: Gas Mileage on a '89 Brougham



Stallion
01-28-07, 07:55 PM
What kind of MPG would an '89 Brougham get?

Thanks!

I~LUV~Caddys8792
01-28-07, 07:59 PM
I think they're rated 17/24 but I'd expect like 14 or so in town, and 21-23 highway in good tune.

Benzilla
01-28-07, 09:08 PM
Pretty much what he said. Less the way I drive.

Cadillac Giovanni
01-28-07, 10:15 PM
Sometimes I'm sort of a leadfoot, and also my town has alot of stop signs so i slow down often, but 14 mpg in the city is pretty good. I was getting better than that when my catalytic converter was MIA, and once i did a bunch of highway driving out to the cape and back, and i got an estimated 28 mpg. It's hard to be exact with those old gauges, but that's still pretty good.

90Brougham350
01-28-07, 10:20 PM
That's damn good! As of late I've been getting probably 12 city. But then again, I've been whippin' shitties left and right in the snow.

Cadillac Giovanni
01-28-07, 10:48 PM
That's damn good! As of late I've been getting probably 12 city. But then again, I've been whippin' shitties left and right in the snow.

HAHAHAHHAHAHA! "Whippin shitties!?" That's the coolest thing i've ever heard!

But yeah, slidin' on the ice eats up the octane like nothin' else. WHenever the local church parking lot ices over, I'M THERE!

badpenny
01-31-07, 01:20 PM
Rejetting and Flashing the computer ,is the only way I can see that I will get better milage. Gosh, I wish I could get better milage. Right now I am getting 13 city and 22 highway.

Cadillac Giovanni
01-31-07, 08:29 PM
That's not that out of the ordinary. The gauge on my brougham is a little whacked, so I estimate about 10 miles to the gallon before i need to fill up again, just to be safe. That way i have a buffer zone in case i need to travel exponentially further in order to obtain gas.

Although once, i ran out and had to push the car (Pushing cadillacs by yourself is not recommended) luckily there was a gas station just up the street. I ran out again later on, but i had enough momentum to coast into the nearest gas station. People look at you funny when you pull up to a pump without your engine running.

ReagansRollsRoyce
01-31-07, 09:17 PM
Sometimes I'm sort of a leadfoot, and also my town has alot of stop signs so i slow down often, but 14 mpg in the city is pretty good. I was getting better than that when my catalytic converter was MIA, and once i did a bunch of highway driving out to the cape and back, and i got an estimated 28 mpg. It's hard to be exact with those old gauges, but that's still pretty good.


Wow, I got the same MPG (28) out on the cape (cod) as well! Only time I ever did that well...I went 55 in the 55 zones and used cruise control.

Lately 12-14 in town, 21-22 highway, 15-17 in mixed driving.

bhoppes
01-31-07, 09:37 PM
I usually get around 20 with mine. I have never heard of 28 though! How do you guys do it?!

Cadillac Giovanni
01-31-07, 10:25 PM
Wow, I got the same MPG (28) out on the cape (cod) as well!


Haha, small world, I did my 28 mpg run out on Cape Cod as well, maybe we'll run into each other (figuratively) sometime.

I found it very easy to get good gas mileage using a little trick. My catalytic converter was hollowed out at the time and would reverberate the exhaust very loudly if i was heavy on the pedal. It would give me a good idea of how hard the engine was working versus how hard I was pushing the pedal. If i could maintain speed while keeping the cat as quiet as possible, I would often get phenomenal gas mileage.

N0DIH
02-02-07, 09:31 PM
I have a 94 Fleetwood Brougham with the factory 3.42's and haven't ever seen over 21 mpg yet... Not matter what I have done.

Cadillac Giovanni
02-02-07, 10:59 PM
Maybe you should take it out to Cape Cod. I think the air out there has some sort of mysterious chemical composition that when mixed with fuel creates phenomenal gas mileage.

ReagansRollsRoyce
02-03-07, 12:26 AM
Maybe you should take it out to Cape Cod. I think the air out there has some sort of mysterious chemical composition that when mixed with fuel creates phenomenal gas mileage.

It's the cranberries I tell you. We should start formulating gasoline blends with cranberry sauce!

Cadillac Giovanni
02-03-07, 12:58 AM
I can see it now!

"87 Octane", "90 Octane" and "Cran-Octane Splash"

Fruit juice in the gas tank! It'll be like V-8 for your V-8!

GenoTheLowrider
02-06-07, 08:05 AM
I get about 17 city and around 25 highway. I got the good ole platinum AC Delco plugs, and the tornado fuel saver, as well as Dual Exhaust that gets me breathing real good for some good mileage!
--Geno TL

N0DIH
02-06-07, 12:03 PM
What year car and engine?

I still want to find out how the 307 does with true dual exhaust....


I get about 17 city and around 25 highway. I got the good ole platinum AC Delco plugs, and the tornado fuel saver, as well as Dual Exhaust that gets me breathing real good for some good mileage!
--Geno TL

GenoTheLowrider
02-06-07, 12:48 PM
I have the 89 Caddy Bro with the stock 307 engine in it....
--Geno TL

N0DIH
02-06-07, 01:57 PM
Got any picts of the exhaust? How did you run it? Both on one side, or cat back duals, down each side?

My 85 Cutlass I worked out how I could easily run 2.5" duals down one side around the cat and then back to one on each side. There was just enough room to do it and do it very well. I assume the 86-90 307 cars could do that just as easy.

Old Fleetwood
02-06-07, 04:32 PM
I have to wonder if the lack of resonance in the cat by feathering the pedal meant that a high VACUUM was being drawn.
THEREFORE - would that mean that for the best mileage does it mean that all ya gotta do to get the best mileage is hook up a VACUUM GAUGE and drive so that THE VACUUM GAUGE READS AS HIGH AS YOU CAN POSSIBLY GET IT? :confused: :stirpot:

N0DIH
02-06-07, 04:42 PM
Some say yes, I don't completely agree, as when I had my MAF hooked up and watched carefully the MAF, Injector Pulse Width and MAP readings, they did NOT correlate with that.

Lowest airflow has to be least fuel flow, as the PCM is maintaining 14.67:1, least airflow is least fuel flow. If highest vacuum was correct, drive around in 2nd gear. At 55 mph you have great vacuum! And then 3rd <60 mph...

Honestly, highest gear you can and lowest vacuum is probably best. The more throttled you are the worse the effficiency. You don't want to lug the engine, but you don't want to throttle it back unnecessarily.

It still takes the same amount of gasoline to make x hp. If you have more cyls, you have more friction to make up the difference and some loss there, but if you compare most engines that make the same amount of hp, they have the same size injectors combined.

Old Fleetwood
02-06-07, 08:07 PM
That's why I put in the "stir the pot" symbol ! ;)
However, as a general rule, high vacuum will often give back decent mileage as when GM, Ford and Chrysler all had some sort of light or telltale on the dash to show the average dimwit when he or she was driving most economically.
I think Mopars had a tiny red (white?) light like a bright light indicator inside the speedometer that lit up when you laid off the heavy foot.
Ford had something like a cheap vacuum gauge and I think GM had something similar.

N0DIH
02-06-07, 08:54 PM
A friend of mine had a 80 Pontiac Phoenix (RWD, Nova Clone) with the "Joe Cool Fuel Economy Gauge", it was as big as the speedometer! If you can learn to drive by it you will get better economy.

I think overall it is a mix of tallest gear you can run without lugging while still keeping the highest vacuum you can. I think it is the mix that makes it best.

A friend of mine insists that cruise rpms below 1500 rpm is dangerous to the engine as there isn't sufficient splash oiling on the connecting rods. I can't say, but my Cadillac has the V4P gearing, 3.42's, and with stock shifting, most of the time does not shift until 1700 rpm, so cruise rpms are rarely below 1400 rpm.

Get a vacuum gauge and drive by it, you can't go wrong at all.

Cadillac Giovanni
02-06-07, 09:05 PM
Oh enough of this fiddle-faddle.

We're Cadillac owners! Are we so petty that we should obsess over such a minuscule detail as gas mileage? For SHAME!

Incidentally, I apologize for using the word "fiddle-faddle."

GenoTheLowrider
02-06-07, 09:38 PM
Got any picts of the exhaust? How did you run it? Both on one side, or cat back duals, down each side?

My 85 Cutlass I worked out how I could easily run 2.5" duals down one side around the cat and then back to one on each side. There was just enough room to do it and do it very well. I assume the 86-90 307 cars could do that just as easy.

I dont have any pics of the undercarriage, but just of the tips coming out....but its ran down the passenger side of the car then shortly after they pass the transmission one pipe slants over to the other side then out the back.........excuse me is my explanation sounds a little cabaret, I didnt actually do it myself, the muffler shop did, I just told em what I wanted.:bouncy:

GenoTheLowrider
02-06-07, 09:44 PM
Oh enough of this fiddle-faddle.

We're Cadillac owners! Are we so petty that we should obsess over such a minuscule detail as gas mileage? For SHAME!

Incidentally, I apologize for using the word "fiddle-faddle."

Gas is expensive, not quite a minuscule detail dude!! As Cadillac riders, we are touched by it the MOST pretty much!!

90Brougham350
02-07-07, 08:21 AM
A friend of mine had a 80 Pontiac Phoenix (RWD, Nova Clone) with the "Joe Cool Fuel Economy Gauge", it was as big as the speedometer! If you can learn to drive by it you will get better economy.

I think overall it is a mix of tallest gear you can run without lugging while still keeping the highest vacuum you can. I think it is the mix that makes it best.

A friend of mine insists that cruise rpms below 1500 rpm is dangerous to the engine as there isn't sufficient splash oiling on the connecting rods. I can't say, but my Cadillac has the V4P gearing, 3.42's, and with stock shifting, most of the time does not shift until 1700 rpm, so cruise rpms are rarely below 1400 rpm.

Get a vacuum gauge and drive by it, you can't go wrong at all.

Those vacuum gauges are pretty neat, my 85 Parisienne had one. You're right, the thing was huge! It was pretty nice to be able to cruise around trying to see exactly how low you could get the needle!

N0DIH
02-07-07, 08:35 AM
I might get the A-piliar gauge pod for mine. I would like to have a vacuum guage (someday a vacuum/boost gauge....), oil pressure, oil temp, water temp, transmission temp. So being they all won't fit, maybe it is time to do something else.

I would like to do some sort of digital bar graph gauge, something that works and is classy in a Fleetwood. I was looking at having something just under the lip of the dash (93-96). Not sure on the 77-92, as I don't have one and haven't been in one in a long time.

But if I could come up with a gauge, say 3-4 inches wide, 1/2" or less tall, would that have some benefit? Gauges are pretty simple (digital). Or even do a numeric digital gauge? If you could mount 4-6 simple digital numeric gauges under the lip of the dash, would that have some benefits to anyone?

You all are gonna make me think about this....

Cadillac Giovanni
02-07-07, 07:04 PM
Gas isn't that expensive.

You wanna know what works great to save gas? The lighter you are on the pedal both during acceleration, and while cruising, the less gas you use. And that's a fact you can take to the bank. What will those crazy engineers at GM think up next?

GenoTheLowrider
02-08-07, 12:00 AM
Gas isn't that expensive.

You wanna know what works great to save gas? The lighter you are on the pedal both during acceleration, and while cruising, the less gas you use. And that's a fact you can take to the bank. What will those crazy engineers at GM think up next?

Sounds like someone has some money......all I am saying is, gas was $0.79 a gallon when I got my drivers liscense 5 years back, its over a dollar more now.

I feel you on that easy acceleration (as well as easy braking), but when I am cruising the streets of Atlanta that Lac drinks no matter what I do, definitly meant for the Highway!!
--Geno TL

Cadillac Giovanni
02-08-07, 01:14 AM
Gas is only expensive if you think about how much it used to cost. Forget that it ever cost less than a dollar. It's really just a mind game.

I don't have any money. I take such pleasure in just driving my car that dropping 20 bucks here and there on a few gallons means nothing in the grand scheme of things. You wanna complain about wasted money, let's talk insurance...

Yeah, the highway is where these cruisers shine. Nothing better than coasting along, one finger on the wheel, a little (insert your favorite band/musical ensemble here) on the radio. I don't know about you, but that's my zen place, right there.

Gwokable
02-10-07, 03:43 AM
Cruise control.

If the cars properly lubed up (wheel bearings are greased, differential has fluid, engine in good running condition, trans in good running condititon) they can definatly get some kickass mileage.

N0DIH
02-10-07, 10:21 AM
Mine should, but never has. It is EPA rated as 17/23, and hasn't seen over 21 more than a couple times, like 21.2 or 21.3. Just hasn't pulled off good mpg like I had hoped. I keep trying to tune for it, but haven't got it to really do much better than stock.

GenoTheLowrider
02-11-07, 11:40 PM
Gas is only expensive if you think about how much it used to cost. Forget that it ever cost less than a dollar. It's really just a mind game.

I don't have any money. I take such pleasure in just driving my car that dropping 20 bucks here and there on a few gallons means nothing in the grand scheme of things. You wanna complain about wasted money, let's talk insurance...

Yeah, the highway is where these cruisers shine. Nothing better than coasting along, one finger on the wheel, a little (insert your favorite band/musical ensemble here) on the radio. I don't know about you, but that's my zen place, right there.

My man, I feel you, despite what I think about gas I "drop coin" in that tank no matter what, because "Big Sexy" (what I call my Lac) and I MUST ride. I must also agree with you, coasting along the highway (especially on a coast) is a beautiful thing, better than sex dude!! :yup:

Hydro626
02-13-07, 09:57 PM
im not sure if anyone has answered it directly yet. im sure they have, but i know mine gets about 21-22 mpg highway. not sure about city miliage though. it really is a common misconception that 80s Caddy's get bad gas miliage, because if more people knew the truth, more people would be driving them.

N0DIH
02-14-07, 08:06 AM
ReagansRollsRoyce did,

Lately 12-14 in town, 21-22 highway, 15-17 in mixed driving.

He has a 87, same drivetrain, same chassis.


im not sure if anyone has answered it directly yet. im sure they have, but i know mine gets about 21-22 mpg highway. not sure about city miliage though. it really is a common misconception that 80s Caddy's get bad gas miliage, because if more people knew the truth, more people would be driving them.

Yes, it is a BAD thing to consider these as bad mpg. Consider a brand new car like:

Cadillac STS-V......15/23
Cadillac DTS.........17/24
Ford Crown Vic.....17/25
Lexus GS430........18/25
Lexus ES350........21/30 (over optioned Camry, and a V6)
Infinity M35.........18/25
Lincoln Town Car..17/25

Now, when you consider that a 16 year old Luxury car gets 22-24 highway and all these brand new cars hardly get any better, you are doing well.

GenoTheLowrider
02-14-07, 09:22 PM
Technology is supposed to be so great, all these devices they are putting in cars now, and the gas consumption is still about the same, thats a crying shame!

N0DIH
02-14-07, 09:29 PM
Yes and no, we have 50 to 100% more HP than before and same mpg, so that helps a bit..

Cadillac Giovanni
02-14-07, 10:38 PM
Plus, those are still larger cars. (Believe it or not, most of those pass as "full size"). The average person is out there driving and entry level toyota or hyundai that gets 40 mpg or whatever.

Old Fleetwood
02-14-07, 10:40 PM
Within reason, GAS MILEAGE BE DAMNED!:want:
In an earlier post, I noted how a young woman in a Chevy Cavalier had that car rear-ended by some slob driving with a 50mph advantage over her 60mph speed.
The resulting crash tossed her Cavalier into a tree which not only split the car half but also killed her dog. And she is still being kept in a coma due to severe head trauma.
Worse, her right leg is so badly shattered due to the dashboard being slammed down against it that she will likely lose that leg in addition to her having a compound fracture of her left leg.
If she had been driving something like the Cadillacs on this BB, I am reasonably sure Jeanine would be up and around.
Gas, and your physical and mental well being, is cheap compared to the alternative when some jerk - whose mother had a loud bark - runs into you. :rant2:

N0DIH
02-15-07, 08:28 AM
I drive 35K+ miles a year just to go to work and back. I don't drive a small car with killer mpg for a #1 reason, safety. A side benefit is my wife says I come home from work much more calm and relaxed since I got a Cadillac.

I have driven my sister in law's Toyota Matrix a couple times to work and back, and it was just plain frustrating to drive 62 miles each way driving a car like that. The quality sucks, the mpg isn't fantastic (I didn't check, but as much as I had to put in the gas gauge moved just as fast as my Cadillac, just a few less gallons used), power sucked, trans was shift happy, it was noisy, the stereo sucked, the seats sucked, everything in the car is placed in the wrong place enhancing the cramped feel. The dash material is hard as a rock, you hit that in an accident and you very likely going to get something broken or hurt badly. And you are already waaaay to close to it. It feels like hard steel with a thin leather sheet on it. Crap if you ask me. Give me my padded dash like my Cadillacs have had.

Yes, I drive a Cadillac, I have a higher expectation. I will pay more for fuel to drive and be relaxed and have a high quality automobile. I don't give a rats behind what the treehuggers think. I have a responsibility to my familiy to put myself in a safe environment on the road so I am always there for them. You can't see an accident coming.

A friend of mine had a 04 Sunfire that he bought for mpg to drive back and forth and ended up in a head on collision, he is a very good drive, among the best, but still someone went into a diabetic shock and came over the median and hit him head on at 40 mph. He saw it in time and jammed on the brakes, and was down to 20 mph, but still, that is a 60 mph collision into a brick wall essentially. He was ok, she never even knew she hit him. But he drives a 03 Bonneville now to have a larger car to have some safety.

They say the #1 thing when buying a new car, spend the extra $1000 and get the next LARGER car, its safety is always better.

AND, my car is PAID for! I CAN afford to spend more on fuel and not care. I don't have $300-$500/month car payments. My money works for me, not some bank somewhere.

Remember, safety is very subjective. It is assuming you hit an identical weight car. But if you are that little car like a Toyota Matrix and you hit my Cadillac, which weighs 2x, it is quite a bit difference scenario. Say a 2500 lb car hits a 5000 lb car, both traveling at 30 mph, the impact to the little car is same as hitting a 2500 lb car at 60 mph. Conversley, the large car is like hitting one same weight at 15 mph. So it is almost ALWAYS safer to be in a larger heavier car.

I have a 94 Fleetwood at 4400 lbs empty and a 99 Suburban K2500 that weighs 5600 lbs empty. You don't want to hit me or get hit by me....

GenoTheLowrider
02-15-07, 11:59 AM
I fully agree, the gas we spend driving the big body Lacs is well worth it, its almost like driving down the road in a TANK!

N0DIH
02-15-07, 01:02 PM
How many accident related deaths in a Cadillac (D Body) compared to small cars? And compare it to the last 40 years to the last 2 years of small cars....

Or compare it to the the last Million Cadillac D Bodies made to the last Million of say a Corollas or some other tiny car that they try to make the perception as safe...

Old Fleetwood
02-15-07, 04:34 PM
Point by point, N0DIH spells it out as good as anybody can. But - as they say in the commercials - there's more!
If you're in deer country, the droop snoot of almost any new car will have you eating raw venison if you and deer happen to meet crosswise at speed.
A friend, driving in Michigan in his '77 Caprice, clobbered one some years ago and ended up with a mashed grill and bent hood.
With my wife's Stratus, a similar collision would have that deer smack dab across the windshield. - - - The D-body Cadillac has a nice blocky front end which would plow that damn deer instead of feeding it to you.
Once more, the "watermelons" (green on the outside but RED on the inside) say cars should have the sloping nose to be aerodynamic to save gas. NUTZ! :rant2:
Also, with a moose, of course, all bets are off.

N0DIH
02-15-07, 05:42 PM
I whacked a deer with my 76 Delta 88. Broke up the fiberglass front end and small dent in the hood. I probably hit at 25 mph, I was going around 35-40 and then saw a flash on my right and instictively laid on the brakes, I must have broke its back but it still got up and ran off. I had 3 cops behind me, they just go done busting a guy for DUI and watched the whole thing. They went and shot it and the switchboard went nuts in the trailerpark nearby.... It took 4 shots of a 38 at close range to put her down.

I keep my big cars.....

My wife and 4 kids got run off the road and hit by another semi in May of last year. A smaller car would have killed them all, easily. The cop on the scene said it was very lucky they were alive at all. This was in our old 96 Suburban. She was run off the road in a construction zone where there was no room to go and ended up sideways in the lane and the other semi hit. No one stopped. 9pm at night too. No lights no nothing. God was watching over them that night without a doubt! The semi's trailer ran OVER the front end. The larger front end allowed for it to be pushed out of the way some, a small nose down car would have got the wheels OVER the front end and flipped the car into the trailer. No chance to be safe. Big IS better.

Cadillac Giovanni
02-15-07, 07:23 PM
Yes, size is an invaluable asset in a collision. Most cars nowadays speak highly of crumple zones and airbags and all that, but you know something you don't hear? The Lincoln Town Car (221 inches long at it's largest, which is almost the same as a Fleetwood) Boasts a 5 Star safety rating in all categories, the only car in automotive history to do so. I wonder why...

in the past, auto companies relied on size to keep the driver safe, and as cars were downsized to save gas, they developed new safety technology. As you can see, when size and technology are combined, they make for an unbeatable formula, which if more auto companies emulated, would probably lead to far less vehicular-related deaths.

I still don't care what anyone says. If i ever decide to buy a new car from a dealership, it'll be a Lincoln Town Car.

For shame on dropping your RWD, body-on-frame construction, GM, for shame.

Old Fleetwood
02-15-07, 11:56 PM
More gasoline on the fire!
When I played "Mr. Nice Guy" and literally gave my Dodge B250 Wagon to my Cousin's Son-in-law's father so he could keep his struggling upholstery business going after his Ford van crapped out, I needed something to tow the PopUp RV my wife lusted after. Ergo the FWB.
But the other side of the coin is that I don't have the coin to toss at a $40k SUV to pull that little PopUp.
And besides, it was a damn good excuse to get a car I had the hots for, anyway! In addition, it sure was cheep! :thumbsup:
Remember:
$6,500.00 for the car
$975.00 for shipping
~$1,700 for the CPT Stage II 4L60E
~$2,000.00 for assorted stuff I wanted to bring it up to showroom and stuff I found in the Service Bulletins that applied to my car with the "early" serial #.
So if some silly 2,500 lb. ricer decides to try a head-on with my "Broggum" as those kids called it, I will definitely bawl my brains out. But only because they dented the bumper and probably scratched the paint. Not due to bodily injury.
And - again - as N0DIH said, his commute isn't one that leaves him full of road rage or makes him a nervous wreck by the time he goes from point A to point B.
One rather strange aside I have noted, however, is that the times I have driven down to Hartford Hospital for various tests, and the area is noted as being "dangerous," I find I get friendly smiles and thumbs up from the black and Hispanic kids which I DON'T get from the car lovers around my own neighborhood.
It seems to be a new kind of reverse-reverse discrimination! Maybe I'm naive, but I have less fear of being car-jacked near Hartford Hospital than I do in the center of West Hartford.
Or maybe it's because I'm such an ugly, mean-looking bastard in a Cadillac!

N0DIH
02-15-07, 11:57 PM
Yup, I would have to say if I HAD to replace my FW with a new car, it would have to end up being a TC. But I would have to beef it up with cop car parts.....

Old Fleetwood
02-16-07, 05:50 PM
Newer TC's have FULL FRAME and could benefit from Crown Vic goodies?:confused:

I~LUV~Caddys8792
02-16-07, 07:10 PM
Yep! :)

As far as I know, the TC, CV and GM all use the 1980 vintage Panther Platform, which means they all have interchangeable suspension components, so you can put the stiffer cop car springs on the Town Cars.