2.5" vs. 2.25" muffler for KJ

tombo_ontario · **Posted:** Mon Mar 24, 2014 6:05 pm

So I need to replace my muffler as there is a whole at one of the edges and it sounds terrible. Anyways, I'm planning on getting a Thrush Welded as I have heard good things about it. I've read through a bunch of forums and am just wondering what is the easiest/most effective way to go...get a 2.25" and just slide it in place, or get the 2.5" and cut off the parts of the stock pipe that go down to 2.25"? As I understand it the pipe does go down to 2.25" right before and after the muffler, though I have read people go with both sizes depending on where they cut the stock muffler off. I won't have access to a welder so everything will be clamped if that matters...

Also, if anyone has definitive advantages of one size or the other it would be greatly appreciated if you shared them.

Thanks!

tommudd · **Posted:** Mon Mar 24, 2014 6:48 pm

Everyone goes 2.5 inch

tombo_ontario · **Posted:** Mon Mar 24, 2014 7:20 pm

ya thats what I was thinking...guess i might as well.

WWDiesel · **Posted:** Mon Mar 24, 2014 8:51 pm

Bigger is better on the exhaust, go with the 2.5". Ditch the CAT if you are able, you wont be sorry!!!! :SOMBRERO:

tommudd · **Posted:** Mon Mar 24, 2014 9:14 pm

No ditching cats esp. if a gasser

streetglideok · **Posted:** Mon Mar 24, 2014 9:21 pm

WWDiesel wrote:

Bigger is better on the exhaust, go with the 2.5". Ditch the CAT if you are able, you wont be sorry!!!! :SOMBRERO:

On CRD's sure. On gas engines, hardly. Pulling cats is illegal at the federal and state level, and usually at the city level too. Bigger is not better on pipe size as well. It's all in tuning, and too big of pipes will hurt low end power. Ever heard the saying "use components that match and compliment each other"? An engine that is tuned for mid range power will not make more power with oversized pipes. You'll soften the lower end of the power curve, and see a slight increase at the top end. Guess what our vehicle needs? Low-mid range power.

tombo_ontario · **Posted:** Tue Mar 25, 2014 7:49 am

Ya Im sticking with the cats...have to anyways for emissions tests.

rick254tx · **Joined:** Wed Mar 12, 2014 10:11 pm **Posts:** 35

Anyone ever try one of these ordered one for $15 free shipping just want to get rid of the stock tub sized muffler. Hope it's not too rice burner sounding on my 2.4.

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tombo_ontario · **Posted:** Sat Mar 29, 2014 7:04 pm

I put in the new muffler today, added an extra length of 2.5" pipe to compensate for the smaller Thrush muffler over the stock one. Sounds pretty "gnarly"...better sound than stock, though I have a slight leak at one of the seams so I have to fix that before it sounds right. Definitely louder than normal though doesn't seem to loud. We'll see what the wifey thinks :lol:

For those who are interested I cut just before the flange (after the cat), and just after the muffler where the pipe goes back to 2.5"...this way the whole exhaust is 2.5" with no restrictions.

2.5" vs. 2.25" muffler for KJ

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