Duner Posted March 24, 2007 Share Posted March 24, 2007 Ok, It's time to alleviate the stock muffler's interference with the d-shaft. It's a simple fix but what I want to know is what sounds good on a renix 4.0? I would like it to sound a bit more throaty it needs something to go with it's improved attitude 6" lift, 33" tires, 4" flares, etc. So should it get a performance muffler? or should it just get a coffee can at the tip to alter the sound? Link to comment Share on other sites More sharing options...
87manche Posted March 24, 2007 Share Posted March 24, 2007 I like how the dynomax sounds on a 4.0 Not a big fan of the flowmasters, too loud and droning at highway speed. I've got a relatively stock style muffler on mine, it's a walker. Sounds nice if you romp on it, quiet at idle. I dislike loud obnoxious exhausts on the trail. Link to comment Share on other sites More sharing options...
Duner Posted March 24, 2007 Author Share Posted March 24, 2007 My dad is a big fan of the dynomax, he said it frees more hp and is much quieter than the flowmasters. He just keeps telling me that inline 6 engines sound funny with performance mufflers probably spent too much time with all those v8's in his day. Link to comment Share on other sites More sharing options...
87manche Posted March 24, 2007 Share Posted March 24, 2007 my brother has a dynomax cat back, it sounds nice, but it's not deafening loud like a flowmaster. Link to comment Share on other sites More sharing options...
comancheon33 Posted March 24, 2007 Share Posted March 24, 2007 I run a flowmaster 40 on mine and love it. Not that loud unless your railing on it. Link to comment Share on other sites More sharing options...
Eagle Posted March 24, 2007 Share Posted March 24, 2007 Let's be honest -- we're talking a low-compression, in-line 6 cylinder engine here. It ain't never gonna sound "good." The closest thing to making a 4.0L sound like a real engine is Gibson. All the rest of them just sound like loud crap. IMHO, except for the Gibson I prefer the stock (or OEM replacements) to Flowmaster or any of the "name" mufflers. If you have driveshaft interference, get a Thrush or Cherry Bomb tubular glasspack and call it done. Link to comment Share on other sites More sharing options...
JohnQ Posted March 24, 2007 Share Posted March 24, 2007 I put a flowmaster on mine, no complaints here. Link to comment Share on other sites More sharing options...
Oizarod115 Posted March 24, 2007 Share Posted March 24, 2007 i managed to get a few clips from people with 4.0s and diff mufflers a while back... check out this thread http://www.comancheclub.com/forums/viewtopic.php?t=2497&highlight=flowmaster Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 24, 2007 Share Posted March 24, 2007 If you have driveshaft interference, get a Thrush or Cherry Bomb tubular glasspack and call it done. I agree. And they sound alright. Link to comment Share on other sites More sharing options...
feerocknok Posted March 24, 2007 Share Posted March 24, 2007 The only 4.0Ls I heard with mufflers changed out had their cat removed. 2 of them were running Flowmaster 40s, 2.5" muffler, 3" behind it, and another one ran stock piping to a 2.5" Cherry Bomb where the cat was, and then shot it out the side (not legal...). The Cherry Bomb had no tone and was ridiculously loud. Ear drum ripping loud, plus it shot 2 foot flames due to the routing. The Flowmasters both sounded amazing. They were very loud, but the Jeeps could almost be mistaken for having V8s. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted March 25, 2007 Share Posted March 25, 2007 i love my flowmaster 40 series on my 91. it sounds great. its not too loud, the only time its really loud is when you gun it and then it quiets down and sounds great when running at a steady pace or idling. my 88 had one too. these will be the only things i put on mine from now on. they sound better then my K-10 with dual straight pipes sounds. Alex Link to comment Share on other sites More sharing options...
Oizarod115 Posted March 25, 2007 Share Posted March 25, 2007 my brother ran a flowmaster 50 series with no cat (and got a ticket for it) but it sounded real good. i can't imagine how much louder the 40 would be with no cat :eek: the 50 was on the loud side without the cat. Link to comment Share on other sites More sharing options...
CEThomas Posted March 25, 2007 Share Posted March 25, 2007 So what would be a good muffler for a 2.5? Right how only have no muffler or cat :nuts: Charles Link to comment Share on other sites More sharing options...
feerocknok Posted March 25, 2007 Share Posted March 25, 2007 So what would be a good muffler for a 2.5? Right how only have no muffler or cat :nuts: Charles I'm running a cat with a 2.5" Magnaflow on mine. I don't know if I'd recommend it or not. Inside the cab it makes no noise at all, but by the tailpipe, it sounds a lil too much like a ricer for my taste. Link to comment Share on other sites More sharing options...
comancheon33 Posted March 25, 2007 Share Posted March 25, 2007 On my 2.5 I am running a stock replacment type with no cat. It sounds good to me. Not loud but good throat when your rowing it through the gears. Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted March 25, 2007 Share Posted March 25, 2007 Personally I see no advantage to removing the cat on these engines. The PO iof mine replaced the cat with a HI-FLO..says that on it! :roll: When the muffler went I threw on a glass pack, cherry bomb on to make it thru the winter. That was 2005. Its still on there... It sounds good, but getting louder. Its about time for a replacement. I have a DYNO-MAX on my TJ and really like it. I have seen the GIBSON's but never tried them. They are a round muffler, right? Eagle where do you get yours?? I'll try one!! CW Link to comment Share on other sites More sharing options...
Eagle Posted March 25, 2007 Share Posted March 25, 2007 I have seen the GIBSON's but never tried them. They are a round muffler, right? Eagle where do you get yours?? I'll try one!! I don't have one. I run all OEM replacements from Auto Zone. A few years ago I briefly dated a gal who drove a Wrangler. First time I heard her Jeep start up I thought somebody had stuck a V8 in it. It sounded SCHWEEEET! I asked, and she said her son had put a Gibson cat-back system in it. It was a very deep, throaty, and mellow sound, completely unlike any other exhaust I've ever heard behind an in-line 6. The "problem" with trying to make an in-line 6 sound good is that the power pulses are perfectly evenly distributed as the engine goes around, unlike a V8 or a V6 where the pulses are not spaced in an equal number of degrees around a full revolution. Where the crank spacing interval is uneven, the exhaust gets actual pulses, whereas with the I6 you pretty much just get "flow." I don't know just what Gibson does, but there's nothing that equals their sound. And Gibson systems are tuned to increase torque ... they got started by making exhaust systems for trucks and SUVs that needed maximum torque for towing trailers and hauling campers. The other brands aren't into torque, they're into horsepower ... which means they are tuned for high RPM not crawl RPM. Link to comment Share on other sites More sharing options...
Duner Posted March 26, 2007 Author Share Posted March 26, 2007 Thanks for all the help I still have not made a choice (looking for Gibson supplier locally just to check pricing). I'm impressed by the way some these trucks sound with flowmasters on them. Link to comment Share on other sites More sharing options...
beaterjeep Posted March 27, 2007 Share Posted March 27, 2007 You guys and your cats. I don't have any on the 86, just straight true duals to glass packs, then the rest of the pipe out under the rear bumper. Quite loud when I get on it, but luckily so far the cops havent said nothing about it, and Ive had one follow me up a hill that I had to kick it down to get up. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted March 27, 2007 Share Posted March 27, 2007 You guys and your cats. I don't have any on the 86, just straight true duals to glass packs, then the rest of the pipe out under the rear bumper. Quite loud when I get on it, but luckily so far the cops havent said nothing about it, and Ive had one follow me up a hill that I had to kick it down to get up. man you are lucky, cuz that thing was way louder then i wanted it to be. if i kept it i would have taken them out and just put pipe in where the packs were at. have no cats, mufflers, anything. Alex Link to comment Share on other sites More sharing options...
offroader461 Posted March 27, 2007 Share Posted March 27, 2007 i have a 40 series flowmaster on my 87MJ....sounds real good and isn't as loud as i thought it would be....i recommend them highly Link to comment Share on other sites More sharing options...
mjeff87 Posted March 27, 2007 Share Posted March 27, 2007 So what would be a good muffler for a 2.5? Right how only have no muffler or cat :nuts: Charles I will be installing a glasspack on mine shortly, as soon as I get a short section of pipe bent to keep the exhaust in line with the rear hangers (to make up for the offset outlet on the OEM muffler). I'm going to run a short piece of pipe out the back to just past the rear hanger and then a turndown tip before the axle. If it sounds like @$$, I'll put another dynomax on it. Jeff Link to comment Share on other sites More sharing options...
87manche Posted March 27, 2007 Share Posted March 27, 2007 on that turn down, make sure you angle it a bit to the side, otherwise the pavement reflects it right back into the cab. that's how mine is anyway, I find it annoying, but I've been too lazy to go and rotate it. Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 27, 2007 Share Posted March 27, 2007 Well, the exhaust fell off my XJ yesterday. I had to help it along a bit because it was rattling on the axle. Now it's just a cat and no muffler. And boy does it sound ghey. I'll probably have to go cut the cat off too just so I can live with it for the next 2 days. Link to comment Share on other sites More sharing options...
project88mj Posted March 27, 2007 Share Posted March 27, 2007 well i got a 60 flowmaster on my 88 mj 4.0 and it is dumped just about 18"before the axle and it is not too loud but about 1000 to 1200 rpm it sounds just like a V8 and on the other note. the "flow" is right when you get on it you can really hear it almost like you got a blower on the motor hey i got a good leak in my intake manifold gasket at between piston #5-6 and it makes a wine sound like got a blower, is this a problem i need to fix or will it be fine (i like it a little) Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now