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Acura MDX vs. Acura RDX vs. Lexus RX 350

neglexneglex Posts: 5
edited January 9 in Acura
I am buying a new car. I currently have an'04 Sienna van with 80,000 miles on it-my 17 year old daughter will drive that mostly. Originally, I was looking at the RDX because I didn't want to have two big cars. It sounds as if the MDX is a lot nicer than the RDX, amenities and ride. I need help figuring out which Acura to get, or if I should look at the Lexus RX 350 AWD. I live in the Boston area so need something that is reliable in the snow and don't want to get snow tires. Thanks for your help.


  • wwestwwest Posts: 10,706
    The RX's F/AWD system is for marketing purposes only, it is NOT truly an AWD system(***), mostly FWD until wheelspin/slip at which point the TC, Traction Control system, braking and engine dethrottling, is used to re-apportion engine torque.

    If you can stand the "business" of the RDX's dash then the SH-AWD system is head and shoulders above any other F/AWD system, systems in vehicles with sideways mounted engines.

    If you purchase the RDX I would suggest "wiring" the wastegate fully open, sacrifice 0-60 times for FE. An aftermarket modification kit for the CX-7 and the RDX might be a great idea, keep the wastegate closed unless the gas pedal is RAPIDLY moved to WOT.

    On the subject of the RX, the statements at indicate that a (desperately needed) entirely new AWD system is in the works. It would be nice if it also included the new 185HP I4, itself upgraded to DFI and Atkinson (miller..?) cycle but that's just wishful thinking on my part.

    RDX vs MDX.... amenities and ride...

    What amenities might one Acura (MDX), that the other (RDX) doesn't have...??

    That couldn't be added aftermarket, better and more reliable products.


    MDX would be HEAVIER, so on that count yes... But for FE... the RDX

    Between the two I'd choose the RDX... EVERY time.

    *** To be perfectly fair it IS AWD as long as all four wheels have roughly EQUAL traction, whatever good that may be in wintertime adverse roadbed conditions. My '01 AWD RX300 has just spent 10 days with the SURETY (enforcement..??) of AWD, tire chains on all four.
  • neglexneglex Posts: 5
    Thank you so much. This was really helpful. I am going to drive the MDX and RDX and then decide. It doesn't look like the FE on the RDX is too great either, but is a little better than the MDX.
  • With all due respect to previous posts.... The three vehicles you list are not generally considered "competitors". The RDX is noisy, rough-riding, and does not have a true AWD system. It is best compared to a Subaru Forester or a Nissan Rogue. The Lexus RX 350 is still popular, but is underpowered, limited in cargo space, and has long-surpassed it run in terms of styling. It is a suburban soccer mom's station wagon. I own a 2009 Acura MDX Sports & Entertainment Pkg, and selected it over the Mercedes ML 550, BMW X5, and Range Rover Sport. After test driving EVERYTHING, REPEATEDLY, over a three month period, I could not get past the performance, luxury, and technology of the Acura!! It is an amazing vehicle. The SH-AWD system is a truly superior technology, and alone, has tipped the scale in favor of the MDX for many enthusiasts. For me, the entire Acura MDX package represented far too great a value to even consider the other vehicles. If YOU are considering the RDX or the RX 350, along with the MDX, a short test drive will solve that problem. Good luck, and best wishes.
  • neglexneglex Posts: 5
    Thanks, but doesn't the RDX have the same SH-AWD that the MDX has. We have a minivan already and don't want something as big as an MDX.
  • The RDX has SH-AWD. You are correct. It is NOT mated with the Active Dampening Suspension system of the MDX. The RDX is lighter, shorter, and narrower than the MDX, and is not able utilize the SH-AWD to it's ability. The RDX is NOT a smaller version of the MDX. They are VERY different vehicles. As long as you realize that, I think you will be happy with your choice of the RDX.
  • wwestwwest Posts: 10,706
    "..and (the RDX) is not able to utilize the SH-AWD to it's ability.."

    What, WHAT...??!!

    Wasn't the SH-AWD first introduced/adopted/adapted for the RDX and then later used to UPGRADE the MDX.

    Yes, the MDX is HEAVIER and therefore more overall traction coefficient on equally slippery surfaces but otherwise the VERY SAME SH-AWD system.

    "The RDX is NOT a smaller version of the MDX.."

    And we can thank the powers that be for that..!!

    If you don't need, or rarely need, the extra space, and can do without the clunky harsh ride of the MDX, then the RDX would be a perfect purchase.
  • And we can also be thankful that we make our own judgments and buy our OWN vehicles. I would never expect you to buy an RDX for me, and I would never buy an MDX for you. Best of luck.
  • No question the MDX is an excellent car, but if you don’t need the extra space and the DVD rear entertainment system, the additional $12,000 paid for the MDX compared to the RDX is really a waste of money! That difference in price is almost the cost of a basic Honda Fit!!! No offense, but both cars are indeed very similar! The SH-AWD is exactly the same in both, but actually first developed or the RDX, not the MDX! The RDX is also turbo with a better sporty handling compared to the MDX, but indeed a bit noisier too. Finally, the RDX also deliver slightly better gas mileage, not a bad thing in these days!
  • wwestwwest Posts: 10,706
    "..RDX also deliver slightly better gas mileage..."

    I would bet NOT.

    The clear majority of the time the RDX's engine runs in derated/detuned "off-boost" mode. In order to allow for the increase in "effective" compression ratio when boost comes on the native compression ratio must be lower that it would be absent the turbo 'feature".

    Obviously, like the CX-7, they could have used a form, combined form, of the Atkinson/Miller cycle. Have a "native", just cruising along, compression ratio of 10:1 (12:1 for the CX-7) and then use the intake valve closing delay technique to keep the effective on-boost compression ratio within tolerance.
  • At one time, I owned both an MDX and an RDX. My recollection was the mileage was @the same. I think the RDX was a little better with highway driving.

    But... depends on how spirited your driving was. The RDX is more tempting than the MDX....
  • indykingindyking Posts: 2
    Hi wwest, your explanation for the fuel consumption looks good and it only proves how ignorant I'm when it comes to car mechanics; however, my argument for "slight better gas mileage” in the RDX compared to the MDX is rather based on the real facts. Go to if you don't know this website yet, you should. It contains MPG data from real drivers and you can see in the website that indeed the RDX gets a better MPG than the MDX overall, not a lot better, but just “slight” like I said... considering the Turbo in the RDX, the better MPG is very nice! Also the RDX has "slight" better MPG in the new EPA estimates compared to the MDX. The old EPA estimates were useless but I actually find the new numbers very reliable since they match almost perfectly with what I get in my CR-V and Odyssey.

    So, once again, the RDX and MDX should not be competitors... like I said, if you need more room, a DVD entertainment system, and have extra 12K to burn, the MDX is the way to go, but if you're like me, who don't really think the extras in the MDX worth 12K, the RDX is a no-brainer.... the RDX is a very similar car, with all the cool toys like the MDX, a nice sporty drive because of the turbo engine, better MPG, and have I told you the RDX has better looks too?
  • wwestwwest Posts: 10,706
    Yes, add DFI to the RDX engine and reduce the instrument panel/dash "clutter" and the RDX would be on my "list" instead of the CX-7.
  • ozzynyc1ozzynyc1 Posts: 7
    You obviously haven't driven RDX AND MDX....It's like comparing driving a mercedes and then kia...RDX drives like crap, it's stiff and bumpy....It's nothing like TL or MDX....MDX is WORTH 12K MORE...It's a 7 seater, it has a sporty, SUV suspension, that's not bumpy, yet not too plus like Lexus..RDX felt like driving a honda civic...CHEAP.... ;)
  • wwestwwest Posts: 10,706
    RDX is light enough that its suspension can be tuned for "sporty" driving. MDX is such an "old folks" "Queen Mary" that it cannot. At those prices, unless I saw real need for the SH-AWD system vs the new RX F/awd system (I don't) I'd be buying a new 2010 RX350 rather than a "cushy", too softly sprung, MDX.
  • I highly disagree with you. I owned both at the same time a little while back.

    The MDX is like a boat compared to the RDX. Don't get me wrong, the MDX is a nice vehicle but the RDX is much sportier. Whether it's worth $12K more or not is obviously dependent on your needs for a bigger vehicle.

    Mercedes to Kia - no way. Maybe Porsche to cushy Cadillac.
  • ozzynyc1ozzynyc1 Posts: 7
    Ok, u win :) ....MDX is like a boat, but sturdy boat...I wouldn't want to have my toddler in RDX....It's a street racer car not a family SUV that MDX is known for...But anyways, i just got a new TL, so it doesn't matter....TL rapes both of these cars in a matter of 2 seconds :)
  • I'm debating between a 2011 AWD RX350 with navigation and the Acura MDX with Tech and entertainment package. When I attempted to "build" the RX on their website, none of the packages appear to have the rear entertainment system. Does the RX come with this option?

    If both cars are equal, with the same options, it's essentially going to come down to what vehicle I can get a better deal on.

    Any information on your buying experiences, would be greatly appreciated!

  • I completely agree. I had a TL, and loved it, but hated the way it handled in the snow. I thought, before driving it, the RDX would be the perfect alternative. Boy, was I wrong. If you want the RDX, you might as well go buy a CR-V for a lot less money. Although the MDX is a bit more $$, it's well worth the comparison. Those cars are like night and day!
    The RDX is essentially an over-priced Honda CRV.
  • wwestwwest Posts: 10,706
    Anyone who can afford an RX350 would generally have enough sense to recognize one can purchase a dozen, or more, portable "rear entertainment systems" for the price of a "captive" one.

    Same goes for GPS, but with the addition information that most portable GPS systems come with the ability to do an INSTANT free update whereas a captive GPS will NEVER be delivered with current info, and updates are expensive in comparison.

    While far from adequate IMO the MDX's SH-AWD system is head and shoulders above the RX350's F/awd system.
  • wwestwwest Posts: 10,706

    The RDX has exactly the same SH-AWD system as the MDX.

    But then the RDX does have rather HORRID FE for the engine displacement and RDX weight and size. But that's what you get when you drive 99% of the time with the engine in detuned mode.
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