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2007 Forester XT Sport
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407 Posts
Discussion Starter #1
What people need to realize is that the AWD system is not the only factor that brings the Subie MPG down a bit. These are heavy vehicles for their size (due to the bracing in the chassis that make our cars so incredibly safe) and the motor is tuned to provide good TQ, and we have larger displacement than many other vehicles in the class. The ones that do have the same or larger displacement, GENERALLY speaking, dont make the same sort of low end TQ that a Subaru does.

Its the same reason Mazda's dont get as good of gas milage as many of their counterparts. Mazda builds the motors really torquey, and they generally use tires that are a little wider, and a little stickier than the norm for a car of a given class. That takes a good bit more fuel than say a Honda or Toyota that lacks low end power.



Also, although I dont have any real solid data to back this up, but I don't think the boxer motor uses fuel quite as efficiently, particularly the turbocharged models (which I theorize is partly due to the turbo being so far from the heads, making us do some fairly aggressive things to create spool down low)

So simply going to FWD, would do little to change the mpg.


Pulling the fuse, while it works, is also not particularly good for the drivetrain over a long distance.
 

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2005 Impreza RS Wagon Auto
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3,683 Posts
Great summary of everything thus far, I vote a sticky so there are fewer whyismysubylessmpgthanthatotherposvehivleihad threads.
 

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99 UK S-turbo
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8,590 Posts
I would add that the EJ engine is a lousy design if you want good thermodynamic efficiency, the bore/stroke relationship is all wrong (which is why the EU and other economy minded markets 1.5 engines in Impreza are 2.5 stroke and new ultra small bore).

The phase 1 (pre 97) engines also have very high friction levels, although phase1.5 is better and phase2 (99My on) near competative.

Subaru were also late to the variable valve timing party, and are still behind in offering inlet only (of course it costs twice as much as its a unit per bank on a boxer where an I4 would have only 1 unit!), no variable inlet manifolding yet either......all features that are common on European cars at this price/size point now.

Simon
 

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2004 Forester XT AT
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215 Posts
I would like to improve my mileage as i just started a job that has a 126 mile, round-trip commute every day.

Besides driving like I have an egg between my foot and the gas/brake pedals, driving 60-65 instead of the 75-80 everyone else around me is and staying on the cruise control as much as I can, what can I do to improve my mileage?

I really need to do something as I'm currently having to fill up three times a week, which is running me around $100. Over $5K a year on fuel is crazy.

My '04 XT is currently stock. Would Stage 1 help me any? What else can I do?

-ste
 

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2017 VW Golf SportWagen 5MT
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10,887 Posts
I didn't see the other thread, but I've seen many others. Sometimes I get a bit frustrated by this.

This car is NOT meant to get good mileage, it just can't. It's a heavy AWD brick with a large boxer engine, some with a turbo slapped on it -- it will not get great mileage. I've owned aircooled VWs and those get crappy mileage too, even with the tiny engine and low vehicle weight -- the boxer design isn't efficient, it seems. Stage 1 map won't gain you much, open up the exhaust and you may see gains in efficiency if you can keep your foot out of it, but nothing earth-shattering.

Advertised mileage on the turbo models is 19/24, why do people keep thinking they can cheat nature and get over that? Sure, you can coast in neutral for miles downhill and shift to 5th at 40 MPH, but that's just nuts.

Sorry, end rant.

Stan
 

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Let not forget the 4.44 gears lending to less than stellar mileage (I wish we could have a 6spd with the same 1-5 gears and a .60 or so 6th gear). However, from my standpoint I think the SG Forester gets great gas mileage. ~30 mpg in n/a form and 25+ with VF39 (or similar) is outstanding if you ask me!
 

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2015 Outback Limited
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1,542 Posts
I would like to improve my mileage as i just started a job that has a 126 mile, round-trip commute every day.

Besides driving like I have an egg between my foot and the gas/brake pedals, driving 60-65 instead of the 75-80 everyone else around me is and staying on the cruise control as much as I can, what can I do to improve my mileage?

I really need to do something as I'm currently having to fill up three times a week, which is running me around $100. Over $5K a year on fuel is crazy.

My '04 XT is currently stock. Would Stage 1 help me any? What else can I do?

-ste
There really isn't much more you can do. I also have an 04 XT and I'm running stage 1 and didn't see a blip in mileage. Will your car be very reliable and safe in all conditions for your daily drive? Absolutely. Is it the best for gas mileage? No. If fuel is your main concern, I'd suggest getting a used 5-sp Civic unfortunately.
 

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2017 VW Golf SportWagen 5MT
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10,887 Posts
What's cool with my car is the mileage didn't get worse with the power mods I've added, if anything it's easier for me to go 300+ miles on a tank now than when it was stock. And, I have lots more powah.

Stan
 

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2004 Forester XT AT
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215 Posts
There really isn't much more you can do. I also have an 04 XT and I'm running stage 1 and didn't see a blip in mileage. Will your car be very reliable and safe in all conditions for your daily drive? Absolutely. Is it the best for gas mileage? No. If fuel is your main concern, I'd suggest getting a used 5-sp Civic unfortunately.
Thanks. I know my vehicle wasn't designed to get great mileage. I just want to be sure that I'm getting the best I can, is all.

-ste
 

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2009 2.5X EJ253 Manual
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2,830 Posts
At the risk of disputing the poor fuel economy belief, my '09 pretty much matches up with the 2007 Chevy HHR I had, which was EPA rated 22/30 and equipped with the global Ecotec 150hp 2.2 liter DOHC 16V and coil-on-plug ignition (but no variable valve timing, the optional 2.4 liter engine got that). Weight wise, the HHR was close to the Forester, and aero dynamics not a whole lot different. The HHR was rolling on Firestone Affinity car tires whereas the Forester is rolling on Bridgestone Dueler Truck/SUV rated tires, which likely have higher rolling resistance than the HHR's car ties had.

I have zero complaints on fuel economy with my Forester. I think it does very well on fuel.
 

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2009 Outback XT-B 5MT
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Subaru were also late to the variable valve timing party, and are still behind in offering inlet only (of course it costs twice as much as its a unit per bank on a boxer where an I4 would have only 1 unit!), no variable inlet manifolding yet either......all features that are common on European cars at this price/size point now.
Define "Late".

AVCS has been used since, what, 2000?

It was only on the intake cam, but that was right on par with Toyotas VVTi release.

And the current GRB STi has dual AVCS.

AND, the single cam EJ25's (obviously, not really single cam...) now have AVCS.

Fuel economy and efficiency are very different things. You can't say the EJ motor is thermodynamically inefficient, because that's ignorant. Look at any year of the 2.5L STi. It makes 120hp per liter. That's a lot. Compare that with something like, I don't know, an 04 Z06. They made 70hp per liter. During average driving, you'd probably see almost identical realized MPG.

Ask anyone with an early 90's Legacy L what kind of fuel economy they get. I'll bet it's in the high 20's or low 30's.

The bottom line is best summed up by a professor I have. "In the summer, my Accord will get 35MPG, while your Subaru will get 26 at best. The difference is that my car is an appliance, and yours is fun... And that's probably worth it."
 

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2015 Highlander AWD XLE 6AT
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The bottom line is best summed up by a professor I have. "In the summer, my Accord will get 35MPG, while your Subaru will get 26 at best. The difference is that my car is an appliance, and yours is fun... And that's probably worth it."
Interesting. Our '06 4-cyl 5MT Accord's best single tank highway run (416 miles, VT to PA) was almost 36 mpg on 87 AKI gas. I managed 33.75 mpg average on a 1,200 mile trip up into New England last March. I suspect it would do better on 89 AKI fuel and with lower rolling resistance tires.

Our '09 4-cyl 5MT forester's best single tank highway run (400 miles, IN to MD) over similar altitudes was 33.36 mpg on 89 AKI fuel. I managed 30.53 mpg on 87.7 - 89 AKI fuel during our >6K mile trip out West this past August. Its best single tank highway run (380 miles) was at altitude in Colorado: 34.06 mpg on 88 AKI fuel.

Our Honda's fuel economy is great, but I am very happy with our Sub's performance so far.
 
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