gas mileage

[Kyle Keller]

This has been bugging me the past week. Last weekend, i filled up a full tank of gas ($78) then i went home and i unbolted my pipe right after the last catalytic converter, just to see how it sounded and i drove about 60 miles with no exhaust going through my muffler then bolted it back up.



Usually i get about 300 miles on my odometer before the "Low Fuel" reminder comes on. Today my "Low Fuel" didnt come on until about 330. I am wondering if disconetting your muffler improves or takes away gas mileage. People talk about back pressure and all that, and although the truck seemed a tad bit slower, i did get 30 more miles on the tank. I maybe filled up about 1/2 gallon more gas than usual and i also drove about 15 miles on the interstate, but it was aggressive (80-90).



So my question is... does it negatively or positively affect gas mileage?



btw. i do have a single in single out Magnaflow exhaust system.

 

[Tom Schindler]

Less back pressure will get you better gas mileage, but not that much better. Now, following behind a semi will get you 3 MPG gains.



Keep a safe distance though. Just let the semi break the wind for you.





Tom

 

[Jim Johnson]

"Just let the semi break the wind for you."



Ha-ha! He said "break the wind."

 

[Kyle Keller]

but i always heard people talk when they unbolt their muffler, you get MORE backpressure but i never could understand because you were letting your exhaust out of the pipe so early and not making it run through the extra 6-7 feet

 

[Larry Gamble]

I just refilled with 353 miles on the trip odometer of my 02 4x4!



i'd been waiting for the light to come on for 30 miles, but it only need 21 gallons.



Just about all of it around town driving, maybe 75 miles at highway speeds.



17mpg!!!



I just did a few things to lighten my foot on the gas pedal. I try (and it's really hard) to keep the RPM's low like 2500 when leaving stop lights. When I can get on a highway, I've been keeping the speed about 65.



Driving slow sucks, but it's paying off at the pump.

 

[Jon Richmiller]

My last fill up i rarely rev'd the engine above 2500rpm, and only time i did was for going uphills in which it didn't go above 3000rpm. I still only average 13mpg.



I'm pretty disappointed and i have no clue why it would be so low. I've always felt like i never got good gas mileage, but only after i put my supercharger on did i start measuring. The supercharger should not be the cause since when the bypass valve is open it's only takes 1/3 hp to turn it.



And when i'm driving like grandma it rarely boosts the engine.



Any thoughts?

 

[Todd Z]

Kinda reminds me of the people that had a carburetor car that would flip over the air cleaner cover.... :wacko::wacko:



Todd Z

 

[Steve Krusich]

Other than sound, what is the general opinion of the Flowmaster muffler? Being really objective, does it really add to mpg and/or performance?

 

[Todd Z]

Steve,



The stock ST muffler is very restrictive. 1 is to quiet the truck and 2 is for emissions, EGR and things like that...



Removing the restriction will aid in a MPG gain...



IF you put in larger pipes and tings like that then you gain the sound also...



You can simply cut out the OEM muffler, Put in a quiet aftermarket muffler and be good to go...



Todd Z