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Fuel Economy in Eagle

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jdarosa View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jdarosa Quote  Post ReplyReply Direct Link To This Post Topic: Fuel Economy in Eagle
    Posted: Mar/19/2019 at 9:44am
I've got an '87 Eagle. 258 and auto, 84,000 original miles, all stock. I've got the carb correctly tuned, and there's no issues driving, idling, or anything like that.

Are there any adjustments (carb? emissions removal?) to improve the mpg without something big like changing to fuel injection? I get about 13 in town, and have seen some other posts with claims around 18/gal.

Thanks!
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Post Options Post Options   Thanks (1) Thanks(1)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 11:30am
If everything is ok....check your tire pressure and how do you drive? Step on it?  I know others will say they get better mileage...but I dont believe that. The gas we use today is formulated for FI...which effects your car..  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 1:51pm
Originally posted by purple72Gremlin purple72Gremlin wrote:

If everything is ok....check your tire pressure and how do you drive? Step on it?  I know others will say they get better mileage...but I dont believe that. The gas we use today is formulated for FI...which effects your car..  


This exactly. Ethanol blended fuels didn't really exist when Eagles were new, and have a negative effect on fuel mileage, as well as driveability, especially in the summer months. My 80 Concord 258/auto was barely getting 13 around town on ethanol blend. Once I switched over to real gasoline (I use the pure-gas app on my phone to find stations that sell non-blended fuel) my city bumped up at least 1 mpg, and highway about 1.5 mpg, along with much better driveability.

Eagles are not known for their fuel mileage- the cars are heavyish, and the drivetrains have relatively huge drag losses, so you'll never get more than mid-teens around town, and if you're lucky, 19-20 on the road with the automatic. But as Purple inferred, getting on real gasoline will help you, perhaps more than anything else you might do.  18 mpg around town in an automatic eagle is, IMHO pure dreaming.



Edited by 73Gremlin401 - Mar/19/2019 at 3:18pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote AMXRWB Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 2:56pm
Ours does 12 in the city.Highway miles unknown.Very heavy car to move around due to the four wheel drive.The three speed trans does not help.It would be nice to have more trans gears like the modern cars.
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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 3:42pm

I've never had any issues with ethanol at all and run it in EVERYTHING - but let's not get into that old argument again - with half-truths and mis-information. People will believe what fits what they read or hear at times. My vehicles are evidence to the contrary - and I've been at it since it was first released in this state.

The Eagle is a brick - and a heavy one at that.  The SX4 is what, 3200-3300 pounds? And it sits high, so air goes under and hits the suspension causing DRAG. 
I used to get 18 easily with our wagon back in the 1980s. It can be done, it's not a myth.
Doug S. gets in the TWENTIES with his SX4............ it's a 258 auto. BUT speed is the major issue with these cars - stick to 45-55 for BEST economy. Science has proven that speeds over about 55-60 the wind resistance increases exponentially........... thus the old 55 mph law.
It was based on SCIENTIFIC fact, not politics as the naysayers wish to believe.

My SX did upper teens prior to swapping engines.
Now I can do anything from 17 (smashing around town, cold weather, etc.) up into the mid 20s and Excel ( the spreadsheet I used to track my fills and mileage) had me showing upper 20s for one tank - driving mostly 45-50 in spring.
And yes, with ethanol. It's all I run.
At our 10% I've frankly never seen any difference in driving or mileage if I end up having to use regular gas. I've always run 10% in my Eagles, and when I first got my current SX4 years ago - ran it- but noted that it DOES clean things like tanks and lines so I had to open and clean out the carb a few times LOL. But when I finally tore into the car for real for engine swap, and pulled the gas tank, well, it looks BRAND NEW inside!

Carb tuning is an art - there are tricks that can be done to that 2bbl carb. Also check for engine physical condition - compression, and so on. Makes a huge difference. 
Plugs gapped right, timing set right, make sure there's no vacuum leaks, bearings are good, and go to synthetic fluids in the differentials.
ALIGNMENT can matter, too...... tire scrub with incorrect angles and wear, etc.

My bet - it's not "bad fuel" but other factors. I'd bet on it. ISU would bet on it, too - they've done many studies. 



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Post Options Post Options   Thanks (1) Thanks(1)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 3:55pm
Originally posted by billd billd wrote:


I've never had any issues with ethanol at all and run it in EVERYTHING - but let's not get into that old argument again - with half-truths and mis-information. People will believe what fits what they read or hear at times. My vehicles are evidence to the contrary - and I've been at it since it was first released in this state.


Billd - I'll continue to respectfully disagree with you on this. Alcohol blended fuels by their very nature will cause a drop in fuel mileage purely from the BTUs they don't contain in comparison to gasoline only, and in summer heat, will cause percolation/vapor lock issues at a greater rate than pure gasoline. Carry on.
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81 Jeep J10 LWB 360/4-spd
83 Concord DL 4-dr 258/auto

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MIPS Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 6:41pm
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?

Edited by MIPS - Mar/19/2019 at 6:46pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Mar/19/2019 at 7:26pm
Originally posted by 73Gremlin401 73Gremlin401 wrote:

Originally posted by billd billd wrote:


I've never had any issues with ethanol at all and run it in EVERYTHING - but let's not get into that old argument again - with half-truths and mis-information. People will believe what fits what they read or hear at times. My vehicles are evidence to the contrary - and I've been at it since it was first released in this state.


Billd - I'll continue to respectfully disagree with you on this. Alcohol blended fuels by their very nature will cause a drop in fuel mileage purely from the BTUs they don't contain in comparison to gasoline only, and in summer heat, will cause percolation/vapor lock issues at a greater rate than pure gasoline. Carry on.
x2.  Ive noticed a difference in how carburators reacted to 10 % ethanol.  For many many years Chysler would say dont run it. And alot of lawnmower engines and chainsaws owners manuals specifically say NO ethanol......so just because it runs ok doesnt mean its good. Ive had problems with ethenol. 
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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 8:50pm
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.



Edited by billd - Mar/19/2019 at 8:54pm
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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 9:18pm

this is 1%, 1.5% territory. YMMV (lol). tire construction and pressure will matter more.

measuring fuel mileage is a lot of work. one tankfull is flatly not enough. back when i ran an LPG 232ci classic wagon, i measured fuel consumption annually, recorded every single fillup. huge PITA. i no long er do this.

fillup to fillup variances are always far higher than you think reasonable. i dont know why. i dont think any amount of skill or care will make one fillup more accurate.

URL above has the complete table.



Fuel: liquid, US gallonsGGEBTU/gal
Gasoline (reformulated gasoline, E10 - ethanol)1.0190111,836
Gasoline (reformulated gasoline, ETBE)1.0190111,811
Gasoline (reformulated gasoline, MTBE)1.0200111,745
Gasoline (10% MTBE)1.0200112,000
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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