How I increased my gas mileage

[Slegacy96]

I figured you would all want to know. I went from 28 mpg to 32 on the highway. I dont know about city yet, because I drive from State College to West Chester for the most part.

First off my Legacy is a 5 speed, therefor 4EATs you prolly wont have the same results. But one can try. I started off by purchasing a K & N air filter. $40, but they last for 1 million miles and kick up the horsepower a few. Second, the hood scoop was originally intended for cooling the engine. I removed the dam blocking it and now its functional. Im still working on modding the air intake, but more air is better. Third, and this is the most expensive, fuel system clean out. $200ish. Subaru reccomends every 30,000 miles Id say 50,000 would be sufficient. Mine had never been done and at the time I had 78,000 miles so it was pretty clogged up.

 

Thats it. I run 87 in the 'ole EJ25 and its faster and more efficient.

[nipper]

sigh... use the search feature, K and N filters are not highly reguarded here. The pil in the filter can damage the MAF sensor. they also allow more dirt. There is always a trade off to more flow, and thats larger poors and more dirt flowing in.

I am not a big beleiver in a fuel system cleaning unless the car has a problem, especially below 100,000 miles. I (used to work) in the industry, and alot of it is a come one. In the last 5 years it has been completly uneccassary as a maintanince item since the fuels are so clean compared to 10 years ago.

Your second point i dont understand, and in actuality hood scoops can cause more drag.

Finally the amount of increase you got could be had just by changing driving habits. i have a 97obw auto, and just by changing my driving habits i went from 19 to 23 mpg in town.

Sorry to rain on your parade.

 

nipper

[Slegacy96]

Ok well I see youe drag argument and I raise you 2 mpg. I too questioned the aerodynamic effect of wind blowing into the hood but I have benefitted from it. I havent changed my driving habits either. I cruise at about 78mph and occasionally humor myself with a brusque acceleration.

 

As for fuel system cleaning, can you guarentee that the gas you are using is clean? Especially nowdays when regulations are being lifted. A few years back my parents Toyota had broken down (throttle control) so they checked the fuel. I still remember looking at the jar and seeing all the chunks floating in it. Therefore I justify cleaning the system.

[cookie]

They tried a bunch of internet fuel savings devices with about zero effect.

It is hard to really know you have made progress on a fuel mileage question without doing it on a dyno or over a long period of time.

[nipper]

Ok well I see youe drag argument and I raise you 2 mpg. I too questioned the aerodynamic effect of wind blowing into the hood but I have benefitted from it. I havent changed my driving habits either. I cruise at about 78mph and occasionally humor myself with a brusque acceleration.

 

As for fuel system cleaning, can you guarentee that the gas you are using is clean? Especially nowdays when regulations are being lifted. A few years back my parents Toyota had broken down (throttle control) so they checked the fuel. I still remember looking at the jar and seeing all the chunks floating in it. Therefore I justify cleaning the system.

 

It takes 4 tanks of gas to justify an increase in gas mileage, all bought at the same station ideally. Things like humidity in the air, altitude, wind and air temp can increase (or decrease) your gas mileage without you doing a thing. There can be a 5mpg jump with a head wind verses a tail wind. In my legacy (RIP) with the 2.2 my mileage would vary from 27-32 on the same trip same fuel stations (driving acrosss pa) along with a 100 mph run after state college.

You can go in any fuel tank of an car and see crud in it.

Get a vacume gauge if you really want to increase gas mileage.

 

nipper

[Suzam]

I'm curious about the time frame here.

 

Winter formulation of gas is know to cause lower MPG. The manufacturers are all converting or converted over to summer blends by now.

 

How long have you been checking the MPG and how long have you had this car and how many similar trips?

 

Our MY95 used to get between 27 at worst to 32 MPG at best on a regularly traveled long haul from SE PA to upstate NY with no mods at any time. Just differences in conditions of the moment.

 

If you can maintain a difference like the one you are now, that would be more convincing...hope you do.

[TheYeti]

Thats it. I run 87 in the 'ole EJ25 and its faster and more efficient.

 

32 mpg on a 2.5 is pretty impressive.

[cookie]

The one time I saw 32 on my Forester I was really excited. The next tank gave me about 20 and I realized the bloody pump had popped off early.

[Slegacy96]

Well Ive been making the trip since January. So thats about 4 trips X 2. Plus I also traveled to South Carolina and yielded the same results except when my friend drove. But he doesnt really know how to drive stick so i dont think he got the idea of downshifting.

 

Now I did the work over Christmas break. That leaves 3 trips before that from SC to WC and like I said I couldnt get over 28 mpg.

 

I forgot. I have had the car since last May.

[avk]

One thing the hood does is protect the engine from rain. I believe it should only have a hole in it if absolutely necessary, such as for intercooler, and then it should be properly sealed all around.

[powderhound]

I dont want to pee on your parade either but it is my belief that the switch from winter gas to summer gas is probably most responsible for any mpg gains. I too have recently gotten back to 28-30 from a winter 25 and I didn't spend a dime (other than 2.89/gal). I notice this every spring and a subsequent drop every fall.

[LosDiosDeVerde86]

sigh... use the search feature, K and N filters are not highly reguarded here. The pil in the filter can damage the MAF sensor. they also allow more dirt. There is always a trade off to more flow, and thats larger poors and more dirt flowing in.

I am not a big beleiver in a fuel system cleaning unless the car has a problem, especially below 100,000 miles. I (used to work) in the industry, and alot of it is a come one. In the last 5 years it has been completly uneccassary as a maintanince item since the fuels are so clean compared to 10 years ago.

Your second point i dont understand, and in actuality hood scoops can cause more drag.

Finally the amount of increase you got could be had just by changing driving habits. i have a 97obw auto, and just by changing my driving habits i went from 19 to 23 mpg in town.

Sorry to rain on your parade.

 

nipper

 

come on nipper.. you know that such a low profile scoop as whats on the legacy would cause less drag than hanging your arm out the window.

[brus brother]

Hey Nipster,

How does this work and would 2 gauges get even better mileage?

Get a vacume gauge if you really want to increase gas mileage.

 

nipper

[Slegacy96]

I dont want to pee on your parade either but it is my belief that the switch from winter gas to summer gas is probably most responsible for any mpg gains. I too have recently gotten back to 28-30 from a winter 25 and I didn't spend a dime (other than 2.89/gal). I notice this every spring and a subsequent drop every fall.

 

Yes but when does that switch begin? Like I said, January was when I first noticed the difference. Then I made another trip home at the end of January and again in early March for spring break. So no I do not believe that the season made a difference. In central PA it is winter until the end of March.

 

 

And lets make this clear. Winter gas or not, 32 MPG out of an engine only rated for getting 27 is exciting. I merely posted what I did to improve so that others could benefit and instead I am being grilled. Take the suggestion or leave it.

[powderhound]

a vaccum gauge will allow you to keep vaccum as high as possible which is where the best mpg occurs.

[friendly_jacek]

Yes but when does that switch begin? Like I said, January was when I first noticed the difference. Then I made another trip home at the end of January and again in early March for spring break. So no I do not believe that the season made a difference. In central PA it is winter until the end of March.

 

 

And lets make this clear. Winter gas or not, 32 MPG out of an engine only rated for getting 27 is exciting. I merely posted what I did to improve so that others could benefit and instead I am being grilled. Take the suggestion or leave it.

 

Can you elaborate on the scoop mod and fuel treatment?

[LosDiosDeVerde86]

Can you elaborate on the scoop mod and fuel treatment?

 

if you have a gen 2 legacy with a hood scoop they're set up not be only cosmetic with no actual function.

 

if you pop open your hood and look at it however, though it's nonfunctional, subaru went ahead and cut a hole in the hood under the scoop and covered it with a black plastic sheild.

 

the mod is as follows:

1) take of the plastic sheild

2) see 1

[friendly_jacek]

they're set up not be only cosmetic with no actual function.

if you pop open your hood and look at it however though it's nonfunctional subaru went ahead and cut a hole in the hood unser the scoop and covered it with a black plastic sheild.

 

Sorry, can't understand. Can one translate this for me, please?

[LosDiosDeVerde86]

Sorry, can't understand. Can one translate this for me, please?

 

lets try it again.

 

the scoop is non-functional from the factory. it just looks pretty.

however, there is a hole in the hood where the scoop is.

open the hood and you'll see that there's a plastic cover over the hole.

 

remove it.

[Slegacy96]

Well mine was a metal shield. Just unscrew it and toss it across the garage avoiding your friends Legend. ....well you dont have to, the Legend is that great of a car.

[Slegacy96]

Oh. You may have to trim some of the heat shield off from underneath the hood. No big deal though. Scissors work.

[nightfield]

for a 2.5 like my impreza 2005 i change the air box same filter but a new tube for air got all winter around 30 too 36 and goes for now juste have to change my air filter more often

[fnlyfnd]

If you re-work your tubing to make it a functional air intake you will most likely yield more mpg. At high speeds it will serve as a ram air that will do barely nothing physically but psychologically, you may feel that you have a more powerfull car. Kinda like taking out the intake silencer (which i just did, and it had this effect on my mind). Your engine will recieve ambient air tempature air, which will give you better performance, and may yield better mpgs.

 

Note: You will have to also make a drain off so your not sucking in that nasty rain that likes to show its face.

[Slegacy96]

for a 2.5 like my impreza 2005 i change the air box same filter but a new tube for air got all winter around 30 too 36 and goes for now juste have to change my air filter more often

 

Yeah my understanding is that the new N/A Legacies are capable of 35 mpg. Nice Subaru.

[Bmm001]

What's the best way to increase gas mileage? Drive like grandma! Easy on the acceleration, keep it under 70-75 mph on the highway, and see a 3 MPG jump like I did.