Muffler deleted, milegae dropped! HELP!!

[Harleysmoker]

I just installed the Cool Duals muffler delete today and I think I noticed something disturbing. I took the truck out for a ride and it seems that the MPG on the display dropped drastically. Now I know the read out is not accurate compared to calculated mileage but I'm basing this on the read out before and after the delete was installed.

My question is: Is there any relationship between removing the muffler and a free flowing exhaust and lower MPG? I was driving as conservative as possible therefore I know I didn't have my foot in it for the noise. Is this just the computer getting used to the new free flowing condition and therefore it's out of wack until it adjusts? Hope so...

 

[DaveBen]

Drive it and keep manual mileage numbers and then compare them. As you noted, the Lie-O-Meter isn't accurate at all. I can't think of why your mileage would drop after freeing up the exhaust.

Dave

 

[Harleysmoker]

Thanks for the vote of confidence Dave. You know how we all watch those displays and realize it's only a guideline at best but the drop was compared using the display. It almost felt like I had to keep my foot in it more to keep rolling. Maybe my imagination; we'll see tomorrow...

 

[Tail_Gunner]

A mileage drop after mods is a very common thing.

Case in point, ever since I put in my new stage I single shot injectors, my truck will go from 0 to 60 in under 8 seconds compared to about 10 to 11 seconds before the injectors. I also noticed that now it goes from 0 to 60 in less than 8 seconds, my fuel mileage dropped like yours. Funny thing though, I'm still trying to figure out why my rear tires are wearing faster since I put the new injectors in.

 

[W4RLR]

A mileage drop after mods is a very common thing.

Case in point, ever since I put in my new stage I single shot injectors, my truck will go from 0 to 60 in under 8 seconds compared to about 10 to 11 seconds before the injectors. I also noticed that now it goes from 0 to 60 in less than 8 seconds, my fuel mileage dropped like yours. Funny thing though, I'm still trying to figure out why my rear tires are wearing faster since I put the new injectors in.

It's because the rear axle is jealous, and wants a new pair of shoes!

 

[powerstrokeguy]

hahahahahahahahaha!

 

[firesoutmatt]

Thanks for the vote of confidence Dave. You know how we all watch those displays and realize it's only a guideline at best but the drop was compared using the display. It almost felt like I had to keep my foot in it more to keep rolling. Maybe my imagination; we'll see tomorrow...

So whats the update ??

 

[BLK PWRSTROKE]

I gained 2-3 MPG after installing the MBRP Cool Duals (cat-delete) on my 05'. Used the MBRP muffler though. I lost 2-3 when adding the 35" tires, then did the MBRP + the AFE stage II and gained it back.