MPG question

[LonghornsATX]

I drive an F-250 7.3 diesel. It didn't have a muffler on it, so I put one on there. My MPG dropped about 3 MPG.

I thought the muffler would increase my mileage - or leave it relatively the same.

Am I wrong? What are some things I should look at?

[bowhunterchris]

muffler=restriction

No muffler=better flow.

[LonghornsATX]

but 2-3 mpg difference?

[Jourdan_D]

yep, I had no cats on a mustnag GT. When i removed the cats my MPG increase 6-7 mpg on the highway. city stayed the same. its all about more flow.

[Jven]

When the motor breathes easier she's not as thirsty.

[smokin6.7]

Go buy a different muffler. It shouldn't make that big of a difference. Go buy a performance "flow through" type muffler.

[KHoes203]

yep, I had no cats on a mustnag GT. When i removed the cats my MPG increase 6-7 mpg on the highway. city stayed the same. its all about more flow.

Not to sure about that one but a diesel doe snot require the back pressure that gassers do and like.

[BigFoot]

Yup, anything in your exhaust system is gonna suffocate your engine. It can't pull as much air to the engine, when the muffler blocks the air from escaping. Plus in Texas, if you have a turbo, you do not need a muffler. Why put one on?

[Cody Malone]

muffler=restriction

No muffler=better flow.

Yep

[justincorbell]

muffler=restriction

No muffler=better flow.

Yep, if it doesn't already you may look into an aftermarket intake, coupled with taking the muffler back off and running a 4 or 5" turbo back free flowing exhaust you will see gains on your mpgs

[ckamp52]

Put a Flo pro muffler on...has flow thru design yet isn't annoyingly loud

[expressfish]

Ive got an aero turbine 4" Id sell ya pretty cheap.

[BigFoot]

You would also stand to gain a little bit of mpg with a larger exhaust system, a 4" is pretty practical, thats what I want to put on my f250

[Javelin]

Yup, anything in your exhaust system is gonna suffocate your engine. It can't pull as much air to the engine, when the muffler blocks the air from escaping. Plus in Texas, if you have a turbo, you do not need a muffler. Why put one on?

This is not true. Back in the day it was either true or just overlooked but at LEGIT inspection shops if you don't have a muffler then you will not get an inspection sticker these days.

[BigFoot]

This is not true. Back in the day it was either true or just overlooked but at LEGIT inspection shops if you don't have a muffler then you will not get an inspection sticker these days.

Straight from TexDot

20.15 Exhaust System. Every motor vehicle shall at all times be
equipped with muffler in good working order and in constant operation.
Muffler defined: Muffler is a device consisting of a series of
chambers or baffle plates or other mechanical design for the purpose
of receiving exhaust gas from an internal combustion engine
and/or turbine wheels for the purpose of receiving exhaust
gas from a diesel engine, both of which are effective in reducing
noise.