In reality, $4 per gallon gasoline has been endured by other parts pf the world, especially in Europe and Asia.

As an example, in Singapore, it's now ~ $2 per litre!!! They been paying $1.50 per litre for the past year. Their way to get around this... well, they still own cars, that didn't stop them... they still drive their cars... but they adapted their lifestyle to meet this new change in the economy... They drove less and use their vehicles for leisure and only when required... Mostly using the public transportation whenever possible...

Over here in north america, where the interstates are quite often used as routes to work, then if one feels the price of gas is too hefty and driving to work is necessary, then in the first place, get a hybrid of some kind and not buy a RDX. When you bought it, did you not know that the fuel economy is not stellar?

There is no such car where you can get high HP kick in the pants performance, and great fuel economy, plus also have the full-time AWD flexibility... It's an oxymoron with the current technology...

Yes, the RDX is a 4-cylinder engine... but it is still a mini SUV, heavy for it's size, has full-time AWD, has a fast spooling turbo...
all in a recipe that does not equate to "great fuel economy"...

So I just don't get it why people are debating the heck out of this topic...

If you want all of the above desired characteristics, then simply wait for the turbo-diesel engine coupled to a hybrid powerplant to arrive in the new RDX... it won't be for at least another 5 years...

Go check out the subarus... you will find that their sedans are not that much better in fuel economy...

 

If some of you are still not convinced that the RDX 18-21 mpg combined is not so bad, check out the subarus in this website, where it gives you the EPA rating for cars.

http://www.fueleconomy.gov/feg/findacar.htm

Select 2009 subaru, Legacy turbocharged AWD,

You will find the city rating is ~ 20 mpg combined. And IT'S A SEDAN!


You want full-time AWD flexibility...? Then there is no two ways about it... PERIOD...

 

All car computers have some 'learning' they can do, and they adjust the fuel tables or timing based upon previous data the computer has received. Specifically in this case, I've seen cars where if you stick lower octane in them, the car will discover the lower octane from hearing the knock, and will pull the timing. Over an extended time, the car will adjust it's running fuel and timing tables, and will begin to assume that this is the constant case. So, after a while of scanning, you will not see any more knock, because it just presumes that this is the way it is always. So, in a really interesting way, you can teach the car to use the lower octane. Now, from what I can see, even though it is not learning to just assume this is happening, I don't see anything bad occurring in the car when you are just driving around, and up to about 80% throttle, which is the range that most of us are driving around in. It's only when you really are trying to extract all the power, flooring it, that the car seems to be bent out of shape, and retards the timing incredibly [like 15 degrees, which is a lot], and pulls down the boost by several psi.

I've been doing some more testing, and the other interesting item is the alcohol. Running with 10% alcohol ALWAYS gives better gas mileage [about 2miles per gallon]. Running with about 15-20% alcohol gives even better mileage [about another 2 miles per gallon]. The cooling effect of the alcohol must be improving the efficiency of the turbo.

So, my all time record now is with 50psi in the tires, between 15-20% alcohol, and hypermiling. I've managed 35 mpg on two tankfuls. Driving normally, I'm getting about 27mpg overall.

Really, this is more about testing different ideas and analyzing, I'm actually really happy with the car, even when it's getting 21-22mpg. I just thought it would be fun to test different concepts on a bigger vehicle.

I'd be interested to hear other reports from people running 89 and what they are averaging for their gas mileage, and see if it aligns with what I am seeing, mainly that overall gas mileage doesn't seem greatly affected if driven normally and not too aggressively.

 

I hope it was just an experiment.

With 50 psi the RDX is riding on the center rib of the tire on a narrow contact patch. The steering may feel responsive, but there is little grip for lateral road-holding or braking.

If you don't wreck it first, the tires will wear hopelessly uneven in 15K miles and your fuel savings will go to new tires.

 

WTF? I pay approx. $1.50 per litre ($5.50 per gallon) here in Ukraine and there is absolutely no problem with this. Last year when I travelled to France twas nearly $8.50 per gallon of 95 octane gas. It's the future and there'll be NO hypermiling on a full-time AWD, turbocharged, high cross-over ! Go for Prius or Inspire or swap to a Tesla like Mr.Brin did

My daily mpg (70% traffic jams, 30% highways) is 15.5

PS: For those who are NOT from the U.S. You can use the formula 235 / x mpg = x l / 100 km

 

It's all in the perspective of things... what you may feel is not a problem, can be very different for others...

As for your point about gas price in Europe, that is a fact, but you fail to mention that people in Europe generally tend to drive small displacement engines, and/or use diesels...

Basically, people adapt to the high prices... and I am not sure how many gasoline powered hummers you will find in Europe...

Yes, of course "it is not a problem" with the high gas prices, if you garage your vehicle full-time... Do not be too presumptious with your comments...

 

It may sound so, BUT as You said correctly "people adapt". There are different cars in Europe and this Europe differs, I can say. Some people prefer diesel (price is almost the same, but they have better economy), some stay with petrol cars. Come to Zurich and enjoy seeing the "gas eaters". In fact buying ULEV RDX is rather conscious decision. Turbos, compressors, other combinations IS the future and I cannot personally understand why crying about high consumption. Why not to choose some hybrid car instead?

Check http://money.cnn.com/pf/features/lis...bal_gasprices/ and this does not even include Turkey with it's $11 per gallon


PS: My annual mileage per one car is nearly 20k.

 

Many people require the AWD system because of where they live... I live in a country where the AWD or 4WD system is necessary when traversing snow covered mountain roads...

Also, the recent dramatic gas price increase was not forseen by many globally...

I have seen $0.40 per litre increase over 5 years, but recently , this $0.40 per litre increase in 6 months is really crazy.

Well, I read the news today, the EU is looking to try to get the oil producing countries to work on bringing down the price a little...

If as you said, "why cry over the high price, just get the hybrid...", then why is EU now desperately trying to deal with this crazy gas prices?

The RDX at 12L per 100km is not great in gas economy, but it is not a gas guzzler either like a hummer... so folks like ourselves got it last year for it's many attributes, but not expecting this crazy price jump in gas over the past 6 months.

So if we cannot affect the gas price, then we can only adapt...

 

XLR8R,

I'm sure that there is some thought behind your statement, and there may very well be tires that when inflated higher than normal lose their contact patch, but I don't think you are on the mark in this case. I did have concerns about what possible impact the inflation might present, so I measured the tire patch before and after, and there is no measurable difference. I also did a panic stop three times from 70MPH for an average that also was no difference. I suspect that the uneveness occurs when reaching closer to the limits of these wheels, for example if I took it to the max tire pressure these tires support, which is about 64psi, then I would expect to see more of the bulging and skittish feel. Or maybe I am just lucky and these are very well made carcasses that hold their set very well.

On the other hand, I will certainly do some research and see if the tire wear increases dramatically, if at all. Underinflation seems to cause more tire than overinflation, but I will chat on some other forums with people who have had their tires overinflated for more than a year, or have gone through a tire change.

As I stated, it's very interesting that things that you can discover in testing vs what 'everybody knows' or presumes. If you had asked me to overinflate a tire, I would have said it would explode, only to research and find that it takes a lot to bring a tire to a danger point. If you had asked me about alcohol and gas mileage, I would have said that it was harmful to the car, only to discover from research and testing, corroborated with others who are also testing, to find that alcohol is a great additive in many modern cars, and can actually increase gas mileage in the right mixture. If you had asked me about running 89 octane, I would have said that the car would run badly, again only to test and discover that there is no harm if used within certain boundries. As an engineer it's always fun to test the presumed and accepted and find it not quite as true. I'm impressed that I have been able to increase the gas mileage over 50% without modifying the car, even with the possibility that the tires will wear out sooner, because that's an overall positive [50% gas mileage increase over the course of 15k miles would still be better savings than normal tire pressure and 20k miles of tires].

Another thing I would be curious of would be how the other mods people have make any difference. Does the CPE intake help or the new cat back exhaust ATL is working on?

This is a fun thread.

 

Happywithmyrdx, your contact patch will not change under your normal static condition of the vehicle because you may be at the minimum contact surface already at previously experimented higher psi. Your braking distance may not be affected on a smooth road either. What will affect it will be jounce and bounces on the road. Your extra bouncy suspension will just mean more air time on the vehicle which is more likely to occur when you get hit or during an emergency maneuver. You're changing the dynamics of the spring rate of the suspension.
Concerning your experimentation with alcohol. What you are doing is just diluting the gas and lowering the octane. Why not just drop to the cheaper gas for that matter? The RDX manual already warns about using lower octane. You will damage the engine. The reason for higher octane in general is to achieve higher compressions in the engine before the ignition point is reached. Honda engines are notorious for the interference clearances in the engine. It is true that the computer will compensate to a point, but you will probably not hear the knocking until it is too serious due to the sound insulation in under the hood and firewall. Just be careful with your testing.
Enjoy your experimenting. What I would do is concentrate on is getting rid of excess weight on the car. Get rid of the spare tire, use lighter rims, lighter weight parts, etc. You will get more benefit from doing that, than playing around with the tires and octane.
On the side, it is a joke how the government is basically diluting 3% of gas at the expense of 30% of corn crop that can be better used to feed people. We are doing this for what? Oil companies so that they can have more gas?

 

Check out these websites:

http://www.watertogas.com/

http://www.waternogas.com/

Back in the day, I rigged a water injection system on my 79 Capri Turbo so I could raise the boost and advance timing with less chance of detonation. The side effect was improved mpg when I wasn't beating the car like a rented mule. All I used was a plastic liter pop bottle, some windshield washer tubing and an aquarium air mix valve, all connected to a spare vacuum tit on the carb. The motor lasted 67,000 miles before it grenaded from a missed shift by Yours Truly.

50% mpg improvement? No. However now we have a brown gas generator, a fuel heater and some sort of black box (probably that 50 cent resistor WildWest rants about). I wonder how that might work with the MAF setup in the RDX. Anyone game for the experiment?

 

Mr. Bongo, I mean XLR8R, is correct. Over-inflating a tire reduces the contact patch. Per Wikipedia:

'The size of the contact patch is inversly proportional to the tire pressure (up to a limit).

'The size of the contact patch in square inches multiplied by the pressure in the tire in PSI is equal to the weight of the car on that tire (1/4 of the total car weight usually).

'This means that increasing the pressure in the tire will reduce the size of the contact patch and vice versa.'

http://en.wikipedia.org/wiki/Contact_patch

 

How exactly did you "measure" your contact patch? Did you park on a glass floor over a service bay and take precise readings? (Where does one find a service bay under glass?) Or did you raise the car, paint the tire tread and lower it onto graph paper?


Right, so "you suspect" that both extreme over or under-inflation "seems to" adversely affect either handling or wear, but all that pressure range in between -- say 25 to 55 -- is exempt from the pressure/contact patch relationship that Bleu M&M has provided the mathmatical formula for? How long have you been running 50psi? Are you monitoring the tread depth with an accurate gauge? You will soon see the effect.

Do you suppose that if 50+psi provided better economy with no adverse effects, that the auto and tire manufacturers might have discovered that by now?


Hyper-tire-ventilating hyper-milers are choosing to ignore physics and pretend to be dicovering something new. It's not the tire wear that concerns the rest of us. It's the smaller contact patch, reduced adhesion and increased suspension bound rates that degrade handling. No wait.....that's just something everybody "presumes"?

 

why would anyone go to these great lengths with a 4lb truck, turbo no less, and a premium oriented brand....dont nerds with honda civic hyrbids do this kind of stuff....this makes no sense to me. if u want to hypermill something, hypermill a car thats worth doing it in.

 

I agree.

Even with sensible hypermilling driving habits, I still don't think one can achieve anything better than 11.5L per 100 km in city driving with the RDX. The goal would be to minimize the impact on the fuel economy, and not end up driving like you stole it, getting only 10-15 mpg.

So all this talk about tire pressure of up to 50psi etc etc... makes no sense... Proper tire inflation will ensure you are getting the fuel economy it was designed to achieve. Higher tire pressures are only recommended if your weight load and speeds exceed regular normal driving conditions.

Like I said, before, either:
1. Trade it in for a Hybrid sedan (which does not make any sense in terms of the cost-savings)
2. or adapt your lifestyle to see if you can use your RDX less often, not make repeated unnecessary trips to various destinations.
Now that I am using the public transportation system more often, I am less stressed by the rising gas prices, still able to enjoy my RDX in the occasional weekday evening nightouts and weekend getaways with the family.
I don't have to be driving my RDX everyday to enjoy it.

 

400km on the odometer, pure city driving (Vancouver downtown rush hour grid lock: hitting a red light at every second intersection for a 30 min drive over a grand distance of 10 km!). My trip computer average reads 16.5L/100km (about 14 MPG). And FYI, my average speed is 22km/hr (which seems about right with my travel time and distance). This is probably the worst fuel econ the RDX will do. Hopefully after my engine breaks in, my fuel econ will get better.

With soaring gas prices, it sure sucks to see such discouraging fuel economy. But I was well aware of this possible outcome before I made the purchase, and I still went ahead to buy it. To me a car is more than "fuel consumption", it's a total package. I think the goods of the RDX (styling, quality, performance, relatively cheap) outweigh its bads (poor fuel econ). And this is enough to make me a happy camper.

 

We drove from Vancouver to Whistler BC this weekend, a total trip of about 300kms in our 10 month old 07 RDX. Getting there (a bit of uphill driving) we got 10.2 L/100km (which translates to 23.29 MPG) and coming back we got 9.8 L/100KM (which is 24.00 MPG). This is with me driving reasonably (not too fast, but avoiding turbo boost when going downhill or flat) probably driving an average of about 80-90 km/h speed (50-55 mph).

That is about as good as I have ever seen this RDX. Typical daily driving (its only a 15 min drive to work) is about 13.4 l/100km (17.55 MPG).

PS .. to arrive at the conversions, I used google.com .. using this example search:
"9.8 L/100km in MPG"

PPS ... this RDX has about 9,000 Kms on it currently.

 

You guys make good points, let me counter here a little:

1: In response to the contact patch, bounce and wiggle, etc:
The formula quoted is if you actually had a completely rubber tire. Tires today are a compound with steel in the carcass, so expansion does not follow the formula, in fact each manufacturer tires will expand and contract differently. On top of that, the weight of the car also affects the contact patch. So, a lighter car will be more quickly affected by a tire pressure increase than a heavier vehicle. Lastly, tire height and width also makes a difference. A taller 70 series tire will behave differently than a 40 series tire.
In conjunction, the formula used in the compound also makes a difference. A stickier tire will hold better than a non-sticky tire and behave less cohesively with the ground in uneven terrain. All these factors are what's to be taken into account if you were to try and guess what will happen. That's why I did some basics with stopping. If the tires were truly losing the contact patch, the car would take longer to stop since it would have less contact patch. What I think I'm trying to explain is that tires are not linear in this fashion, there is a bell curve in terms of adhesion or grip, contact patch and expansion. My testing verifys this, otherwise every 2-3 lbs would produce a very measurable change in behavior. But, it doesn't work that way.
Tied in with this was the statement concerning the suspension. I hate to say this, but the tire pressure does not alter the suspension. The spring rates don't change, the shocks don't change. The will still handle the micro movements of an higher inflated tire while moving down the road. The tire does not suddenly become a rock of immovable force, it's still flexing and absorbing energy and motion.

2: Question of alcohol: I again hate to have to clarify, but it is clear that some people don't know enough about alcohol to make a correct statement. Alchohol actually has a HIGHER octane than gasoline. Running E85 is 105 octane, over 10 points higher than premium, pure alcohol is about 115 octane. So, you can see than running alcohol mixed with the gasoline produces a better fuel, not a worse fuel. And, as I've mentioned before, I test the car constantly with a scanner, reading normal driving conditions in the real world with these mixtures to make sure I have not pushed the vehicle past it's limit.

3: Free lunch statement: Do I think there is no give and take? Of course not, but that's not what the discussion thread was, it was about what does it take to get better gas mileage? At the same time, some tradeoffs are things people can live with, and some are things people cannot.

What is interesting is how a combination of things can produce remarkable increases. Tire pressure alone gives you a couple a miles per gallon because you are reducing rolling resistance. In that same statement, you can see how that means the car might not be as responsive at the limit. But, that's the key phrase 'at the limit'. Since most of the time I am not driving at the limit, I find it an acceptable trade off for this test. The alcohol testing has me very curious, since it does seem to be a viable alternative fuel, as witnessed by countries like Brazil, which completely converts every car that comes into the country to alcohol, and there is not any more breakdowns or trouble than when the vehicles are running gasoline.

I'm not making any statements here like you guys need to up your tire pressure, or you guys need to be running alcohol. But, my testing might open up some minds here that if you are willing to make some tradeoffs, you can pick up some mileage. You can take everything I'm doing, minimize it, and still pick up mileage. Take the tire to 36psi, use 10% alcohol, drive gently, pick up 3 miles per gallon.

And, if you don't want to, or care to, that's totally cool. People should do what they want with their cars. I happen to like to experiment a little on mine.

 

May I ask what engineering background you have? I engineer Class 8 heavy duty trucks. It amazes me what I see sometimes when customers "re-engineer" our trucks. For that reason, I think the Honda engineers have done what they reasonably can to engineer the best fuel economy out of the "intended" use of the RDX. I didn't buy the RDX for the fuel economy, but I'm enjoying driving it in a smart way that I am not wasting fuel.

1) I don't quite agree with your counterpoints on the tires. The entire suspension and input to the chassis is dependent on the entire suspension assembly and design. The tire is one input into that entire system, and it is dependent on many things including pressure. Imagine replacing your tires with a flintstone tire. You don't think this will change your ride? Your generalization of how much the tire pressure contributes to the overall fuel economy seems a little too much. If you simplify the problem, it is contact patch and friction. My suggestion to you is to change your rims and tires versus overinflating your factory tires (+5psi is fine, but +30psi seems a little much). Do your research and perhaps buy smaller rims, narrower tires, with higher tread wear rating. Do your research though because the factory tires for the RDX have stiffer side walls for handling.
2) Concerning ethanol, you're correct about the octane in ethanol, but there is less energy per volume. As well, it raises the vapor pressure of gasoline and increases the water content. Ethanol will also degrade seals, gaskets and hoses. That's why the RDX manual recommends maximum mixture percentages.

 

So far all city driving wit A/C on 22MPG!

I'm breaking into the mid 12K mileage wise...

 

I rarely use A/C...so City: 23 and highway: 26ish
Mileage: 137k

 

CDEng,

Please don't get me wrong, I think that Honda has done a fantastic job with the RDX. 20+ MPG for a big vehicle that is fun to drive, and has excellent driving dynamics. What's not to like? It's my favorite vehicle to drive. So, let's get that out of the way. This is not a discussion [from my point of view] of how great the car is, or any pointing of the finger as though there was something wrong with it. It's a discussion of various ways to increase the gas mileage of the vehicle and understanding the TRUE tradeoffs made when using the vehicle in normal day-to-day driving situations.

We can disagree about the dynamics of the tires. Your flintstone tire example is taking the example too far. Changing the tire pressure is a much smaller change. Have I stepped outside the normal range of the tire? Yes. Has it wrought destruction of the vehicle? No. Can it be adjusted to find that happy medium where I might pick up a few miles per gallon and still be a grippy fun vehicle? Yes. Am I making this a less grippy car where I have it now? Yes. Am I going to slide off into the sidewalk with every turn? No. Why? Because my testing of the RDX with the settings in it right now show that it still is a safe vehicle, just a little less grippy [but not dangerously so], and little firmer ride. I'm not advocating that anyone else go out there and try this if they don't want to, I'm merely demonstrating that certain basic assumptions are not always correct, and that it's interesting to see what happens to the dynamics of the vehicle when certain adjustments are made.

I really also don't want to get into what my background is or who holds the highest degree in engineering since I have no interest in excluding from this conversation people who may have done personal research or worked in fields outside of their scholarly pursuits. What I will discuss that is pertinent is that I work as part of a research branch for racing teams. Spring rates, tire pressure,ambient temperature, humidity, angle of entry, vehicle weight, fuel type and octane, coolant temp, air flow, weight distribution, tire temp, tread depth, etc, etc etc are all things that we monitor and test and push the envelope with. I also happen to have a friend who works for a national tire company who tests tires all day long, both their own manufacture and the competition. We compare a lot of notes, and we have both tested a lot of vehicles. Am I an expert? No. But I'm reasonably intelligent and I like to test. Lastly, my hobby is road racing, drag racing, and land speed racing. I've gathered a lot of data from that also and spent a lot of time researching to improve my car.

Ethanol, E-85, and Methanol are all fuel types that have been tested by me personally on a variety of vehicles. While I agree that methanol has the corrosiveness that you mentioned, ethanol and E-85 do not. We commonly can switch a vehicle from 93 octane to E-85 without changing any items in regards to gaskets, fuel lines or pumps. I've personally seen cars running E-85 for anywhere from 50,000-100,000 miles in tests with no problems whatsoever, from brand new cars to as old as 15 years old. I've flipped over several production cars to E-85, with the worst item being that the fuel filter needs to be changed on a high mileage gasoline car because of the junk that gets cleaned out of the gas tank for the first few miles. Adjusting the fuel injectors for a longer squirt per cycle and moving the timing forward usually puts the vehicle at the same horsepower and fuel mileage as regular gasoline. I've spent dozens of hours programming several of these cars myself to obtain either maximum horsepower or maximum gas mileage, depending on the situation. And these ran the gamut from turboed to supercharged to naturally aspirated. Turboed and supercharged vehicles on average actually gained both horsepower and mileage over gasoline due to the extraordinary cooling effects of alcohol.

Your are also correct that to improve my efforts, switching wheels would make sense. A much thinner wheel, a tire with less rolling resistance [less grippy], a lighter rim, removing weight from the car, etc would also improve my gas mileage. Again, I go back to my original thought, which is that I am not unhappy with the vehicle, I am more the curious type who decided to play with the vehicle in small ways to see what actually happens on the street. When I am finished, I will probably perform several items to a lesser degree [such as 40psi instead of 50psi], but it was good information that I gathered and thought this was as good a forum to put forth what I discovered.

Your background and experience with Heavy duty trucks brings insights I would be very interested to hear about, such as maximizing towing capacity, improving low end torque, load capacities, etc. with the RDX. Again, not that I want to turn my Acura into a dump truck, but as an excercise as to what improvements are possible, even if not necessarily practical.

 

Actually it does.

(from Hunter, Inc)

As shown in Figure 13b, the relationship of tire pressure to adhesion is an inverse relationship.


Figure 13b: Effect of Tire Inflation Pressure on Adhesion

(from Hunter,Inc)

In the automotive suspension, the tire spring is in series with the suspension spring.

The tire spring, however, has a spring constant usually five to ten times greater than the suspension spring constant. This results in an equivalent spring constant equal to approximately 80% to 90% of the suspension spring constant.

(from Hoosier Racing Tire)

The actual in-service tire spring rate will often differ as it is dependant upon the actual tire operating pressure........... The basic rule is: 1-psi change is equal to a 40-lb change in spring rate.

It isn't necessary to drive fast to find the limit. By drastically altering the tire spring rate, the limit has been lowered. It may find you first.

 

Hmm....thanks for making me look at that graph on adhesion again, it does show it to be more linear than it feels and what my driving tests have shown me.

This is also why I've done a lot of testing with each 5lb increase in tire pressure. Starting at 28lbs and working up to the 50psi mark. What my data is showing me is that the SH-AWD and the tire itself are more than up to the task of running at the higher pressures, with little loss of traction in either straight line takeoff, repeated hard braking to complete stop, or turning within normal boundries. I'm not testing this at 100MPH, I'm doing repeated tests from 25 MPH to 70MPH, in 10 mile increments, on normal road surface, not race track conditions. I'm also performing this same test on wet road as well. Testing has shown no measurable brake loss in terms of distance, and an approximate 10% loss in terms of traction in rapid takeoff and sharp turning at above 35MPH.

Now, here's where I felt that there is some kind of bell curve or rapid fall off. When going over the 50psi mark [55psi and 60psi], there is an incredible loss of grip. I couldn't safely test at higher speeds, the grip had fallen by well over 50%.

I'll be setting the car back down to about 42psi for now, and run through a couple of hundred miles to see what gains I'm still getting. It's about 5psi above normal, so I should see a gain about 1-2MPG.

Thanks for the feedback, this is a bright group of owners.

 

I think the Acura SH-AWD compensates a lot for the CG shift during turning. The SH-AWD keeps the CG of the RDX pretty stable which is why you're not feeling the effects of the traction loss during turns. Just my 2 cents.

 

For a forum that started off based in a legitimate need (it's nice for prospective purchasers of a relatively new model to hear real-word experiences in mileage vs. EPA and dealer fiction on the subject) this discussion appears to have gone into the weeds in a big way. First off, it's moved from it's stated mission of giving mileage feedback to talking about traction and tire issues. Secondly, I've never hear such teeth gnashing and crying about mileage for an AWD PERFORMANCE SUV in my life. Yeah, the RDX is a four cylinder, but if mileage was your number one priority, then you should have bought a Honda Fit, a hybrid or even a CRV if AWD is an absolute necessity. Give me a break! If anyone is purchasing an RDX with the primary goal of MPG, you are just kidding yourselves. Let's move on - clearly the rig can get in the low to mid 20's if driven gently in the right conditions....

 

thought id check back in. I just turned 7200k....i thought i was seeing things the last 4 fill ups...but, going from avg about 16-17 80% city im now seeing 19+ and 22+ highway. call me crazy, but things have gotten better. not sure if its the summer gas blends or what, but nothing has changed driving habit wise and if anything ive had more people in my car and more trips to the summer house.....

 

Picked up my new 08 RDX last week. First gas of tank was 14.99 L/100 km or
15.7 mpg. This was mainly city driving with lots of stop and go trafifc.

Average fuel calculated on the MID was 11.7 L/100 km.

 

I am at constant 20MPG average, with 4,100 miles on the odometer. Yes, 4,100 with a 2007 RDX, purchased July 15th, 2007.

I have a daily driven 2003 4cyl 2wd-XE frontier that gives me 26 mpg, and I really don't go anywhere, other than work and running errands.

 

somebody pinch me. i rolled 24+ mpg today, 85 degrees out 70 mile round trip for work. bizzaro world! lol ill take this...

 

So far, 5 tanks and about 1850 miles in I am running at 19.4 MPG. Best was 20.5 which had a lot of highway miles on it, and worst was 18 MPG when my wife had the car for a couple of days. Most of my wife's driving is short city trips where the car barely warms up. She runs at around 15.8 MPG cumulative on her CX-7 and has seen as low as the 12's in the winter on tanks that are all around town driving The CX is comparably rated for EPA estimates to the RDX. I was hoping for a little better than I am getting mileage wise, but am not too worried about it. I was getting 22.2 MPG lifetime on my Mazdaspeed 6 which was rated at 17/23 by the EPA, so was hoping maybe 20-21 on the RDX, but not so far....

 

When I first got my RDX (March 07) I was shocked at the low 12mpg I was acheiving. But then again I was coming from a 4 cylinder 04 camry which gave me 30+ mpg. Now that over one year has passed, I noticed that the RDX is getting much better mpg, very close to the avg manufacturer mpg of 20.5. I'm getting about 17-19mpg now with 80% city and 20% highway.

There was this one time where I just took the RDX on the highway for an hour straight going 60mph no congestion and my mpg indicator said 26mpg. Not bad for a 4000lb turbo SUV.

 

no idea whats going on....turned 28.7 mpg today, 7500miles, 86 deg, ac on 1 click....65 mile trip mixed driving say abouy 75% highway. WHAT??????????

 

Allright! Mike's in the club! Now Bluto has to give you your new name....

 

i know right, i really still cant believe it....seriously just started happening like someone flipped a switch under the hood.

and hopefully...the K&N may even help it even more adding maybe 1mpg+ who knows

 

Back during the last 'gas crisis' a neighbor bought a VW and wouldn't shut up about the great mileage he was getting. We decided to fan the flames by sneaking over at night for a week and dumping some gas in - too much fun.

Of course, we didn't have to deal with locking fuel doors...

 

There's actually an old story that talks about a guy raving about his VW's mileage, so his friends gradually started adding a little fuel progressively to his car on a weekly basis--a little at first, but more every week. After 3 or 4 weeks, the guy is going nuts about getting 45 MPG with his Bug. Then his friends switch to siphoning fuel every week. So the guy is freaking out about going from 45 MPG down to 12 MPG.

 

I have been finding that the computer MPG is a bit off from actual, but not too bad. Mine usually reads right at about 20MPG on the computer but when I compute it it is .5-.7 MPG off. I will admit, I am a dork and I track my mileage every tank to budget what my wife and I spend on fuel per month.

 

While my RDX only has about 750 on the ody I am quite pleased with the mpg. Have gotten as low as 16 in city and up to 26 on the highway. Overall I would say about 22 mpg in mixed driving. I am sure these numbers will change once the engine is totally broken in around the first oil change. My buying an RDX was never about the mileage I would be getting. Hope this helps those of you who are keeping score.

 

Have just returned from the nearly 2k miles trip with almost highway drive and averaged 20 mpg within 60mph. Actually sometimes I drove 100-120mph and sometimes I cruised 20-40mph in the Crimean mountains on S drive.

Now my odometer reports 12k miles totally with 15.4 mpg figure. I'd love to have the better mileage but it's not 400h unfortunately (or successfully)