CRD muffler question

Jeep4ever617 · **Posted:** Fri May 09, 2008 5:49 pm

I was looking on magnaflows website for a muffler for the CRD and could not find one listed. What are the dimensions of the stock muffler so I dont get the wrong size of the universal.

DarbyWalters · **Posted:** Fri May 09, 2008 9:18 pm

You might try no muffler first and see how you like it...more than a few of us have and like the results. I went with 3" from the joint back. I like the sound and the price was pretty good...I did a custom job with mandrel bent tubing.

STATELINE · **Posted:** Fri May 09, 2008 9:24 pm

according to the article in Diesel Power magazine (I subscribe & read it myself) the cat back system for the 3.7 gasser is a direct fit for the CRD alsoo

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=32151

Joe Romas · **Posted:** Fri May 09, 2008 9:25 pm

4 cylinder gas, 6 cylinder gas and our crd's use the same cat back :wink:

that's one good reason to replace it with a good 2.5" system. If you look you'll see restrictions on both sides of the muffler. 3" is overkill.

Desert_Busa · **Posted:** Fri May 09, 2008 9:50 pm

Joe Romas wrote:

4 cylinder gas, 6 cylinder gas and our crd's use the same cat back Wink that's one good reason to replace it with a good 2.5" system. If you look you'll see restrictions on both sides of the muffler. 3" is overkill.

noise wise, I can't tell the difference between using a cherry bomb or open exhaust. The turbo takes most of the noise out. Try disconnecting the exhaust at the muffler and wire it up to test it out. This is not your grandpap's gasser. IMOP using a gasser catback would be a waste of money. The straight pipe really cleans things up down there too.

bhysjulien · **Posted:** Sat May 10, 2008 6:52 pm

I second the straight pipe/glass pack option. I've had a glass pack on mine since 150 miles on the odometer. There isn't an increase in noise and the turbo spooled faster. It was also cost effective, read that as cheap. :wink:

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

My ears may be sensitive, but I got a nasty resonance in my Jeep with an el-cheapo $20 glasspack (worst right around 40-50 mph). I swapped over to a Flowmaster 50, and absolutely love the sound. Makes the CRD exhaust note purr rather than pop.

Desert_Busa · **Posted:** Sat May 10, 2008 8:12 pm

I have very sensitive hearing, with all the windows open it's difficult to tell the difference. It's inexpensive going strait piped, I wouldn't call it tacky... you wouldn't know it without looking under the jeep.

robert46123 · **Posted:** Sat May 10, 2008 10:22 pm

The most cost effective method would be to leave the stock muffler in there for the 100,000 miles it's designed to last. I doubt there are any power gains to be seen from removing it as there rarely are gains from any cat back exhaust system. Also, the turbo isn't what "takes most of the noise out", but rather the catalytic converter. Trust me, my turbo charged WRX minus catalytic converter with a Borla "Hush" CBE was plenty loud with turbo, "Hush" and all.

cxturboboost · **Posted:** Sun May 11, 2008 8:47 am

I replaced my muffler with a 3" magnaflow straight through and 3" pipe going back. I gained about 1mpg. It also runs better at low end.

Pete

dgeist · **Posted:** Sun May 11, 2008 8:53 am

I had a local Meineke slice off my stock flange and muffler and replace it with a section of 2.5" tube last night. They didn't have a match for the flexible flange, so they put a true 2.5 flat-faced flange on in its place just slightly closer to the Cat. Two minor 45-deg bends and a slip-fit/weld at the up-sweep by the wheel, an hour, and about 120 dollars later I was done.

I noticed immediately that the exhaust volume wasn't altered but the tone was. It added a low grumbling note (probably one of the first few harmonics of the engine RPM that was filtered out by the offset of the in/out on the factory system). Kinda makes it sound more "truck-y". It definitely spools faster during acceleration and over 30 miles of driving yesterday, I noticed about a 1mpg increase in mileage. That's worth my 120 bucks. It'll pay for itself shortly.

Joe Romas · **Posted:** Sun May 11, 2008 10:41 am

Threeweight wrote:

My ears may be sensitive, but I got a nasty resonance in my Jeep with an el-cheapo $20 glasspack (worst right around 40-50 mph). I swapped over to a Flowmaster 50, and absolutely love the sound. Makes the CRD exhaust note purr rather than pop.

And there's been a lot of negative stuff brought up about glass packs actually restricting the flow and in some post a decrease of preformance is mentioned :shock:

CRDMiller · **Posted:** Sun May 11, 2008 12:13 pm

Jeep4ever,

Do yourself a favor and disconnect stock muffler at the flange, and give it a twirl. Possably bolt the incorrect side of the flange to the incorrect side of the opposite, to keep it from sagging or rattling. And see if you like it.

I wish i had, BEFORE i dropped 300 into a flowmaster (super 44) it sounded stock with a VERRY mild purr at idle/w throttle feathered.
The muffler shop guy said, that's the most aggressive muffler they make (i already knew that)
i took it back the same day and said, i want somehting louder. And he said, that's it, maby it will pick up "once you cook it in"
It did, but not nearly enough.

I emailed flowmaster 2 months ago and asked them what they would advise for the crd, and i'm still waiting.

I ride with it disconnected, turbo defiantly louder, (grin) definatly spools up faster. (even over the super 44)
It's not really Louder, it's deeper. with the windows up i cant tell a difference at cruising speeds. (65-70) However it will/can rattle other objects in your car specifically when you first hit tc lockup at @ 55. In my case, my fire extinguisher sounded like a bad bad bad subwoofer :P

I wonder how different it sounds open at the flange vs straight back from the cat. I'll proally just pull the muffler and pipe off the flange and leave it that way, if i can find a strap or something for the end of the cat.

Crappy quality, but here we go!

DarbyWalters · **Posted:** Sun May 11, 2008 9:23 pm

Having a turbo "changes" the noise quality/texture and lessens the noise volume a bit. The 3" straight back pipe is not too loud and does make a difference in spool up and mpg. The other thing about a straight 3" is it is cheaper than adding a new muffler.

dieselenthusiast · **Posted:** Sun May 11, 2008 9:34 pm

DarbyWalters wrote:

Having a turbo "changes" the noise quality/texture and lessens the noise volume a bit. The 3" straight back pipe is not too loud and does make a difference in spool up and mpg. The other thing about a straight 3" is it is cheaper than adding a new muffler.

X2 - that is exactly what I plan to do

ed. · **Posted:** Sun May 11, 2008 9:45 pm

DarbyWalters wrote:

Having a turbo "changes" the noise quality/texture and lessens the noise volume a bit. The 3" straight back pipe is not too loud and does make a difference in spool up and mpg. The other thing about a straight 3" is it is cheaper than adding a new muffler.

Could you get away with a 3" mandrel bent back pipe?

DarbyWalters · **Posted:** Sun May 11, 2008 10:40 pm

That is what I did...check earlier post for pics

ed. · **Posted:** Mon May 12, 2008 12:04 am

Sorry I was meant to say press bend!

DarbyWalters · **Posted:** Mon May 12, 2008 5:36 pm

You can buy mandrel bends from Flowmaster and cut and weld...that is what I did.

CRD muffler question

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