Least obnoxious free flow muffler for 4.0?

[DAA]

I'm tossing around the idea of a cat back system for my '06 TJ Unlimited. Or, more likely, just a free flowing muffler and have an exhaust shop install it. The factory tailpipe section needs to be modified to clear the skid on my new safari tank anyway, which is what got me thinking about this in the first place.

All I'm hoping to get out of it is 1 MPG and I'd be plenty satisfied to get that. But, it wouldn't be worth it to put up with any highway drone or ricer roar.

So, I need experienced opinions on which muffler (or whole cat back system) is the LEAST obnoxious. And by that I mean, the one that is the quietest. More important than being purely quiet at idle and off idle, is that it doesn't have any "drone" at 3200 rpm on the interstate. Exhaust drone on long trips is one of those things that seems like it becomes physically painful after awhile. After three or four hours of it, I start to want to kill every person, plant and animal I see. So, can't have any highway droning...

Really, I do like my exhaust to be as quiet as possible. So, maybe, I'm best off just sticking with the factory muffler? Can I really hope to get 1 MPG out of just a muffler or cat back? Can it be done without making too much noise? What do you guys that have tried other mufflers think?

- DAA

 

[kmboren]

I just had a glass pack put in and it is quieter than the flow master. I do not notice any drone but I am not really paying attention to it either.

 

[Gravy]

I just had a glass pack put in and it is quieter than the flow master.

I completely agree. After hearing both I'd just go with a loong cherry bomb.
I'm not kidding, I swapped a 16" or 18" onto my Cherokee when I crushed the stock exhaust and my xwife (who daily drove it & was super picky ) never even noticed.
That's what I'm running now in my TJ and it's nice and quiet up to about 3,200 RPM and it sounds GREAT taching out. :greg:

 

[rholbrook]

Run up to Ray's Muffler on 5th West, ask for Steve and tell him what your looking for. Steve likes to Jeep and will know what you want.

 

[Anchor_Mtn]

I ran a 2 chamber flowmaster for years and it was fine. It was nice and small so it fit easy too.

 

[xtremexj]

I've run both Flowmaster 2-chamber and Magnaflow. I think they are both around the same 'loudness' but I like that the Magnaflow is straight through and stainless.

 

[Thursty]

I have a Magnaflow on my Cherokee and I like it.

 

[SUPERFLY]

If you want quiet and quality go to mineke on state, in the same parking lot as kirkams ask for a guy named fritz, tell him you want the cherrybomb turbo... It's cheap sounds good at high revs but most Important it's super quiet. I've had three trucks with this set up and have been super happy. fritz deals with rock crawlers a bunch so he knows some tricks to keep the exhaust high and out of the way of rocks. His price is right and the quality is awesome!

 

[iamsparticus]

I use the Aero Turbine muffler i have had it on for 3 years no problems, its loud when you gas it but quite at idle and cruising. If anyone here has heard my rig it is loud only because my exhaust ends in front of my axle but when i had a full exhaust it was quite

 

[muddyjeep]

I'm running a flow master 40 series on my XJ. It is way too loud!

 

[jeep-N-montero]

Hey DAA, I have a series 40 in the garage that I put about 6k miles on and it sounds great behind the 4.0. Only reason I swapped it out is because my new system uses a beefier casing muffler. Hit me up if you are interested. This is what I currently run http://www.ironrockoffroad.com/Merc...=IROR&Product_Code=IR-Z_IEK&Category_Code=PFZ but they don't make a TJ version.

 

[DAA]

Appreciate all the input from everyone so far! Still not sure what I'm going to do though...

Hey DAA, I have a series 40 in the garage that I put about 6k miles on and it sounds great behind the 4.0.

I'm running a flow master 40 series on my XJ. It is way too loud!

Kind of like the old beer commercials. Sounds Great! Too Loud! I really do appreciate both comments, but, also have to say that I agree with muddyjeep. I've heard a couple 40 series on Jeeps and they are too loud for my taste.

A few people have recommended the Spintech muffler for what I want. Have listened to a few recordings online, but that really doesn't tell me what it would be like to live with it while driving.

The only reason I'm even considering exhaust mods, is in the hopes of improving the MPG a little bit. But, from the research I did yesterday, now I'm really not too sure that any muffler will actually improve MPG at all. It would be stupid to make it louder and not get any gain from it.

Dunno... I think I may just stick with the factory muffler after all.

But if I could get another 1 MPG without making it "too much" louder though...

- DAA

 

[iamsparticus]

Yes a new cat back system will help, just a muffler probably not.

When i added my cat back system i made my self i went from 16 in town to 18 and from 22 to 24 on the freeway!

That said it varies from engine to engine, meaning some engines are more corked up than others but the principle stands engine can breath easier with some back pressure= engine can suck in more air and mix it better aka better fuel economy
After a good exhaust set up you can add cold air intake for another small MPG increase.
Remeber also that all this builds horsepower and if you have more horsepower you have to use less throttle to get up and go and to cruze on the freeway.
I have several friends that switched to a V8 from a V6 and they get better horse power and MPG's because they can afford to be lighter on the throttle all things you have to consider for getting better MPG's

 

[DAA]

Run up to Ray's Muffler on 5th West, ask for Steve and tell him what your looking for. Steve likes to Jeep and will know what you want.

That's where I was planning to take it anyway .

Decided to just stick with the factory muffler and just have the tailpipe moved to clear the new gas tank. Didn't seem too likely I'd pick up any MPG with just a muffler and I didn't want to make it any louder either.

But... Steve said he really thought I would pick up a "little bit" of MPG. Especially since I've already got a CAI and the Edge module and TB. And, he assured me that it wouldn't bee too loud and that I would not even be able to notice it on long hiway runs. So... I changed my mind .

He stocks Magnaflow, so that's what I got. Way too soon to say whether it got me any MPG or not. But I think he was right about it not being too loud. I can really only hear it at all at idle and lower RPM when I'm not on the throttle. Anytime I'm on the throttle, my custom CAI (airbox inside the cowl) is loud enough to drown out the exhaust. Have only done a couple short freeway hops with it so far, but cruising at 75MPH, so far, I honestly can't hear it anymore than the factory muffler.

Time will tell on the MPG. I'll be more than happy if I see a 1MPG increase. Really don't know if I will or not, like I said, time will tell. So far though, loudness with the Magnaflow really does seem to be a non-issue.

- DAA

 

[Greg]

Good call, I had a Magnaflow on my TJ (with the V8 and headers ) and it sounded great. I think Magnaflow builds some quality exhaust products. I've also been happy with the Aero Turbine muffler I had in the past.

 

[mbryson]

I had a Flowmaster 70 series on my XJ and on my wife's ZJ. I liked both of them quite a bit. My "Jeep" has a Magnaflow and I REALLY like how the small block sounds through that.

 

[iamsparticus]

I forgot who makes the hushpower muffler, i think thats what it is called. Anyway they are pretty small and quiet and they keep cooler, better for a old jeep that has the exhaust close to the floor

 

[_Auzzy_]

dont use a blown up glass pack, i can barely hear people around me above 2000 on the rpm lol