This question goes out to all those folks that have installed mufflers under the cab of their JKU's. I'm not talking about the catback systems - just the muffler using stock pipes.
I'll be ordering the muffler from an online dealer and have my eye on a Borla ProXS muffler that is 9.5" wide x 14" long and comes in either Offset/Center or Center/Center in/out configurations.
I believe this is the same width as the Flowmaster 40 series that a lot of you use so I expect it to fit the same way. Of course I plan to have this mounted under the cab but which configuration fits best. And yes, I've already measured, but it looks like either one "might" fit. But why guess when I can call upon the wisdom and experience of my fellow Jeepers.
FYI, I ended up going with the offset/center configuration at the recommendation of my muffler installer. It fits up there very nice and I have a straight shot back from the front to the back bumper and the tail pipe has been relocated to the left (driver's side).
Review of the Borla ProXS Muffler:
The muffler shop tried to talk me into a Flowmaster. He's been brainwashed by someone to think their design is the best. I did a lot of research on my own and even came across a dyno test of all the leading mufflers done on a Mustang several years ago. They compared straight through, stock, and everything in between. By the way, straight through performed worse than most mufflers. The Borla ProXS, which is considered the budget series by Borla, actually outperformed their more expensive models, according the this particular dyno. It also showed that the Flowmaster actually decreased horsepower and torque. That was all I needed... I bought the Borla. I should note that by decision was based on performance and sound volume. I wanted performance without setting off car alarms when I drive by. The Borla is also stainless steel and carries a 1 million mile warranty. Another plus.
I paid about $100 for the muffler. The guy at the muffler shop looked at it and said it looked like a typical straight through muffler, aka "glass pack". He wasn't impressed. After he was finished and started it up the first time, he was surprised at how quiet it was for such a small muffler. Louder than stock, but not the loud, obnoxious volume of most performance mufflers. Just a nice rumble at idle, barely more than stock, but a nicer tone. I then jumped in and headed out to run it through its paces. I immediately noticed the difference from the stock muffler when I took off. Louder, yes, and no more mini van sound. This sounded like I expected a Jeep to sound from the beginning. Again, not a loud hot rod, but more of a performance sound that was very nice - deep, rich, and just enough growl. Something else I immediately noticed, whether it is imagined or not I'm not sure, was it seemed to me that I accelerated with less effort. That I now took off smoother and the engine wasn't working as hard to get up to speed. Again, it might just be imagined, but after about a year, I still think it accelerates faster. Don't get me wrong... I'm not challenging anyone to a race at the stop lights or anything, but I am very pleased with the sound and performance I now have, imagined or real.
As I mentioned, this is the Borla ProXS that was almost identical in size to the Flowmaster 40 series, although it's quieter. The exhaust tip is also by Borla. I liked this shape simply because it was a little smaller profile than the typical round tips and the "fins", as I call them, would hopefully add some strength to the tailpipe in case I ever introduce it to a rock.
I tried using my Logitec webcam this morning to record a sound clip but all I could hear was a hissing kind of sound at idle. Maybe my mic isn't designed for that kind of thing. Anyone have any experience recording an exhaust? What kind of system works best, short of professional sound equipment?
Sounds really good had a borla on my old tacoma and loved the sound .not in the budget yet to replace. but these northeast winters will make it wear premature ..loved pissing off neighbors at 5:00 in the morning when i left for work ..miss those days