ilh Posted December 20, 2006 Share Posted December 20, 2006 I'm a bit baffled. On my usual weekly commute I get about 21-22mpg, sometimes down to 20ish in the summer with A/C going full tilt. This commute is about 1/3 at 40mph relatively constant speed on rural roads (Concord, MA), 1/3 75mph highway (Route 2), and 1/3 0-30mph stop and go (Cambridge, MA). What has me baffled is my past two weeks (tanks) are both over 23mpg. I have NEVER seen over 23mpg before except for pure highway jaunts. Usually, mileage seems a bit worse on winter gas. Could my Nokian RSi be that much better for mpg than the RE92s? That would be somewhat surprising given how soft the RSi tread is. I suppose I am babying the Nokians a bit on our bare roads. Still, I am pretty much traveling the same speeds as year round. I still go WOT a few times a day. I am stock. --Lee Link to comment Share on other sites More sharing options...
Impulse Posted December 20, 2006 Share Posted December 20, 2006 (i'm guessing) maybe if there was a difference in the size of the tire, your computer would think that its actually going farther than really is. thus giving you a slightly better gas mileage. i have the same thing going on too, but it happened after an oil change... Link to comment Share on other sites More sharing options...
ilh Posted December 20, 2006 Author Share Posted December 20, 2006 They are about 2% larger diameter (205/50 vs 215/45), but that means my actual mileage is even better because the odometer would read about 2% low compared to actual. Link to comment Share on other sites More sharing options...
jagcars26 Posted December 20, 2006 Share Posted December 20, 2006 Colder weather FTW Link to comment Share on other sites More sharing options...
Underdog Posted December 20, 2006 Share Posted December 20, 2006 colder charge temps = worse fuel economy.... duh! Do you monitor your tire pressure pretty consistently? I would guess it's the pressure thats making the difference since compound vs. compound the RSi's should be getting worse mileage with our recent temps. The circumferential difference would only work out to be about +/- .5 mpg anyways... The Crimson Dynamo Link to comment Share on other sites More sharing options...
ilh Posted December 20, 2006 Author Share Posted December 20, 2006 I do monitor tire pressures consistently. I am actually running my RSi 1-2psi lower than my RE92s, although I will probably bump it up. I ran RE92 at 38/36. Link to comment Share on other sites More sharing options...
jagcars26 Posted December 20, 2006 Share Posted December 20, 2006 colder charge temps = worse fuel economy.... duh! Do you monitor your tire pressure pretty consistently? I would guess it's the pressure thats making the difference since compound vs. compound the RSi's should be getting worse mileage with our recent temps. The circumferential difference would only work out to be about +/- .5 mpg anyways... Did I say anything about charge temps?? Duh!!Temp has alot to do with mileage other then charge temps:rolleyes: You guys are picking nits anyway. Link to comment Share on other sites More sharing options...
Underdog Posted December 20, 2006 Share Posted December 20, 2006 I drive those same roads at roughly the same rate and @ 3,600 miles I have an average fuel economy of 18.9mpg running 35/35psi (half on RE-92's half on stock sized Dunlop M3's). Jagcars26: Sorry I didn't mean to come off patronizing... I just can't think of any way cold temps help fuel economy in this situation. Also, it's been ~50F here for the last several weeks. The Crimson Dynamo Link to comment Share on other sites More sharing options...
jagcars26 Posted December 20, 2006 Share Posted December 20, 2006 Jagcars26: Sorry I didn't mean to come off patronizing... I just can't think of any way cold temps help fuel economy in this situation. Also, it's been ~50F here for the last several weeks. Not a problem,,,I thought it was colder up there ,,still warm here too:) Link to comment Share on other sites More sharing options...
jingjing Posted December 20, 2006 Share Posted December 20, 2006 damn, i only have about 680 miles on my 07, its an auto na and i only managed about 20 mpg. that was mostly city driving though Link to comment Share on other sites More sharing options...
rallysquirrel Posted December 21, 2006 Share Posted December 21, 2006 The mpg gets way better until you hit about 7,000 miles. At that point it should be fairly consistent. This has happened to the other 3 subies I've had. Link to comment Share on other sites More sharing options...
RayDhaIn Posted December 21, 2006 Share Posted December 21, 2006 So, rallysquirrel, what mpg do you get on the 07 spec.B? Does the 6-speed and the SI drive helps? Have you tried what you can get on the Intelligent mode? Link to comment Share on other sites More sharing options...
rallysquirrel Posted December 21, 2006 Share Posted December 21, 2006 Intelligent mode with 93 octane and 17" Prodrive rims and 205/50 Nokian RSi's gets me 28-29 mpg at 85mph on a straight highway, with 5k miles on the odo. At least that's what I was getting going from Portsmouth, NH to Boston, MA on 95. On rolling hills doing same speed nets me about 25-27mpg in intellingent mode (I consider it highway mode). Link to comment Share on other sites More sharing options...
godwhomismike Posted December 21, 2006 Share Posted December 21, 2006 205/45??? It's a bit less tire than stock. How's that working out for you? Link to comment Share on other sites More sharing options...
rallysquirrel Posted December 21, 2006 Share Posted December 21, 2006 Fixed. godwhomismike thanks for pointing out my mistake Link to comment Share on other sites More sharing options...
NSFW Posted December 21, 2006 Share Posted December 21, 2006 Any chance the new tires were inflated to a higher pressure than the old tires? Or, put another way, were the old tires running a bit low? Link to comment Share on other sites More sharing options...
ilh Posted December 21, 2006 Author Share Posted December 21, 2006 Nah. I just wonder if I have discovered a new form of RE92 suckage. Link to comment Share on other sites More sharing options...
Garandman Posted December 21, 2006 Share Posted December 21, 2006 I'm a bit baffled. On my usual weekly commute I get about 21-22mpg, sometimes down to 20ish in the summer with A/C going full tilt. This commute is about 1/3 at 40mph relatively constant speed on rural roads (Concord, MA), 1/3 75mph highway (Route 2), and 1/3 0-30mph stop and go (Cambridge, MA). What has me baffled is my past two weeks (tanks) are both over 23mpg. I have NEVER seen over 23mpg before except for pure highway jaunts. Usually, mileage seems a bit worse on winter gas. Could my Nokian RSi be that much better for mpg than the RE92s? That would be somewhat surprising given how soft the RSi tread is. I suppose I am babying the Nokians a bit on our bare roads. Still, I am pretty much traveling the same speeds as year round. I still go WOT a few times a day. I am stock. --Lee FWIW, I put the RSI's on last week and my mileage jumped up compared to the Goodyear F1 GS D3's. They're a season old but still have around 11/32nd tread. It might be because I don't push as hard on my squishy snows. Who Dares Wins スバル Link to comment Share on other sites More sharing options...
tantal Posted December 21, 2006 Share Posted December 21, 2006 Yea, it's funny, as my wife's been driving our LGT more, our mileage in that car has dropped. Last tank was just over 22 (measured, not guage) and the tank before that 20. I've put four tanks full in my new RX-8 now and I got 19.7, then 20, and last night I got 21 (woohoo!). And I've been increasing the revs slowly over those tanks - just began redlining it (seriously woohoo!). I am used to getting about 24.0 to 25.0 in our LGT, measured. Link to comment Share on other sites More sharing options...
SLegacy99 Posted December 21, 2006 Share Posted December 21, 2006 I'm jealous. If you havent noticed, Ive been complaining about winter fuel additives all week. I typically achieve 21/32. But now Ime getting 20/27. It makes me sad. Anyway, if you havent already calculate your gas mileage without the using the car's computer. Link to comment Share on other sites More sharing options...
Spec B Posted December 21, 2006 Share Posted December 21, 2006 Can it be due to less traffic due to the holidays?? Link to comment Share on other sites More sharing options...
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