Author Topic: How many miles per gallon on your older Cadillac?  (Read 10207 times)

Offline homeonprunehill

  • JIM CLC #15000 THOMAS 1938 La Salle 5027
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Re: How many miles per gallon on your older Cadillac?
« Reply #20 on: April 13, 2009, 09:13:08 PM »
readers, theres something wrong with the posting feature I wasn't ready to post my last post.what
USED,ABUSED AND MISUSED CADILLACS AND LA SALLES

Offline Brian McKee

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Re: How many miles per gallon on your older Cadillac?
« Reply #21 on: April 13, 2009, 09:22:01 PM »
I average about 17 miles per gallon in town, 24 miles to the gallon on highway driving with my 1993 Fleetwood Brougham.   I average 19 miles per gallon in town, 26 miles to the gallon on highway with my 1995 Sedan DeVille.

I don't have a Cadillac from the 1970s (which is my favorite era of Cadillacs ever), but if I did and it only got 15 miles per gallon highway, I wouldn't complain.  I would just be glad to have one of those beautiful Cadillacs from the 1970s.
Brian McKee, CLC #24993
1989 Eldorado Biarritz Coupe
1993 Fleetwood Brougham
1995 Sedan DeVille

Offline Glen

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Re: How many miles per gallon on your older Cadillac?
« Reply #22 on: April 14, 2009, 12:58:19 AM »
I think there are a lot of  us more concerned with smiles per gallon than miles per gallon.   :D
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Offline P W Allen CLC# 20193

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Re: How many miles per gallon on your older Cadillac?
« Reply #23 on: April 14, 2009, 04:15:51 AM »
I think there are a lot of  us more concerned with smiles per gallon than miles per gallon.   :D
You got it! Well said!! :D
Paul
53 Coupe
Twin Turbine

Offline baxterculver

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Re: How many miles per gallon on your older Cadillac?
« Reply #24 on: April 14, 2009, 11:54:04 AM »
Fred,
Don't check your LaSalle's gas mileage.  Love the car for all of it's beauty.  Doug Houston's post gives you all the info you need to know about 39's and early '40's.   I know my '39 60S, once only, averaged 16 on a tour.  Usually, it's between 12 and 14.  The Cadillac weighs less than my 2000 Dodge Dakota, but has the aerodynamics of a large brick. 

But then, I don't drive it that much and it is still better than my newly acquired '65 Buick Riviera--with dual quads and a 425 engine.  On that one, when I step on the throttle the gas guage moves to the left faster than the car can accelerate. 

Another car that won't be driven all that much.
baxter culver clc#17184

Offline Walter Youshock

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Re: How many miles per gallon on your older Cadillac?
« Reply #25 on: April 14, 2009, 12:16:12 PM »
Every time I hear a 500 from the early 70's start up, I swear they say: "FEED ME!  FEED ME!!!"

Absolutely right--ENJOY THEM!!!!  Automobiles like this will NEVER be made again--at least not in this country.  These rolling Time Machines are a part of our Heritage.  I'm thankful that I'm old enough to still remember when some of these were new and that there are clubs like ours that exist for the promotion of nostalgia and a little bit of insanity.
CLC #11959 (Life)
1957 Coupe deVille
1991 Brougham

Offline Richard Sills - CLC #936

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Re: How many miles per gallon on your older Cadillac?
« Reply #26 on: April 14, 2009, 12:32:19 PM »
I have been driving Cadillacs on a regular every-day basis since 1973.  I can tell you that Cadillacs have consistently gotten better gas mileage than most other full-size cars of the same era.  In my experience, people who claim Cadilacs are "gas hogs" are usually know-nothings who have have never owned or driven a Cadillac.  They just make an assumption based on the Cadillac's dimensions, and because it is easier for them to target people who drive Cadillacs rather than Plymouth Furys or Pontiac Catalinas.

The cars I have owned with conspicuously worse gas consumption have included a 1963 Ford Galaxie 500-XL with the 390 V-8, and a 1979 Continental Mark V.  Both of those cars never broke double-digits in the gas mileage department, even when cruising on the highway.  (I still enjoyed them, though.)



Re: How many miles per gallon on your older Cadillac?
« Reply #27 on: April 14, 2009, 01:21:53 PM »
Fred,
Don't check your LaSalle's gas mileage.  Love the car for all of it's beauty.  Doug Houston's post gives you all the info you need to know about 39's and early '40's.   I know my '39 60S, once only, averaged 16 on a tour.  Usually, it's between 12 and 14.

I was browsing through my copy of Roy Schneider's "Cadillacs of the Forties" last night and I came across fuel economy figures for the 41-61's (I assume they are from GM proving ground tests) that confirm your figures and Doug's: At 50 MPH 15.8 MPG with the 3.77 axle and 17.3 with the 3.36; at 70 MPH 11.9 MPG with the 3.77 and 12.7 with the 3.36. Keep in mind that Cadillac touted the improvement in fuel economy of the '41's over the '40's; one of their print ads told of driving a '40 and a '41 between two cities and how the '41 would make it all the way while the '40 would run out of gas so many miles short of the second city.



Offline David #19063

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Re: How many miles per gallon on your older Cadillac?
« Reply #28 on: April 14, 2009, 02:03:20 PM »
My '68 Fleetwood Brougham with a freshly rebuilt 472 with the 3.21 Limited Slip Axle and dual 2" exhaust would get 11.5 - 12 mpg with the cruise set at 74 mph and the AC on.  Around 9-11 mpg in pure city short drive driving.
David #19063
1996 DeVille Concours

Offline Eric S. Maypother #15104

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Re: How many miles per gallon on your older Cadillac?
« Reply #29 on: April 14, 2009, 06:32:22 PM »
I think there are a lot of  us more concerned with smiles per gallon than miles per gallon.   :D

I second that, a few Cadillac's ago I had a Smiley Face bumper sticker that said "This cars gets 100 Smiles Per Gallon"

On the 1990 Brougham with a 5.0 I just bought, driving 100 miles highway, 75 miles around town it averaged 14MPG. It burns oil and needs a tune up, the idea of the 5.0 over the 5.7 was suppose to save fuel but I was told the 5.7 FI gets better mileage, I never checked the mileage on my 5.7, the speedometer wasn't accurate. On a 1985 Fleetwood Brougham I had I think I averaged around 16 around town, driving to Florida and back I averaged 21MPG. I think my 1969 Sedan Deville got about 10MPG, my 1966 Sedan seemed a little better.

I'd only start to worry if I got less than 10MPG and gas goes over $5 a gallon.

I've also heard from people that Cadillac's got better mileage than full sized Ford's and Buicks, I know a guy who sold used cars who said people would trade in their Buicks for a Cadillac because the Cadillacs got better mileage.

I use to work in a gas station and people would always have some comment about how much gas I must use, how can I afford it, etc. Then I'd see their repair bills for Toyota's and other small cars, what they saved in gas they paid twice in repairs, not to mention they were paying monthly payments plus higher insurance
Eric :)
1990 Cadillac Brougham

Offline Guidematic

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Re: How many miles per gallon on your older Cadillac?
« Reply #30 on: April 15, 2009, 09:42:47 AM »

 These 70's Cadillacs can get some decent mileage figures if they are properly tuned. My '75 Coupe used to get 23MPG. I was a fanatic for keeping that thing in tune. Now my '70 with the 472 will pull 20MPG on a highway run at about 70-75MPH. Seem fantastic? I'm also a fanatic for tuning that engine. HEI is a huge factor in attaining good fule economy.

 Now, I have a couple of 80's Cadillacs. Last weekend on a trip I averaged 21MPG with my '89 Brougham. That was the average for the whole trip which included idling, running into town a couple of times and cruising at 120KPH. The car was fully loaded. 4 passengers and a packed trunk. On a straight highway run it will pull 25MPG.

 My 1988 Eldorado with the 4.5 will run 33MPG on a highway run, and averages 29MPG over the same trip that I went on last weekend.

 I have found that meticulous tuning on the 472/500 can yeild some very impressive mileage for the type of cars they are.

 On 80's cars, they usually respond to timing set as much as 4 degrees ahead of factory settings. They were set retarded for emissions reasons. My Brougham is running 24 degrees as opposed to the 20 recommended. The Eldo is set at 14 as opposed to the 10 as recommended. They are also more responsive, and in the case of the Eldo, it has become somewhat of a screamer. Both still run fine on regular gas.

 On the '70 it is set at 10, and the distributor advance is connected to manifold vacuum. The TCS has been removed. I also have installed an HEI distributor.

 All mileage figures are quoted in Imperial Gallons. There are 4.55 litres in an Imperial Gallon as opposed to 3.79 in a US gallon.

 Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

Offline Otto Skorzeny

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Re: How many miles per gallon on your older Cadillac?
« Reply #31 on: April 15, 2009, 09:58:59 AM »

All mileage figures are quoted in Imperial Gallons. There are 4.55 litres in an Imperial Gallon as opposed to 3.79 in a US gallon.

 Mike

So, if I did my math correctly:

My '75 Coupe used to get 23MPG.                                                                                                                  Is really 19.16mpg
Now my '70 with the 472 will pull 20MPG                                                                                                         Is really  16.66mpg
Last weekend on a trip I averaged 21MPG with my '89 Brougham                                                                        Is really 17.49mpg
On a straight highway run it will pull 25MPG.                                                                                                      which is  20.82mpg
My 1988 Eldorado with the 4.5 will run 33MPG on a highway run, and averages 29MPG over the same trip                27.49mpg,  24.16mpg
« Last Edit: April 15, 2009, 10:02:34 AM by ottoskorzeny »
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Offline Coupe

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Re: How many miles per gallon on your older Cadillac?
« Reply #32 on: April 15, 2009, 11:53:02 AM »
The only time I checked my '57 was on it's trip home from Devils Lake, ND when I bought it. I thought this thing is getting pretty good mileage and then I ran out of gas just past the Ashby, MN exit. 18 gallons got us 245 miles, 17 air horns and too many smiles to count. I haven't checked it since, why bother,  if I wanted mileage I'd have restored a VW.
1957 Coupe de Ville
1962 Sedan de Ville (4 window)
1993 Allante

Art Woody

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Re: How many miles per gallon on your older Cadillac?
« Reply #33 on: April 15, 2009, 01:29:48 PM »
I will drive my '53 and enjoy it thoroughly if it gets 10 mpg or fuel goes to $5, but if it is supposed to get 18+, I'm going to tune on it until it is right. I'm not wealthy in terms of dollars by any means, and even if I was , there's all lot of other things I would rather spend them on than gasoline.

Offline Guidematic

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Re: How many miles per gallon on your older Cadillac?
« Reply #34 on: April 15, 2009, 10:35:39 PM »
So, if I did my math correctly:

My '75 Coupe used to get 23MPG.                                                                                                                  Is really 19.16mpg
Now my '70 with the 472 will pull 20MPG                                                                                                         Is really  16.66mpg
Last weekend on a trip I averaged 21MPG with my '89 Brougham                                                                        Is really 17.49mpg
On a straight highway run it will pull 25MPG.                                                                                                      which is  20.82mpg
My 1988 Eldorado with the 4.5 will run 33MPG on a highway run, and averages 29MPG over the same trip                27.49mpg,  24.16mpg


 Yes, you would be right. I always go to Imperial gallons since that was the measurement we used before the metric fever hit us in the mid 70's.

 A gallon is 4.55 litres and a mile is 1.6 kilometres.

 And the English scale on the DIC on the Eldo converts to US measurements, so I have to do a quick conversion in my head to get the Imperial measurement. An Imperial gallon is approximately 20% larger than a US gallon.

 Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

Offline Kevin Bielinski #13320

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Re: How many miles per gallon on your older Cadillac?
« Reply #35 on: April 16, 2009, 06:29:14 PM »
My '70 gets about 9mpg in the city and around 15 or so on a good highway run.

Offline Otto Skorzeny

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Re: How many miles per gallon on your older Cadillac?
« Reply #36 on: April 17, 2009, 07:00:27 AM »

 
I think my 1954 Cadillac 62 is doing quite a bit better than that ... but I've been afraid to check it ... 
 
I'm just happy to see actual mileage being quoted on this thread ... instead of just wishful thinking that you usually see bragged about  ...  ::)

 
Don't be afraid to familiarize yourself with this aspect of your '54's performance, David.
 
I've been aware of the fuel mileage performance of every car I've ever owned since high school. Part of it is idle curiosity but most of it is germane to keeping my vehicles in perfect operating order.
 
Being aware of a vehicle's fuel consumption can play a key role in keeping them tuned up correctly and heading off trouble. If a vehicle (old or new) starts consuming more fuel than normal, that is a sign that other problems exist or may be on the way. With old cars it could mean that it's time for a basic tune up or that the carburetor needs adjustment or a rebuild. On modern cars it could indicate a more serious problem with various electronic modules and sensors.
 
Abnormally high fuel consumption can also be a sign of more serious trouble with your car but you get the point; knowing the average mileage is an important tool in keeping a vehicle in good working order.
« Last Edit: April 17, 2009, 01:53:56 PM by ottoskorzeny »
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Offline Guidematic

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Re: How many miles per gallon on your older Cadillac?
« Reply #37 on: April 17, 2009, 09:50:06 AM »


 That's exactly it. You have to monitor the fuel economy of your car on a regular basis. Most of the time poor economy is the result of a poorly tuned engine. This can be the result of lack of proper maintenance, or poor techniques.

 Also, as in the case of cars built in the 70's and 80's before the advanced engine management systems we have today, many were somewhat detuned from their potential in the interest of low emissions. One of the more common approaches was retarded ignition. Others such as cam timing and profile, along with EGR systems stole away the efficiency of the engine. There is not much you can do about camshaft timing and profile unless you replace the cam, but spending some time with the car and working out your own tuning techniques can yield both better performance and fuel economy. Remember, that was how successful racers did it in the old days. Much was astute tuning.

 But, outside of tuning and maintenance, other factors can contribute to both poor performance and fuel economy. Engines with excessive wear resulting in lower compression in any or all cylinders, and a worn timing chain could be the bigger factors. These are not so easily fixed, though.

 Throughout the 50's, Cadillacs were celebrated for their fuel economy that rivaled or bettered lesser, lighter cars. This carried on pretty much through the 60's and into the 70's. I'm not saying that you will get 6-cylinder economy from a 390 or 429, but there is the potential for decent fuel economy by paying attention to the details.

 I have proven that for myself, and the numbers I have posted are not whimsical numbers, but real numbers. In the case of the '75, I worked out the calculations three times before I convinced myself that the number was indeed correct.

 Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

Offline EdDougher

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Re: How many miles per gallon on your older Cadillac?
« Reply #38 on: April 18, 2009, 04:57:01 PM »
My '79 CDV with CA emissions gets 13 mpg.  Not bad for a 7 liter engine when you consider that my 7 series BMW gets 15mpg with a 4 liter V-8.

Offline Chris Conklin

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Re: How many miles per gallon on your older Cadillac?
« Reply #39 on: April 20, 2009, 04:41:36 PM »
There were a lot of jokes made about this in the last election, but maintaining your tires, along with all other mechanical items, can give you another mile... and keep you safer. There was a recent thread on the forum about tires and I recall somebody saying that the air stems on his car were hidden under the wheel covers and not readily accessible. I shuddered a little bit when I read that one. Anybody out there that has spent a fair amount of time in two wheeled pursuits could attest to what tires can do for you (and to you).
Chris Conklin

 



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