, it yielded a 13hp gain, so I would not in any way attribute 8-9 hp to the Xpipe alone. Besides, the original poster asked about the Xpipe alone, not any particular combo.I would still be very interested in seeing someone do a before and after dyno with only an Xpipe change and specify whether or not that was with headers or catback. I still say 1 hp, and I would qualify that with some good headers, not the stock exhaust manifold. As you point out, it's probably more of a sound thing than a performance thing.
Having said all that, if I were putting equal length headers on my car, I would probably go ahead and do the Xpipe too. But I wouldn't waste my money on it with stock exhaust manifolds.
02-18-2008, 11:56 AM
#23
Race Director
Boy are they ever a bunch of idiots there.
FYI,
I think the X makes a difference, but only about as much as a good exhaust, which itself is pretty minimal at best. Probably get better results by having the driver go on a diet for a month!
Last edited by nj02vette; 02-18-2008 at 11:58 AM.
02-18-2008, 01:13 PM
#24
Le Mans Master
Many mods work better when used in conjunction with others such as Xpipe AND catback/headers. But even in the combo catback-Xpipe scenario, it yielded a 13hp gain, so I would not in any way attribute 8-9 hp to the Xpipe alone. Besides, the original poster asked about the Xpipe alone, not any particular combo.I would still be very interested in seeing someone do a before and after dyno with only an Xpipe change and specify whether or not that was with headers or catback. I still say 1 hp, and I would qualify that with some good headers, not the stock exhaust manifold. As you point out, it's probably more of a sound thing than a performance thing.
Having said all that, if I were putting equal length headers on my car, I would probably go ahead and do the Xpipe too. But I wouldn't waste my money on it with stock exhaust manifolds.
It provided me gains in the 1/4 mile so yes they do something if you doubt that they do.
02-18-2008, 02:20 PM
#25
Le Mans Master
I'm still not following your logic. If the catback x-pipe showed 13hp gains together and we generall assume an 8-10hp increase with a new catback you can attribute 3-hp to the xpipe on average.
It provided me gains in the 1/4 mile so yes they do something if you doubt that they do.
It provided me gains in the 1/4 mile so yes they do something if you doubt that they do.
My question to you would be if the gains you noted were with the Xpipe alone? Now be honest.
The truth is that most people do not do the Xpipe as a standalone mod and it is usually installed along with something else. So there is little or no conclusive evidence of how much it actually provides. I've agreed all along that it might add a slight bit if you have good headers on the car already. Without the headers, I still say it does little or nothing. I still might be wrong and I'm willing to stand corrected by hard facts.
02-18-2008, 02:21 PM
#26
your not reading the bottom line on the article..
He dynoed it With exhaust, and stock H pipe
then
Dynoed it with Exhaust and X pipe.
He picked up a measly 2HP and 1.8Ft lbs or torque...
Not worth the money. Bottom line, If you have a H pipe Just keep it.
He dynoed it With exhaust, and stock H pipe
then
Dynoed it with Exhaust and X pipe.
He picked up a measly 2HP and 1.8Ft lbs or torque...
Not worth the money. Bottom line, If you have a H pipe Just keep it.
02-18-2008, 04:10 PM
#28
Le Mans Master
I guess that was more in response to Humvette who claimed 8-9hp. I said 1 or 2 from the beginning but that had to be in conjunction with headers, not as a standalone mod. So if we "generally assume" 8-10 for a catback, it is not unreasonable to get 3 for the Xpipe. But then most of the manufacturers of the catbacks would really frown if you claimed that their systems were only worth 8-10. I've seen ads that claim 25-30 for mufflers alone. They would freak out if you said the Xpipe provided a third of that.
My question to you would be if the gains you noted were with the Xpipe alone? Now be honest. The truth is that most people do not do the Xpipe as a standalone mod and it is usually installed along with something else. So there is little or no conclusive evidence of how much it actually provides. I've agreed all along that it might add a slight bit if you have good headers on the car already. Without the headers, I still say it does little or nothing. I still might be wrong and I'm willing to stand corrected by hard facts.
My question to you would be if the gains you noted were with the Xpipe alone? Now be honest.
The truth is that most people do not do the Xpipe as a standalone mod and it is usually installed along with something else. So there is little or no conclusive evidence of how much it actually provides. I've agreed all along that it might add a slight bit if you have good headers on the car already. Without the headers, I still say it does little or nothing. I still might be wrong and I'm willing to stand corrected by hard facts. ill contribute most of it to the tires
but the chart clearly shows the x pipe added 3hp
Last edited by Got uid0; 02-18-2008 at 07:14 PM.
02-18-2008, 07:55 PM
#29
Safety Car
A side benefit of an X-pipe, over an H-pipe, in addition to a greater scavenging effect, is a "smoothing" of the exhaust tone and a reduction in the "popping" sound, that seems to come with many aftermarket exhausts, and some people don't like. With just an H-pipe, each exhaust pulse travels down it's exhaust pipe until it comes to the H-pipe. At that point, some of the pulse will cross over into the other exhaust pipe because of differential pressure (lower pressure on the non-firing side), creating the aforementioned scavenging effect. As some of the pulse is crossing over, and, therefore, taking a longer path out to the tailpipe, the result is basically non-synchronous pulses out the tail pipes, and one larger than the other.
With an X-pipe, both exhaust paths join. So now, when an exhaust pulse exits the X-pipe, a relatively equal amount of pulse is traveling down each exhaust pipe. The result is relatively equally sized, synchronous, exhaust pulses exiting the tailpipes, thereby "smoothing" the sound. This is in addition to a greater scavenging effect due to the larger pulse exiting the non-firing side tailpipe.
Power-wise, the June, 2001, issue of Hot Rod conducted an X-pipe test. They discussed how they work, then ran a car on a dyno, and the strip, with open headers; mufflers & pipes w/o a crossover; mufflers and pipes with an H-pipe; finally, mufflers and pipes with an X-pipe. These are the results:
a) Test Vehicle / 1970 Olds 4-4-2 w/350 block and modified
b) Where first seen / NASCAR guys began using X-pipes
c) X-pipe design theory - "By running the two exhaust pipes together in this fashion, the alternating pulses in each bank can work to create the same type of scavenging action in the other."
d) Works best on a V8 engine running 300-500 hp because the volumetric efficiency is not as great as on a 700-800 hp V8 engine.
e) Dyno pulls:
1) Open header - 430 hp @6850 rpm, 384 lb-ft @5600 rpm
2) 3" exhaust pipes w/Straightline mufflers and no crossover - 412 hp @6650 rpm, 371 lb-ft @5600 rpm
3) Same setup as #2 except with an H-pipe - 419 hp @6600 rpm, 378 lb-ft @5600 rpm
4) Same setup as #2 except with an X-pipe - 428 hp @6600 rpm, 391 lb-ft @5600 rpm
Strip tests:
1) Open header - 1.65 sec 60', 10.885 sec @123.89 mph
2) No run with the exhaust system w/o a crossover
3) Exhaust system w/Straightlines and full pipes and an H-pipe - 1.55 sec 60', 11.007 sec @121.33 mph
4) Exhaust system w/Straightlines and full pipes and an X-pipe - 1.62 sec 60', 10.897 sec @124.13 mph
This car, which used to run open headers at the strip, now runs with a dual exhaust system with an X-pipe. More details in the magazine, naturally, but very interesting, I thought.
However, as mentioned earlier in this thread., X-pipes are most effective when they are mounted right after the headers.
Ed
With an X-pipe, both exhaust paths join. So now, when an exhaust pulse exits the X-pipe, a relatively equal amount of pulse is traveling down each exhaust pipe. The result is relatively equally sized, synchronous, exhaust pulses exiting the tailpipes, thereby "smoothing" the sound. This is in addition to a greater scavenging effect due to the larger pulse exiting the non-firing side tailpipe.
Power-wise, the June, 2001, issue of Hot Rod conducted an X-pipe test. They discussed how they work, then ran a car on a dyno, and the strip, with open headers; mufflers & pipes w/o a crossover; mufflers and pipes with an H-pipe; finally, mufflers and pipes with an X-pipe. These are the results:
a) Test Vehicle / 1970 Olds 4-4-2 w/350 block and modified
b) Where first seen / NASCAR guys began using X-pipes
c) X-pipe design theory - "By running the two exhaust pipes together in this fashion, the alternating pulses in each bank can work to create the same type of scavenging action in the other."
d) Works best on a V8 engine running 300-500 hp because the volumetric efficiency is not as great as on a 700-800 hp V8 engine.
e) Dyno pulls:
1) Open header - 430 hp @6850 rpm, 384 lb-ft @5600 rpm
2) 3" exhaust pipes w/Straightline mufflers and no crossover - 412 hp @6650 rpm, 371 lb-ft @5600 rpm
3) Same setup as #2 except with an H-pipe - 419 hp @6600 rpm, 378 lb-ft @5600 rpm
4) Same setup as #2 except with an X-pipe - 428 hp @6600 rpm, 391 lb-ft @5600 rpm
Strip tests:
1) Open header - 1.65 sec 60', 10.885 sec @123.89 mph
2) No run with the exhaust system w/o a crossover
3) Exhaust system w/Straightlines and full pipes and an H-pipe - 1.55 sec 60', 11.007 sec @121.33 mph
4) Exhaust system w/Straightlines and full pipes and an X-pipe - 1.62 sec 60', 10.897 sec @124.13 mph
This car, which used to run open headers at the strip, now runs with a dual exhaust system with an X-pipe. More details in the magazine, naturally, but very interesting, I thought.
However, as mentioned earlier in this thread., X-pipes are most effective when they are mounted right after the headers.
Ed
02-18-2008, 07:58 PM
#30
Instructor
Member Since: Jul 2007
Location: SE Michigan
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02-18-2008, 10:52 PM
#31
Le Mans Master
02-18-2008, 11:25 PM
#32
Le Mans Master
The only thing the X-pipe has over the H-pipe is it provides the catback system a more laminar airflow. As stated above, this allows the catbacks to function more efficiently and you squeak out a few more horses.
