mpg?

billjay54 · 10-18-2009, 06:13 PM

I have an 81 LTD with a 5.0L with a carb on it. I just took a trip and was getting 17 mpg with it at an average 75 mph. I just bought the car a couple of weeks ago and want to know if this is decent milage or not. I was getting 16 around town.

What do you have and what kind of milage you get.

mark v · 10-19-2009, 12:22 PM

Seems very good to me.

billjay54 · 10-20-2009, 05:12 PM

I was thinking this was pretty good, but it has been a long time since I've owned a V8 so I wasn't sure.

Thanks

GalaxieJeff · 10-22-2009, 12:15 AM

With my old '79 LTD, 302/carb and C4 I would get 19 and change at 70-75 and low 18's at 75-80. Through the mountains it dropped to 16 at 55-65 mph.
Couldn't tell you what city driving was, I've long forgotten, only remember the highway mpg because that was on a couple vacation trips and I logged those in a record book. Back then it was 2 adults an one child (and a trunk partially full of luggage).
Though no over drive, the axle ratio was 2.29!

I did put duals on it, factory pipes but turbo mufflers.

If you have an AOD on your '81 I would expect a little better mpg, mid 20's at 65-70.
A friend has an '89 Caprice (bone stock), 305 4bbl with 700R4, he easily gets mid 20's and has gotten as high at 28 with 100% gas (not this 10% ethanol crap) at a steady 65.

mark v · 10-22-2009, 11:11 AM

Gas mileage all depends on where you live, weather, humidity, tires, altitude. Gas has also changed a lot over the years. If I run the old gas I can gain approx 2 to 3 mpg, with the reformulated gas I loose 2 to 3 mpg.

Bat out of Hell · 11-04-2009, 08:53 PM

Right now I'm getting 14 mpg with a mix of in town and highway driving. a new carburetor helped a lot! I have a 78 LTD with a 351w and a c4 tranny.

GalaxieJeff · 11-05-2009, 12:17 AM

Your '78 is a completely different beast, almost 4800lbs vs the downsized '79 and later 3900-4000 lb cars.

GalaxieJeff · 11-05-2009, 12:26 AM

Speaking of different beasts, my first car, a '67 LTD 390 2bbl (originally and at the time I took these trips) and 2.75 rear gears got a tick under 19 mpg on one trip driving a steady 60-65, posted 55 the whole trip. The next trip to the same place, same weather conditions at 70-75 dropped it to 16.5. Though most of my driving was city, lived in Chicago, I never bothered checking out mileage, didn't much care at 50¢ a gallon!
Some 16-17 years ago when my current Galaxie, also a '67 still had her bone stock 289 2bbl and 2.80 gears, would get the exact same mileage as the LTD did decades earlier, 18.8 at 60-65. I can only attribute this to the 10% ethanol used in todays gasoline. Straight gas I can see the 289 getting 22 at the same speeds.

Bat out of Hell · 11-05-2009, 09:30 PM

What kind of mpg would I be able to get if straight gas were ran through my 78?
I'm happy to be getting 14! it's a lot better than the 10 mpg I was getting just a couple weeks ago! I probably could get a little better gas mileage if I tweaked the timing but it's running good right now (except for the heat going out on Monday)! so I'll probably leave it along until spring.

GalaxieJeff · 11-05-2009, 10:11 PM

About 1 to 1.5 more maybe 1.75.
Depending on the car the mpg increase between E-10 and straight gasoline is 5-15%.