icenoir

Just got my 08, and am happy to report 23 mpg with often stop and go commute - 90 miles per day. 500 miles total.
Just want to let prospective buyers know the mileage isnt close to 13 that some reviewers have listed. Of course, I'm not stomping on the gas, but not babying it either.

AbovePrime.

How do you calculate your MPG?

Boon

Wow, that's pretty good. I've been doing 100% city driving lately...stopped babying the RDX....but not pushing it hard either. Getting 14-15mpg. Not very impressed.

zuzzu

At the 1,000km mark (roughly 600 miles) on an 07, I have averaged 17.4 mpg with both me (careful) and wife (notrious pedal masher) driving. For the first couple of tanks, it was only me driving, I was getting a shade under 20mpg. This is normal driving, 90% city and 10% highway.

icenoir

AP- so far, its based on the MID. I will confirm accuracy when i fill the tank again. (i did not receive the car full).

XIS

My MID is consistantly over-stating MPG by at least 1 MPG. Not that big of a deal...

My first month or three, I was getting 15-16 (90% city)

Now I get 17 ish in the city and probably drive it harder than before.

flags

My mileage has steadily improved over time. Just passed one-year with my 07 tech at about 10000 miles. I now average about 21 mpg per tank (based on fill-up calculations, not MID) with 90% city driving. I would say I do not baby the car, with occasional WOT.

ACURascal

Best highway mileage by Trip Computer: 27.4
Best highway mileage by calculation: 27.8

Mixed mileage (Mostly city) by Trip Computer: 15.6
Mixed mileage (Mostly city) by calculation: 15.7

deafblind

Those numbers accurately reflect my manual calculations, 90% city. On a run I got up to 26 on based on the MID

mav238

Cool... that is pretty impressive... I got that kind of mileage when I first got my 07' last April. but that mileage was during the warmer summer months, with stop and go traffic.

But now with the winter season kicking in, temp. ~ 2-4 celcius in the morning work drives, I am getting around 19-20 mpg with the stop and go driving we get here in Vancouver. And Vancouver has lots of roads with decent grades, so not really flat at all...

If you drive mostly in California or Arizona or the southern states weather, then I would not be surprised at the gas mileage you are getting... Try driving in real cold weather, and you will definitely see your gas mileage go down...

AbovePrime.

Thats some impressive MPG, for any gas SUV in the city.

wrzt

Wow, I have to strongly disagree with your view on that. I live in Arizona and I can say with the utmost certainty that high ambient temps have had a negative effect on the fuel economy of my RDX. Up until about 2 weeks ago, daytime temps here were consistently 100-110 F, and not only did my fuel economy suffer but engine performance took a hit as well. Over the last 2 weeks daytime temps have dropped to around 85-95 F, and I've watched my MPG (according to the MID) rise from a consistent 17-18mpg in the heat to 21-22mpg. Same driver, same driving behavior.

Maybe there is an ideal ambient temp for optimal fuel economy, but I can definitely say that it is not a linear increase with rising temps. Perhaps the ideal temperature falls between how hot it is here and how cold it is there. I don't know, but again I KNOW that the hot temps are detrimental.

There is also another factor at work, which is that ambient temperature has a strong effect on the true amount of fuel you put in your tank when filling up. The hot temperatures here make the gasoline less dense, and so when I put a gallon of gas into my tank, it doesn't truly end up providing a gallon's worth of energy from the gasoline. On the other hand, when the temperatures are cold, the fuel is denser and you are technically getting more than what is shown at the pump. Food for thought

AbovePrime.

Turbo engines run better with colder air, this is a known fact.

porsherules911

Of course turbos love cold air as does any engine. I dont know who said warm air was better but its common sense that cold air is better. I can't wait till the temps go down...

XIS

WRZT is so correct. The MPG and power goes way down here when you have two straight months of 110+

AZ is hot, and it is wonderful here.... I would never want to live anywhere else!

mav238

On that last point, gas stations always adjust the feedrate of the pump to account for temperature changes, and they are never ever going to "lose" money by giving the consumer free money in savings if they can help it.

When I mean warmer temperatures, I don't mean baking hot temps like what you get in Arizona, where it works against your engine, because the air breathed into the intake is so hot, it is not optimal for efficiency.

I never said it was a linear effect did I? I didn't say that if you drive in a 50 Celcius climate, you get a 100% increase in gas mileage. Be reasonable... In fact, in that kind of climate, you have other problems, which is ensuring the engine is surviving the heat, and not wearing down prematurely...

But you will undoubtedly find a difference in gas mileage if you compare driving at near freezing point climate as compared with summer temps like 25-30C.

My point to the original post was that any gas mileage one gets is connected in some way to driving conditions and climate temp. (assuming the car is brand new to begin with).

And although cold air is indeed better for the engine (both turbocharged and NA), we are not simply talking about empty roads, dry roads in the winter months, where you are driving on... also gasoline is formulated differently in the winter months (at least they do here in Canada) and this does impact fuel consumption by up to 10% in some cases.

ACURascal

Winter gasoline has a lower RVP (vapor pressure) than summer gasoline primarily because it has a higher butane component. Summer gasoline tends to be warmer when it is dispensed, meaning that the molecules have expanded due to the heat. This makes the energy per gallon of warm fuel lower than the energy per gallon of cold fuel.

Cold (winter fuel) will provide better mileage (because it contains more energy per gallon) than warm (summer) fuel.

mvwood

don't you also have to adjust for the duration and intensity of A/C usage? My understanding is A/C makes a big difference in fuel consumption.

Nyjumpman23

Best city for me = 15-16
Best highway = 19-20

JMJ3rd

Best highway mileage by Trip Computer: 31.0
Drafting fedex truck fron Bmt. to Houston.

Best highway mileage by Trip Computer: (No draft) 26


Mixed mileage by Trip Computer: 19.2 so far @ 5000 miles
Reset "B" when bought. It was a demo.

Haven't done actuals with gas receipts gals. and odom. readings. One day...

Fishbulb

23 MPG in stop and go is beyond impressive. Either you've got a freak car, or you're powering the car flintstones style.

ltngbg99

With 1800 miles on the odometer we are averaging 21mpg as indicated per the MID. Driving is mixed city and highway with steep mountain grades and my wife's new found lead foot.

icenoir

Looks like the mid may be off a bit- manual calc after fill up puts mpg at 21.5 - still pretty good.
fyi - the whole commute isnt stop and go, maybe a third.

rpeete

I have almost 15k miles on my 07 RDX (after 6 months) and my highest MPG has been 24mpg highway. My regular driving gets me between 19-21mpg. It has been getting better as time goes on.

JMJ3rd

My dealer said the mpg would probably go up as miles increased toward the 15k range.

Checked today: 19.3 for 6k on "B" trip computer.

13k total so far.

catnippants

Mav, I think I've mentioned this before, but my findings mirror yours without question. My car is used 95% for my commute to work - so read that as the same type of driving all year 'round. Here's my latest mileage data. These are the actual calculations from every fill up since I got my RDX in Aug of '06. There are some fliers, but the trend is pretty clear - higher in the summer, lower in the winter. I have been using my B odometer all summer to see what my avg is, and after 5000 miles, I'm at 22.8. I expect that average to drop as it gets colder. Most folks I talk to up here in the northeast know and expect this....so it's not just my RDX.

Mike

catnippants

Don't ya love it when science doesn't work?

Technically, I thought the same thing - but for different reasons. I just haven't seen it actually work out.

Mike

AbovePrime.

I wouldn't exactly call your findings accurate, because you just bought the car, break in, etc.. How many miles do you have on it now? It does seem like you're getting better MPG now, when it starts to cool down.

ACURascal

Well, I think it's a bit much to call your experience a repudiation of science.


More likely, it's the obvious. That during the colder winter months the mileage-detrimental effects of short-duration trips is exacerbated because engines operate for a shorter period of time at their most efficient operational temperature. (It takes longer for the engine to warm up to its ideal temp.)

www.fueleconomy.gov/feg/factors.shtml

Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Note: Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

And, the following from the above link:

The energy content of gasoline varies seasonally. Typical summer conventional gasoline contains about 1.7% more energy than typical winter conventional gasoline.

Coupling these factors with the fuel temperature helps explain seasonal and temperature variations in mileage performance.

catnippants

You might be able to say that my experience may not exactly echo everyone else's, but to say my to say my findings are inaccurate is a stretch - unless you think I screwed up the math. For the first two months of ownership, I was getting about what I'm getting now. As the weather got colder, the AVERAGE dropped. It didn't get better as you would expect due to break in. As the weather started warming up again, my mileage went back up. The summer lasted longer this year, and it's only now starting to get a little colder here - and my mileage is SLOWLY starting to drop again.

For what it's worth, I have over 16K miles on the car now, and my trip to work is about 20 miles each way - so the car does warm up. It's mostly 40-50mph, relatively flat country driving, with 3 or 4 traffic lights.

I'll be keeping track - we can always have this discussion again next year.
Mike

AbovePrime.

I just said that because of the new car break in, time it was being broken in, and potentially the way it may have been driven, new car and all. Most RDX owners see better MPG after 4K miles.

catnippants

Maybe I'm missing something, but everything in your post explains why we get worse gas mileage in cold weather, not better as was originally claimed.

As far as the science is concerned, real world findings very often don't mirror theory, calculations and the results from experiments made under very controlled conditions. In this case, my point is that external factors contribute to the fact that you can't simply rely on the theory to expect better gas mileage in the winter - which was the original claim. If you look at what it means to the average driver, the 'science' didn't work.

Mike

catnippants

Agreed. I was watching for that when I hit 4-5K. Unfortunately, I think the weather outweighed any increase I might have gotten. This chart will be interesting to revisit next year I think...

Mike

ACURascal

Well, maybe you're just reading with a little bias. Both of my posts state the facts. Cool fuel provides more energy per gallon than warm fuel, but the vehicle is predisposed (because of cool temperature) to use that cool fuel less efficiently.

What's hard about that for ya?

catnippants

No need to get sarcastic. Remember, your original statement was "Cold (winter fuel) will provide better mileage (because it contains more energy per gallon) than warm (summer) fuel."

In reality, the average driver sees poorer fuel economy in cold weather - which was my original point. I suspect that most drivers wouldn't give a crap about whether colder fuel provides more energy per gallon.

Mike

ACURascal

Yes... that was my original statement and it remains my statement. Again, what's hard about that?

feichiek

I just got myself a 2007 RDX TECH Pkg., all loaded up with 19" chrome wheels, front underbody, wooden trims and the likes. I love this vehicle except for the gas consumption which to date comes in at rather low 18.6 mpg, 75% highway and 25% city. I'm really easy with the pedal and hardly ever inducing the turbo boost to kick in.

The first week was so bad that I could barely get 12 mpg mixed driving that I was actually contemplating on getting rid of it. I hope it will get better as I accumulate more miles. It's really amazing to see that yours can do 23 mpg brand new and who knows how much better it can get later on. It gives me hope that mine might improve over time.

feichiek

What was your mpg during the first couple of weeks? Your current 22.8 mpg is a pretty good number in relation to the horsepower this thing is generating.

catnippants

Keep in mind that I got my RDX in late summer '06, so the weather was still quite warm. However, my first 5 tanks of gas yielded:

23.19
21.39
19.87
23.18
21.31

During the first month, I made a few trips out of state to visit family, so my driving style during that time would have varied. All in all, I'm pretty satisfied with the mileage I'm getting now. If it drops to 19 again in the winter like I expect it to, I'll be whining...

Mike

MRP2008

Just got my 08 and after like 4 days of driving had to fill up (I drove alot), but when I calculated the mileage, I got 22 mpg with mixed driving. Looks like I'm going to get close to that on the second tank as well. 305 miles, car took 13.9 gallons. Not too bad coming from a V8 sports car.