Madd Dog

Never did better than 27, and that number was barely brushed on a 100% highway drive at around 65 mph.

I drive fairly conservatively now, and if I get 25-26 on a pure highway run, or 21-22 in everyday suburban driver, I am happy.

fogdoctor

The highest I have seen is 28mpg on a trip from Philadelphia to Lancaster @ 65mph on cruise. It's not flat though, lots of rolling hills.

On the way back I followed a 911 at higher speeds and it dropped to 21mpg.

Madd Dog

Agreed fuel economy on the highway is very speed sensitive, more so than a sedan. Which makes sense.

Jordster

The "information" began as a conversation with a trusted mechanic and continued what info I've gathered from lots of personal observations specifically around fuel economy. I'm the kind of guy who used to run a bluetooth OBD2 reader to get stats from my engine in real time because I'm fascinated by these things. Turbo engines run rich (use more fuel) until they are very fully good and warmed up. You can't trust the guage, either, especially in newer cars that don't show the actual temp but just some bar graph or notches. When it's not fully warm, you can try as hard as you want, you'll never match the FE of an engine that's been running for 20+ minutes or 10+ minutes if you're on the highway at steady medium RPM.

The last car I owned that wasn't a turbo was a 2008 Civic Si. The engine stopped asking for a rich mixture after 5-6 minutes, usually befefore the gauge even reached it's normal operating position.

It was explained to me that this is done on purpose because there is more risk of deposits building up when a turbo engine is cold. Something about the wastegate? I'm not a mechanic and I dont' want to pretend to know the correct terms.

So there it is. Unscientific? Yes. But my observations are no wrong.

horseshoez

iTrader: (2)

Well, as an engineer who has worked for three auto manufacturers, I would argue, there is virtually zero difference in horsepower minutes output from the engine before the OBD-II system switches from Open Loop to Closed Loop. As a general rule, a warmup cycle is defined as a trip which includes a change in engine temperature of at least 40ºF and where it reaches 160ºF. The above said, if the driver is romping on it, the extra heat generated in a turbocharged engine will, if anything, warm the engine up faster and switch to Closed Loop sooner.

DKraky

Probably 60% rural Highway and 40% City in rural Wisconsin... also a few morning warm ups in the garage mixed in there!

Gear Head

This car is a poser in all ways. So angry we purchased it 2 months ago - averaging 17.1-17.5 in mixed, and only 19.xx on long highway drives. Haven't even hit the bottom number of the sticker.

It's been back for innumerable problems in design and manufacture also. It's a really awful car. So sorry we bought it. Already thinking of trading it in after 60 days and taking a loss versus feeling like a fool everyday for buying this junk. Should have kicked in the extra 10K and waited for the dang Tesla Modely Y..

russianDude

Sell the car. I’ve been enjoying my 2020 rdx since October of last year

anoop

Have you tried taking it in to the dealer. You could demonstrate to them by resetting the mpg in the trip computer, taking it on the highway, and showing the low mpg reading.

What are the other problems you’re experiencing?

NooYawkuh

Do we really care?

yankee7

Starting from when I purchased the 2020 AWD Tech:

first 350 miles - 200 of them on the highway (70-75mph) and 150 in the city, in pretty busy traffic - average of 19mpg.
next 250 miles - commute in busy traffic plus some suburban traffic - average of 18mpg
next 250 miles - highway, cruising at 75mph - average of 24.3mpg
next 40 miles - highway, cruising at 65-70mph - 27mpg

My initial impressions:

1) The fuel consumption apparently improved after the first 500 miles or so.
2) The EPA city average of 21mpg is not realistic, as expected; the actual numbers are somewhere around 16-18mpg, depending on whether you use the start/stop engine function, on the traffic conditions, on the driving style etc.
3) The EPA highway rating of 27mpg is achievable, as long as you stay below 70mph, drive on flat roads, use the Comfort mode, don't accelerate suddenly and so on.

Madd Dog

From wiki about the ‘highway’ test.

Speed of 48MPH, will get you pushed off any highway in America.

If you keep it under 70, like Yankee said, you can do OK.

hans471

1) If you hate this car so much why did you buy it?
2) After a year of driving my 2019 RDX I can only think you must have a different car than I bought...mine has been very dependable and had only one minor problem (an occasional brake squeal under certain conditions) which was quickly and correctly fixed by the dealer once the new parts were available.
3) My best fuel economy was driving across Norther New Mexico on the Interstate. 70 MPH steady speed and got 32 MPG for over 100 miles. In the hills of Kentucky driving on the interstates here where the cops look the other way and people drive 75-80 up and down our hills and mountains it drops to 26 plus or minus. Normal flat road driving at 65 to 70 yields 28 MPG or more. BUT, speed and my right foot has more to do with economy than anything. When I get really low MPG its due to my driving more than anything. I can get 23- 25 MPG in the city if I don't race around testing the turbo. OR, I can hammer it racing around and make it drop to 18-19 MPG...but its MY fault not the car's.
As for EPA ratings....the EPA lays out strict guidelines of how to run the test, its not up to the car maker. The idea is everyone will drive the cars the same to make the comparison a little more fair. No one gives a warranty that the care will match those numbers. Our Honda Fit easily beats the EPA ratings by 3 to 4, or more, MPG. Ratings can be higher or lower than what the sticker says.
Finally: If you really hate your car so much, do yourself a favor and get something else, really. Life is too short to be stuck with a car and its clear you really hate this thing. Take the hit and move on to something you like better. Its only money.

hans471

I too worked for a couple of car makers as a technical person (developed and delivered advanced training for field people). Engine management systems and OBD II were one of my specialties.
1) Cars are made to go into "closed loop" as quickly as possible. In Closed Loop the O2 sensor is being used to help keep the mixture right where it needs to be. I have spend hundreds of hours monitoring engine control modules and fuel controls and just can't recall any cars that "stay rich" for very long at all as this would prevent them from going into Closed Loop operation.(an exception to this is starting the engine and letting it idle...not enough fuel being burned to heat up the coolant so a richer mixture is normally used. This is one reason for shutting off engines at idle used on many cars now). For "Closed Loop" there are many factors of course, one is the O2 sensor needs to be warmed up. To make this happen quickly they have electrical heaters and get hot FAST. Also, there are a list of other criteria to be met on many cars, one of course is the ECT (engine coolant temperature). Different engines use different criteria depending on their individual operating characteristics. .

2) "Warm up cycles" are one of the methods for clearing coded in OBD II. Normally when a "trip" fails and sets a code the ECM needs to see three passing tests to self clear the code. Some "trips" are run very rarely so the Warm Up cycle is an alternate way to clear the code. I have seen cars that were run for a couple of years and had yet to run certain "trips" so their ECM's could not self clear a trouble code even if the system was OK. OBD II is a great system but when you read through the manuals you get the feeling it was co-authored by a computer programmer and a lawyer! Lots of very strict rules and lots of terms that you need to understand.

"

Warm-Up Cycle

Warm Up cycles are used by the PCM for automatic clearing of DTCs and freeze frame data. To complete one warm up cycle, the engine coolant temperature must rise at least 40ºF (22ºC) and reach a minimum of 160ºF (71ºC).

Trip

A trip is a key-on cycle in which all enable criteria for a particular diagnostic monitor are met and the diagnostic monitor is run. The trip is completed when the ignition switch is turned off. (Note: during one "key-on, key-off cycle you can only get credit for one pass of a particular code)

Drive Cycle

Most OBD II diagnostic monitors run at some time during normal operation of the vehicle. However, to satisfy all of the different trip enable criteria and run all of the OBD II diagnostic monitors, the vehicle must be driven under a variety of very specific conditions.

Automatic Clearing

If the vehicle completes three consecutive "good trips" that is: three consecutive trips in which the monitor that set the DTC is run and passes, the MIL is turned off, but the DTC and freeze frame remain stored in PCM memory (Note: as a "history" fault, not a current fault) . If the vehicle completes 40 warm-up cycles without the same fault recurring, the DTC and freeze frame are automatically cleared from the PCM memory. (Note that when the programing uses "warm up cycles" to clear a code there is no requirement for the test to actually run...it just can't fail)"

Its a fun subject that is very involved and complex as you dig into it. It was fun working with it when it first started and then watching it evolve. I will say this: There are few dealership techs that really understand it in great depth. Much of the programing is "hidden" and scan tools only show you what the engineers want you to see.

horseshoez

iTrader: (2)

Thanks @hans471 it seems we are singing from the same page of the hymn book.

russianDude

How did low MPG thread turned into “its a horrible car”. Amazing.

Waetherman

On a long enough timeline, all threads turn into “this is a horrible car” or a discussion of whether regular or premium gas is better.

NooYawkuh

Acurazine's variations on Godwin's Law.

Gear Head

Good to hear you're have a better experience with the vehicle than I am. Are you also seeing very low MPG?

Gear Head

Why wouldn't you care? The problems we're having have all been acknowledged as inherent problems. Each one the dealership, and moreover the Acura Rep have acknowledged are recurring. The dealership, including the employees driving the same car aren't seeing MPG near the sticker either, BTW. But perhaps rather than being glib, you could benefit from being part of a forum and listening? Just a thought.

Madd Dog

I was thinking a new law needs to be established for car threads. “As an online discussion grows longer, the probability of a comparison involving Teslas approaches 1.”

Reducto ad Teslarum.

russianDude

I drive mostly highway and get 25-26mpg as per sticker. City MPG varies from person to person, the city test they do may not be the same city driving you do. I find that my RDX is within the sticker boundaries.

sonyfever

My experience - with Hondata Stage-2 my mpg actually improved. I feel I can better stay out of boost and still have decent speed in 1-3 gears. My car also coasts better (with less drag from the powertrain) after I did the throttle sensor reset procedure before moving to Stage-2. The net result is my mpg went from 18-19 to 19-20 in similar condition.

Waetherman

That’s interesting...and a good justification for doing the Hondata upgrade. The MPGs is the main reason I haven’t done it. Are you happy with the tune?

DJA123

Lots of good analysis and theorizing in here. No one asked, but my simple explanation and justification for shitty mileage is... torque. I like the pull in low gears and I press harder on the "gas pedal" to get it. Small turbo engines make you pay for that in a way that is likely more deleterious to efficiency than NA engines.

Please, carry on.

sonyfever

See my recent posts here:
https://acurazine.com/forums/3g-rdx-...a-tune-983994/

Gear Head

There's something remiss with the MPG, I just had an X3 rental for a week and it was easy it was to get into the high 20's without restraint.

We downsized from a GMC in an attempt to reduce our carbon footprint by 20%-25% based on the Manufacturer and EPA estimates. My wife drives the same route with this car as she has the prior 4+ cars for her daily commute. It is the most complex mechanically, is the smallest, with smallest displacement, and by a good margin has highest manufacturer and EPA estimates. However, of those past four it gets only 1 MPG more than the Sienna AWD, the exact same as the Buick Enclave and a GMC Acadia Denali, and less than the Honda Pilot. It also gets worse highway MPG than all of them.

The dealer and Acura have reported this is within the acceptable range, and consistent with what they're seeing.

I am truly bewildered.

fogdoctor

I have personal experience with the Sienna AWD Limited. The one I traded was 12mpg city and 18mpg highway driven conservatively. If I kept it at 55mph, sometimes it would get 19-20mpg - technically never 20mpg but close. Several times, the Toyota dealer said it was "withing the acceptable range."

I'm doing the same commute in the RDX SH-AWD advance and sit at 25-26mpg with the same driving habits and the same commute. Both the reported and measured fuel economy of my RDX have been excellent using 87 octane Wawa/Sunoco gas. Have you tried to reset the trip and get on the highway with cruise on at 65?

Gear Head

We road-tripped the heck out of the Sienna. Bulletproof but thirsty it usually averaged around 19, sometimes 21 on the highway momentarily with a strong tail wind, and about 16-17 overall.

So, we're not seeing north of 21-xx on highway with RDX. Reset trip meters, calculated manually, tip tier gas. Recently road trip Washington DC to NY, averaged 19.xx overall with some suburban driving at both ends. Granted, going more than 65, but in comfort mode and the same driving style hasn't resulted in such a disparity between EPA/published to realized in any of our other vehicles.

It appears there's quite a range of MPG results; some lower some higher. So it is what it is. I just wish it did as least close to "what is says on the tin".

fogdoctor

19mpg highway is pretty bad. My Subaru Legacy is a full 20% below EPA estimates, which is extremely annoying. I’m giving it to my son so I don’t care that much any more. One of the reasons we left Subaru after buying 4 was the dealers are terrible and the fuel economy was really bad for the performance. There was never anything wrong they could find or they could not reproduce anything - even if I had a video of it happening! Have you tried a different dealer or direct through Acura?

Of our three current vehicles, the RDX is the only one living up to it’s numbers. The Outback is not too bad but still short of what I expected.

NooYawkuh

Unless you were carrying bricks or you hit a lot of bumper-to-bumper traffic, there's something wrong.

jc411

I'm averaging 19 mpg with my 2020 A-Spec, currently at 1500 miles. I've only been using top tier fuel.

Madd Dog

We drove from Naples, FL back to NY, 1300 miles. Got around 25-26 doing about 70. Doing 75 or so, that dropped to just below 25, doing 60-65 it almost hit 27. The power is there, but when you use it, you pay for it.

gooberman

My wife has the RDX and I have an Audi a4. I do drive the RDX some because she works from home and I'll drive it to put some miles of it.

Both are FWD and both are a 2.0 turbo. Both are direct injection. The Audi is a 7 speed DCT the RDX id a 10 speed.

Driving both in "town" I guess because we aren't city or highway. I get 32 to 37 in the Audi and 18-22 in the RDX. The RDX weighs 300 lbs more. Aerodynamics might play a small because I never get above 50ish.

The RDX only has 3000 miles so far so there might be some break in left but I don't think much.

That is a pretty big difference between them. I thought the extra 3 gears might make it better but apparently not.

anoop

That's some amazing mpg from the Audi. What you're getting with the RDX is pretty typical unless you feather foot it.

Waetherman

But are you talking about the one with 180 HP or the one that's closer to 250? The latter only gets 24/32 according to EPA estimates. And unless you're comparing that one to the 272 HP RDX, it's really apples and oranges, even more so than just comparing a compact sedan with a mid-size crossover.

gooberman

252 HP and 273 torque.

Also forgot to mention that I disabled the auto stop in the Audi.

The RDX is 1 inch longer and 10 inches higher. and 300 lbs heavier (maybe less as I'm not sure if the weight quoted is FWD or AWD. So sedan to SUV compare shouldn't be that big of a difference should it?

Waetherman

Well aerodynamic matter. Less at low speed than at high, but they still matter. And If I had to guess, I'd say the RDX has about twice the front surface area of an A4. 300 lbs doesn't sound like much, but that's still close to 10% heavier than the A4. So 10% less gas mileage (2-3 mpg) doesn't seem unexpected.

fogdoctor

Is that measured or reported? If it is actually measured then it is amazing. I had an A4 2.0t for 2 weeks and I got 32.0 mpg on a 99% highway 250 mile road trip at 65-70 mph. It was reporting 36mpg but I filled at the same pump and it was actually getting 32 mpg, which is still very good. My Sienna used to do the same thing - reported 24mpg and the best it did was 18-20mpg. Anyway, the rest of the time I got 29.4 mpg on my usual commute where I get 25.5 in the RDX (@3000 miles with 87 octane). It certainly gets better fuel economy than the RDX but I did not see the dramatic difference you did and I found it was consistent with the EPA estimates in both cases.

Jordster

There are some interesting observations to be made by comparing to BMW, using the numbers that C&D got on their fairly well established and scientific 200 mile 75 mph trip.

Same engine with two driven wheels in a car:
BMW 330i RWD: 42 mpg
Honda Accord 2.0T: 36 mpg

Now, in an SUV w/ AWD:
BMW X3: 31 mpg
Acura RDX SH-AWD: 25 mpg

Both lost 11 mpg in going from a 2-wheel drive car to a AWD CUV. That's a pretty big difference. But it does to show that you get what you paid for - you want a tall car with AWD that weighs 4000 lbs? You probably should accept the fuel bill that comes with it. Want better mileage? Use your brakes less. Using your brakes (AKA reducing the power you've paid for into worthless heat) is the opposite of good MPG. You can get decent mileage even if you're not soft on the throttle, but you'll never get good mileage if you're overusing your brakes.

The BMW has that trick alternator/battery setup where excess power can be stored and later used to draw power and temporarily disconnect the alternator, saving the need for the engine to power the electronics. They also have a dedicated ECO-Pro mode that actually does something other than just numb responses (it can disconnect the wheels from the engine when coasting freely will save power over coasting in gear, remembering that there is saved power to keep the electronics going). It's a cool and complex setup that at least partially explains BMWs knack for excellent fuel economy.