looking to get rid of my stock muffler on my 4.7 2003 durango with 85,000 miles and upgrade to a dynamax flowmaster or magna flow muffler. any opinions on wich is better?

also does changing to a k&n cold air intake system help the fuel milage at all?



thank you for any input.

I don't have any personal experience with dynomax, but you won't be disappointed with Magnaflow. I like them because they sound great without being excessively loud. I have no drone at all cruising along on the highway.

Unlikely you will see mileage improvement with either upgrade

Another plus 1 for the magnaflow. I have one with the high flow magnaflow cat and it has a nice rumble and no drone. No experience with the others.

mileage improvements on paid off V8 truck that is 12yr old = FAIL.

I got the Dynomax Ultraflo and like it, especially the price. You can do a cat back for about $250 or just the muffler for around $70.

I put a Flowmaster Super 40 Series muffler on mine. Needed to extend the pipe underneath, as the muffler is shorter than stock.

Here is a video I put together to show the difference between stock and Flowmaster Super 40 series.


Note: I have the 4.7L Motor with 2.5" exhaust.

I tell you which one I bought, and it actually sounds awesome. I got the Walker quiet flow SS muffler. It's a direct replacement for stock, and it's not quite true to it's name Quiet..lol But no drone at speed. For my Rango being a family vehicle for the most part it's just right. $86 dollars at Rock Auto. As for air filter upgrades improving mileage I agree won't happen. One reason why is you get it in your head it's got 20 more HP and your in the throttle twice as hard and the mileage go in the toilet. FYI no upgrade to air filter or anything except the muffler and I wouldn't call that an upgrade and I get 17-19 around town and 21-23 on the highway. no BS All I do is run Rotella T-6 full synthetic oil.

MagnaFlow all the way....IMHO

I wanted to, that or the Flowmaster 40 but the wife made the mistake of watching the videos with me..lol