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Exhaust size.
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=4&t=52857		 Page 1 of 1
Author:  Powerman04 [ Tue May 18, 2010 10:08 am ]
Post subject:  Exhaust size.
Just looking for the actual size of the stock muffler to compare with what I'm in need of. The muffler I'm looking at comes in 2 sizes, 4x8x16 and 5x10x24. Just wanting some feedback on what size yall would use, since I'm trying to open up the exhaust a little to sync well with my CAI. Thanks!
Author:  Daksport [ Tue May 18, 2010 10:59 am ]
Post subject:  Re: Exhaust size.
Don't worry about the size of the stock muffler. It is just an oversized pig designed to make the KJ be quiet.

What brand are these mufflers you are looking at???

Any decent high flow muffler will work well with you CAI. Magnaflow, Borla, Dynomax are just a couple examples of companies offering good high flow mufflers.
Author:  Powerman04 [ Tue May 18, 2010 12:04 pm ]
Post subject:  Re: Exhaust size.
Daksport wrote:
Don't worry about the size of the stock muffler. It is just an oversized pig designed to make the KJ be quiet.

What brand are these mufflers you are looking at???

Any decent high flow muffler will work well with you CAI. Magnaflow, Borla, Dynomax are just a couple examples of companies offering good high flow mufflers.

So this means the larger it is the quieter it is? Sorry to ask so much, it's my first time replacing things with aftermarket stuff so I'm not 100% on what it will actually do.

The muffler I'm looking at is from Bassani. Anyone used this before? It's around the same price of the others, but I always have the urge to be different. :wink: While I know different isn't always better, if it all works out, that just gives us KJ owners more options.
Author:  Daksport [ Tue May 18, 2010 12:47 pm ]
Post subject:  Re: Exhaust size.
Generally speaking, bigger is quieter. So the 5x10x24 will be quieter than the 4x8x16.

Never heard of Bassani so I can't say anything about them.

If you are doing this yourself, you might find it to be in your better interest to get a kit that you can install quickly and easily.
Author:  Powerman04 [ Tue May 18, 2010 1:08 pm ]
Post subject:  Re: Exhaust size.
Nah I have help with someone who has done a swap before, and with the searching I've done here, it's cheaper and nearly the same effectiveness as pouring money into a whole system. What does the size difference do other than simply make it louder or quieter, if anything?
Author:  JeepinJarhead03 [ Tue May 18, 2010 2:13 pm ]
Post subject:  Re: Exhaust size.
nothin really

larger the size the more baffles and fiberglass wadding, if so equipped, that can fit in the given space

the stock muffler was basically a big resonator, i dont think it had baffles but had offset in's and out's and a crap ton of wadding

the rule of thumb of size versus volume really doesn't hold up, it's just cheaper to make a quiet muffler using a large volume, there's quiet mufflers out there that are no bigger than the flowmaster 44's, for instance dynomax super turbo, and summit turbo (maybe same muffler actually) are about the size of the 44's but probably 1/4th the volume level

straight through's with a single baffle and glass wadding tend to be the loudest and lowest profile, naturally you could go with a super trap if they still make those, which is probably the smallest as it bolts on to the end of the tail pipe, adding wafers is the method on that one to change the tone and volume
Author:  Powerman04 [ Tue May 18, 2010 2:28 pm ]
Post subject:  Re: Exhaust size.
Alright so regardless of the size, sound can change. It then goes to what's actually inside, the size of the inlet/outlet, and the offset of them? Since the Stock muffler chokes itself to 2.25 then I imagine the performance gain is replacing it with one that is 2.5 all around?

And since the stock muffler sounds like a giant, the bigger the replacement, the easier it will install and stay in place?

Again sorry for all the questions. I really hate diving into something I have no idea about. :?
Author:  JeepinJarhead03 [ Tue May 18, 2010 3:39 pm ]
Post subject:  Re: Exhaust size.
eh, not really going to find an aftermarket muffler the same size as the stock muffler so you or whoever installs it will end up clamping or welding additional pipe in to connect it up so it boils down to getting whatever you want to get that is known to have the sound level and type you desire to have

back pressure assists in torque, free flow assists in horse power, there's drawbacks to everything but in terms of the liberty and the 3.7 unless you're talking about running true duals off headers it's not going to make a beans difference on the torque side, pretty much all the back pressure is farther up the pipe between the manifold and the last cat so what you're doing is freeing up the rest of the pipe so it can evacuate instead of getting farted around inside a gong muffler

when i bought my super 44 flowmaster i dont remember if there was a difference in the terminal sizes of the in and outlets but it was right on the shelf and welded right up with a bit of extra pipe
Author:  JustinP [ Tue May 18, 2010 8:33 pm ]
Post subject:  Re: Exhaust size.
Just an addition to this, when your deciding on a muffler, youll typically see two types, fiberglass/glasspack, and welded, glass is cheaper, and in my experience has produced a smoother tone at idle, a welded muffler, in my experience, has produced the more "typical" exhaust rumble, and gave it a meaner sounding note, think typical flowmaster, either way, it will be neat.
Author:  KJWildman [ Tue May 18, 2010 11:03 pm ]
Post subject:  Re: Exhaust size.
Bassani has been making performance/race pipes & mufflers for bikes and quads for a few years now. Good engineered stuff for motorcycles, don't know how their other products are.
Author:  Powerman04 [ Fri May 21, 2010 7:55 am ]
Post subject:  Re: Exhaust size.
Would a dual outlet on the muffler cause issues for the KJ? And also, if the outlet of the muffler is different, say its 3" and not 2.5", besides noise, what would that do? Thanks for putting up with my questions. :seuss:
Author:  JeepinJarhead03 [ Fri May 21, 2010 4:45 pm ]
Post subject:  Re: Exhaust size.
a 3" outlet isn't going to do much from the outlet other than maybe lower the tone of the exhaust and possibly not even that
Author:  Powerman04 [ Fri May 21, 2010 10:13 pm ]
Post subject:  Re: Exhaust size.
And the dual outlet?
Author:  JeepinJarhead03 [ Fri May 21, 2010 10:17 pm ]
Post subject:  Re: Exhaust size.
nothing post the entrance of the muffler is going to really have any performance increase over the stock pipe or a turn down, short of a crushed tail pipe :P

duals would probably mellow it up but then ya got two pipes to crush on a rock instead of one :P
Author:  JustinP [ Sat May 22, 2010 9:16 pm ]
Post subject:  Re: Exhaust size.
I think youre asking for trouble with a dual outlet, assuming of course you plan on running dual tips out the back, with the dual outlet, youll have to pipe one of the duals to the left side, doesnt seem easy on a kj, you cant really go over the driveshaft or rear diff, and i dont think theres enough room between the diff and the gas tank, and if there is, im not sure you want the pipe that close to either, you could cross over behind the tank and bumper, but i still dont think theres enough room, and it would probably have to hang too low, cause problems and look funny. Out of all the muffler brands, I think I can say my favorite is Borla, as far as sound is concerned of course, every engine/vehicle sounds different, but Ive liked everything ive heard with Borla.
Author:  KJWildman [ Sun May 23, 2010 12:57 am ]
Post subject:  Re: Exhaust size.
My Borla is a dual outlet. Like JustinP said, one side of it comes around the back of the tank and exits on the left side. It's up high enough that I've never had any problem with it.
Author:  JustinP [ Sun May 23, 2010 6:01 pm ]
Post subject:  Re: Exhaust size.
KJWildman wrote:
My Borla is a dual outlet. Like JustinP said, one side of it comes around the back of the tank and exits on the left side. It's up high enough that I've never had any problem with it.

If you get a chance could you post a pic or two of this. I would love to see it. I bet it sounds fantastic.
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