My USDM 2002 Legacy GT (5MT) burned 8.445 US gal. of Mobil premium unleaded in 270.1 miles of 72 mi/h driving. That's almost 32 mi/gal!

 

I might add that the crankcase is filled with Mobil1 15w50!

not too bad, BUT...

 

my 1989 GL wagon with 189,000 (and counting) regularly gets over 30 mpg on regular unleaded running about 70 mph going back and forth to work every day. I am putting approximately 500 miles a week on this car - fuel mileage ranges from 30.2 and 31.4 mpg...have gotten as high as 31.8 mpg....also uses about 1 qt of oil a week!!

Now if you were to get something like 35 mpg, then I would really be impressed!

not too bad, BUT...

 

my 1989 GL wagon with 189,000 (and counting) regularly gets over 30 mpg on regular unleaded running about 70 mph going back and forth to work every day. I am putting approximately 500 miles a week on this car - fuel mileage ranges from 30.2 and 31.4 mpg...have gotten as high as 31.8 mpg....also uses about 1 qt of oil a week!!

Now if you were to get something like 35 mpg, then I would really be impressed!

 

You have an EJ25 in your GL?

Right, you know what they say about apples and oranges... I got over 30 m/gal. on my '85 Accord up until I gave it away at 222,000 miles and over 40 m/gal. on my motorcycle. Myles, just curious about the M1 15W/50: I've only used it in my motorcycle with excellent results (noticeably smoother shifting on the wet clutch). Do you use this weight in your Legacy only during the warmer months? I imagine the flow rate is substantially less than that of M1 5W or 10W/30 so the downside might be increased engine wear upon startup during New York winters, but I also imagine that a 50-weight oil must make your bearings happy. Also, do you know how the flow rate for M1 15W/50 compares to a 5W or 10W/ 30 conventional oil?

 

By the way, some resources that I've read report that unnecessarily using a higher octane fuel acutally increases deposits in your combustion chamber. Higher octane fuels prevent knocking due to preignition because they are less volatile, hence to use a higher octane fuel in an engine that does not require it - I'm not sure about your car but mine does fine on 87 - wastes money and fouls up your combustion chamber. Makes a lot of sense to me; any thoughts?

Myles, just curious about the M1 15W/50: I've only used it in my motorcycle with excellent results (noticeably smoother shifting on the wet clutch). Do you use this weight in your Legacy only during the warmer months?

I only use the 15w50 during the summer months. In the winter, I run Mobil1 10w30.

By the way, some resources that I've read report that uncessarily using a higher octane fuel acutally increases deposits in your combustion chamber. Higher octane fuels prevent knocking due to preignition because they are less volatile, hence to use a higher octane fuel in an engine that does not require it - I'm not sure about your car but mine does fine on 87 - wastes money and fouls up your combustion chamber. Makes a lot of sense to me; any thoughts?

My EJ25 runs terribly on 87-AKI gasoline, even after a Seafoam treatment (removes carbon from the valves and combustion chamber). Tipping the throttle results in much bogging. Remember, the Phase-II EJ25 has a compression ratio of 10:1. Seems a bit high for 87-AKI gasoline.

Right after my bro got his 86 GL wagon (MT), he drove from WA to WY and averaged 35 mpg on crap gas. (I think that car was at it's peak then)

My record high in the Forester was on a trip up and down western washington where I got a little over 33 mpg. WHEEEEE You people must have lead feets!

BRAT = 12~14 MPG

 

Impreza = 18ish

The traffic was light and I got to use cruise control a lot and got similar gas mileage on my 2002 GT wagon (5MT) of 32 mpg on a highway trip to D.C. and back last year. I was doing about 70 mph almost all the way. I was also using 89 Octane for the whole trip. I typically average about 26 mpg between tankfuls with combined city/highway driving. Oh yeah, I use Mobil-1 15W50 too...are you my evil twin or something?

My best was last summer between Scranton, PA and home in VA. I somehow managed 34.1 mpg doing between 70-75 for most of the trip. It was regular gas with dino-valvoline 5w-30 in the engine. Im back down to about 29 mpg with my 5MT 01 legacy sedan. Im hesitant about the mobil syn oils....

My USDM 2002 Legacy GT (5MT) burned 8.445 US gal. of Mobil premium unleaded in 270.1 miles of 72 mi/h driving. That's almost 32 mi/gal!

 

I might add that the crankcase is filled with Mobil1 15w50!

Sound impressive, but I would be cautious in interpreting MPG only after partial tank (8.445 gal). Early pump cutoff can introduce large error with this small volume. I noticed that you (and others) report great MPG with 70-75 MPH. This must be the secret! I drive a little bit faster on hwy so no wonder my MPG is lower...

 

My driving must be bad becouse cannot get more than 31 MPG in my 03 Toyota Corolla (1.8L) on hwy. People boast over 40 MPG with the same car, makes me guess what speed they do...

Sound impressive, but I would be cautious in interpreting MPG only after partial tank (8.445 gal). Early pump cutoff can introduce large error with this small volume.

 

True, however I used the exact same pump for the "before" and "after" fill-ups.

Hei all, I've been around Subarus since 1971. My dad worked for SOA up until '02 when he retired. Back in '81 we drove a fwd sedan to Minn. getting 33+mpg all the while flying along at 85mph with 4 adults in the car. That was impressive, dad said the wind was blowing us along. On the way back he mostly drove 65 mph and only got appr. 27-28 mpg. Again he said it was the wind blowing against us.

 

Then in Summer '97 I drove my '96 OB round trip to Baltimore at times reaching 100 mph for many miles, the return trip was much slower with my sister and her family. The average was 28.8 mpg for the 500 mile trip.

 

Seems our Subies generally like sustained higher speeds (65 +).

Why in God's name would you use such a thick oil?

My best was last summer between Scranton, PA and home in VA. I somehow managed 34.1 mpg doing between 70-75 for most of the trip. It was regular gas with dino-valvoline 5w-30 in the engine. Im back down to about 29 mpg with my 5MT 01 legacy sedan. Im hesitant about the mobil syn oils....

Thats allmost all down hill the helps!

Why in God's name would you use such a thick oil?

Living in Arizona i run 15 w 50 9 months out of the year because of the heat! Anything lighter then that and it turns thin to get good oil pressure!

Living in Arizona i run 15 w 50 9 months out of the year because of the heat! Anything lighter then that and it turns thin to get good oil pressure!

 

 

When engineers design a motor, they recommend a particular oil based on the bearing tolerances and the oil pump volume.

 

If you use too thin an oil, the pump can't keep up. When you use too thick an oil the pump overworks itself and it can't pump rapidly enoug, not to mention the parisitic losses and the damage to your gas mileage.

 

You always want to use the oil weights suggested in the owners manual because that's the viscosity the engine was designed for. If you're worried about the heat, which is a valid concern, run a good quality synthetic. Mobil1 is good enough, albeit just barely. Amsoil is even better. If the cost bothers you, change you oil once every 6000 miles and your filter every 3000.

 

Personally, I go a whole year on my Amsoil, changing the filter every 3,000 miles, because no matter how good the oil is, it'll still get dirty just as fast.

The Amsoil product I use is their "good" stuff, that's rated for 25,000 miles, although in one year I only do around 15,000.

 

 

Look, I used to be a big believer in heavy oil too.

 

But when I owned my VR6 Passat, I decided to try the Mobil1 10-30 in the summer. I picked up noticeable power and TWO MILES PER GALLON.

From then on I used 10w30 in the summer, 5w30 in the spring and fall, and 0w30 in the winter. I drove that car another good 50,000 hard miles before I sold it. Now I'M sold on correct weight, high quality synthetic oil.

 

 

It's your car, you can do what you like. I just wanted to make sure you had the information.

When engineers design a motor, they recommend a particular oil based on the bearing tolerances and the oil pump volume.

 

If you use too thin an oil, the pump can't keep up. When you use too thick an oil the pump overworks itself and it can't pump rapidly enoug, not to mention the parisitic losses and the damage to your gas mileage.

 

You always want to use the oil weights suggested in the owners manual because that's the viscosity the engine was designed for. If you're worried about the heat, which is a valid concern, run a good quality synthetic. Mobil1 is good enough, albeit just barely. Amsoil is even better. If the cost bothers you, change you oil once every 6000 miles and your filter every 3000.

 

Personally, I go a whole year on my Amsoil, changing the filter every 3,000 miles, because no matter how good the oil is, it'll still get dirty just as fast.

The Amsoil product I use is their "good" stuff, that's rated for 25,000 miles, although in one year I only do around 15,000.

 

 

Look, I used to be a big believer in heavy oil too.

 

But when I owned my VR6 Passat, I decided to try the Mobil1 10-30 in the summer. I picked up noticeable power and TWO MILES PER GALLON.

From then on I used 10w30 in the summer, 5w30 in the spring and fall, and 0w30 in the winter. I drove that car another good 50,000 hard miles before I sold it. Now I'M sold on correct weight, high quality synthetic oil.

 

 

It's your car, you can do what you like. I just wanted to make sure you had the information.

Thanks for the info i will Try lighter oil next time i change !

If you live in desert areas, or tow a lot of trailers, then the owners manual recommends the following:

 

---

Page 11-13 Owner's Manual of 2002 Legacy/Outback:

In choosing an oil, you want the proper quality and viscosity, as well as one that will add to fuel economy. The following table lists the recommended viscosities and the applicable temperatures.....

 

5W30 preferred temps below 40C/105F

10W30/10W40 above -20C/0F

 

....Engine oil viscosity (thickness) affects fuel economy. Oils of lower viscosity provide better fuel economy. However, in hot weather, oil of higher viscosity is required to properly lubricate the engine.

 

Recommended grade and viscosity under severe driving conditions:

 

If the vehicle is used in desert areas, in areas with very high temperatures, or used for heavy-duty applications such as towing a trailer, use of oil with the following grade and viscosities is recommended.

 

API classification SL or SJ: SAE viscosity No.: 30, 40, 10W50, 20W40, 20W50

 

----

 

There you have it. Use an oil that best suites your use and climate.

Well.......my '92 Loyale Wgn (209K miles), MT, front drive only AND running warm/hot. has been getting around 32-33 MPG. This IS scaring me! It must be ready to blow! My A/C doesn't so I don't use it. I don't have the heater motor on. There's more daylight, not running lights. Less load on the motor. As I said in the other old Subee forum, I had a little 50 mile trip to Albany, Ny a few weeks ago, it's hilly, long type of hills. It was running hot, about 3 or 4 needles from the dreaded REd Hot area. I checked my fluids the next day. It consumed alot of oil, about a quart. I really don't know if it did it in this one trip, it had been a while I last checked. It also need a little more fluid in the over flow tank for the anti freeze. I have been running ( about 2 years)Lucas Oil treatment to try and get rid of that knock at about 3,200 to 3.700 rpm (when it's warm outside). I have only used about 10% ratio. Well I didn't add just oil when I topped it off, I added ONLY Lucas! It's about to do this MPG again. This is only local driving, no highway! It must be ready to blow!!

 

 

I'm said to read about Legacy 2.5's getting these poor MPG's. I've been thinking about getting (finding) a GT Wgn. I don't know if I could liv with 22 Mpg!!!

 

Damn, SubeeTEd

I have a 97 OBW, for comparison. Best tank is 28.4. If I take it easy, 65-75, I get 26-27. If I go 75-80 and do more city driving, it's 24-25.5.

 

If you don't use cruise control and drive hills like the truckers do, you'll get better mileage. Let 'er roll downhill, hitting 80 if you have room. Use that momentum on the uphill section, tapering to maybe 65mph. Towing a boat with a Ford van, this technique was good for 1-2 mpg, and there's a big difference in range between 11.5 and 13.....

25.6 mpg on a trip from New York City area to Maryland suburbs of DC. Alone in car, 65-70 mph, no traffic delays.

 

22 mpg on a recent weekend drive to mountains of western MD. 2 adults, two children, camping gear, very large sack of gear tied to roof rails. I-68 is hard on any car; I took this to be a sign of progress as the engine breaks in.

 

Just under 10,000 miles, automatic transmission.

When engineers design a motor, they recommend a particular oil based on the bearing tolerances and the oil pump volume.

 

One word (actually, one acronym): CAFE.

I get 44 mpg. When I drive my girlfriend's Honda. \

 

Most I've squeezed out of the EJ22 is 34, which was with one heck of a tail wind. Average is more like 28. I can't wait til there is snow again and I can feel better about taking the Subaru instead of the Honda.