Does high flow muffler = higher mpg on CRD???

e_poirier2004 · **Posted:** Wed Mar 11, 2009 9:02 pm

I would like to know if any of you tried changing their muffler and saw a serious improvement in mpg. If so, which muffler are you using?

ATXKJ · **Posted:** Wed Mar 11, 2009 10:48 pm

stock to Magnaflow added ~ 1 mpg - not huge but it feels better -
I think the folks that eliminated the muffler completely did better
(the Turbo acts as a muffler, but check local inspection laws)

blake1827 · **Posted:** Thu Mar 12, 2009 9:15 am

I wasn't calculating my mpg a whole lot before I finished most of my mods but w/ a magnaflow muffler on mine the turbo did seem to spool a little quicker, stock muffler is junk on our diesels. aftermarket muffler or straight pipe seems to be the consensus.

chefdab · **Posted:** Thu Mar 12, 2009 1:35 pm

Maybe this should be moved to the CRD section for more exposure.

bugnout · **Posted:** Thu Mar 12, 2009 4:05 pm

I don't know about mpg gains, but it sounds better. I have a Cherry bomb glass pack. I think as far as performance, the turbo spools up a little faster.

In the CRD, the turbo charger does most of the muffling, you could run a straight pipe or glass pack with out increasing the db level much.

805gregg · **Posted:** Thu Mar 12, 2009 10:36 pm

I doubt much mpg but alot better throttle response, less turbo lag.

superj · **Posted:** Fri Mar 13, 2009 10:13 pm

i thought on diesels that the faster you cleared the chamber and sent it out the back the more power and mileage you could get (if you drove conservatively) i know all my truck buddies run larger diameter exhaust and pull the restricter plates out of the system to free the exhaust gas extraction process and have gained mileage as a by product of the power added.

usually a limiting exhaust is how power is reduced on diesels. exhaust is the first mod for most diesel guys going after power/ mileage.

take this though from someone who has not yet owned a diesel and only chooses to listen in or read on these things

ATXKJ · **Posted:** Fri Mar 13, 2009 11:08 pm

The stock exhaust is 2 1/2" except for the Muffler - it's 2" - so just going to a straight through 2 1/2" helps - the only folks who've gone up to 3" exhaust have had full custom's - which are expensive.

So best bang for the buck is a straight pipe if you can get away with it or a straight through muffler.

mrkake · **Posted:** Sat Mar 14, 2009 2:53 am

I have tried running a straight pipe, Magnaflow with no cat, Magnaflow with cat, and a Cherry Bomb with no cat. There was a difference in how quickly the turbo spooled up (and obviously how loud it was). But only marginal improvement in mileage. The best thing I have found for improving mpg is keep it light, inflate tires to the upper limit of the tire's rating and keep your foot off the skinny pedal as much as you can. I haven't found the illusive "silver bullet" for increasing mpg.

Does high flow muffler = higher mpg on CRD???

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