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Removing muffler?

22K views 24 replies 16 participants last post by  SoDakSooner 
#1 ·
Will I get any increase in horsepower if I remove the muffler and go straight pipes on a 2015 jku sport?
 
#2 ·
You need things like back pressure to maintain some intake/exhaust velocity. Remove the exhaust and your JKU would lose some bottom end and sound like a 9 year old after they ate 15 lbs of taco bell. Aftermarket exhaust systems are relatively cheap and easy to install so why not break open your swear jar and do it right?
 
#7 ·
You need things like back pressure to maintain some intake/exhaust velocity.

This is a complete myth, "back pressure" does not improve exhaust velocity, or improve power. Correct sizing of the pipes and exhaust temperature determines exhaust gas velocity but a baffled muffler pretty much ruins it no matter what. It's also not exactly true that more exhaust velocity is always better. It all depends.

Anyway, the thing that's not a myth is that removing the muffler will not improve performance, at least not in an appreciable or measurable way. Replacing the muffler with straight pipe, along with a thorough redesign of the exhaust system to reduce bends, reduce bend radius, optimize tubing diameter, etc. coupled with a different engine tune may allow for more power. All of this is overkill for the like 3-5hp you could potentially gain.

If you really want improved power by exhaust mods then check to see what the RAM 1500 exhaust differences are, since due to "more space" for exhaust they were able to tune 20 more hp from the same engine as your Jeep has. My guess is it can't be done on a JK, but who knows? Worth looking? Could be simply a much longer exhaust path making it possible to reduce bendds and allow for bigger tubing. You'd have to reflash the RAM 1500's ECU tune.

BTW I'd have to guess that removing the muffler completely will make this Jeep very, very loud. My previous car had pretty much track-only exhaust ... 1/2 the engine displacement, open element air filter with a very short intake run, tube header, 2.25" mandrel-bent exhaust with minimum bends but with one 24" long resonator and an additional 12"x4" glass-pack where the "muffler" would be, and that thing was crazy loud. With 3" exhaust tubing, 2x the displacement and 1/2 the resonators I guarantee you the Jeep will be obnoxious and probably illegal on the road.
 
#5 ·
You will lose power its not a lot but you can feel it at the pedal. I ran a week straight pipe from the time between when I installed my XRC atlas rear bumper which facilitated its removal and when my afe muffler arrived. Which was 1 week of far canister driving. It was fun being annoying for the first couple days then it just got annoying.
 
#6 ·
People remove the muffler and run just the resonator all the time, some like it, some dont. A little more noise is all you will get.

I had full custom exhaust built from the cats back, with a flowmaster HP2 (pretty much straight pipe) where the stock resonator used to be, and a pipe dumping right after the rear axle. It sounds mean but I would not want to run it on the highway. At idle you cant even hear the motor from 15 feet away, but it gets loud real quick.

http://www.youtube.com/watch?v=p_lKxwT8rH4
 
#8 ·
Yes, removal of the muffler will not DECREASE or INCREASE performance in any way. The ONLY thing the muffler does is..well..MUFFLE sound. Now, taking out the cats and going to a Straight Pipe format will change performance. A simple MUFFLER DELETE will only make your Jeep loud. I have had the muffler off for 9 months and I still have it off. I actually like how it sounds, but then again I have a manual.
 
#16 ·
I ran the stock resonator with no muffler for a couple of days. Sounds obnoxious - does not sound good at all. Now I run the FlowMaster American thunder system which is basically the HP2 muffler mentioned above. It sounds a lot better and is very nicely tucked up. It does get a little loud. Here is a video clip that I made if anyone is interested.

https://youtu.be/ILwRoGxrlaM
 
#19 ·
Had mine off for almost a year now. It's loud on startup but then levels out nicely. Doesn't sound too "ricey" or obnoxious at all either in my opinion. But I rarely shift after 2,500 rpm and am just cruising around a majority of the time. I was a little hesitant to do it at first because others made it sound like I would be waking up the neighborhood and giving myself a headache. That's far from the truth in my opinion...but I guess I'll have to go get a flat billed hat now :rofl:
 
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