16mpg??

[specDiddy]

Mine did the same thing untill I filled up with gas and reset the trip-o-meter at the same time. After that it was an instataneous 21.5 mpg.

Try it ...

[jbowman]

after one day of owning my 5spd LGT my average according to the display was 15mpg... day 2 and on I was done playing with it to compare it to my WRX and now by day 4 I'm up to 17.4mpg with a 50/50 mix of highway and city driving.

[Lagacy GT]

So guys with Stage 2 are getting better mileage? So... faster car and better gas mileage? Holy crap, I need to start saving up for Stage two.

[legacygt05user]

My car has been hesitating since it was almost new. I took it to the dealer three times before they sent the ECU to subaru to get it remapped. the new ECU tune didn't work much better. I found out about the engine reset by removing fuse 12 from the engine bay fuse panel the night before, then put it back in the morning and started the car. Over the 2 days, I drove 1200 miles, mostly highway. On the first tank of fuel, I got ~24 MPG with poor acceleration all the way around. The second tank, I got ~25 MPG, and things were smoothing out. by the third tank, we were on ~26 MPG with good acceleration. ~150 miles into the 4th tank of fuel, the fuel computer was reporting 31.8 AVG MPG ! Acceleration was very smooth, and the car only hesitated slightly at low speeds. I finished that tank of fuel using 12.3 gallons for 365 miles = ~30 MPG. The computer read 30.9.

Temperatures varied between 95 and 75 F (the last two tanks were around 75 F), and driving speeds were highway limits (65-70).

 

I'm getting about 24 mpg around town as well. I'm open to suggestions on interpreting what happened. the best I can tell, the ECU needs a lot of miles of clean highway driving to "learn" itself into a good condition. I started data logging today to find out.

[legacygt05user]

Yeah the leggy isn't exacly a fuel sipper. I've tried various ways to maximize the fuel economy of my car as well. What I've discovered is....... I recommend to anyone who wants to improve their driving technique for fuel efficency keep that instantonus consumption read out on and learn to work the car to keep those numbers as high as possible.

 

My observations.

 

1) Fuel grade seems to have little impact on fuel economy I get about the same fuel millage with 87 vs 93 octane. Over many tankfuls and months of each

 

2) I average about 19.8mpg with a 50/50 city/highway mix with most of my city driving sitting at lights idling. If I drive like an absolute granny and skip shift 1-3-5 and use the cruise control on the freeway (requires me to go slightly slower then the general flow of traffic) I can kick fuel economy up to about 20.5ish. If I don't run the A/C I can get about 21ish on the same commute

 

3) Drafting has a huge impact on fuel economy in the LGT. If I'm behind a typical gas guzzler read SUV, I find I can push my car to 28-30mpg on the highway. When the legacy punches its own way through the air I see about 24.5-25.5 on the highway at 75.

 

Makes me think the areodynamics aren't that good on the LGT as I can get about a 20% increase in fuel economy by drafting. Easy to do with the congested freeways around here.

 

 

4) I find that the quality of the gas has an impact. I see generally better millage with shell.

 

This is all very unscientific, but the LGT is not a fuel sipper. My GF's 06 Passat with the 2.0T is a fuel sipper. I can routinely get 34-36mpg at 65mph on the freeway and driven very carefully around town I see 26. I'm amazed how well the Passat responds with the right driving technique.

 

I've also noticed to on the LGT that its very hard to keep it from dipping really low in fuel economy. If you watch the instantanous display on the mpg meter it waivers alot without changing throttle position. Also its hard to get it above 25mpg in anything other then flat steady speeds. I can't even get it to keep 25mpg at 25mph in 4th.

 

yeah I got 30.9 with the A/C on drafting a semi. Sometimes even being next to one and behind another can help out. But what's odd is that even after doing that for 20-30 miles, the ECU seems to have leaned out the mixture. I am now routinely getting 28-30 MPG on the highway at 70.

[legacygt77]

Break in period my ARSE! My 5spd get ~19.5 with accessport and my heavy foot

 

MY 5EAT wagon who is driven by my better half, always low revs etc. get only ~16.6

 

Oh well life happens right? To this day no one can give me an answer why except break in period.....beh!

[johnAWD]

My car is a commuter, 60 miles/day. I average 25-26 mpg driving 75-85 on the freeways.

[walshie999]

I believe my turbo is plumbed to my gas tank and not the air intake, as i can see the gas gage plummet if i really get on it. No need for a tach just wath the gas gage. I avg about 17-18 with a 10 mile commute mostly 2 lane country road at 65,and 2 miles of city traffic(2500miles). A good tank is 19. Even driving like an old lady only got me 20mpg. Traded an avalanche for this to get a more fun ride and better milage, and that hog got 16mpg avg on the same commutes, and it towed 10k lbs when needed, and still got 12mpg.. Hopefullyswitching to synthetic and better brand of gas will boost the milage. Not regretting my decision but it takes the fun out of it when each romp on the gas costs 1/4 tank. Gonna have to put in an extra tank to get more than 180 miles a tank.

[njkayaker]

21.5 mpg over the last 4k miles or so with about 60% of that traveling at 80mph on the interstate and the other 40% running around cities/towns. If I owned a civic my average would most likely be 4mpg higher, yet every time I had to drive the car I'd become depressed. And seriously, having a slightly higher mpg doesn't save you that much money.

 

A car that consistently gets 5 mpg higher than another car will save you around 1500 dollars after 100k miles. The legacy GT is worth an extra 1500 over a civic. I'm just ranting cause a friend of mine is determined to buy a civic in order to save on gas. I just don't think its worth it.

One would really need to drive lots of miles per year to save any money on fuel.

 

The difference is about $40 per month driving 20k a year between 28mpg and 40mpg with fuel at $3 a gallon. For people spending $24k or so on a car, complaining about gas prices is a bit silly (the high cost of fuel is overhyped).

 

3) Drafting has a huge impact on fuel economy in the LGT. If I'm behind a typical gas guzzler read SUV, I find I can push my car to 28-30mpg on the highway. When the legacy punches its own way through the air I see about 24.5-25.5 on the highway at 75.

 

Makes me think the areodynamics aren't that good on the LGT as I can get about a 20% increase in fuel economy by drafting. Easy to do with the congested freeways around here.

Actually, the aerodynamics (coefficient of drag, CD) of the Legacy wagon is quite good: 0.30 for the sedan, 0.31 for the wagon, 0.27 for the new Camry, and 0.26 for the Prius. It looks the Legacy takes only a 0.6-1.0 mpg "hit" compared to the Prius due to CD alone! The wind resistance is still significant but it's really hard to improve the CD enough to have a significant effect on MPG.

 

The benefit of drafting can be much more than not having to push still air out of the way! If done correctly (hard to do safely), the leading vehicle actually pulls the trailing vehicle along.

 

Of course, any benefits to drafting would be nicely erased if the guy you are drafting stops short...

[VTGT]

It seems like lately even driving like a grandmother won't yield better than 16-17 mpg. That is basically 85% shifts around 2000-2500, and only a handful of bursts up to 5k.

[Vimy101]

So far I've been averaging 24-25 mpg on my commutes which is ~80 miles round trip and usually includes one 40-55 minute segment in heavy rush hour traffic to cover ~20 miles. When the freeway is moving, I keep between 70-75 mph as I have found that the cops don't pay you any attention around here at that speed. I wonder if the larger Spec.B tires/wheels might have a slight positive effect on mpg vs the LTD. I'm turning about 3k rpm @ 70 mph.

[SC GT]

How does quality of gas affect MPG? Does crappy CA 91 yield less MPG than 93? If so, does anyone know how much?

 

BTW, right about now I'd kill for 16 MPG. I've been getting 12-13 lately. On the bright side, a tank of gas tends to last me at least 2 weeks.

[captainmorgan]

If you're getting seriously low numbers consistently, go get an alignment. You can improve your gas milage by maybe 10mpg if your alignment is bad enough. Oh, and go somehwere where they have Hunter Engineering aligment equipment. It's totally worth the little extra.

[Vimy101]

One thing I remember from my thorough reading of the manual is that the Turbo boxers have a lower compression ratio than the NAs. This leads me to believe that even if you are careful to lay off that amazing boost you'll still need more fuel to get the same output as an NA at the same RPM.

[MIKEBRAVO]

I have a 5MT and with some experimentation I was able to get around 22 average in mixed driving, driving nicely.. However after a week of driving like a grandmother I said fuckit, i can afford the extra fillup or two even with the current gas prices, and driving like an asshat i averaged 19.2 with mixed city and highway driving over a week or so.

 

Whats interesting is I've never reset my B trip-odo so my B is an average of my gas milage since I bought the car (i have avout 14k on it now) and its at a rock steady 19.2 over 14k

 

EPA estimates are 19 City 25 highway for the 5AT, so unless you do a lot of highway driving with steady 70mph or so runs for 20-30 plus miles you'll probably be at the same average i am.

 

Asshat driving rules!!!

[Vimy101]

Getting 24.3 mpg (as per computer) in mixed drivng in 90F+ heat w/AC here in steamy Chicago. I can't wait for 60F air. 20F and snow? I'm more than ready.

[Lagacy GT]

Lucky bastards. 5eat with 91 octane = bad bad bad mileage.

[azca]

I get 24-25mpg avg 80% freeway 75-80mph and 20% city 6k rpm acceleration

 

shell 91 and Mobil 1 0W-40 fully synthetic with racing 17" wheels (14lbs each) and AVO drop-in filter

[pillboy]

Last weekend I was a rolling chicane for 220 miles...the only thing I passed was a tractor (I kid you not). Used cruise control as much as possible, drove 61 in a 70 and 55 in a 55. Auto trans and averaged 26.4mpg. Anyone who says they get 28mpg while going 75 to 80 is a flippin' liar.

[DukeTrout]

Last weekend I was a rolling chicane for 220 miles...the only thing I passed was a tractor (I kid you not). Used cruise control as much as possible, drove 61 in a 70 and 55 in a 55. Auto trans and averaged 26.4mpg. Anyone who says they get 28mpg while going 75 to 80 is a flippin' liar.

 

You weren't going 75 to 80. Get in the passive boost some, and the milage might surprise you.

[azca]

Last weekend I was a rolling chicane for 220 miles...the only thing I passed was a tractor (I kid you not). Used cruise control as much as possible, drove 61 in a 70 and 55 in a 55. Auto trans and averaged 26.4mpg. Anyone who says they get 28mpg while going 75 to 80 is a flippin' liar.

 

on auto maybe; also try going downhill

[VTGT]

I set the cruise control from 75-80 and easily average 27-29 on several 300 mile trips.

[MilesA]

You weren't going 75 to 80. Get in the passive boost some, and the milage might surprise you.

 

What do you mean by passive boost?

 

The amount of fuel the engine uses goes up directly with the mass of air it takes in. If I am running boost, won't I burn more fuel as a matter of course?

[skyphix]

I always get better gas mileage in the STi going between 75 and 80 than between 65 and 70. My driving is about 95% highway with that car. It will be the same drive with the new OBXT, so I'll see how aerodynamics come into play (although I can't really believe the bug catcher scoop and park bench on my trunk help with the STi's aerodynamics).

 

Why? The engine is closer to its peak power, generally, when an engine is at the beginning of its power curve, which means its running a bit more efficiently, and doesn't need to lug to accelerate.

 

Thats my theory and I'm stickin' to it

[DukeTrout]

What do you mean by passive boost?

 

The amount of fuel the engine uses goes up directly with the mass of air it takes in. If I am running boost, won't I burn more fuel as a matter of course?

 

"Passive" isn't exactly the meaning I am trying to convey, but I can't think of a better way to say it. Similar to ^, what I'm trying to say is that Load X at 2500 rpm and near 0 boost is less efficient than Load X at 3200 rpm and low boost of like 8 psi.

 

To maintain speed, you still need to apply power from the engine to overcome friction from air resistance, the tire-to-ground interface, and internal components of the rolling stock. That's the load on the engine while cruising. What appears to be the case with the LGT and STi is that running just inside the boosted power band provides a more efficient match than 1. going slower in order to stay out of boost, or 2. upshifting to reduce rpms to stay out of boost. Fuel being fed into the cylinders isn't the only factor in efficiency. The resulting output is equally important. If you get proportionally more output from some level of boost than the amount of additional fuel it takes to match the air load, then you are running more efficiently at boost than without.