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Long first post here ... hope you don't mind reading.

I drive a 1996 Subaru Outback (http://www.fueleconomy.gov/feg/calculatorCompareSideBySide.jsp?column=1&id=12938), originally rated 22/29/24 mpg with its 5 speed stick and 2.2 engine. I always felt lucky having a '96, because the 1996 stickshifts were the only Legacy-bodied Outbacks to ever be equipped with a 2.2 instead of the thirstier 2.5. With the stick the 2.2 is good for 0-60 in about 10, and that's been fast enough even for me. I found the 22 mpg EPA city estimate to be fairly accurate for summer gas and tires, generally getting around 21 mpg if I drove "enthusiastically" or 22-23 if I toned things down. This is in mixed urban driving: city streets and boulevards as well as short freeway trips at 60-70 mph.

I'd always been skeptical of claims that driving style could make a difference of 30% or more in fuel economy, having only noticed a variation of 5-10% in my own driving. Seemed like hype to me. But then recently, while investigating potential vehicle options for my family (hybrids, EVs, economy cars) I ran into hypermiling.com and this site. After crawling through the glossary and lots of posts I decided to put it to the test. Here's what I did on my first "experimental" tank:


Increased tire psi from 32 to 36 psi. Contrary to my expectation, I think the car corners more solidly and grabs the pavement better at this pressure without tire squeal. For the next tank I'll try 40 psi (tires are rated max 44, door jamb recommends 29).
Eased up on the throttle and kept the revs down: Upshifted at or before 2000 rpm in most situations, minimized use of first gear, did 2nd gear starts whenever feasible, more consciously stayed in the highest feasible gear.
Kept my speed down, generally to the speed limit or less. Max 55-60 mph on local freeways.
Lots more coasting. The freeway portions of my commute include a climb up Sylvan Hill to 750', followed by a long descent that requires the use of the engine at 60 mph. However, at 50 mph (which, incidentally, is the speed limit on the east side of the pass), I can coast all the way down.
Used cruise control at speeds of 50 mph or above. At lower speeds my CC is uneven, and I suspect it consumes more fuel than an attentive driver.
Generally tried to drive as if my brakes didn't work: watched further ahead, left more gaps in front, etc.
Occasional FAS, both stopped and rolling. Today I FAS'ed all the way down off Sylvan hill - that's about 3 miles with the engine off!
Brake less for corners and curves. To be honest, as a former "enthusiastic" driver, I've had lots of practice at this, though I still had to change how I enter and leave corners.


The result? Yesterday I just finished off my first tank: 27.8 MPG! Wow, that's better than I usually get on the highway! Now I realize that I'll have to sustain this result across several tanks before truly claiming success, but this seems like a very good start. At least for this one tank, I improved my mileage by about 30% versus my earlier, more aggressive style. Wow! I'm also realizing that (1) I still have quite a bit to learn/practice on hypermiling techniques and (2) I need to get myself a ScanGauge.

Now some questions (why I posted here instead of the Intro forum):

Is there any way to FAS a Subaru (while rolling) without killing the headlights? What's involved in installing a kill switch?
Anyone else doing second gear starts? I know Chevy has used a first-gear lockout on the Corvette for many years so that EPA testers will start in second gear, but so far I haven't read anything on this site about people doing that. I'm doing this whenever I can, probably about half of my starts from a full stop, and almost always from rolling stops.
How much do electrical accessories (lights, fan, stereos) impact mpg on non-hybrid cars with conventional 12V systems? Having driven with headlights on for safety for 25 years, I'm not willing to turn them off completely, but I would be willing to limit myself to parking lights during daylight hours -- and convert the parking lights and taillights to LED. IF it matters.
Can anyone actually quantify how much extra fuel it takes to push a bike (on the rooftop, versus a hitch rack) through the air at highway speed? I know it's significant, but I haven't been above to find hard data anywhere. Seems to me this should be fairly constant regardless of the vehicle. Being able to carry a bike is non-negotiable for me, because I'm an avid cyclist and my typical commute involves driving 5 miles to my child's daycare and biking the remaining 7 miles to work. Converting to a hitch rack would cost some bucks and impair the Outback's (already limited) parallel parking ability into tight spots, but I'll probably do it eventually if the fuel savings are substantial.
Speaking of racks, does anyone know how much drag is due to the rack itself versus the accessories on the rack? I suspect that bikes, skis and cargo boxes add more drag than the rack itself. I can pull the bikes off easily enough, but I do use the rack (with a cargo box) for family roadtrips often enough that I'm reluctant to remove it. Numerous high-mpg websites advise to "remove the roof rack when not in use" -- Ha! As if that's as simple as folding down the seats or something. Generally a dirty 10-20 minute job. Not a huge deal, but not something I want to be doing all the time.
Anyone know how much practical difference low-rolling-resistance tires make in non-hybrid vehicles? My tires will probably need replacing later this year. I'm not willing to give up performance (I live in Portland, and wet grip is extremely important to me) but I would consider the expensive Michelins if I thought it would get me a noticeable mpg improvement. And I will switch my snows to Arctic Alpins (which I've had before, and like) when my current mushy Nokians wear out.
The Outback's high gears are MUCH shorter than I'd like (especially having once owned a Civic VX), with 5th gear still requring over 3000 rpm at 60 mph. is it even conceivable to swap out 4th and 5th gear for taller ones? So far I've only heard of this being done with VWs.
I know I could achieve slightly higher gearing with taller tires, but it seems there are no tires in existence (for any rim size) that are taller than my 205/70r15s without also being wider. Might going to a wider tire (215 or 225) cost me more in mpg than I save with taller gearing?


Once I've gotten some more practice at ecodriving my Subaru, we'll have to work on my wife's car: a 1983 Volvo Diesel sedan, which she bought several years ago specifically so she could burn biodiesel in it. She only gets low 20s in town (still better than the gas version she used to have) and I'd like to see if we can improve that. Fortunately she gets low 30s on the highway, which is making us think about eventually making this our family roadtrip car. That would give us the option of replacing the Subaru with a true commuter car, ideally an EV. But that's a couple years off. Meanwhile, I'm focusing on getting better mpg with the cars we already have.

Thanks for reading.

- Dan

Hi Dan:

___Welcome to CleanMPG and you posted a heck of an introduction. With that, let us get started …

___Tire pressures, go higher. Go max sidewall to start and we can work you up and beyond that if you are willing over time.

___CC, stay off of it. Your eyes, mind, and foot are a lot smarter and far more accurate at judging undulations and especially on small hills then CC. Trust me on this one ;)

___DWB is always a great practice.

___Hills are meant to be FAS’ed down. God’s gift for those that know what they are doing :D

___Maintaining momentum can be almost as much fun as not consuming the fuel. Just be careful on routes you have little experience with is all …

___Your questions … When you reboot, you should have control of your head lights. Is your Subaru equipped with DRL’s by chance? Supposedly safer but running 100 W + continuously costs you in fuel consumption :(

___From a dead stop, just use first for a quick and I mean quick launch. Within 5 seconds you should be in or darn near in third gear with short and fast shifts at the lower RPM’s.

___I have over 850,000 mile sunder my belt w/out DRL’s and never had an issue of that sort. Running your headlights in a non-DRL equipped automobile runs a heck of a lot more then just the headlights unfortunately. No matter the size of 12V or alternator’s cap, you will have trouble as well as FE that will always be held back This is up to you but I leave the headlights for night driving. If I had DRL’s, I would disable them. The reason for a hit is you cannot FAs at will while trying to save that 12V for lighting her back up. A 3 mile long FAS in the dead of winter with the lights on and you won’t be starting her back up is almost a guarantee. Clutch starts will get you going again but that 12V draw is a killer when your 12V has maybe 1/3 to ½ its original warm weather cap in 10 degree F temps.

___I remember some Ford Engineers passing along that info but I never wrote it down :( Here is some other info you may be interested in wrt an FEH:

Accessory FE loss including the Radio: .1 MPG
Rear Defrost: .8 MPG ,
Headlights: .9 MPG
Fan on High: 1.3 MPG

___The racks themselves are not to bad but load them up with bikes, Kayak, or camping gear and her air drag goes up quickly. Driving higher speeds with a loaded rack is about the worst thing you could do of course :(

___Low RRc tires come on any number of automobiles, not just hybrids. In fact, the original non-Insight specific Bridgestone RE92’s came as OE on both the Prius-I and Camry. The GY Integrity’s that are OE on the Prius are also on the Corolla and a ton of other automobiles. The Integrity’s are just OK low RRc based tires. The Michelin MXV4 Energy’s found on the Accord and any number of other higher priced sedans have very low RRc’s. When you purchase, just make sure you pick up what you need but in a Low RRc tire is all. We have pdf lists of the darn things all over the site ;)

___Swapping out tires to gain a taller gear has some negatives. Your speed/odometer calc’s are fubar and if you purchase a much heavier tire, it can hurt you. Going to a wider tire is not doing anything for you from my standpoint. You get better traction in the snow and such with a thinner profile tire let alone the weight issue again.

___Sorry I had to be so short with my response but I have a ton of other things to catch up with here at CleanMPG :( If you have any more questions, let us know.

___Good Luck and again, welcome. Let us see 30 from the old Sube on the next tank and then you will really be speaking our language ;)

___Wayne

My previous car was a Subie legacy wagon, and I went through
*hell* trying to *disable* the **** DRLs. I finally had to
cut a trace *and* add a jumper to the headlight switch module,
or something, and finally managed to kill them for good.
I figure if I want to turn on the headlights, that's what
the *switch* is for. [The supposedly reduced brightness that
controller was supposed to provide was totally bogus.] In
my mind, 100 otherwise useless watts I got back.
.
_H*

As far as roof racks go: http://www.metrompg.com/posts/roof-racks.htm
That is in a Geo Metro, but it is at least a semi-scientific test.

Headlights: You should always reboot the car as soon as the engine dies, and you'll have your lights back. Not sure if you're doing this already, but it means they're out for only 2-3 seconds.

... and... Welcome to CleanMPG! You're off to a good start. I want to see how much you can do with that AWD system.

Thanks for the warm welcome everyone, and for the great feedback.

Tire pressures, go higher. Go max sidewall to start and we can work you up and beyond that if you are willing over time.I'll try it.

CC, stay off of it. Your eyes, mind, and foot are a lot smarter and far more accurate at judging undulations and especially on small hills then CC. Trust me on this one ;)Even at 60 mph? Somewhere on this site I saw test results that showed CC being detrimental (at least on one particular car) below 50 mph, breaking even around 50 mph, and actually helping at speeds above 50. I can see why CC would not be good in rolling terrain though.

When you reboot, you should have control of your head lights.
Headlights: You should always reboot the car as soon as the engine dies, and you'll have your lights back. Not sure if you're doing this already, but it means they're out for only 2-3 seconds.I've been turning the key back to "RUN" as soon as the engine dies, but even 2-3 seconds is going to draw a lot of attention at night. No big deal while I'm stopped, because then I can always kill the engine with the clutch. But I'd very much prefer to be stealthy about FASing while rolling, which I'm pretty sure is illegal around here. I'm very sure it's illegal (for me) after dark, since that means I'm turning off my headlights while rolling.

Is your Subaru equipped with DRL’s by chance? Supposedly safer but running 100 W + continuously costs you in fuel consumption :(
My previous car was a Subie legacy wagon, and I went through
*hell* trying to *disable* the **** DRLs. Whew! Glad mine's old enough not to have DRLs. Back in the 90s when they were mandatory in Canada but not yet in the US, a lot of vehicles there used the parking lights as DRLs rather than dimmed headlights. Seemed like a better solution, especially compared with GM's idiotic DRLs that just dim the high beams. I had those on a Saturn a decade ago, and boy did they ever blind people a lot.

From a dead stop, just use first for a quick and I mean quick launch. Within 5 seconds you should be in or darn near in third gear with short and fast shifts at the lower RPM’s.So are second gear starts only beneficial for cars with excess HP like the 'vette?

Accessory FE loss including the Radio: .1 MPG
Rear Defrost: .8 MPG ,
Headlights: .9 MPG
Fan on High: 1.3 MPG
Whoa, that's huge. I didn't realize electrical accessories were that costly. Any idea what car was used in those tests? I had calculated that 100W of headlights, even at only 50% alternator efficiency, should only amount to about 1/4 of a horsepower, but apparently car alternators are a lot more inefficient than that. Guess I'll keep the headlights off during the day (again, no DRLs) and limit myself to parking/taillights, which I'll replace with LEDs.

The racks themselves are not to bad but load them up with bikes, Kayak, or camping gear and her air drag goes up quickly.
As far as roof racks go: http://www.metrompg.com/posts/roof-racks.htm
That is in a Geo Metro, but it is at least a semi-scientific test.That is awesome! Thanks for the link! Looking in terms of fuel consumption instead of MPG, the rack caused an increase of about 0.25 gallons per 100 miles, and adding a bike increased the penalty to 0.7 g/100mi. Translated back to my Outback's MPG, that's a penalty of 1.5 to 2 mpg for the rack, and 4-5 mpg for rack+bike. That's a little more than I thought -- but only a little. I suspect my rack setup -- crossbars mounted to longitudinal factory bars -- is slightly more aero than his tower setup, but even so it sounds like it's costing me.

Looks I really should put on a trailer hitch and get a hitch mount rack. My coworker has a hitch-mount cargo box I can borrow, and most of the time I use the rack it's for bikes or a cargo box but not both. I would still need a roof rack is for the few times I do carry both, which is only once or twice a year for big family camping trips. Still looking for objective data on whether bikes or a box are worse on the roof, so I know which to carry in back and which to carry on top on those rare occasions. I should also practice up at removing and installing the rack itself quickly. That should be easier with the style I have (which clamps to the longitudinal factory rails) rather than with the tower style, and if I only had to do it a few times a year I could probably accept the hassle.

The Michelin MXV4 Energy’s found on the Accord and any number of other higher priced sedans have very low RRc’s.I'll probably bite the bullet and go for the Michelins since they are so highly rated in addition to having a low RRc.

Going to a wider tire is not doing anything for you from my standpoint. You get better traction in the snow and such with a thinner profile tire let alone the weight issue again.Not surprising, I guess. Actually a taller tire wouldn't likely mess up my odo/speedometer since those read about 5% high currently. And good point about the weight -- I hadn't thought of that. Another drawback of upsizing is that I'd need to invest in new 16" or larger wheels. I'd rather not spend those big bucks unless the MPG gains were significant, which appears not to be the case.

I want to see how much you can do with that AWD system.Ha! Me too. Actually, I'd just as soon not have AWD -- I've always believed putting good rubber down is more important, and I run snows in the winter and am perfectly capable of chaining up when things get really dicey. But when I bought this car it was about the only choice in midsize family wagons, and here in the Northwest you can't throw a rock without hitting one. Looking at the EPA ratings from when not all Subarus were AWD (which has only been the case since '95) it looks like I'm paying a mileage penalty of about 2 mpg. I'd love to convert my OB to 2WD, but I suspect that is a very non-trivial operation.

Sorry I had to be so short with my response but I have a ton of other things to catch up with here at CleanMPG Short? Are you kidding? That was great! Thanks for all the help, everyone!

- Dan

Sorry about the late welcome. :o Welcome to CleanMPG. Sounds like you are definitely on the right track for excellent FE. I know what you mean about the Saturn DRL's. I disabled mine and, when I went to put the jumper in to restore the right high-beam light, I jumpered the wrong terminals and fried my instrument panel and lost my speedo and odometer.:mad:

Well, I've been increasingly pessimistic about the tank I filled up last week. As I was pulling out of the station I had noticed a sign that said "Contains 10% ethanol" without any mention of it being seasonal or winter only. Crap. There goes my MPG.

Or so I thought. I just filled up again last night, and it looks like I pulled 28.9 mpg out of that tank anyway. Since last week I've increased tire psi to 42 and taken the roof rack off (the bike is -- sort of -- fitting in the back for now while I'm saving up for a trailer hitch).

Also, I ordered a ScanGauge yesterday. Hopefully I can get myself up to and over 30 mpg with its help.

Wow! heck of a start. Think your gonna love that instant feedback that the SGII gives you. Really helps you test out new theories. You've got lots of good responses, but one thing I'd suggest about the tires is the alignment.

When I replaced the tires on my wife's Odyssey, we got an alignment job on it. It had a slight pull that had been bothering me. First tank after the tires+alignment = 10% boost in FE. I don't think the tires alone gave me that much of a boost, but I can see how alignment could really drag FE down.

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