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Subaru Legacy/Outback: MPG-Real World Numbers

130 messages,  Last post on May 04, 2012 at 4:49 PM

You are in the Subaru Legacy & Outback Forum.

What is this discussion about? Subaru Outback, Fuel Efficiency (MPG), Sedan, Wagon

Messages Page 11 of 13

#101 of 130 Re: Mileage [kidali] by kidali

Jul 13, 2010 (11:53 am)

Replying to: kidali (Jul 13, 2010 11:46 am)
Here's a year and a half's worth of almost obsessive observations:
 
My average week is somewhere around 11l/100k. (about 21.3 mpg).
I've been vigilant about putting in a good fram air filter.
I recently decided to try a synthetic oil to help both my gas mileage, and engine knock that I've been getting. It's helped with neither. (Castrol edge).
On weeks that I put in higher grade gas (91 octane), I get better mileage than weeks where I put in a lower grade (87), but then the trade off is the higher gas price, so there are no savings.
 
The car seems to like travelling best and runs smoothest at about 95k/hr (about 59 miles an hour). Deviate from this, and it affects mileage.

#102 of 130 Re: Mileage [kidali] by kidali

Jul 13, 2010 (12:00 pm)

Replying to: kidali (Jul 13, 2010 11:53 am)
Regarding my last comment:
 
If I usually drive between 105 and 120 (65 - 74mph), I still usually average somewhere between 19 and 21mpg if I'm doing 70 to 80 % highway driving.

#103 of 130 Re: Mileage [lgandad] by jccinoh

Jul 15, 2010 (5:26 am)

Replying to: lgandad (Jul 13, 2010 11:27 am)
Have had my 2009 Outback 2.5 now for about 18months. Mileage (90% city/10% highway) is currently standing at 25.2mpg.

#104 of 130 Re: Mileage [kidali] by steve_ HOST

Jul 29, 2010 (11:31 pm)

Replying to: kidali (Jul 13, 2010 12:00 pm)
I lost track of this discussion a couple of years ago.
 
Sorry to see you're still having mpg issues, Kidali. I'm way behind updating my spreadsheet on my '97 but I'll try to do that soon. Last April I was getting 23.10 lifetime. Got a bit over 78,000 miles on it now.
 
I've had about 5 tanks that have held over 13 gallons, but this week I set a (dubious) record, thanks to some poor planning. The Outback held 13.797 gallons. Hard to believe the tank really holds 15.9 gallons - I was sweating it a bit.
 
Steve, visiting host

#105 of 130 Re: Mileage [steve_] by steve_ HOST

Jul 30, 2010 (6:37 pm)

Replying to: steve_ (Jul 29, 2010 11:31 pm)
Updated my spreadsheet.
 
Worst tank so far this year was 19.28. Best was 33.03 on a road trip. Lifetime average is up to 23.31.
 
I'm only driving ~6,000 miles a year.

#106 of 130 Re: Mileage [steve_] by kidali

Aug 03, 2010 (11:05 am)

Replying to: steve_ (Jul 30, 2010 6:37 pm)
I have no idea how you managed 33mpg. That's insane.
 
Your lifetime average is a little under mine (had the car about 19 months now).
I'd still say mine is around 21. Though lately I've been having terrible mileage, even with 94 octane gas I'm around 20. Maybe it's the air conditioner running in this heat.
 
Still trying to figure out my throttle response issue right now. Maybe I'll start a new forum. As stated in earlier posts, check engine has been on for months. My guy decoded it as an 'engine knock' sensor. Reset it. It went out. But a week later came back on. That was in the winter. I'm just living with it. Some days though, it goes out, and the car feels like a rocket. It will come back on after 10 miles or so, and once it does, I almost have to floor the gas for the a/t to drop a gear or kick in at all.
 
Anyone else have this problem? My untrained analysis is there's a faulty computer on the car. Anyone?
 
PS> Anyone have an issue with spider cracking in the paint on the hoods of these 97's? Mine looks horrible, and worse after waxing. No real way to resolve it, just curious if others also experience this with the 97 outbacks.

#107 of 130 Re: Mileage [kidali] by steve_ HOST

Aug 03, 2010 (6:43 pm)

Replying to: kidali (Aug 03, 2010 11:05 am)
That was on a California road trip, loafing along in mild May weather. Tanks were 21, 27, 30, 33 and 30. Then 24 a few weeks later back home. On a road trip in July '09 the best tank was 28 - probably got hammered by the AC.
 
Most of my driving is around town or 50 miles RT up to the ski hill in the winter, and those are the 21ish tanks. Worse tank ever was 13.16 one January.
 
Mine's red btw, and the paint looks pretty good. Dings and chips, but no spidering.

#108 of 130 Re: Mileage [lgandad] '97 Outback by kidali

Apr 11, 2011 (7:36 pm)

Replying to: lgandad (Jul 13, 2010 11:27 am)
For the last year or so, I've been hovering between 10.5 and 11 litres per 100km (or between 21.4 and 22.4 US MPG).
 
Since December though, I keep getting between 13 or 14 litres / 100k
(16.8 - 18 US MPG) !!! Horrible. 50/50 Highway/City, which means my CITY mileage has got to be atrocious.
 
Tires are inflated. Used injector cleaner. Rarely used my heated seats. (Obviously no AC this time of year in Canada). Use full synthetic oil. Often try the 91 Octane gas, and sometimes, stupidly, even the 94 Octane! No, I'm not made of gold. Just trying to make a perfectly fine car last longer.
 
Any suggestions? Can my mechanic (not a Subaru specific guy) diagnose if it's a PCV issue without taking the car apart?
 
Dom

#109 of 130 Re: Mileage [lgandad] '97 Outback [kidali] by xwesx

Apr 11, 2011 (9:37 pm)

Replying to: kidali (Apr 11, 2011 7:36 pm)
If the PCV valve is old, that's an easy and cheap replacement. The part might cost $5 and the time perhaps as many minutes. It is absolutely the easiest DIY maintenance one can perform.
 
Another possibility is that the oxygen sensors are giving poor feedback so the car is not trimming the fuel/air ratio as efficiently. I noticed my fuel economy taper off somewhat once I was north of 150,000 miles on my '96 Outback. It used to give me between 22 and 28 mpg (or better!) except during periods of extreme cold (< -25F). In its later life (I had it to 220,000 miles, and it still ran great), the low dropped to about 17 with the tops at about 25. During periods of extreme cold, it would drop as low as 13-14 mpg. I wish I could say I replaced the oxygen sensors and it made a marked improvement, but I planned to replace them in spring of 2007... yet fate had other plans.

#110 of 130 Re: Mileage [lgandad] '97 Outback [kidali] [xwesx] by pilot1226

May 25, 2011 (9:01 am)

Replying to: xwesx (Apr 11, 2011 9:37 pm)
I've had the new `11 Outback 2.5i CVT for a month now, here are my numbers:
 
Highway is about 36 MPG 55 MPH Cruise Control according to the dash computer. (To clarify, this is what's displayed after getting fuel and pulling right back out onto the highway. It actually goes higher - above 40 MPG - but because I typically only drive on a stretch of 5 miles of highway to/from work, it starts to go down when I idle at a light pretty rapidly)
 
Combined over the last 1k miles in the last month between about a 50/50 split of highway & city driving shows me between 26 and 28 MPG, depending on traffic. Not bad at all. Better than my 4AT 09 Legacy 2.5i.
 
I use Trip A for my current tank of gas, and Trip B for the time since last maintenance.
 
I was a big proponent of diesel-based Subarus coming over here and probably would have been one of the first to get them, since the MPG is significantly higher. We'll see what time brings.

Messages Page 11 of 13

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