I bought my CRD with a straight pipe in place of the catalytic converter and I would like to put a catalytic back on to make it smell better and maybe quiet it down a tad. Does anybody have a recommendation on an aftermarket CC that will work with this engine that is not too expensive and is not restrictive? There is a Thrush Turbo Muffler after the straight pipe and I believe all the piping is 2.5 inch.

Would this work??
https://www.amazon.com/MagnaFlow-99006H ... G83T09N565

I suspect this would be money well wasted. You'll get almost no noticeable effect on an idling engine when the EGT's are low.

The better bet would be to get a proper tune (Green Diesel Engineering is the go-to for engine tunes) to get the engine running as efficiently as possible across all engine RPM's. The GDE eco tune would give you better mileage, power and emissions all at thre same time, and likely reduce your exhaust smell SOME (not sure how much). I really don't think a CAT is going to do what you want it to.

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2006 Limited CRD: Frankenlift II, Fumoto Drain Plug, DIY Stage 1 Tune, In-Tank Lift Pump

Don't waste your money, just install a better muffler like a big Flowmaster 50 Series or Super 50 Series to quiet it down a good bit and keep the performance advantages, forget the CAT!

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Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

I do have a GDE tune (Eco full torque). This thing stinks! Way worse then my diesel Sprinter with a GDE tune. I personally don't mind but I am clearly annoying others around me with the smell. And its not oil or antifreeze. I am hoping its the catalytic converter that is making the difference in odor.

I'm pretty sure my exhaust stunk even before I removed the cat. But maybe it wasn't quite as bad.
Unless you need it to pass an emissions test, I wouldn't bother putting a cat back on.

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U.S. Army Retired

Mine def smells a lot more now that its off. I am considering putting it back on since I cant idle the jeep in the garage anymore, and I only cut it out because I thought it was plugged and causing boost issues. Turns out it wasnt the cat at all.

Its also noticeably louder without it, and I had already removed the muffler years ago. Its very raspy. You can hear the turbo a lot better now though.

You can also get fined for it, even if its a non-testing state(which most of UT isnt). I know i have heard of a few diesel guys around here that got fined a lot of money for deleting their trucks.

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2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

GDE themselves don't seem to be a fan of removing the cat:
source: http://www.greendieselengineering.com/jforum/posts/list/8.page#p127