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jdogg's avatar

Which has better gas mileage, sedans or coupes?

Asked by jdogg (871points) June 21st, 2010

Just to settle a little argument between friends :)

Observing members: 0 Composing members: 0

17 Answers

dpworkin's avatar

It’s likely to be idiosyncratic and due to many other metrics other than body style.

ApolloX64's avatar

It comes down to more factors than just sedan or coupe, but in the long run a coupe is usually lighter than a sedan (for obvious reasons) which means if you took a coupe and a sedan with identical powertrain (for example, let’s go with a pontiac sunfire coupe vs sedan, with a 2.2l ecotech and an automatic tranny) the coupe will get better mileage just because it’s about 400lbs (or more) lighter overall.
That’s the short bit, but there are always more factors down to driving style, engine choices and passenger load, not to mention tire style/type/resistance, fuel quality, air pressure, avg speed, etc etc etc.

stranger_in_a_strange_land's avatar

Same engine and basic body style, the lighter of the two is likelier to get better fuel economy. The coupe may not always be the lighter car though, they tend to be loaded with more luxury equipment than sedans. Also, coupes may have performance gearing, which lowers fuel economy to obtain better acceleration.

jerv's avatar

Pretty much. There are quite a few “touring cars” out there; coupes that claim to be sporty because they have two seats but are loaded down with A/C, premium stereos, mushy suspension, and other stuff designed for comfort on long cruises (touring) that wind up heavier than a sedan.

One factor that is not mentioned here (at least not explicitly) is that coupe owners are more likely to drive like ‘tards, and that tends to lower your MPG, often considerably.

stranger_in_a_strange_land's avatar

@jerv Exactly. The sportier a car looks, the heavier the foot on the throttle.

LuckyGuy's avatar

Go to Fueleconomy.gov . It has all the fuel economy figures you need.

IchtheosaurusRex's avatar

If you constrain the question to the coupe v. sedan version of the same car, you’ll get slightly better mileage out of the coupe, all other things – engine size and HP, transmission type, being equal. This is because coupes are a little lighter than their sedan versions. The difference is so small you would not notice it in normal driving.

jerv's avatar

@worriedguy That really isn’t accurate. For instance, the ‘89 Ford Aerostar was rated 15/21 MPG, and while I did get 15 MPG when I first got it, some adjustments to my driving technique managed to get it to just over 23 MPG without driving any slower. Now, that is in 80% highway driving. Hmm… from less than the city rating to more than the highway rating with no mechanical alterations…
On the other hand, my ‘85 Corolla is rated at 24/31. Well, this is the second one I have owned and 23MPG in mostly highway driving seems to be closer to the truth when I compare my odometer to the number of gallons I used to go that far.

It sounds to me like those figures are merely rough estimates.

ApolloX64's avatar

Those estimates they use are gathered when said cars are brand new, with no wear and tear on them (and yes, most are estimates given by PR henchmen, especially for cars pre-1995). Hence the inaccurate measurements compared to the same vehicle now. No matter how well you look after it, a 10, 20 or 30 year old car/truck will never perform the same as it did from the factory.
The advent of OBDII instruments has greatly enhanced our ability to calculate and adjust a vehicle for optimal fuel efficiency. There is a wonderful little gizmo called the ScanGauge which provides a ton of info on your car while you are driving it, check it out.

jerv's avatar

@ApolloX64 First off, bad link. I’ve done that myself a few times. Is this what you were talking about? Somehow, I don’t think my car has all the sensors that thing needs to work.
Second, you are correct, but I find those figures pretty useless for almost every car I have ever owned, mostly because they were predominantly pre-OBDII.

I agree that that site seems pretty close for newer cars. but it isn’t all-knowing. Also, that Aerostar proves what a difference an adjustment to the nut behind the wheel can make in a vehicle’s actual MPG rating, and the same is true even with modern (OBDII) cars.

ApolloX64's avatar

@jerv lol thanks, didn’t notice it did that. And no, your car would not have the sensors, only an OBDII compliant vehicle has the sensors for a ScanGauge which is what I was getting at.

Ron_C's avatar

I had a 2000 VW Jetta TDI. It was advertised for 40 MPG but I typically got 50 or more. I drove from Northwestern Pa. to Portsmouth Mass. and still had a quarter tank left. Too bad it had a terrible electrical system (made in Mexico).

jerv's avatar

@Ron_C The old Diesel Rabbits were around there too. Oddly, my buddy’s ‘80 gas Jetta generally got in the 40s and sometimes low-50s as well, so as far as MPG, VW has gone back to where they were 30 years ago.

Ron_C's avatar

@jerv I was severely disappointed by the Jetta. I had a 2 year old ‘68 and a brand new ‘70, and a brand new ‘72. I sold all of them for more money than for what I bought them.

The 2000 ran well and the diesel was the clean quietest one that I ever drove. Unfortunately the electrical system was crap. I went through two computers and at 24000 miles, they wanted to replace the wiring harness. It turns out that it was a common problem on VW’s built in Mexico but VW wouldn’t cover it on a warranty. I guess I bought my last VW.

jerv's avatar

@Ron_C Ummm… you must have it confused with something else. See, the Jetta didn’t exist until ‘79. The first-gen Golf (known in the US as the Rabbit) came out in ‘74, so that can’t be it either.

Personally, I do not trust any VW made after 1990 (mostly due to electrical issues, and that is especially true around 1999–2001), nor do I trust any of the Mexican made ones. My wife and I both had ‘89 Golfs; mine from PA and hers from Mexico. Even though hers was in better shape overall, it inherently had issues. VW was having serious issues with their Mexican plants at the time, and we found out how serious after we got her car.

I know many people who own or have owned VWs and the only ones that actually love/d them are the pre-‘90 crowd.

Ron_C's avatar

@jerv I was referring to the beetles, I had prior to the Jetta.

The Rabbit and Golf were too fragile for our Pennsylvania climate. Salt would get in and rust everything especially door hingers and the body parts supporting the struts. What a shame, they fix all of that and blow their reputation using cheap labor.

jerv's avatar

@Ron_C The way you wrote your last post, I thought you said you had Jettas of that vintage. Derp!

Funny though, since I never thought of PA as being rougher than NH, and I never had rust in those spots despite NH enough road salt that the roads remain white for months after all the snow has melted.
Granted, my wife’s ‘89 Golf was the only Golf/Jetta I knew that had the original floorboards with no hole (patched or otherwise). My ‘89, my ‘94, the ‘85 “project car”, my co-workers ‘93, and many others owned by people I know either patched theirs or could/can see the road. Hell, I knew that that project car of mine had no floorboards before I even finished reading the ad; “1985 Golf” is pretty much a euphemism for “Needs floor repairs”, and that ‘94 got taken off the road and scrapped after the rocker panels rotted to the point where the car started to sag in the middle.

But as I said, the door hinges and the strut mounts were never an issue on the VWs I’ve owned. And probably the only parts that didn’t rust :P

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