help me improve the mileage in my subaru impreza
 

this car belongs to my wife, who does not care about gas mileage other than the fact that the impreza is supposed to get 36mpg. the best i've seen her avg is 38. i tried a number of things i found on this site and they didn't seem to help. i still haven't tried underbody panelling and i wanna try a grille block. my wife also wants the car to look good so i can only get away with things you don't notice at all. im also contemplating taller tires to see if that would help. does anyone else with a subaru have any hypermiling tips?

heres a pic of car as it sits https://fbcdn-sphotos-d-a.akamaihd.n...6a2400028484ba

Max sidewall psi on the tires is a great place to start. Here's a couple more tips:

65+ Vehicle modifications for better fuel economy - EcoModder.com
100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com

Here are some ideas:
- remove the roof rack
- belly pan will be awesome - corrugated plastic works well
- try some friction modifiers like ws2 in the engine oil & differentials
- go full synthetic for transaxle/cvt, diffs, and engine
- see after going synthetic if you can block the upper half of the upper grille
- make some wheel spats if it doesn't have any
- get led headlights/drl (ebay is great for this)
- nokian low rolling resistance tires (get better as tread depth decreases)
- lightweight rotary forged wheels (like enkei pf01 or centerlines rotary forged)
- get an elm327 Bluetooth obd2 transmitter from dx.com and Torque Lite (free) for Android to watch your real time temps

Nice ride!

I agree with spdfrk except for the whole Torque thing. Use dashcommand instead, I have found it much easier to use and has a much faster boot up time than Torque.

The combined EPA for my Forester is 20 MPG, but I was getting twenty-seven, before my ex started driving it. I left her my Ultragauge, hoping it would help her drive better, so she closed the car door on it.

Did the car come with the roof rack cross-members? I removed mine (and then my ex harassed me, saying that she needed them), but read that to remove the rails, you need to remove the headliner--it would be a mess.

Improving fuel economy is great, but only if the investment pays off. Sometimes we make modifications that do not have a return on investment, but maybe someone else can take our idea and do better.

What have you tried that did not work?

i want to remove the roof rails but it will take several hours. i would like to add sound deadening foam and put in an amp and subwoofer so i might do that. i also would like to try 16" wrx wheels with coroplast covers but the only way i can get away with that would be with snow tires.

i tried a few things before and saw no improvement.
-i took out the spare tire and tools
-removed the mud flaps
-tried 42psi, i usually use 35psi all around
-disconnected DRLs


i just need to keep harrassing her about how much fuel she is wasting and how much more wine she could buy if she paid attention.

The main part of the problem is here.

You can't get good mileage out of a car if you have a driver who doesn't care about mileage. Putting stealthy mods on the car are one thing, but hypermiling tips? They don't work if the driver doesn't care.

i know, i know. just looking for little things that would help just a little bit for an unsuspecting driver. i wouldn't doubt this will become my commuter one day.

Try the Nokian Hakka's for winter tires. My mileage actually went UP in winter with these. These a good vid on youtube if you look for NOKIAN ROLLING RESISTANCE TEST.

If you do some of the mods to remove friction in the powertrain with better lubricants, eventually the other half will realize they're driving more erratically by not changing their driving habits. Get ceramic brake pads which dig in more aggressively and this will become FAR more evident.

Worked on my better half

the nokian studdable 8 or studless r2? since we get very little snow here i don't know if i can convince her into winter tires. ill look into the synthetic lubricants and switch to ceramic brake pads when the stockers wear out. im wondering about replacing the stock tires since they need to be replaced asap. the stock size is 205/50/17 but im looking at 215/55/17 continental tires with ecoplus. the taller sidewall should lessen the gap between the tire and the fender and ride a tad better, plus less chance of her curbing a wheel and a fractionally higher step in height. nabisco confirms the tires will fit. the (215/55/17)tires are only 5mm wider and 1 pd heavier than stock. but i could also get 205/55/17 michelins(much more expensive) or maybe i should just stick with the stock size.