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fuel efficiency?

Posted: Mon Dec 24, 2007 11:44 pm
by mexicanzero
so i just got a 1992 legacy 2.2L turbo, unfortunately its automatic but i had no choice since i cant really afford whatever i want right now

it costs me about 60$ to fill up the tank and then its at the halfway mark after 150-160km of driving

300-320km on 60$ seems pretty bad to me is this normal for this car?
other than some obvious things like fuel leaks where should i start in my attempt at making the car gimme more distance to a tank.

i don't drive much on the highway but i'm not one of those kids that like to floor it at every light so my driving habits aren't whats killing it, and its winter here so there's no a/c on either.

oh and in the manual it says to use premium fuel will it kill the car that much if i just use regular to save a few bucks?

also i find that half the time (more so when the car is left sitting for the night or a long while) when i go to start it it takes a few seconds to start up, if i dont leave car sitting too long it will start up the second i turn the key. i've been told it could be a problem with a leaky injector leaking into the cylinder or possibly the rollover valve leaking back into the tank, in any case its a problem with fuel pressure being lost when the car is sitting. Does anyone know of a common problem with subaru's where i can start or am i lost to figure it out on my own?

thanks
-Alex

Posted: Tue Dec 25, 2007 2:25 am
by ericem
Since it is a turbo car yes it can kill it that much surprisingly. My 93 non turbo gets about 400-450km a tank depending how often its in the city. Still its not even driving correctly, seems like my car needs new wires and a oxygen sensor.

If you want to try and improve your cars fuel economy I would start by giving it a good cheap tune up. If you go by your local subaru dealer pickup a PCV valve, air filter, spark plugs (OEM) and wires (OEM). Also pickup some fuel injector cleaner and put it in the tank. Give her a go and see if it makes any difference. 300km a tank still does seem low even though its turbo. Are you running any mods?

Another thing to keep in mind, the guage is often not accurate. Next fillup calculate how much gas you put in and your mileage you go so far. Its a 60L tank I believe.

Posted: Tue Dec 25, 2007 6:23 pm
by mexicanzero
wires and plugs are newish and the air filter isn't really dirty but i was going to go pick up a k&n one because its reusable and is supposed to improve the mileage a tiny bit so in the long run it'll probably make it worth it.

do you think the pcv valve will make that much of a difference? i'm assuming they are cheap?

i have no mods on the car and when i fill up the tank from half way i usually put about 35-40$ in which equals 30L of premium fuel nowadays.

Posted: Tue Dec 25, 2007 9:03 pm
by Brat4by4
PCV valve is real cheap and very easy to replace (and can possibly make a huge difference). Definitely pick up what Ericem mentioned, and a fuel filter. The one in the engine bay is easy enough to replace.

Putting cheap gas in the car will make it run like crap and your mileage will fall through the floor. So you don't save a penny. Not to mention you open yourself up to the possibility of hurting the engine.

And the turbo cars will never get great gas mileage in city driving. There is just too much power made down low in the car whether you try to or not and it sucks down the gas.

Posted: Wed Dec 26, 2007 4:25 am
by ericem
Another thing to point out. Get a OEM PCV valve. Only like $5 or $6 from your Local dealer.

Posted: Sun Dec 30, 2007 8:51 pm
by mexicanzero
when you say i should get an OEM pcv valve do you mean th eone i just picked up from canadian tire is not good? its still sealed int eh package so i can still return it... whats the difference between oem and something bought from a parts store?


Now just an update in case anyone is interested I've been driving all weekend keeping my RPM's under 2500, preferably at 2000, because around 2500 to 3000 is when the turbo fully spins up. It sure isnt the funnest driving i would rather spend an extra 20$ on gas but for the sake of my "experiment" i decided its worth it.
to my amazement I just hit the half tank mark and I've driven 280 km.
thats about 120km more than with my usual driving.
I'm going to keep going until my car runs out of gas to see how accurate the gauge actually is (i have a gas can in my trunk with 10L for when that happens since i don't fee like walking in -20 weather to the gas station)
if I'm able to get 560km out of it i will be in awe. so wish me luck
-Alex

Posted: Mon Dec 31, 2007 4:04 am
by ericem
See, and yes return that one from Canadian tire. I bought a Canadian tire one and used it, my car started burning oil, and when I took out the canadian tire one and compared it to a new OEM pcv I just got the weight seemed different AND the ball in the middle itself was different.