look at this exhaust
11-25-07 | 09:23 PM
#1
Thread Starter
Lexus Test Driver
Joined: Sep 2007
Posts: 1,097
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From: Dallas
look at this exhaust
im confused why theres no x pipe or h pipe. just straight tubing on this exhaust. Ive ben talkin with this shop and plan on having them build mine, but why would you want one like this vs one with a good x pipe.
edit..in the first two pictures of the exhaust, those are the x design. The small weld in the middle of the two tubes is because they are cut open in the middle and exhaust is able to pass from the left to the right tube and right to left. ... so im guessing this is just a crappy x pipe..?
http://dallasperformance.com/DPExhaust/index.htm
edit..in the first two pictures of the exhaust, those are the x design. The small weld in the middle of the two tubes is because they are cut open in the middle and exhaust is able to pass from the left to the right tube and right to left. ... so im guessing this is just a crappy x pipe..?
http://dallasperformance.com/DPExhaust/index.htm
Last edited by Lextasy89; 11-26-07 at 10:21 AM.
11-26-07 | 10:53 AM
#4
I also suspect that a more deliberate "X" would give better results than simply allowing the 2 pipes to share a few square inches of open space.
EDIT: Intuition suggests that the perfect X-pipe would direct the exhaust gasses from both inputs directly at a knife edge on the other end of the X-pipe that would exactly split every exhaust pulse equally between the two outputs. That would increase the pulse frequency by exactly 2 while decreasing pulse amplitude by exactly half. If this is correct, then I would expect an X-pipe like this one to be far from perfect.
EDIT: Intuition suggests that the perfect X-pipe would direct the exhaust gasses from both inputs directly at a knife edge on the other end of the X-pipe that would exactly split every exhaust pulse equally between the two outputs. That would increase the pulse frequency by exactly 2 while decreasing pulse amplitude by exactly half. If this is correct, then I would expect an X-pipe like this one to be far from perfect.
Last edited by Gernby; 11-26-07 at 11:48 AM.
11-26-07 | 11:58 AM
#7
Pole Position
Joined: May 2007
Posts: 383
Likes: 0
From: Arizona
as much as it's forced induction, it also forced exhaust. The exhaust is being pushed out by the hot side of the turbine. There would be no exhaust pulses after the turbine, just continuous flow.
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11-26-07 | 12:20 PM
#8
Driver School Candidate
Joined: Nov 2007
Posts: 29
Likes: 0
From: TX
Hi guys,
Much speculation here... The location of this X was determined based on where the factory X was located and the most simplistic location based on very tight clearances closer to the engine. I have also found that moving the X location further back will produce less popping through the exhaust.
Keep in mind that scavenging does not apply to a twin turbo vehicle in that sense. On a naturally aspirated vehicle this is a different story and the use of a tuned length merge collector and a well positioned X in the exhaust system with little restriction after this will produce excellent hp gains while maintaining torque.
Street cars with quieter mufflers will find little power gains as the mufflers diminish these and disrupt flow, create turbulence, etc.
The only point of the X-merge created for that particular vehicle was to equalize some exhaust pressure and smooth out the tone. It sounded wonderful.
Much speculation here... The location of this X was determined based on where the factory X was located and the most simplistic location based on very tight clearances closer to the engine. I have also found that moving the X location further back will produce less popping through the exhaust.
Keep in mind that scavenging does not apply to a twin turbo vehicle in that sense. On a naturally aspirated vehicle this is a different story and the use of a tuned length merge collector and a well positioned X in the exhaust system with little restriction after this will produce excellent hp gains while maintaining torque.
Street cars with quieter mufflers will find little power gains as the mufflers diminish these and disrupt flow, create turbulence, etc.
The only point of the X-merge created for that particular vehicle was to equalize some exhaust pressure and smooth out the tone. It sounded wonderful.
11-26-07 | 12:45 PM
#9
I can see how the turbine would diminish the exhaust pulses, but there ain't no way that the turbine is pushing the exhaust. The exhaust is what pushes the turbine.
11-26-07 | 03:41 PM
#10
Driver
Joined: Mar 2007
Posts: 179
Likes: 0
From: Texas
Dallas Performance
Hi guys,
Much speculation here... The location of this X was determined based on where the factory X was located and the most simplistic location based on very tight clearances closer to the engine. I have also found that moving the X location further back will produce less popping through the exhaust.
Keep in mind that scavenging does not apply to a twin turbo vehicle in that sense. On a naturally aspirated vehicle this is a different story and the use of a tuned length merge collector and a well positioned X in the exhaust system with little restriction after this will produce excellent hp gains while maintaining torque.
Street cars with quieter mufflers will find little power gains as the mufflers diminish these and disrupt flow, create turbulence, etc.
The only point of the X-merge created for that particular vehicle was to equalize some exhaust pressure and smooth out the tone. It sounded wonderful.
Much speculation here... The location of this X was determined based on where the factory X was located and the most simplistic location based on very tight clearances closer to the engine. I have also found that moving the X location further back will produce less popping through the exhaust.
Keep in mind that scavenging does not apply to a twin turbo vehicle in that sense. On a naturally aspirated vehicle this is a different story and the use of a tuned length merge collector and a well positioned X in the exhaust system with little restriction after this will produce excellent hp gains while maintaining torque.
Street cars with quieter mufflers will find little power gains as the mufflers diminish these and disrupt flow, create turbulence, etc.
The only point of the X-merge created for that particular vehicle was to equalize some exhaust pressure and smooth out the tone. It sounded wonderful.
11-26-07 | 09:43 PM
#11
Pole Position
Joined: May 2007
Posts: 383
Likes: 0
From: Arizona
Sure there are pulses before the turbine, but after the turbine it's forced out and all you want is nice big diameter piping with very little restriction, like a big blow dryer
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