Hey there everyone. I currently have an mbrp system on my 16 3.5 ecoboost and I’m getting terrible mpg. I am wondering if changing the muffler would yield better results. With the stock system I was getting 22-23mpg on the highway and with the mbrp I get like 16 at best. I don’t have a heavy foot or anything like that I drive like a old man.

 

I don't know what mbrp is. however turbos need a certain amount of back pressure to work properly

 

no they don't

Your exhaust didn't cause you to lose 6mpg. 22-23 mpg is just about unheard of unless you're at a 60-65mph cruise on a 2016 3.5. 16mpg average with mixed driving is about right for that truck. Put stock back on if that's really the case.

 

I have had mbrp before on my 2017 2.7 ecoboost and it sounded great and I did not lose fuel economy. I also added an Air raid CAI snd I still stayed in the 22 to 23 range highway. I would point to something else being amiss. I lifted the truck 4 inches and added 35 inch tires and the fuel economy shot down to 15 to 16 mpg. I expected that would happen but the cool, aggressive look was the trade-off.


I would check on your fuel delivery system, maybe add some Techron fuel cleaner, change air filter, etc. if you are not lifted as I was above then also consider age of truck and mileage.

If all you did was change the exhaust then maybe try another system like Borla or Corsa.


keep us posted.

 

I'd put the stock back on for two reasons... 1. if you really lost 6mpg, that's reason enough. 2. exhaust systems on 3.5ebs sound like rice-rockets.

 

here is picture proof of the mpgs befor the exhaust.

 

More than likely it's your spark plugs

 

lol, mine will do the same with a full tank of fuel and fresh trip reset. Your screenshots mean absolutely nothing and your exhaust didn't cost you mileage. Put your stock exhaust back on and hand calculate your mileage and then put exhaust on and run the same trip at same speed and hand calculate it, then report back.

 

A muffler swap has absolutely zero influence on your fuel mileage. Perhaps you’re heavier on the throttle now because it sounds different.
Edited to agree with ecoboost mileage estimates. 25+mpg on a 3.5 ecoboost is grossly above the norm.

 

Hand calculated it was averaged 21-22 before the exhaust and after the install it’s 15. I’m not losing my mind. I will put the stock system back on and report back. Maybe my truck just doesn’t like me lol