Jump to content
Ultimate Subaru Message Board

1987 GL-10 Turbo Wagon MPG?

Recommended Posts



Is 19mpg normal for an '87 GL-10 Turbo wagon?


I bought a really clean '87 GL-10 Turbo wagon with an automatic 3 speed transmission a couple months ago. The previous owner only drove it a couple hundred miles for the year he had it. It only has 123,000 miles on it (just a baby!) I'm not really getting the mpg's I was hoping for. I've been driving really conservatively, but I only average about 250 miles per tank (250/13 gallons =19mpg). My question is: Is 19mpg normal or is that low?


I realize that pretty much anything that goes wrong with a car is going to hurt your gas milage, but is there anything in particular i should look into given the year and model? Any common problems out there? Anything with older cars in general that should be done to restore gas milage?



-supposedly the fuel tank capacity is actually 15.9 gallons, but the fuel gauge says its empty at 13, so thats when I've been filling up again and calculating miles.

-I also replaced the oxygen sensor and got a new timing belt.

-I replaced the fluids when I got it and I've been using a couple different additives

-new tires

-One thing I've noticed is that the car doesn't coast very well at all. Even on a good decline, if I'm going 35mph and I let my foot off the gas, it'll slow down quite a bit, whereas in my wife's new forester, the car will continue to gain speed just from rolling down the hill. I'm a newbie and certainly no mechanic so please educate!

Link to comment
Share on other sites

I'd say thats normal. My 87 gl-10 wagon gets about 25mpg and I have the 5 speed. the 3 speed will rob you of a lot of mpg. i  have over sized tires, but i also have a 3.9 ratio transmission, instead of the 3.7.


when i drive it hard i get about 20 and if i drive it easy about 26, on the highway i get close to 30.


123k??? that is a baby, mine has twice that. 250k still going strong.


the tanks is 15.9 gallons, and it will read empty at 13 gals. the other 2.9 is reserve. you can go quite a while on empty.


you might get slightly better mpgs with a good seafoaming.

Edited by AKghandi
Link to comment
Share on other sites



Is it full-time 4WD? If so, that combined with the turbo, along with the 3-speed is probably the worst combo you'll get. Part time 4WD will definitely help, if you don't already have it. A 5-speed manual transmission will also boost your MPGs.


I've never owned a turbo, nor an automatic wagon, so I can't say about that. But if I drive conservatively, I can get upwards of 35 MPG in my wagon. However, driving like that takes all the fun out of the car, since I'm driving so slowly. Under my normal driving, I'm probably getting around 25 MPG, and that's usually a bit of full-throttle acceleration and a redline or two every day.


One of the big things I'll say is weight reduction. Take everything out of the car you aren't using. This could mean stuff in the back, or stuff in the engine..., or people.  :P I generally keep my car clean of random crap, although I carry my tools with me everywhere, which doesn't help. But I've also taken out some A/C parts from my engine, as I never use the A/C. I always roll the window down if it gets hot.


I've heard that that coasting problem is common on these autos, but most of the reading I do are with manuals. You can always put it in neutral when coasting, although that is considered to be dangerous in the event that you might need to accelerate to avoid an accident. Also, putting it in neutral at red lights might save some fuel, but that might be a myth, and it might be negligible.


But yeah, I'd say the 3-speed is the biggest problem. Third gear at 60 MPH for me is like at 4500 RPM, which is not good for MPGs when going long distances.


My car has ~262K and, once I get a new cylinder head, it'll be going strong.  :rolleyes: This car will last you a long time, if you put care into it!  :headbang:

Link to comment
Share on other sites

thanks so much guys! ya... the three speed is the only thing i don't like about it... i drove 4 hours to buy it and i found out it was automatic when i got there. bit of a let down, but its still a champ. 


luckily it's only part time 4WD so at least that helps. 

Link to comment
Share on other sites

Sounds about right.


3-speed auto is a gas sucker unless you drive under 60 on the freeway.


Also, the 3-speeds after 84 have a torque converter that locks under decel for better control in snow and offroad.  You can actually engine brake with the 3AT, with no electronics. 


Unlike the 4EAT, which can lockup, but requires solenoids and a computer to do it. And won't do it unless it really thinks you want to engine brake(forrester trans)

Link to comment
Share on other sites

What Gloyale said.

Though it only will engine brake when you're going over 33-ish mph.

Try coasting down a long hill from 20 mph on. You'll see that the car will gain speed as you would expect it to, but just around the 35mph mark you'll get a little jolt (still without you doing anything on your end) and it'll start to engine brake. Thought it was pretty neat after I got used to it.

Link to comment
Share on other sites

My RX delivers around 30MPG if I keep it between 45 and 55 MPH on open road; over 60 MPH or in stop-and-go traffic, it goes down to about 24, which makes my RX-7 a better freeway car, surprisingly (it can deliver between 24 and 26 MPG at about 70 MPH). It's kind of disappointing. A fantasy of mine is to rebuild my transmission with the taller 4th and 5th gears from a 5-speed SPFI GL which would hopefully bump my MPG up to 30 at 65 MPH.


Also, unless you're in Colorado or some other high-altitude area where regular unleaded is less than 87 AKI, or you live in a very hot climate and have noticed some performance issues and/or knocking, you'll only need to run regular fuel with a good EA82 turbo in a stock state of tune. These cars are designed and specified to run on 90 octane fuel per the owner's manual, which converts to 87 AKI here in the States. This is because these engines run a very low-pressure turbo (7 PSI optimum, fuel cut at 10 PSI) and are tuned very mildly from the factory (I mean, in the States it's only about a 15HP increase over a regular MPFI EA82). Even the FC RX-7 Turbo II is specified to run on 87 AKI, as are a number of other '80s cars with low-pressure turbos. However, if you up the boost or have a car that's been poorly maintained (or you're concerned the gas station you've stopped at has questionable fuel), you may get some knock on regular unleaded, at which point you'd want to go up a grade.

Link to comment
Share on other sites

I ran 87 octane in mine here in TN, and I never had any trouble with detonation. Overheating...sure, but that wasn't the fuel's fault. The turbo EA82 only has 7.7:1 compression.


I used to get 23-24 around town and 26-28 highway in my old 5-speed 87 GL-10 4WD Turbo Wagon. Honestly, I was disappointed with that, because my dad's old 2WD 5-speed turbo XT used to get 32-35 in mostly highway driving, and my old slushbox 2WD XT6 got 20 city and 27-28 highway.

Link to comment
Share on other sites

Are we sure this isn't a 4EAT? I had an '88 turbo GL and it was the 4EAT (wikipedia doesn't even recognize it was ever used in any ea car except the XT). I could get 24 mixed with 27 being my high on the hwy, so I'd say you may want to check for a dragging brake caliber and do all the basic tune up stuff like plugs, wires, disty cap, rotor, air filter. And BE SURE that thing never overheats. New water pump, new SUBARU ONLY thermostat, upper and lower radiator hose, heater hoses, and any other coolant hoses you can find. REPLACE THEM!!!!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...