Quote:
Originally Posted by MyersOB
 Thanks for the feedback. So far I have not noticed any losses but then it's only been a couple of days. I almost went with the single. I fell in love with the JBA's old school kind of sound (reminded me of my 67 Mustang with cherry bombs). I'm sure that this is not the best way to decide on an exhaust system but I was bitten. I did keep the stock system just in case. Please tell me more about " what you have learned over the past months", if I do decide to make a change, I could use all the knowledge available. Have you installed a CAI system to compliment the exhaust? |
The JBA seems like a pretty well built cat-back. The problem on the dual version is there decision to use 2.5" piping all the way back. The most important thing I've learned is that when you use exhaust piping that is too large, especially on the pipe or pipes that run back to the front of the muffler, it actually causes the exhaust gases to slow down in speed before reaching the muffler and that causes a loss of power/torque in the lower RPM range which is where we spend most of of time when driving around normally.
What I was thinking about doing with the JBA was either replacing the 2 front pipes with smaller diameter pipes, either 2 1/4" or having the front pipes on the stock exhaust cut-off and installed in front of the JBA since you can't find 2 1/8" pipe, to my knowledge, in the aftermarket.
The other option, and cheaper as well, that I came up with was having a cross pipe or H-pipe installed in between the 2 front pipes right after the bends on the way back to the muffler. I've read that his can help restore any loss of low end power and possibly help with any drone as well. I noticed that flowmaster has done this with their dual cat-back system for the Tundra.
I ended up removing the JBA instead of modifying it and am in the process of going another route so I can't really say with any certainty just how well the H-pipe would have worked but I know that the smaller piping would have helped.
If you look at the JBA single exhaust, you will notice that they use a Y-pipe in front of the muffler which is 2- 2 1/4" pipes into 1-3" collector pipe going into the muffler, ( the Zoomers is similar in design as well), and this causes a scavenging effect with the exhaust gases which helps keep or maybe even increase low-end power. I think JBA should have used this Y-pipe on their dual exhaust as well instead of the 2 seperate pipes and went with a single in dual out muffler or stuck with 2 1/4" piping like Borla did.
I noticed that JBA doesn't even offer a dual system for the Dodge Ram or Nissan Titan. They do offer one for the Chevy trucks I think. They don't offer any exhaust at all for the Ford F-150 for some reason. I only bring this up because, I spent some time on the titantalk forum and the JBA exhaust is thought of highly over there, but again it is a single exit system that uses a 2" Y-pipe running into the muffler.
If you have any plans to install headers then I would'nt worry about anything since that would fix any problems. I actually think JBA designed their exhaust to be used with their headers.