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2Cor6.9-10

86 gl 4wd wagon

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I've recently got an 86 gl (non-turbo) wagon, carbureted w/ optional hi/lo 4wd. I'm running 3k rpms at 65mph in 5th gear (2wd). I want to get the rpm's down and I'm not concerned with my 0-60 time, I'm concerned with gas mileage. I read that gl's came with 3.54, 3.7, 3.9, and 4.11 gears. I would like to know how to find out what mine has (probably 3.9 but I'll check for a label on the front diff.) and I would like to know if I could find a solution by switching a diff. or the gears within my front/rear diff. Which gears would be best - 3.54 or 3.7? Which diff would need to be switched- front/rear/both (It's FWD when not in 4WD)?

 

Other questions:

Anyone know how I can find out which engine I have (E81/EA82 etc.)?

Is it true that the engine block and heads are aluminum (I did a magnet test and it did not seem to stick)?

Other gas saving tips will be appreciated. I've considered eliminating 4wd but only if there would be a significant increase in mpg (I suspect there wouldn't be).

 

 

I'll greatly appreciate and activate the soob info. Thank you.

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You have and EA82 engine. You also have a 3.90 gear ratio. You absolutely do not want to mess with any gears. The easiest way, is to go with larger tires. Many non-turbo gl's came with 175/70/r13. The 185/70/r13 is a lot nicer ride and you sit noticeably higher off of the ground. Once you try them you will never go back. Yes the engine block and heads are aluminum. Forget about putting any money into changing the transmission. The cost would more than offset any gas savings, which probably will not happen anyways. Your 4wd is on demand besides, and does not cost you a penney when it is not engaged. The easiest way to get better mileage is put more air pressure in your tires, keep good plugs in it, keep the rotor cap poles clean, and keep good plugs wires in it.

Edited by scoobiedubie

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Thank you for the info. Scoob. I've considered the larger tires but I spoke with someone who runs some large tires and he says that the larger tires actually require much more torque, making the engine work harder. He says the gear change will be better for the engine.

 

I'm curious about why you say do not change the gears or diff. It's common to switch out diff.s for the R160 LSD. I don't need the LSD but I think I could use the 3.54 (not sure whether it would be front diff. only or both). Not only do I want better fuel efficiency but I want a better cruising gear.

 

Thank you again.

Edited by 2Cor6.9-10

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The transmission gear ratio and the rear differential gear ratio must match. Good quality replacement equipment is hard to find. New equipment will cost a fortune. Taking the transmission out, working on it, and reinstalling it, is very expensive. I estimate that your idea will cost you at least $2000, if you can get good used equipment. Most wrecked vehicles have at least 180,000 miles and the transmission have synchro missing is one gear. Better find exactly what vehicles have that mysterious 3.54 gear ratio, before considering this further. The gear shift may not end up being in the right place, for instance. I have the 86 subaru maintenance manual and it says nothing about a 3.54 gear ratio anywhere. It is either 3.70 for the turbo, or 3.90 for the non-turbos.

 

Techniquely, any larger diameter tire will require a slightly greater torque for acceleration. However, the larger diameter gets you higher off the ground where you can see better and have more safety. It also has more air cushion to give you a better ride. If you primarily do highway driving, it requires no extra torque to cruise at a constant speed than with smaller tires. The car also looks like a real car instead of a child's toy, with the larger 185/70/r13 tires. With a 3.70 gear ratio and 185 tires, my engine turns at about 3000 rpm at 60 mph. 86 subarus did not get excellent gas mileage, turbo or non-turbo.

 

90 to 94 non-turbo Loyales get 30+ mpg. You can buy a nice condition, low mileage loyale for the cost of doing this change that you are thinking of, and still have your gl for emergencies.

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Thank you, Scoob. I appreciate your info. on the cost and finding the parts; that's not my main concern right now (I've looked into it and I'll manage).

 

"The transmission gear ratio and the rear differential gear ratio must match." I could understand that both front and rear diff.s may need to match so that all 4 wheels spin at the same speed in 4wd but I'm not understanding why I would need a different trans; wouldn't 3.7 front and rear diff.s work with my 5sp? I've read about people switching Datsun 510's, etc. to the R160 Limited Slip Diff. but I don't recall having to change the trans (2wd but they used their same trans non the less).

 

I'm finding some more info here (also more mention of the 3.54 gears):

http://www.ultimatesubaru.org/forum/showthread.php?t=32542

 

You say you have a higher gear ratio and larger tires yet still run at even higher rpm's at 65?? Something doesn't add up. What model do you have? I've seen youtube videos of gl-10's that would cruise low rpm's at 60. According to the info you provided, they would be running the 3.7 and some of those use the same 5sp trans as my gl I think.

 

I see that some 85-86 5sp gl wagons get about 29mpg highway (not bad for a 4wd). Hopefully I can get a better cruising gear and at least maintain my current fuel economy.

http://www.fueleconomy.gov/feg/bymodel/1985_Subaru_Wagon.shtml

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i'm running 185/80/r13 on my gl they are taller and narrower that gives better mileage, also changing tires does the same thing as changing gear ratio essentially. front diff is part of the transmission so it would be much wiser just to change tires. subies are trans axles look under your hood you will understand. i have seen gl's that get 30 mpg if you arn't getting good mileage try doing a tune up. 3k at 60 is fine and no matter what tire you run it will run right around 3k at 60-65 unless you do a five lug conversion, six hole redrill, or put 14 inch pugeuot rims on with bigger tires. and yes 2wd is front wheel drive. if it is carburated (witch i doubt) than it has to be an e81, that means you could do a weber swap witch will give you more power if done right. more than likely it is spfi witch looks like a carb until you pull off your air cleaner then you will see the injectors, and that means it is an ea82. the engine identification number is stamped into the block in the front of the engine on the left side. also if it is an ea82 it will have timing belts so you might want to check that they need to be replaced at 60k intervals

Edited by mikaleda

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Thank you, Mikaleda. You got a turbo or just the gl like mine? I've heard about the 6 lug re-drills and I may do the larger tires but they don't seem to reduce highway rpm's. With larger tires I would get more inches of travel per turn of the engine but with a gear change I would get more turns of the wheels per turn of the engine. I'm aware that it isn't nearly as easy as a tire change. Not a prob. though.

 

I'll check on the carb. I've heard about the webers but I'm probably not going to upgrade power right now (I'll daydream about what turbo would do).

 

When I find the engine I.D. what numbers distinguish the 81 from the 82?

 

That's right about the timing belt/chain; I'm planning on changing it in a couple of weeks.

 

Scoob, I checked on a 90 loyale and noticed someone stating the same issue - 3000 rpms at 60. Could be that some of the other models did better.

 

Thanks for the info. boys. All this aside, I really like the little soob. Someday I hope to put the 4wd to a small test (at that time I'm sure I'll prefer the larger tires and maybe even a 2" lift and a brush guard).

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With larger tires I would get more inches of travel per turn of the engine but with a gear change I would get more turns of the wheels per turn of the engine.

 

Ummm....

"more inches of travel per turn of the engine" is the same thing as "more turns of the wheels per turn of the engine."

 

A 10%(say) change in tire circumference affects gearing exactly the same as a 10% change in final drive ratios.

 

Wheel only makes about a 1/4 turn per engine revolution in high gear.(not multiple turns)

 

Larger circumference tires are usually wider and thus have higher rolling resistance resulting in lower gas mileage everything else being equal.

According to tests I`ve read,the difference is larger than most people realize.

You want skinny rump roast tires for the MPG win.

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When I find the engine I.D. what numbers distinguish the 81 from the 82?

 

a 86 wagon is a ea82 if it was a ea81 wagon it would be 1981-84 the ,ea82 was made from about 84-94 from 84 to about 90ish they made the gl and dl models then from about 90-94 they made the loyale the same thing as the gl

 

and mikaleda has a 1980 gl ea71 wagon (the ea81 body style but with the older motor, it was made before they released the ea81 motor) and he has a first gen legacy wagon

http://www.ultimatesubaru.org/forum/showthread.php?t=134146

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I went with 14 inch pugs and 195 70 R14. My revs only lowered about 500ish rpm in 5th gear, and thats with almost 3 inches bigger of tires. the rolling resistance is what will impact your mileage (like the width mentioned earlier), but the slight increase isnt really worth the loss of traction. no good getting a car to get an extra 1 mpg to just run it into the back of the guy in front.

 

the goal should be to tune and drive in whatever way keeps your foot off the pedal. it does no good to sacrifice power to then have to give it more pedal to get up the hill. Dropping into 4th to keep the power and rpms up to pull a hill will actually save you gas over lugging down the motor. stock tire size and gearing will put more power down, so I would stick with it. get all the maintenance done right and get the motor running top notch. The car was designed to get good mileage and its hard to squeeze out any significant amount of increase

 

Google "hypermileing" or "hypermileage". they will be full of tricks on how to drive in a manner that will save gas, but I wouldnt do anything besides making the stock setup run as perfect as it can. all the tricks your talking about add up to a couple of miles per gallon in exchange for all the cost and hassle.

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if your engine has timing belts than you have an ea82 an that also means you have spfi, that is a good engine you should get fairly good mileage with stock tires. your best bet is to just stay with stock tires. the block number will say ea82 that means you have a fuel injected 1800 and ea81 means you have a carberated 1800, also the ea82 has sohc and the ea81 has timing gears and push rods.

just thought i would add this if you want good milage and don't mind spending close to 2,000 on changing gears get a legacy i have a 90 2.2 all wheel drive i get around 30mpg highway and has alot more power than any gl i have ever driven

Edited by mikaleda

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Good info. Thanks djellum for your tire size info. Did you mean you increased your tires 3" in circumference or diameter or radius? My tires are about 22.5" diameter/11.25" radius/70.68" circumference.

 

My gear change interest is more about lowering RPM's (don't want to hurt my fuel economy though). I'm not concerned that my 0-60 time will decrease.

 

If anyone has changed gears or driven mid 80's 5sp subarus with different gears (3.54/3.7/3.9/???), I'd like to know the rpm differences you experienced.

 

Mikaleda, about your 90 legacy 2.2, is that a 2.2 liter engine? Turbo or non? 5sp or auto.? Do you know what gears it runs?

 

As for the engine numbers and the carb., I hope to check today. I need to know so that I order the correct timing chain/belt/belts. When I replaced the distributor cap the parts store had options for carburetor or FI with the 86 gl Fwd/4wd non-turbo 5sp wagon.

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some of this info is not true my sister had a 87 ea82 gl wagon 5 speed dual range 4wd and it was carburated not fuel injected, we had a 85 gl wagon two wheel drive which was fuel injected so i know the difference, and 90 loyale four wheel drive push button 5 speed and thats thats fuel injected so its a spfi

 

there is a set of lower gears that are stock from the factory but there very rare the only reason why i know this is i rote a paper about subaru's from the 70's-80's for school, wish we didn't sell the 87 wagon it had them in it:(and the wagon only got around 18mpg because of the lower gearing, not sure about the gear numbers right now but it was a huge pain in the rump roast to find

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Thanks Turbo. Sometimes I get some conflicting info. but that's to be expected; it's alright cause it all offers ideas to look up; it'll sort out and I'll get what I need and readers may learn something new too.

 

You're right about the gears. I need higher (higher gears but lower number - probably 3.7 or maybe 3.54). Maybe someone who runs these gears will spot this thread and give some feedback. Hopefully I'll find out which years/makes/models ran these, whether the gears/diff.s are compatible with my gl (very likely when dealing with Subarus), and what effect they have on 5th gear rpm's.

 

I hope to get some pics up of the car, the engine, and the diff.s soon.

Edited by 2Cor6.9-10

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You're right about the gears. I need higher (higher gears but lower number - probably 3.7 or maybe 3.54). Maybe someone who runs these gears will spot this thread and give some feedback. Hopefully I'll find out which years/makes/models ran these, whether the gears/diff.s are compatible with my gl (very likely when dealing with Subarus), and what effect they have on 5th gear rpm's.

 

It is simple arithmetic.

3.7 is 95% of 3.9 so RPM in any gear will be 95% of what you have now.

91% for 3.54.

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Check with your dealer for a new 5th gear that goes with a 3.70 turbo GL-10 or turbo loyale transmission, if you are an expert at disassembling and reassembling transmissions. You will need an extra car to drive in the meantime. Or you could just swap out for the entire GL-10 5 speed tranny from an auto wrecker. Then you would also need the rear 3.70 differential out of the same models. I have an extra 3.7 open slip rear differential that I could let go for the right price. You would also need need front CV axles because there are 23 splines on the GL-10 tranny verses about 21 on the GL.

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Good info. Thanks djellum for your tire size info. Did you mean you increased your tires 3" in circumference or diameter or radius? My tires are about 22.5" diameter/11.25" radius/70.68" circumference.

 

My gear change interest is more about lowering RPM's (don't want to hurt my fuel economy though). I'm not concerned that my 0-60 time will decrease.

 

If anyone has changed gears or driven mid 80's 5sp subarus with different gears (3.54/3.7/3.9/???), I'd like to know the rpm differences you experienced.

 

Mikaleda, about your 90 legacy 2.2, is that a 2.2 liter engine? Turbo or non? 5sp or auto.? Do you know what gears it runs?

 

As for the engine numbers and the carb., I hope to check today. I need to know so that I order the correct timing chain/belt/belts. When I replaced the distributor cap the parts store had options for carburetor or FI with the 86 gl Fwd/4wd non-turbo 5sp wagon.

2.2liter dohc final drive ratio 4.11 non turbo

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Thank you, men. Naru, that's a very handy bit of info. to know. If that's true, even the 3.54 would only bring the rpms down to 2700 at 65mph (not much difference). Which leaves me wondering why some gl (maybe just the gl-10's) are getting lower RPM's at 60mph.

 

Maybe it is an overdrive 5th gear like Scoob. mentioned (if I understand scoob. correctly the gl10 5sp is not the same trans. as the gl 5sp. (different 5th gear and different spines)). Anyone know the model #'s of gl and gl10 5sp trans? Also, is the gl 5th gear an overdrive or straight through? If the trans. is the difference maker then I'd say it would be easier to switch my engine to a gl10 car than to switch a gl10 drive train to my gl.

 

Maybe, like Djellum mentioned, they are using larger tires to get the lower rpms. It's true you can take off about 500RPM's or more with larger tires. My current tire (185/70/13 - 70.68" circumference) turns 896.43 times to travel one mile (at 60mph that means 896.43 per minute which = about 2900rpms in 5th. So in 5th gear the engine is spinning 3.24 rev.s per wheel turn. So, to do the same distance at 2500rpms I would need to cover 25.35" per engine rev. 25.35 times 3.24 = 82.11" circumference tire would be needed which is 26.14" in diameter (which is 3.4" more diameter or 1.7" more radius than my current tires). That wouldn't be hard to do but would it need a 1" lift to avoid rubbing the frame and fenders when turning (the gl has a nice tight turning radius)?

 

If any lower than 2500rpms at 60mph, I would be concerned that the engine couldn't pull it (possibly why it would only be found on turbo models or larger engines).

Edited by 2Cor6.9-10

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Here is the 3.70 gear numbers for the subaru gl turbo

5th gear 2800 rpm @ 65 mph w/ 185/70/r13 tires

4th gear 3575 rpm @ 65 mph w/ 185/70/r13 tires

 

Nice work! Please tell me where you found that so I can compare some other makes/models.

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I went from stock tires like you have to ones that are 25 inches in diameter give or take. you dont need a lift to do it, but I wouldnt go any higher than 25 inches (actual diameter from the manufacturer, they vary). also my car is an 87 carbureted EA82 wagon with a high low trans. they had both injection and carbs on our years so you will have to check. it will say SPFI on the top of the motor and have a hose that goes to the air cleaner if its injected. if its got a standard old airbox and filter on top its a carb.

 

this link has all the trans drive ratios. with them you can math out the actual rpms with the different tire sizes

http://www.ultimatesubaru.org/forum/showthread.php?t=84798

 

Your really just not going to see a cost savings anywhere here. properly tuned, the difference between 500 rpm at freeway speeds just doesnt save you any amount of gas that is measurable by normal means. by the same token you wont see much harm from larger tires, so I opted to go with 14's for the 1.5 inch lift and tire selection, since I only need to worry about highway miles primarily.

 

bottom line is that it takes an amount of energy to propel your car at 60 mph. the only way to increase the mileage is to reduce the traction, reduce drag, lighten the car, or increase the energy (run more efficiently). you wont see gas savings from lower rpm, you will see them from remaining in the proper power level to keep the motor from working harder. the best way to save gas is not to push the car, let it settle in where its comfortable and has power in 5th gear and go that speed.

 

even if you change gears, select the least rolling resistance tires available, and hypermile the crap out of it, I doubt you would see more than a few miles per gallon out of it. It would likely take you a year just to make the money back on the tires, and you sacrifice traction and power to do it.

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I will repeat it again, the 90 to 94 Loyales, can get gas mileage in the high 30's. That will be your simplest and cheapest way to save gas $$$ in a Subaru. And then you offset the purchase expense by selling your 86 GL wagon. High School and College kids love them.

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in my opinion if he has the spfi motor than there would be little differance in milage getting a loyal they have the same engine and also with the five speed he should be getting at least thirty. personally i like my legacy if your not off roading they are the better choice (in my opinion) they are all wheel drive get around 30 mpg if you have the 2.2 and are much more comfortable than the loyal and defiantly have more power

Edited by mikaleda

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Good info. Thanks for the link djellum.

 

I'll be doing interstate driving and I hoped to do 75mph like the other cars on the interstate without my engine running 3400rpms. Even a 500rmp reduction adds up real fast (500 rev.s per minute is 30,000 less per hour; one 5 hour trip adds up to 150,000 less engine rev.s = less wear on rings, cam, valves, cylinders, etc). However, if the gl is made for continued high rpms (over 3000 for hours at a time) and endures much more engine wear, then so be it. I'll have to drive at 75mph for a few hours and make sure my fuel efficiency doesn't plummet to the low 20's and my engine doesn't blow.

 

I'll look into a Loyale. I'd hate to let the little car go but it may not be the best fit for my needs. I've had a numbers of offers to buy it though I've never attempted to sell it.

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