Terrible mpg

[Hank Roberts]

Chuckle. Flamewars get the lowest mileage of any fuel-burning activity. I'll join ...

 

My '88 GL 5-speed 4wd is still ... a challenge. I'm on my 4th mechanic, finally found the quiet little guy on the far side of town who actually knows older Subarus.

 

The rebuilt engine's been back to the rebuilder and re-rebuilt twice now, in less than two years, and it's now dripping from a third spot (the right head gasket), after they fixed the first two loose/leaky seals. I can certainly recommend their warranty, and I do know some people get the string of bad luck, that's statistics (grin -- not calculus ...). Waiting to decide if it needs a fourth rebuild to hold oil.

 

But the mileage has been awful -- about 19 around town.

 

Can this bad gas mileage be caused by a clogged catalytic converter maybe?

 

The front one was both melted and half clogged, and I had the guts of it replaced, welded back into the old case because that was good. Rear cat is partly melted but not clogged so was left alone this time. (I gather some of the mess the leaky engine put through the system may have clogged up the cats?)

 

SPFI, stock wheels, standard tires, newish wires and plugs, all the things that ought to be done with a rebuilt engine, and it's now just passed California smog. The first three soi-disant "mechanics" had left the timing set to 30 BTDC. The latest guy set it to 20, he said; smogcheck says it's at 22 BTDC a week later (can it be slipping?)

 

I'll try a freeway trip after I top up the oil.

 

Just for the record: smog report was good, way below the average. And here, particularly kids living near the freeways are really hurting from the bad air. It's my personal choice to do the best I can on smog control, and losing some mileage for best air quality.

 

Your air may be different, no argument about that from me.

 

But -- 19 mpg??

[GeneralDisorder]

But -- 19 mpg??

 

SPFI should be real close to 30. Maybe even a bit higher. 31, 32 isn't out of the question under ideal conditions. The FI can do more about conserving fuel than the carbs can.

 

When was the O2 sensor changed last?

 

GD

[jacobs]

Clearly you don't understand. Emperical evidence is not proof. We require hard data. You can jump up and down and claim the earth is flat all you want - I nor anyone else here will believe your claims without reproduceable data. That's how science works. Sorry. If I'm a jerk for saying what we're all thinking.... well so be it then.

 

We would all love to get this mythical unicorn mileage you have - so help us out. Be all you can be. If it's true maybe CNN.... Leno - who knows. Sky's the limit man.

 

GD

Rick,

I can give you hard data, but I can STILL give you erroneous figures. I can supposedly have an unbiased person verify what I give you, but will you accept that....I think not. The only way to prove it to you is for you to actually experience it yourself.

 

PUT YOUR MONEY WHERE YOUR MOUTH IS OR SHUT UP!!!!!!!!!!!!!

[GeneralDisorder]

No - I won't shut up. Produce repeatable methodologies that ANYONE here can reproduce on their own, I'll produce the data myself, and only THEN will I believe the claims. That is accepted scientific method. Labs don't bet money on results. They produce unbiased data, and draw conclusions from it. Without the *exact* specifications of your test rigs and test parameters your claims mean nothing just like the rantings of UFO researchers, so-called cryptozoologists, and dozens of other crackpot sciences that otherwise smart people came to believe for non-smart reasons.

 

You continueing to berate me with lots of CAPS sentances telling me to shut up is just strengthening my argument against your claims. Children act like that - it's called a "straw man" argument - attacking the person rather than the data in the hopes of distracting the listeners. Perhaps take some classes on argumentative writing:

 

http://en.wikipedia.org/wiki/Straw_man

 

GD

[Bill90Loyale]

GD-

You're really being too kind to young Jacobs - who needs, while he's in the Wiki, to look up "ad hominem" also. This, as the Disorder (at least) would know, is when someone with a lame argument seeks to divert attention from the factual defects by waging a personal and unrelated attack on their adversary. For example: "2 + 2 is indeed 5, and, while we're at it, you have a big nose." Jacobs, stand down. You've got to learn not to start fights that you cannot win. The answer: about 22 mpg when it's really cold, and 36 in ideal conditions on the freeway with a tailwind. 40? Not.

[jacobs]

Rick,

You wanted to know how I acheived my results, read on....

 

As you should know, every vehicle is different. Different compression ratios, different clearances, turbo vs. n/a, different vehicle milage, different transmissions, and etc. As you also know, I use carburetors. Are you willing to install a carb and get rid of your computer controlled distributor? If not, I doubt you’ll ever experience any gains.

 

1. Carburetion - I experimented with different jets and float levels in my carb to see what works best and no it isn’t stock. Since every engine is a little different, you’ll have to play with jetting and float levels to see what works best. It was a matter of trial & error but it is leaner than stock and the float level is lower.

 

2. Timing, Initial - Once again trial & error but much more that factory specs.

 

3. Timing, Total - Again, more than factory

 

4. Drive 55 mph max. and accelerate like there’s an egg under your foot.

If you do these four things, and drive on level ground, any decent carbureted Subaru will get 36+ mpg. One set of specs. won’t apply to every EA82. It’s a matter of much trial and error and a lot of time to see what your engine likes.

[GeneralDisorder]

Rick,

You wanted to know how I acheived my results, read on....

 

As you should know, every vehicle is different. Different compression ratios, different clearances, turbo vs. n/a, different vehicle milage, different transmissions, and etc. As you also know, I use carburetors. Are you willing to install a carb and get rid of your computer controlled distributor? If not, I doubt you’ll ever experience any gains.

 

Unecessary. Anything a carb can do, FI can do as well. I'll chalk that statement up to little or no understanding of electronics. Timing, mixture and a lot of things that carbs can't do is all done in software with FI. Besides that I own and drive both.

 

1. Carburetion - I experimented with different jets and float levels in my carb to see what works best and no it isn’t stock. Since every engine is a little different, you’ll have to play with jetting and float levels to see what works best. It was a matter of trial & error but it is leaner than stock and the float level is lower.

 

Ok - what jets did you use? What float setting, and on what carb? I can't test it with "trial and error". For the most part, the exact settings you use should give close enough results to prove it one way or the other.

 

2. Timing, Initial - Once again trial & error but much more that factory specs.

 

How much?

 

3. Timing, Total - Again, more than factory.

 

Again - how much above max advance, and how exactly did you modify the distributor to accomplish this.... or is it just the same added to the bottom of the timing curve at the top?

 

4. Drive 55 mph max. and accelerate like there’s an egg under your foot.

 

Unrealistic for most people, but for testing purposes it's doable. 55 for a few long freeway stretches with the CC set should do it.

 

If you do these four things, and drive on level ground, any decent carbureted Subaru will get 36+ mpg. One set of specs. won’t apply to every EA82. It’s a matter of much trial and error and a lot of time to see what your engine likes.

 

When I have enough info, I'll attempt to compile some results....

 

GD

[jacobs]

Rick,

 

You are at a different altitude so my specs won't apply to where you are even if your engine was identical to mine as to wear & etc.

 

Like I said, it's a matter of trial & error to see what works. If you don't want to spend the time, you'll never know what works and what doesn't.

[Frank B]

I can attest that it is possible to get 30 to 40 mpg from a subaru. I had an all stock 86 4wd 4 speed hatch that got 37 mpg best with snow tires on it! My present 89 hatch 4wd 4 speed gets 32 mpg best with a worn disty and carb. When Wagonsonly drove the 89 GL-10 I sold him home from VA to CT, he got 35 mpg!

Don't call BS on something just because you haven't done or seen it.

[casioqv]

Unrealistic for most people, but for testing purposes it's doable. 55 for a few long freeway stretches with the CC set should do it.

 

I don't think he's lying, but I would like to see some more information. If you drive 45-55mph and are very gentle on the throttle, many cars will give incredible fuel economy improvements. I would get a graduated cylinder full of fuel, and drive at a perfectly constant 55mph on level ground (measured with a GPS) while the passenger times how long it takes to use a specific amount of fuel. It could be dangerous to have a cylinder of fuel in your cars cabin, but I'd bet the fuel economy would be over 40mpg. It's basically impossible to always drive like that. Unless you live in Nebraska, sometimes you have to stop or turn. I would really like to see someone try this, and report how the fuel economy differs over the range 40-80mph with 5mph intervals.

[GeneralDisorder]

Rick,

 

You are at a different altitude so my specs won't apply to where you are even if your engine was identical to mine as to wear & etc.

 

Like I said, it's a matter of trial & error to see what works. If you don't want to spend the time, you'll never know what works and what doesn't.

 

Yes, but it's not *just* me that may use the info. And there are other board members that are closer in elevation to you. Plus it's something to work off of, and will give us the ratio of primary to secondary you are using. It's not completely useless to tell us what you are running. But you are thinking more along the lines of how you should be by noticing the altitude difference. All those factors are things that we need to take note of so testing can be as complete as possile, and the results can be repeated by others.

 

Besides, what's the difference? If you know the numbers, and have recorded the data then it should be a simple matter to tell us what all has been done.

 

And besides jet sizes I asked about your timing. The method you used to increase the max advance for example is not dependant on elevation.

 

I'll also add, that while you are about 2650 feet higher than me, air density at your elevation isn't a whole lot different. If it's tuned right it shouldn't make a whole lot of difference in ranges under 3,000 feet. Granted it will change *some*, but overall I should still see within 2 to 3 mpg using the same jetting setup.

 

GD

[GeneralDisorder]

I don't think he's lying, but I would like to see some more information. If you drive 45-55mph and are very gentle on the throttle, many cars will give incredible fuel economy improvements. I would get a graduated cylinder full of fuel, and drive at a perfectly constant 55mph on level ground (measured with a GPS) while the passenger times how long it takes to use a specific amount of fuel. It could be dangerous to have a cylinder of fuel in your cars cabin, but I'd bet the fuel economy would be over 40mpg. It's basically impossible to always drive like that. Unless you live in Nebraska, sometimes you have to stop or turn. I would really like to see someone try this, and report how the fuel economy differs over the range 40-80mph with 5mph intervals.

 

It's not so much a lie that I'm worried about, but rather a flaw in either his testing methods, or his calculations. While the math isn't complicated, it's amazing how many people can't do it correctly. There's also the matter of making sure the tank is always filled properly, and averaging your results from several tank-fulls to eliminate filling differences, etc. In the grand scheme getting 50 mpg on a single tankfull makes little difference if you are averaging 25 mpg at all other times. Statistics raises it's ugly head yet again....

 

GD

[subie_newbie]

Chiming in a compliment...

 

I bought my old Subaru and subsequently found this message board about three weeks ago, and I must admit I didn't have high expectations of its patrons (think toothless and creepy). I'm a Mechanical Engineer and was thinking I'd find tips about sticking toothpicks in the choke to make 20 h.p. and how to wire in a DVD player to your 86 beater. However, what I've found is willing help, reasonable discussions and points being argued in a civil and intelligent manner, and a hell of a lot of brow beating. And, of all things, discussion of calculus and statistics. All of these make for a lively and interesting place to visit every day, and so I'd like to thank all of you active and inteligent members that make owning this new toy much more interesting and fruitfull.

 

And I get 12mpg. But the motor's aincient and I haven't done anything to it yet...give me time.

[Hank Roberts]

And on mine (19mpg); that's the last 180 or so miles on the odometer, and it's miles accumulated on the previous mechanic's work ---- before I found the current mechanic; so it would have been on 30btdc (and it was pinging), and on the clogged and melted front cat. That's been corrected, it's on a new oxygen sensor, and reset the odometer on a fillup of 87 octane.

 

It takes me two or three winter months, or one summer weekend trip, to go through a tank of gas. So I'll report back sometime around who knows. Watching meanwhile.

[jacobs]

It's not so much a lie that I'm worried about, but rather a flaw in either his testing methods, or his calculations. While the math isn't complicated, it's amazing how many people can't do it correctly. There's also the matter of making sure the tank is always filled properly, and averaging your results from several tank-fulls to eliminate filling differences, etc. In the grand scheme getting 50 mpg on a single tankfull makes little difference if you are averaging 25 mpg at all other times. Statistics raises it's ugly head yet again....

 

GD

Rick,

 

If you'll notice, on Interstates there are mile markers. While they are not always exact, due to accidents and getting knocked out and being reset in a slightly different location, if you check your odometer against them for 100 miles, you'll get a very accurate correction factor for your odometer. I know when they were originally set, they are very accurate because they are set by survey crews. They are accurate to 0.10 ft. in Colorado.

 

I keep a log book for all fuel purchases and maintenance. When I calculate fuel milage, I use an average of 10-15 fuel purchases and like I stated above, odometer milage is corrected.

 

I've kept accurate records of ALL fuel purchases for the last 40 years on all the vehicles I've owned. When I say I get XXXXX mpg, IT IS ACCURATE.

 

I've given you all the details you are going to get. I've worked hard to get the milage I'm getting. If you want to get the maximum milage possible, you'll have to too.

 

I'm done with this @#$%$#@#$% forum. I've got better things to do than to argue with an IDIOT.

 

Goodby.

[GeneralDisorder]

I've kept accurate records of ALL fuel purchases for the last 40 years on all the vehicles I've owned. When I say I get ##### mpg, IT IS ACCURATE.

 

I thought we had established that your word wasn't good enough.....

 

I've given you all the details you are going to get. I've worked hard to get the milage I'm getting. If you want to get the maximum milage possible, you'll have to too.

 

Well - that certainly is a helpful attitude. I guess we'll never know then. It's fun to speculate on the existance of unicorns though isn't it?

 

I'm done with this @#$%$#@#$% forum. I've got better things to do than to argue with an IDIOT.

 

Cool - can I be the *villiage* idiot?? Anyway, with your extrordinarily helpful attitude towards replicating your results, I'm sure you'll be sorely missed here

 

GD

[WoodsWagon]

YOu should be able to walk away from an argument about of all things fuel milage without ditching a whole forum.

 

Whats sad for all you poor lower than 20 mpg suckers is that I'm getting 20 mpg, running on 3 cyls, and commuting through 17 stoplights during peak traffic times in a 3000lb wagon riding on BFG all terains.

 

The power of mpfi on an EJ22. Now if only that injector hadn't leaned out and fried the cyl and valves, it would be getting 23mpg consistantly. I even had it up to 27 cruising at 80 on the highway going to wyoming.

 

I'm on the vehicular Atkins diet.... I avoid carbs.

[Prospeeder]

My little Turbo sedan is getting decent milage for having the intake gaskets leaking and 90% city driving. I dont know exactly what yet, because my Trip odometer JUST unstuck itself the other day, so i filled it up to the top and im gonna see how many miles i can go on a tank.

[daeron]

 

Sad to think that I went to what was considered at the time to be one of the top 100 HS's in the country, and yet my math teacher was unable to tell me how my handlheld calculator can figure the SIN of an arbitrary angle without measureing the lengths of the sides of the triangle.... come to find out later when I took Calc that it's a Taylor Polynomial..... he really should have known that to be teaching HS math IMO. Whatever.

 

GD

 

Well, thats what I was ORIGINALLY gonna comment on, so I will start with that...

 

GD, you learned that in your calc I class in college I take it??? So, that being the case, pretty much anyone who has had college-level calc I should have access to that info.. meaning that, your HS teacher probably, at one time, heard all about that...

 

Unfortunately, it was Charlie Brown's Parents.... BUT we cannot expect every college student planning on being a high school teacher to absorb all these details and retain each like a sponge. Is it sad that your math teacher didn't know? Yes.. but he is only human.

 

Regarding the whole rest of the thread.. GD has actually TOTALLY moderated his own tongue more than he usually does, MOSTLY because you, jonas (if you are reading) have responded well. All he wants is the specific numbers of your car's setup. Are you planning on building it? Is your car a secret prototype that you plan on making a million dollars off of?

 

These forums are here so we can help each other. If you have really found a *GREAT* niche in your build on your engine and carb setup, everyone else would like to know what the skinny is!! thats all!! and you aren't dishing out the goods!! NOBODY is getting angry at you, accusing you of falsehood, or insulting you in ANY way, man.. but you keep on telling us little snippets, and avoiding giving us the entire formula to try and replicate your results. What have you got to lose in telling us exactly what your jet sizes are, exactly what your timing is set at, and heck, why not even toss a compression test in???

 

EVERYONE else wants to get the best possible MPG, that is no secret. Nobody thinks any less of you for making a claim like this, but to make this claim, be asked for specifics by someone interested in trying your design, and then clam up is kinda selfish, if you ask me.

 

And you are talking to (reading the words of) the man who got up and barked at GD for being a little to sharp in the treatment of other forum members... while he and I are on good terms with each other as forum members, we all know he can get his shorts in a twist, and I have called him on it in the past. He is NOT out of line here, he just wants the specs. So do alot of us.

 

Maybe you should try some drugs. Although I have always considered it more of a "nutritional/holistic herbal supplement" than a drug...

[Ginger48]

I’ve been lurking in the background for a long time and I finally decided join so I could respond to this thread since there doesn’t seem to be any guys here that knows or remembers their history.

 

40 mpg is not unrealistic fuel milage. If fact it is actually low considering “Mobil Economy Run” teams were getting close to 30 mpg with full size american cars back in the 1950's and 1960's. This is a well documented and established fact! Since they could get that kind of milage way back then with 4000+ pound automobiles, why shouldn’t a lighter weight automobile with much less frontal area, with radial tires with lower rolling resistance, and with modern ignition and fuel systems get proportionally greater gains?

 

I Googled “Mobile Economy Run” but found little information. If anyone is really interested, I guess you’ll have to go to your public library and look for old Motor Trend magazines. They had many articles on this subject.

[shift]

so,lol, how would i achieve a higher mpg with my wagon? i have no fuel return line, the carb was poorly rebuilt(and has no sense of rich or leanness when the screw is turned) and spits flames. i havent replaced the wires or the plugs. the cap is in good sondition, and the disty is fairly new?? not really sure how much or how far back it is set for tdc, and alot of other things are new on the engine. plus no ac what so ever, just the pulley and belt to the alternator and crank pulley.

[Gloyale]

i should also mention, i put all that new stuff on because the car hadnt been run in about 6 years when i got it....but the sucker fired right up first time!

 

Have you done a compression test? A motor that sat for 6 years could have some pretty sad rings and big rust grooves in the cylinders. Just as thought added to this wild tangent rich thread.

[daeron]

so,lol, how would i achieve a higher mpg with my wagon? i have no fuel return line, the carb was poorly rebuilt(and has no sense of rich or leanness when the screw is turned) and spits flames. i havent replaced the wires or the plugs. the cap is in good sondition, and the disty is fairly new?? not really sure how much or how far back it is set for tdc, and alot of other things are new on the engine. plus no ac what so ever, just the pulley and belt to the alternator and crank pulley.

that got thoroughly answered earlier in the thread :-p

 

I forget who, but you basically need to re install alot of that to make sure everything was working right.. go re read the thread from the beginning, and ignore the flamewar that threadjacked you.

[kingbobdole]

Cool - can I be the *villiage* idiot??

GD

Yes. :-p

I actually used to get about 32 on my SPFI car and about 26 or less carbbed as the carb had issues. I now have 29's and its hard to manage 22 MPG out of the thing, but then I know its running rather Rich(E-test guy told me so)

 

I personally think that anything a carb can do, EFI can do better. I'm a big EFI fan, I've converted 3 Subbis now too

I'm on the vehicular Atkins diet.... I avoid carbs.

+1

[goobaroo]

thanks guys...i was waiting for the war to end before jumped back in.

 

im gonna get that EGR cleaned out real good, then when i get the tools i'll do a compression test.

 

which is better of test? the type that uses compressed air to pressurize the cylinder or the one that just reads the pressure when u crank over the engine?

 

i have a compressor so i think im gonna get the first type. plus then i can tell where the air leaks out i.e. through the coolant into the radiator; bad headgasket, or through the crankcase; bad rings, or through the carb; bad valves..... i think is easier to do and u can really get more info out of it then just PSI numbers.

 

but i'll accept all opinions.