5.4 Dual in/ Dual out muffler

[6.2]

Maybe you just mash the pedal more cause it sounds good haha.

I know I do.

 

[Maxx2893]

OK ever since I had this exhaust installed I've noticed a huge loss in MPG and POWER LOSS.
Is this NOT strange that a more open exhaust system would cause this???
Would less back pressure cause this?
Any help would be greatly appreciated.
Plans are to change the exhaust out when the weather gets warmer.

It goes against everything I've heard, but I know what your going thru. Happened when I had my Flowmaster Original 40 installed. Could immediately tell there was a loss in torque. I don't think it caused me to get worse mileage directly, but indirectly because I had to give it more gas because of the loss in torque. Mileage went down about 2mpg. Ive since replaced that with a Magnaflow Magnapack instead, and the torque and mileage are back. I'm not sure if they are back to stock though because it was a solid 3 months I had the Flowmaster and had become used to that.

 

[IRONMAN]

Maybe you just mash the pedal more cause it sounds good haha.

I know I do.

hahaaa Yeah it gets mashed more but I've been doing tests and it's just drop a lot.
Kanakry was getting way better MPG during the snoball run and he has no headers or anything.
HWY he was also getting great MPG like I use to get.
I use to be able to get on the HWY 18MPG easy and now I struggle to get 14MPG.
What gives?

---------- Post added at 03:42 PM ---------- Previous post was at 03:40 PM ----------

It goes against everything I've heard, but I know what your going thru. Happened when I had my Flowmaster Original 40 installed. Could immediately tell there was a loss in torque. I don't think it caused me to get worse mileage directly, but indirectly because I had to give it more gas because of the loss in torque. Mileage went down about 2mpg. Ive since replaced that with a Magnaflow Magnapack instead, and the torque and mileage are back. I'm not sure if they are back to stock though because it was a solid 3 months I had the Flowmaster and had become used to that.

I've been on the fence on going back to just my SW headers with the factory exhaust cause that's the set-up I had on while getting 18+ MPG.

 

[6.2]

It is weird. Normally there's barely a change at all in mpg with exhaust mods.

Definitely not that big of a change.

 

[IRONMAN]

That's what I thought as well.

 

[Hockster]

Tires...

 

[IRONMAN]

Tires...

Pretty much back to stock size just Duratracs not BF's

 

[Hockster]

Pretty much back to stock size just Duratracs not BF's

so you have weight and tread design... On my 5.4 everything I did was a help until I changed the front bumper and lost all I worked for...

 

[IRONMAN]

so you have weight and tread design... On my 5.4 everything I did was a help until I changed the front bumper and lost all I worked for...

Thing is I was running my summer wheel and tire set up while still getting great MPG, not until I got the exhaust swap is when I noticed this then I switched to my stock rims and Duratracs and still the same outcome.

These tires are much wider then the Duratracs.

 

[Hockster]

Thing is I was running my summer wheel and tire set up while still getting great MPG, not until I got the exhaust swap is when I noticed this then I switched to my stock rims and Duratracs and still the same outcome.

These tires are much wider then the Duratracs.

You running the tuner still?