Have you seen major MPG improvements since you replaced your stock exhaust with the Maganflow? I am not sure if I am crazy or not but today I got 18.4 MPG with highway/stop and go to work, plus I filled it up before I left!! I never got anything over 16.3 MPG with the FlowMaster!! I am consistently seeing a 1 to 2 MPG improvement. (not that I am recommending this to anyone for MPG gains)

Just wondering if you have seen the same thing, maybe it is just the difference between the Magnflow and the Flowmaster 40's.
Or better yet I am finally loosing my mind.

 

I'm not RockPick.

I did, however, stay at a Holiday Inn Express last night.

Seriously, though...

I've had my Magnaflow exhaust on my truck for five days now, and in that five days, have seen an improvement in gas mileage. I can't say how much exactly, but before the installation, the computer was saying 12.3, 12.5mpg. This morning, as I backed into my parking spot at work, having not reset the computer since a few days before the install, I noticed it said 14.0mpg.

So, I'm getting a 1-2mpg improvment. In a couple days, I think I'll reset it again, and see what I'm getting after a couple weeks.

 

A Magnaflow exhaust isn’t going to give you 2mpg better fuel mileage. If that were the case Ford would install them at the factory for better Corporate Average Fuel Economy (CAFE) ratings.

 

well, it sure seems like it is.

My driving habits are the same. What else could it be?

 

I noticed an immediate difference in mileage as soon as i filled up after taking my exhaust off my truck. I ran 2 1/2 inch stainless from the cats right out the stock location. btw the factory muffler weighed enuff to take 1 mpg away.

 

I believe I have noted a change in MPG... for the better...

I attributed this to the fact that I had disconnected the battery to reset the PCM and thus, it was relearning my habits. Who knows?

 

I replaced the stock system with the 3" cat back magnaflow. The change made a noticeable difference in MPG and power at all RPM's.

Take a look at this site!
https://www.f150online.com/forums/li...atalogno=15821

 

I might believe that if Ford dodn't have their hands tied by the EPA's noise emission standards...Kevin

 

Hey nightranger, how does it sound without a muffler and running straight from the cats. I was thinking of doing the same thing, but didn't know if it was going to be to loud.

 

JP,

Remember I am comparing my MPG from the Flowmaster 40 SIDO. I never had the stock exhaust on my truck as the FM was installed by the dealership. I thought I was crazy. But I verified today that the difference is huge.

While this isn't scientific I always reset the MPG gauge at the same light every morning from a dead stop. When I get to downtown Dallas at a specific intersection (Akard and Elm) I take the reading. The driving is a combination highway and local driving. The highways are usually stop and go unless you get lucky. Today I would consider it a heavy traffic day and I still got 17.8. Like I said before I have never had above 16.3 with the FM.

Kevhunt,

I read a post that you had 3" pipe welded from the y connection to the Magnaflow and lost a lot of torque. I have a muffler shop that was going to do the same thing tomorrow. Did I read this right? I sure don't want to mess a good thing up. The shop that did my Magnaflow di it wrong and they are going to fix it. the rear pipes are not from the catback kit and are basically junk. He has the correct rear pipes and was also going to weld the 3" at the Y". Any information would be appreciated!!!

 

Crash,
Here is what I had done the first time: Replaced the stock y with Flowmaster 2.5" in 3" out y, 3" pipe to 18"Magnaflow 3" in dual 2.25"out, pipes exited at rear corners.
Now I have the stock y and Magnaflow part number 15834(SIDO stainless catback system) which the intermediate pipe goes from 2.5 where it connects to the y(on my regular cab)and goes back out to 3" to the muffler which is 3"in, dual 2.5 out pipes exit out the rear.
Not very much difference between the two, but enough to make a very noticeable difference...Kevin

 

It's only loud when you are in an alley or have on a load. at highway speeds you hardly notice it and i most always have music on so i dont here it at all. my friends say its sweet when i'm pulling out hard on the throttle. we did it across the street from where i live at a local muffler shop for 30 bucks

 

 

K&N filter, and custom exhaust will improve my gas mileage huh?

Someone wanna call my wife and explain that to her for me? She just looks at me like a puppy hearing a high pitched tune when I try and explain it to her.

 

Not to flame on you guys but, why is everybody so concerned about mileage? We all drive trucks, most of us chose to buy one. Trucks are big, heavy, and they suck gas. If mileage was such a concern when you were looking at a new vehicle, there are MUCH more effecient vehicles out there. the Escape hybrid comes to mind.

My truck is bone stock and I get anywhere from 14-17 MPG/city (depending how much lead is in my shoe ). I average anywhere from 4-7 days on 1/2 a tank (I have the optional larger tank). As far as mods helping mileage, I don't buy it. The more you guys upgrade and improve the performance, the heavier your right foot gets!

That's a proven scientific fact!