Hey everyone, I own a 2012 cummins (just turned 12K) I am doing all my deletes tomorrow I have done a 6" cold air intake custom bent, Smarty Jr. programmer and now doing the EGR delete and DPF delete!! My question is-is there any real benefits from switching to a complete 5" exhaust over 4" exhaust? I am not going to do any other mods to my truck just the above deletes... I am going to be deleting the muffler too so it will be straight piped over the axle and exit in the stock location. but really is there a need to go larger diameter? Your help is MAJORLY appriciated!!!

 

Power, performance, and ,mileage wise? No. %" will give you a different, deeper sound. That's all.

 

Update: I did the deletes and went with the 4" exhaust with no muffler, It sounds AWESOME my son loves it and I am seeing currently 19.7 mpg originally before the deletes as pulled into the shop I was sitting at 15.9 mpg it is still climbing but I wont know till I run another tank of fuel through it as this is calculated averages. The truck has 12400 miles on it now... I expect fuel mileage to go down a bit once the 35" tall tires are put on but I am very pleased with the truck now... even more happier with it than my 02 and 05 (all the creature comfort stuff)!!!

 

Just make sure you hand calculate fuel mileage and don't go by the Lie-O-Meter.

 

My 2012 lie o meter is right on. Exactly. I heard some are way off tho.