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Acura RDX Fuel Efficiency Concerns



  • mark4490mark4490 Posts: 16
    I've only had my RDX for 3 weeks and I've only driven 1100 miles, but I'm getting ~20mpg. I think the other person that responded it right about not driving too slowly. A vehicle has it's maximum efficiency at a certain speed, say 60 mph. Go slower or faster and you're wasting gas.

    When I'm going up mountains or steep hills (i.e., Mt Tam in Marin), the fuel economy drops to almost zero when I'm going too slow. So I give it gas more gas to speed-up and my fuel economy actually improves. The engine is doing having to do less work since the RDX is already moving. I generally punch the trottle/ goose the turbo to get moving and then back off when I get up to speed.

    City driving reduces fuel economy dramatically. In my V6 Accord, I'd generally get 270 miles of city driving out of tank of gas vs 450 miles while on the highway.
  • wwestwwest Posts: 10,706
    Has anyone tried "wiring" the wastegate fully open to determine the FE improvement..??
  • Have you, wwest? You have been posting that same line on every Acura message board for the past 3 years. Why don't you try it and post some results.
  • wwestwwest Posts: 10,706
    Can't really afford to buy an RDX, or the CX-7, just to experiment. But should I decide to purchase then the CX-7 with DFI would be more likely. The DFI aspect would undoubtedly offer the most potential for FE improvment.

    Surprising that the RDX doesn't have DFI, soon to come..??
  • Are you serious that you got 27mpg on the highway?

    Was the TRIP COMPUTER reading or MANUAL calculation based on how much fuel you had to refuel with?

    Hell...on flat highway at 75mph I'd be happy to see it get 24-25mpg!
  • My '07 RDX with ~17000 miles on got 24.5 mpg driving 73 mph with the air running, on a mostly flat surface during a 700 mile round trip 95% highway last summer. Lately it has been averaging 20.9 with 50% city driving. Once summer is over, ethanol % is less, and resume to 30% city the mileage should return to average 22.5. These are all by the car readings, not by hand calculation.
  • On a recent trip to North Myrtle Beach from Frederick Md (450 miles 17.5 gal got 25.7 MPG)

    Yes this was manually calculated and I am positve about the number of gallons.

    Mostly highway (I95) till Wilson NC where backroads takeover.

    This was my driving.

    Around town, which for us is rural Carrol/Howard county, my wife consistently gets 22.5 to 23 MPG. This is also manually calculated.
  • Just came back from 300 mile trip avg 24.5mpg per computer with mostly highway 75mph w/AC - 2 adults. Normal in-town driving is 20mpg.
  • wwestwwest Posts: 10,706
    Drop the turbo and adapt the engine to DFI, 12:1 compression ratio, and the hwy FE would probably rise to ~30 MPG.

    Or even use Toyota's new HSD extended VVT-i technique to transition the engine from "Otto" mode into Miller cycle mode as the throttle opening rises. With the addition of DFI that would allow a 15:1 compression ratio for low engine loading, cruising, and transition to 10:1 to accumodate rising turbo boost with increasing throtte openings, acceleration or high enegine loads/loading.

    35 MPG and 300HP.
  • wwest,

    What's wrong with you?
    This isn't an 'engineer your own engine thread'
    Or a 'WIRE your wastegate open forum'

    Maybe you should spend some more time at your local community college, where
    your ideas can be exploited.
    Instead of suggesting people self destroy their $40,000 luxury vehicles!

    Good luck to you wwest!
    Stay away from open microwave ovens...
  • wwestwwest Posts: 10,706
    "...self destroy..."

    I'm comfortable, very much so, that anyone following my advice will have the knowledge to do so beyond the requirements of a community college.
  • "...accumodate..."

    Small town community college at it's finest!
  • steverstever Posts: 52,571
    Anyone got RDX MPG to report?
  • wwestwwest Posts: 10,706
    Yes, for an I4, horribly POOR....!!

    Isn't the CX-7 due out soon with a non-turbo I4...??

    That will be a good point of comparison as to just how wasteful a factory turbocharged engine is, can be.
  • hms1hms1 Posts: 9
    Picked up a brand new 2010 RDX base 2WD in Atlanta last week and drove it directly
    Clearwater, FL. I was following a friend towing a jeep behind his truck so our speed never went much over 70. The highest the computer got to was 29.6 and the average, when getting home, was 28.4. I was really impressed. Don't know what it will be at my usual 75 to 80 mph highway driving. The city driving, which hasn't been much in this car this week, has lowered the computer mpg to 27.5. Still running on the gas purchased in Tifton, GA about 300 miles from Clearwater. Turned in my leased 07 MDX and even made $1300 on the lease. The car is for my wife, downsized for $$ reasons and purchased this time. Wife loves the RDX. Hooray! I like it too.

  • duncan01duncan01 Posts: 2
    I just picked up my new 2010 RDX last and did not realize that it required premium gas. That information may have changed my purchase of the RDX. Is it truly a requirement - has anyone use regular instead? Any negative issues with using regular?
  • wethertonwetherton Posts: 6
    With turbo, you really need to use premium. I just traded in a 08 tsx that stated premium, we put in plus for 49K and had no problem, but a local acura service manager told us it would be fine. That being said, I will only put prem in the rdx, we have 93 octane locally. At 20-25 cents more per/gal you most likely will get an extra 1-2 mpg which will make up your difference. Don't sweat the prem just look for cheapest/brand name gas in your area.
  • wwestwwest Posts: 10,706
    Required or RECOMMENDED..??

    With the advent/use of the new knock sensors the engine control ECU will simply enrich the A/F mixture if need be to prevent knock/ping.

    But you're in for some rather HORRID FE in any case.

    In order to accomodate the turbo boost when you use it the engine is derated when off-boost, 98% of the time for most of us.
  • wwestwwest Posts: 10,706
    Other than engine lugging, fuel grade, regular or premium, only makes a difference when you are putting a full charge in each cylinder, basically only when WOT. And how much time, overall, do YOU spend at WOT....?
This discussion has been closed.