Yet another exhaust combo question...
Thread Starter
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Mountain Pass
Joined: Jul 2009
Posts: 178
Likes: 1
From: Richmond, VA
Yet another exhaust combo question...
Spun off from another thread where there was too much "mine is bigger than yours" Richard swinging...
Thoughts?
-cmc-
If anything I think it's safe to say that in terms of exhaust there is no one size fits all, every motor is different and ever driver is different and both will determine what is the best exhaust system for them. Without a doubt if maximum peak HP is your only goal then the closer you can get to open headers the better. If however you want the broadest powerband possible then you'll want to be a little more conservative.. but only upto a point because if the system is too small it'll hurt the whole powerband. As I have said many times the system should be sized to the engine airflow capacity, and that means the specific engine in question not just it's displacement, a 302 with big heads and cam is going to require a much bigger system than a stock F150 5.0. ... That system wasn't really much bigger than the stock exhaust but it did flow a lot better, headers vs manifolds, mendrel bent pipe vs crimp bent tubing, a high flow cat and muffler vs the whisper quiet stock pieces.
-cmc-
Posting Guru
Joined: Jan 2005
Posts: 1,299
Likes: 2
From: The Vieux Ford, Kansas
I don't think running two 2 1/2s into a single 2 1/2 makes a lot of sense, maybe go with two 2 1/4s into a 2 1/2 or a 3. Just doesn't seem right to force two pipes into one that is the same size, even when this was done from the factory the pipe got bigger after the Y. Heck my 89 Bronco with the inline six was 3" cat after the two pipe came together.
-Johnboy
-Johnboy
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
The phrase "a chain is only as strong as the weakest link", can be converted to an exhaust system.. an exhaust system only flows as well as the smallest portion. The stock Y pipe assembly on these trucks crimps down to less than 2" in places, and while the catback is 3" in diameter in places it's more like 2.25" in other spots.
The size tubing used on the Y can be misleading, the system I had built for my by a muffler shop used 2.5" tubing but the hydraulic bender reduced it to 2.25" or 2.125" at the bends. There will be more bends in the Y pipe so even if it's all build from the same size material the end result is effectively something like a 2.25" Y into a 2.5" catback.
By contrast the system I built myself consisted of mendrel bends cut and welded together so the tubing is a consistent 2.5" in diameter everywhere, the catback is 3" into a 3.25" tailpipe(stock Powerstroke piece). The difference was immediately obvious the first time I drove it.
The size tubing used on the Y can be misleading, the system I had built for my by a muffler shop used 2.5" tubing but the hydraulic bender reduced it to 2.25" or 2.125" at the bends. There will be more bends in the Y pipe so even if it's all build from the same size material the end result is effectively something like a 2.25" Y into a 2.5" catback.
By contrast the system I built myself consisted of mendrel bends cut and welded together so the tubing is a consistent 2.5" in diameter everywhere, the catback is 3" into a 3.25" tailpipe(stock Powerstroke piece). The difference was immediately obvious the first time I drove it.
Thread Starter
|
Mountain Pass
Joined: Jul 2009
Posts: 178
Likes: 1
From: Richmond, VA
The phrase "a chain is only as strong as the weakest link", can be converted to an exhaust system.. an exhaust system only flows as well as the smallest portion. The stock Y pipe assembly on these trucks crimps down to less than 2" in places, and while the catback is 3" in diameter in places it's more like 2.25" in other spots.
The size tubing used on the Y can be misleading, the system I had built for my by a muffler shop used 2.5" tubing but the hydraulic bender reduced it to 2.25" or 2.125" at the bends. There will be more bends in the Y pipe so even if it's all build from the same size material the end result is effectively something like a 2.25" Y into a 2.5" catback.
By contrast the system I built myself consisted of mendrel bends cut and welded together so the tubing is a consistent 2.5" in diameter everywhere, the catback is 3" into a 3.25" tailpipe(stock Powerstroke piece). The difference was immediately obvious the first time I drove it.
The size tubing used on the Y can be misleading, the system I had built for my by a muffler shop used 2.5" tubing but the hydraulic bender reduced it to 2.25" or 2.125" at the bends. There will be more bends in the Y pipe so even if it's all build from the same size material the end result is effectively something like a 2.25" Y into a 2.5" catback.
By contrast the system I built myself consisted of mendrel bends cut and welded together so the tubing is a consistent 2.5" in diameter everywhere, the catback is 3" into a 3.25" tailpipe(stock Powerstroke piece). The difference was immediately obvious the first time I drove it.
Would you mind posting it again?
Thanks!
-cmc-
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Certainly... Here's a pic of the first Y pipe I built and a link to my whole exhaust picture collection.. http://www.flickr.com/photos/motorst...7602458567072/
Former ******
Joined: Nov 2004
Posts: 4,901
Likes: 2
From: Salt Lake City, Utah
Running two pipes together into another pipe of the same size can be ok under some conditions, because the pulses of exhaust that come from each cylinder will not pass through the y-pipe at the same time. However, you still as a general rule want to go slightly larger after the y-pipe.
