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Comments
On highway with cruise on at 75 mph it gets 32 - 34 mpg (6.7 - 7.0 L/100 km) amazing!!!
I was hoping that I would get better mileage than this, but I guess it's good for me since I drive better (safer) to get better mileage and use the cruise control much more now. I love this car!
Sticker says 20/26, getting around 16/21 after 2100 miles of easy driving.
We have a 2004 TL 6-speed rated at 20/30 and it gets 16/30. So our City mileages are comparable, but your highway mileage seems very low. Even our new 911S, rated at 18/26, gets 15/26 after 3,000 miles. All of my last 4-5 new cars have matched or exceeded the EPA highway estimate at 70+/- mph. My marketing director has an E320 CDI which also exceeds its highway EPA. And a business associate had an E55 which managed 22+/- on the highway not sure of the EPA). So if your C320 doesn't start improving soon (i.e. 25+), I'd have it checked out.
This one is just 3 months old and milage sucked from day one. I took it to service guys and complained. The loaner that I got at that time averaged around 26 combined miles. That car had 8K miles. I am not sure if its going to improve with time. Service guys though had no answer on this. Work order read "Could not duplicate". :mad:
Do you know what the RPM are at exactly 70 mph?
I do not know why the 3.3 cannot get better highway mileage than 26-27 since the EPA highway figure is 29. I would think that an efficient 6-cylinder engine could do better than 26-27.
Happy TG to you to Fred.
I have discussed this issue with a friend who holds a Masters in ME from Duke and has been a car nut for 25 years on the side. As he explains it, every engine has a sweet spot in terms of efficiency that usually coincides with the point at which torque is sufficient to maintain a cruising speed without requiring excessive fule input or, in the case of an automatic, shifting to deal with hills, wind, tire friction, etc.
Anecdotally, my last several cars show a big variation between EPA highway estimate, actual highway mileage and RPM's:
1995 Nissan Maxima (5 speed): EPA 27; Actual 28-29; RPM's at 70 mph = 2,850.
2002 Honda S2000 (6-speed): EPA 26; Actual 29-32; RPM's at 70 mph = 3,850.
2004 Acura TL (6-speed): EPA 30; Actual 28-29; RPM's at 70 mph = 2,200.
2005 Porsche 911S (6-speed): EPA 26; Actual 25-26; RPM's at 70 mph = 2,750.
As you can see from the above, the TL has the best highway rating, probably due to the testing methods and the low 2,200 RPM's, but in actuality is the worst performer in that it rarely gets its EPA estimate. The Honda S2000 is tied for the worst EPA highway estimate with the 911, but got far better than all others spinning away at over 4,000 rpm at 75mph.
Bottom line is that low RPM's appear more correlated to good EPA estimates, but inversely proportional to the ability to achieve them in real world driving, at least in the cars I've owned.
Here's mine:
2000 Olds Intrigue, EPA 28, actual 28-30, RPMs @ 70 = 2000
2005 Camry SE-V6, EPA 29, actual 26-27, RPMs @ 70 = 2400
Since these are similar size cars with similar size engines, actual mileage appears very well correlated to engine speed. I suspect the Olds engine has a broader torque curve and was therefore able to run efficiently at a lower rpm. The sweet spot comment probably applies in this case.
Bottom line is there is really no way to predict whether a car will fall short or exceed its EPA highway rating without accumulating lots of highway miles.
There are a few other factors that play into the mileage equation.
Before the engine threw a rod a couple of days ago, I had an 88 Cavalier with the 2.0 4 cylinder. If I drove at 55-60 MPH, I could get as much as 34-35 on the highway by my estimates. If I drove at 65+ it could be 25-28.
Other factors that play into mileage are as follows, power output capabilities of the engine. Displacement (aka engine size), driving conditions, speed, weight of the vehicle, and automatic vs standard transmission. Don't forget whether or not the engine is in good tune, and well maintained.
There are a few others as well, but these are the biggest.
Light vehicles, with manual transmissions and small, efficient engines tend to average the best mileage.
Hybrids do better because they're using a small, efficient engine to drive an electric generator which powers electric motors in the wheels.
Hybrid technology is by no means new, it's just been improved.
Locomotives have been using this technology for decades.
2003 BMW M5 6-speed, EPA rated 13/21 ($2,200 gas guzzler tax)
In 39,000+ miles, I've averaged 19.2 mpg overall, with a 70% highway mix. On pure highway, I get 22-24 mpg. The best speed for this car is 70-80 mph. If I attempt to go 55-60, I need to drop to 5th gear and mileage goes down slightly.
Regarding the RPM vs. mileage debate, I would add that high performance, precisely engineered "tight" engines tend to have "sweet spots" that are about 50% of their redline. You can see this on BMW M engines, most AMG engines, all Porsche and Ferrari engines. They can also be run at or near redline without adverse consequences. Less precisely engineered engines tend to lose their efficiency much more rapidly as RPM's increase above 30-40% of redline. And if you push these engines for any extended period at or near redline, you may just see engine parts in your rear view mirror.
So it does not surprise me that a Honda S2000 gets it's optimum mileage at 4,000 rpms, whereas an Olds Intrigue gets it at 2,000 rpms.
I had always thought the M5 was quite a powerful car.
As a former Acura Integra (1987) owner myself, its lack of torque made my "low torque" Honda S2000 feel like a Dodge Viper. I would have had a tough time maintaining 40 mph in top gear on a level highway drafting a semi. Unless you are downshifting into 3rd or 2nd gear every time you need to accelerate, I'd hate to see the carbon build up inside of that engine. Same goes for a Toyota Corolla putting along at 1,400 rpms at 40 mph. Somebody actually told you this is good for the engine? Sue them.
Everyone has their own driving style. But after getting an A+ check-up at 150,000 miles with my Nissan Maxima 5-speed, I am pretty comfortable with mine. Even with my habit of not shifting below 3,500+ rpms, I averaged 24.1 mpg overall and upwards of 28 mpg on the highway. More importantly its compression test showed all cylinders within 3-5% of a new car tolerance. And virtually no carbon build up whatsoever. My service manager has given me a standing offer to buy the car for 100% of it's "excellent" retail book value, if I ever decide to sell it.
Don't take my word for it. Ask experts that know and understand high performance, high output (70-90+ hp/liter; 7,000+ rpm) engines. I'd be "shocked" if you got advice different from what I've received.
I don't like to rev engines when cruising (accelerating is different of course). different strokes I guess.
My Sienna is only going 1,700 rpm @ 60 - no problem. A corvette is only going 1,400 rpm @ 60. Low revs do not hurt a modern engine unless it is knocking.
BTW the Integra does have more than 70 hp/liter.
Some cars are designed to do better than 55mph. If GM designed their cars for higher speeds I think they would be better of.
Krzys
The bad news is that I am afraid it is pretty clear that I will never achieve the highway EPA rating. (Unless the gas mileage improves as I add more miles – though at 7,000+ now, I doubt that.)
I drove from Atlanta to Carrabelle, FL and back. I filled the tank once I cleared the metro area. I filled the tank again at 232 miles (last gas in Georgia) and filled again in Tifton, before re-joining I75 North for the slog home on Sunday PM. (I did not want to count that mileage, as the traffic became bad & worse – as feared \ expected.)
I averaged these 2 fills, since they were not the pumps I typically use – and there are variances. The 2 fills = 470 miles. Total fuel used = 19.35 gal. Average MPG = 24.3. (Excel, not DIC.)
I did not exceed 80 MPH on the Interstate section southbound. Once off the Interstate, the speed limits and (um) aggressive enforcement mean that I find 65 the highest ‘reasonable & prudent’ speed.
A little experimenting with various steady speeds on relatively level roads strongly suggests that DoD is much more likely to engage at 60 – 70 than at any higher speeds. With resulting steep downslope to MPG as speeds rise above 70.
[ edit:
RPM at 60 = approx. 1700.
RPM at 70 = approx. 1950.]
YMMV.
- Ray
Still full of Turkey . .
City 20-22 mpg. never less than 20 mpg
Highway Trips (70-74 mph) 28-30 mpg
21 - 23 mpg for the city/highway mix.
34 mpg for highway at 65 mph. This is what the 0.28 drag coefficient of ES300 does for mpg.
My Integra (EPA 24/28) gets as low as 16 mpg in the winter when I warm it up for 15 minutes before driving in the city(temps well below zero), and as high as 45 mpg if I drive 60 mph with no wind, no hills, no A/C, and the car is already warm when I fill up. It does not take much of the really bad city mileage to bring the highway mileage way down.
-Dudley
At 1500 miles, your engine has not broken in yet. Once you approach 7000+ miles, you should see an increase in fuel economy, and by the 15000 mile mark, you should get mileage well into the 30's.
Keep in mind that the EPA ratings haven't been changed since the 1970's - with the car running at 55mph without air conditioning
I'd beg to differ. We had an 03 Civic EX and left on our first long trip when it was less than two weeks old. We got 42 mpg on two different legs of the trip which also covered about 1500 miles. I've never heard of a car performing so poorly.
Furthermore, I had two rentals over the past six months, one a Chevy Cobalt, the other an 05 Corolla. They are essentially the same car. The Cobalt with only 700 miles on it got better than 30 running around in Nashville Traffic and the Corolla with about 7000 miles got 36 or so on a 200 mile round trip up and and down the hills of southern Missouri.
If a car doesn't get at least it's city mileage on the highway, you've either got a real :lemon:, you are an extremely aggressive driver , you've got the O/D turned off, or you're driving with your left foot on the brake.
Krzys
I beg to differ. 1500 miles is not sufficient mileage for proper engine break-in (especially the piston rings). You can check any website or major automotive publication's long term test on vehicles, and you will see for yourself that performance/mileage figures improve as the engine breaks in (usually starting at 5000+ miles or higher).
>If a car doesn't get at least it's city mileage on the highway, you've either got a real , you are an extremely aggressive driver , you've got the O/D turned off, or you're driving with your left foot on the brake.
I'd bet the poor mileage probability breaks down like this:
Agressive drivers - 80%
Lemon - 5%
Everything Else - 15%
So what you're saying is the mileage I got in my Civic should have improved from the 42 mpg it got when the car was only two weeks old?
I don't know about the automotive publications or websites, but I do know that no new vehicle that I've ever bought has ever shown any significant increase in fuel mileage over what it averaged on the first tankful. And my guess is that most people have had the same experience I have.
I do, however, think your probabilities are quite accurate.
Has anyone else had similar experience? And what's your theory?
With today's manufacturing tolerances, I don't think the break-in period is nearly as long as it used to be.
The mfgrs. are just playing the game as it is, and designing cars specifically to do well at precisely those conditions that are not an accurate representation of the ways we actually drive. In fact, the tests are not done on roads at all! The CR article does call for revising the tests - but, the cheating, as you call it, is a condition of the rule book, not any particular mfgr.
I have no complaints with that level of fuel economy compared to the performance this car is capable of
http://www.usatoday.com/money/autos/2006-01-10-epa-fuel-economy-ratings_x.htm
1997 Ford F150 4.2L V6 Auto 125k miles loaded work truck 14mpg avg almost 20mpg hwy.
1995 BMW K1100LT 1100cc 5spd cycle 78K miles 38-42mpg avg with city/hwy mix.
1995 Toyota Avalon 3L v6 Auto 200k (yes 2 hundred thousand) 33mpg mostly highway
1993 Honda Accord EX 4cyl Auto 165k miles 24mpg avg
1993 Honda Cicic LX 4cyl Auto 119k miles 40mpg mostly hwy
1988 Honda Accord DX 4cyl 5spd 280K (yes 2 hundred and eighty thousand) 33mpg avg.
1988 Honda CRX SI 4cyl 5spd 112k miles 36mpg hwy driving
I have no complaints with that level of fuel economy compared to the performance this car is capable of"
Interesting, at 4,300 miles, sustained highway speeds of 75-80, with short 90+ mph bursts, I also see 24-25-26 mpg. In my 911S Cabriolet. In our Acura TL 6-speed, loaded with the family and luggage, we're at 29-30 mpg.
And, in both cases, I have no complaints compared to the performance capabilities.
I just traded for a 2006 Passat 3.6L. I hope my mileage will be just as good.
carconsumption.com
https://www.fueleconomy.gov/
Some "real world" metrics from some anonymous volunteers:
https://www.fueleconomy.gov/mpg/MPG.do?action=browseList