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Fuel Economy in Eagle

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tyrodtom View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tyrodtom Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 9:19pm
When people talk about their mileage,  they tend to tell you about the best mileage they ever got, or the worst they got,  not what they usually get.

My around town mileage in anything is usually horrible,  I live less than 2 miles from where I work.
So during the week my car barely reaches running temperature before I shut it off.
66 American SW, 66 American 2dr, 82 J10, 70 Hornet, Pound, Va.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 9:23pm
also, 18 - 20 MPG highway is pretty good for pretty much any AMC small chassis (01 or 10) with a six and three-speed auto. 15, 16 around town is excellent and 20 on the highway is top-10% territory.

back when i ran a stock 195.6 OHV with 3-speed OD trans, good tires hard, and upgraded ignition, i got upwards of 25 mpg (1963 American). that is VERY GOOD mileage! tiny, stingy engine, OD, etc.

i got 19 - 20 mpg on my 232 in the classic wagon, BW 3 speed auto, and GM fuel injection and motorcraft TFI spark. this was about 1 - 2 mpg better than i got with a carb on the same everything. that was peak MPG, not what i got every time. "always" better than 16MPG, and "usually" 18. i drove 60, 65 mph in that car.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 9:32pm
I tracked mileage over time. 
I created a spreadsheet - I put the date, miles on the ODO, gallons I put in (always filled to "approximately" the same full amount by sound)
I figured the MPG for that tank, cost, cost per mile, and more. It figured the MPG for each fill and the average MPG over time.
I had extremes - the low was about 15 (cold, and I drove it hard and fast on the highway) to a high of upper 20s (cool spring, moist air, and drove in the range of 45-55 mph most of that tank)
I proved that cool wet air was better for my car, as was moderate driving. Town driving didn't hurt all that much but then the stops were few and short. 
Best MPG for me was driving on our country roads and secondary highways keeping it 45-55, and on a cool humid day.
Higher than 55 and the MPG dropped, higher than 65 and it PLUMMETED. Cold weather = bad MPG (even on todays' vehicles like Barbara's 2018 Grand and my son's 2018 Compass Trail Hawk cold weather = BIG loss in MPG)
You can't track MPG by a tank full. You MUST track multiple tanks - at least 3 or 4 tanks. The slant of the stations concrete, direction of your vehicles, and more, can impact how much you fill. 

Doug Shepard has an SX4 with 258 and auto. He used to drive it to work, again, MODERATE MPH of about 55 TOPS and he got in the 20s pretty consistently but he said topping 55 made it drop a lot, too - again, that's SCIENCE - wind resistance increasing exponentially above about 60. 
I agree - with my T5 I could do that.

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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 9:33pm
Originally posted by tyrodtom tyrodtom wrote:

When people talk about their mileage,  they tend to tell you about the best mileage they ever got, or the worst they got,  not what they usually get.

My around town mileage in anything is usually horrible,  I live less than 2 miles from where I work.
So during the week my car barely reaches running temperature before I shut it off.


Cold engines get bad MPG. That's why I made the comment on the stat being too cold - it can make a fair difference if the engine doesn't get hot enough. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 9:41pm
Originally posted by MIPS MIPS wrote:

My initial math on my own Eagle with an "okay" engine and an untuned carb (running rich, so higher than normal consumption) is 13MPG, consisting of daily round-trip distances of 45km. (30km highway at 80-100km/h, 15km city at 40km/h average) Folks without the SelectDrive or SelectDrive left (or stuck) in 4WD will see a significant reduction in MPG.

What was AMC trying to bluff if you had an option-less Eagle with the Inline 4 and lived where it was flat? 25MPG?


Actually AMC's own studies showed only about a 1 MPG difference between 2wd and 4wd modes in the Eagle, not "significant"
 - thus they dropped the select drive in later years. Note modern vehicles are full-time or all-time 4wd - because it makes little difference in reality - because the weight is the biggest factor. The weight is still there. 
My own experience shows some drop but I've not actually measured it scientifically. 
My current Eagle has been my good weather daily driver for over 10 years. (since mid-2007)
I've owned multiple SX4s and owned a 1984 wagon bought new, special ordered, in December 1983
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2019 at 12:45am
My Eagle with an intact 258, lockup 998, select drive, and a 2.35 axle gets high teens in the city and low to mid twenties on the highway. Average. With ethanol gas.

My Hornet does the same. They both get right around 20 MPG at a steady 80 MPH in most conditions.

There were times when I'd run my Hornet really hard, as in floored or nearly floored most of the time for the better part of a fill-up. It never once got worse than 14 MPG. I'm pretty sure the theoretical minimum MPG on it is about 12.

My engines run really good.
1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2019 at 5:49am
Originally posted by billd billd wrote:

The drop in economy is minimal - not 3, 4 or 5 mpg.
Granted you have "some" loss in economy, but it gets blamed for more than a couple MPG drop.
I've never ever had a vapor lock issue on any car, regardless of fuel. I find that interesting in itself, indicating perhaps I keep my cars far better tuned and running better than most?

Chainsaws and trimmers - the cheap plastic fuel lines used have some trouble handling it. How do I get by? Keep spare fuel lines. However, I've found that it only seems to shorten fuel line life by a couple of years. Yeah, I ran plain gas in a trimmer and in 4 years the line was shot - not much different than the one I ran ethanol in. 
There's another reason they say it - the TINY carb orifices are one reason, lack of filter, other things unique to the tiny size. Ethanol like any other alcohol, is a cleaner - anything in the tank goes to the carb. You'll find the troubles are more related to dirt and moisture than the ethanol itself. Again, why don't I have trouble? Hmmmm.......... extreme care of things in general.
I'm on my third John Deere lawn tractor - ethanol since they were new each time. NEVER a fuel system trouble. In fact, they start and run better in the winter and I no longer have gas line freeze due to moisture! So it actually SOLVED a problem for me with iowa climate.  ;-)

Carburetors - I've been to school on those and have certificates and papers from GM, etc., papers from Sun corp, and others.......
 there WAS trouble in the late 70s/early 80s - due to the float valves and seats, and other rubber and plastic parts. TOMCO and others devised solutions. Replace the rubber lines, and put a kit in the carb -no more issues. Remember, alcohol cleans things and will absorb water - car makers warned because of warranty - little else. 
The problem is that those who have no true scientific education on it are the ones spreading the information about how bad and nasty it is and all the troubles.
find my other threads - since the 1970s I've run it in everything (save for the NEW trimmer I have, still under warranty....... then all bets are off)
In any case, this is a thread about Eagle MPG - not ethanol. 
He says 13 mpg and is comparing to others getting 18 - good grief, ethanol won't cause a 5 mpg drop. 
Can't blame the fuel for that. 
how about a bit less "guessing" or blaming and a bit more science and troubleshooting. 
All I'll concur with is a slight drop in mileage ethanol over straight gas. 
Again, been to tech classes on fuel systems, and have had experience since the 1970s with it. Facts, not guesses because someone won't warrant a product and so on. Remember, makers of all things want to cover their butts............ 

How about aiming at the question - what should be looked at for more MPG from an Eagle?
Tires, pressure, alignment, fluids in the TWO differentials, oil in the engine (I run synthetic in all engines save for my 73 because it eats oil for lunch)
Brakes, engine TEMPERATURE (too cold a stat - lower MPG!), I could go on.
I know he said the carb was "ok" but unless I've seen it personally, I will still say - uh, I'd bet it could be better........... those carbs can be tweaked. How's the exhaust system - does it have a CAT???? Those can cause lower MPG big-time. They DO plug and go bad, so can mufflers..........
Why did I get such good MPG - even running ethanol? That tells me there's something BESIDES the fuel going on.

Read what I said to begin with.  I said the gas is formulated for FI.  I never said a thing about ethanol.  I try to take care of my equipment. I have a 25 year old chainsaw, I bought it new. And its had ethenol..since new.  Ive never owned a JD rider, but I have a JD push mower that was built in 1979....it still runs. I have an old Great dane zero turn, its pretty old since it doesnt have the safety stuff on it. 
Ive went to school too.  And Ive also worked as a mechanic too.  
Theres certain things I cant do. I cant do weedeater or chainsaw carburetors..I shake too much..so I just dont do them.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2019 at 8:29am
Actually it's not "formulated for" FI. That's a rumor.
It's formulated for octane, oxygen content/emissions, etc. Not specific to carbs or FI. Fuel injection only does one thing - introduce the fuel to the chamber "atomized". It came into play to reduce emissions by keeping the ratio more controlled and consistent to help the auto makers comply with the 50K miles emissions rules. Actually with injectors, they could be more relaxed with their formulations.... but the states step in with specific requirements to reduce emissions - both evaporative and tail pipe emissions. 
Fuel is controlled more by governments than anything else. Oh, they can advertise they "keep your injectors cleaner" - but they were saying that about carburetors, too, so it's more a marketing thing.
I knew a women who worked for one of the major petrol companies in CA - to hear her talk most of what's said about fuels is myth and rumor spread by folks trying to explain other things, or to cover gripes. 
For example, one of the lies spread about gasoline is that it "loses octane" with time - buzzzzzzzzzz - wrong answer. It does not. If properly stored in sealed containers it doesn't lose octane rating/ability. It can be stored for months without any losses there. (but other things can happen, especially if there's air in the container or it's not sealed)

Anyway, back to Eagle mileage - since some folks can indeed get their Eagles to push upper teens or even into the 20s, doesn't that imply that for those sitting in the LOW teens with fuel economy when DRIVEN at reasonable speeds that are best for economy, that there's something else going on with the low MPG?
It's not like folks like Doug, myself or others have magic carburetors the petrol companies never got destroyed, it's not like we have some tricky system or have a one-off car. 
The fact that even some of us get pretty good economy from our Eagles should suggest that those experiencing only LOW teens at best have some things to consider looking at, be it tune, driving habits (re: SPEED in a car not designed for 70 mph economy), physical engine condition, vehicle condition (tires, alignment, is the car JACKED UP?) fluids in the differentials (even hypoid gear lube can get thick with age and contamination - change that fluid, check the differential carrier and pinion bearings)
I used to commute to college with an AMC 6, I drove another to Denver, all through the Rockys in that state, commuted to work with an AMC 6, and drive one today as a good weather daily driver. If I had gotten only 13 mpg - trust me, that drive to CO from IA would have been expensive and loaded with fuel stops. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2019 at 8:33am
Originally posted by FSJunkie FSJunkie wrote:

My Eagle with an intact 258, lockup 998, select drive, and a 2.35 axle gets high teens in the city and low to mid twenties on the highway. Average. With ethanol gas.

My Hornet does the same. They both get right around 20 MPG at a steady 80 MPH in most conditions.

There were times when I'd run my Hornet really hard, as in floored or nearly floored most of the time for the better part of a fill-up. It never once got worse than 14 MPG. I'm pretty sure the theoretical minimum MPG on it is about 12.

My engines run really good.


Good grief, Matt - your mother may see this post! Yikes!!!

LOL - just messing with ya...

Seriously, that's good MPG at that speed. It's speed that kills mileage with ANY vehicle due to the astronomical wind resistance at speeds over about 60.
Your mileage pretty much fits my experiences with all of the 6 cyl AMCs I have owned. your Eagle pretty much matches what Doug got with his SX4.
Further evidence it's doable and not out of the ordinary.
No chance for carbon build-up in that Hornet, eh? Wink

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jdarosa Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2019 at 11:33am
The exhaust system is stock, and I'm not sure if it's been gone through, although there are no leaks. I do like the idea of full synthetic in the two diffs, and in the engine. Mine goes through a quart between oil changes even though it doesn't leak. I've been under the car and it's pretty clean down there.

The carb's been tuned by a shop that specializes in carbs and older cars, although there's probably some tweaking that can be done. I figured the in-town driving, weight, and auto tranny would lower the fuel economy...just checking around to see if my numbers were on par with everyone else's.

Thanks!
1968 American 440 – 232/AT 4dr
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