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Acura MDX vs. Acura RDX vs. Lexus RX 350

neglexneglex Posts: 5
edited January 2014 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: 9
    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: 9
    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.
  • lyaolyao Posts: 71
    We disagree with you. We just bought the MDX with Tech/Entertainment yesterday. Luv it! We're not OLD like you said!

    We got 3 kids (2 elementary kids & 1 baby). We, in fact, have a 2009 Honda Odyssey EXL with Navi/Entertainment. My hub, at first wanna buy a mid-size sedan, but ended up he chose the MDX. Why? Even though Odyssey is a loveable vehicle, it didn't have 4WD. Our kids love skiing, so we must buy a vehicle that's suitable for skiing in Winter.

    We did take a look at the RDX, cheaply made (plastic dashboard, etc). Just looks like a CRV. So, if we ever wanna buy a smaller RDX, then we would choose the CRV instead (could save tons of $$$$ for other purpose). Next, we could also let the parents join us for a ride/vacation during Winter (like skiing).

    If you don't have the $$$$, why don't you go ahead to buy the CRV and save that $$$$ for gasoline. CRV is more economy b/c Honda only requires 89 regular gasoline instead of 91 premium gasoline, much cheaper.

    We did contact the local Lexus dealerships for RX 350. They're pretty nasty. Didn't even wanna email me any price quotes, instead wanna us to visit their dealership for test drive and everything. With Toyota is recalling more and more cars, we wouldn't wanna spend the $$$$$ for unreliable, lemon cars. Lexus is part of Toyota! We hope you know that!

    This is just an opinion. We hope it could help you in a way of making a selection for cars. Thanks!

    We truly like the MDX. Btw, the wireless headphone that we have for our Odyssey is compatible with the Acura MDX. ;)

  • drr98drr98 Posts: 80
    edited April 2011
    Its all about how much money you chose to spend and how many pass. you need to carry.

    From $30k/5p to $45k/7p. Both cars, er, trucks, ah, crossers, or what ever you call 'em, are very nice.

    Lux, comfort, performance and easy on the eyes.

    The RD center console lid is one piece as opposed to two piece center split.

    What else is different?
  • In the market for a new sport utility for my wife. She currently drives a 2004 MDX. Nice vehicle in terms of ride, amenities and very good in snow. She looked at the RDX and test drove one. Not impressed; in fact disappointed would better describe her reaction. Cheap feeling interior and a ride that she labelled uncomfortable at best. Before the MDX she owned a toyota landcruiser. Another very solid albeit gas guzzling vehicle. But the ride was solid and smooth and she loved the MDX ride.
    If your considering an MDX, shoot on over to the transmission discussion raging there. My wife's well maintained MDX just died this past month. The Acura dealers won't fill you in on this but it's an all too common failure judging by the 85 page post that's still very active. So yes, the MDX is a beautiful driving SUV. But can you justify spending $45,000 plus and running the risk of a $6,000 transmission replacement which in some cases ended up in a second failure & replacement?
    We can't. Acura has lost our business for good. We drive easy highway miles. No rush hour. The car LOOKS new. We keep our vehicles well maintained with regular service.
    My wife's MDX has 150,000 miles on it. So our first thought was well it's just a bad break because we have owned Hondas and Toyatas with slot more highway mileage than her MDX. Normal wear and tear of course- but transmission failure?? Never. Nothing even close. Then we started realizing we were LUCKY! A number of MDX owners were experiencing failing transmissions with a third the miles of hers and in some cases in the 20,000 to 35,000 mile range?!?!? Wow!
    At first we were inclined to replace the transmission and just keep the car thinking it'll run another 100,000 no problem. Then I started researching the transmission issue and WOW was I surprised. So much for Honda "reliability". There is a very real, well documented transmission issue with this vehicle and if you're thinking of plunking down $40-50,000 of your hard earned cash- I'd STRONGLY suggest browsing through the MDX transmission thread so you at least know what you are getting into.
    By the way, my wife's business partner drives an '05 with 90,000 miles. Same issue- transmission is failing and needs replacing. Acura dealers will "play dumb" on the issue, but as you'll see if you venture over to the thread- this HAS to be a well known issue. Too many documented failures for my liking. Make sure you do your homework or cover your @ss with a warranty policy. Then dump the vehicle before you have the disappointment that we've experienced.
  • wwestwwest Posts: 10,706
    edited September 2011
    You might take note that the early Lexus RXes, '99-'00, had much the same issue, premature transaxle failures. In the case of the '01+ RX, Lexus changed out the VC fluid formulation to make it less functional and began using trac, frictional braking at the front, to apportion engine torque to the rear. With the advent of the RX330 the VC was dropped entirely.

    So, whereas Lexus went with the CHEAPER, less AWD functionality, at least Acura addressed the problem in a positive way.

    The 2010 and after RX350 series uses the more functional Ford Escape F/awd system but IMMHO that's still no where as good as the SH-AWD system.

    Not that I would ever buy an MDX....

    An RDX w/SH-AWD, absent the turbo, but with DFI and 12:1 CR would be more my cup of "tea".
  • mdxer7mdxer7 Posts: 8
    I have a 2001 MDX (orig owner) and have loved it. However, I too have had one failed torgue converter/transmission at 101K which was replaced and paid in full by the dealer. Now I have over 215K and the torgue converter has been failing for that past 5K miles. The car cuts off unpredictably. I'd LOVE to buy another MDX..but don't what the hassles but I cant find another SUV that compares.

    I no longer need that large of vehicle but love riding high in the seat so I wont be going back to a car. I've test driven the RDX, CR-V, RX350, RAV4 & Toyota Highlander (limited). Surprisingly, I liked the Highlander the best. The RDX was ok but requires premium gas and the MPG isn't all that. The CR-V & RAV4 were unremarkable. The RX too soft..hated the feel of the mushy steering (felt old lady-like). The Highlander had a nicely appointed interior and rides very much like my MDX cost a few $$ less and takes regular gas.

    I've been driving Honda's/Acura's for the past 30 years so going to Toyota would be a big switch for me.

    Any thoughts? Any known issues w/the Highlander? I'm big on reliability and longevity. As you can tell, I like keeping my vehicles for a L-O-N-G time.
  • wwestwwest Posts: 10,706
    edited January 2012
    The MDX torque converter high failure rate in the earlier models seemed have been fixed by the adoption of the SH-AWD system as opposed to the VTM-4 system used in those early models.

    Now here we are at 2012 and the torque converter failure issue seems to have yet gain raised its ugly head.

    The only way I can think of to account for this is some sort of revision to the firmware controlling the rear drive engagement. Now having been revised to provide an even more "robust" feeling, yet even closer to that of a actua RWD vehicle.

    I even have a possible explanation should this latest firmware revision have been made.

    When the issue of premature transaxles failures first become obvious with the old VTM-4 system the very first thing I would have done would have been to instruct the programmers to lower the "robustness" of the rear drive coupling.

    So now we arrive at ~2010, the transaxle failure rate problem appears to be alleviated via the use of the new system, so why not now reverse, remove the earlier firmware revision, that served to "derate" the MDX' "awd" functionality. In the words of Toyota/Lexus "protect the drive train".

    If I were Acura I would add a "snow" PB. The SH-AWD system would go into fully ROBUST mode only in actual adverse roadbed conditions as discerned, suspected, by the driver. Engine start up would aways revert to"normal" (poor[??]) SH-AWD functionality.

    Or even automatically, in addition to the PB enabling, go into fully robust mode if the current drive cycle were to encounter even the slightest level of wheelspin/slip due to engine torque, leading or lagging.

    Other than the MDX the only "AWD" vehicle in the same price category that will yeild equal or better wintertime driving dynamics, adverse weather/roadbed conditions, would be the Porsche Cayenne base V6.

    "...RDX requires premium gas..."

    Not likely...more likely premium gas "recommended". However, due to the design requirements for a turbo engine their base/native compression MUST be derated, lower than would be optimal for a non-turbo engine.

    Results: Substandard FE 99.98% of your driving time.

    The HL and the pre-2010 RX share the same, mostly non-functional, F/awd system. The 2010 RX now uses the same F/awd system as the Ford Escape, more functional than previously, but still no where near up to the standard set by the "base" FWD MDX SH-AWD system.

    I would expect that Toyota will soon, if not already, adopt this new F/awd system, first used in the new Venza, to the HL and the Sienna.

    Speaking of which, have you test driven the F/awd Venza? With the I4..?

    I can't understand why that new 187HP I4 in the Venza hasn't been revised to the use of DFI....210HP...? Or a Venza/h using an Atkinsonized version of that new I4, inclusive of DFI, of course. 15.5:1 base/native compression ratio, wow.

    Were I to purchase a F/awd Venza, it would most definitely be the I4, and I would immediately add a modification such that I could fully engage the rear drive coupling "at will". Maybe with a 10 minute time delay to automatically disable the modification unless I renewed the modification's function before the time delay expired. That way it would not be upon me, my (failing) memory, to turn off the function.
  • cding5cding5 Posts: 3
    edited January 2012
    I am pretty sure some of the VC is legit. But at least for mine, the dealer's incompetence has exagerated the problem. I had a problem with my 2003 MDX at around 110k where the tachometer fluctuated up and down at around 20 miles on a mild uphill slope. I brought it to my dealer here in Austin. Dealer told me the TC was bad and asked me huge money for it. I bought it to another auto shop and showed them the problem and the technician recommended a complete transmission fluid flush (normal flush only covers 80% and this will cover high 90% or something like that) and that cured the problem. I have not had any problem since. One thing I can tell is MDX is slightly underpower. I bought my MDX brand new. But at 30k I found the car requires premium gas to get the horse power to run the car smoothly. I use premium gas ever since. Right now I have 150k miles on it. 2 days ago, I brought it to the dealer again because a noise at idle and get worse when I turn my steering wheel. The dealer told me the steering pump is bad and caused the steering fluid leak and that pump fix is $500 and rack and pinning is also bad and that is $1700. I broght my MDX to the same shop again. They just told me the pump may be ok. And they refill the fluid and ask me to observe a couple of days. It is completely different atitude. I may eventually need to replace the pump (because there is indeed some clear fluid leak on my driveway from last week). At least I can still drive my MDX without the noise till I find my next SUV (maybe another MDX). This reminds me the story in "American Greed" that some doctors would recommend unnecesary operations just to make more money. It is same thing here. The system is being taken advantage of and there is no check-and-balance. I guess some still remember the San Diego man faked the Prius problem just shortly after Toyota unintended acceleration problem becomes the headline. It is not just companies, laywers, even an individual would want to add salt to the injury.
  • 869099869099 Posts: 1
    Has anyone purchased a certified Lexus RX 350 that was previously a dealer loaner car with low miles (ie less than 10,000)? If so, would you do it again, and how much of discount were you able to negotiate?
  • mgoldsteinmgoldstein Posts: 54
    Is it true that the 2012 MDX still comes with a 'stick' key and not a smart key?

    I have a 2009 MDX and was hoping for a smart/electronic key with a new MDX.

  • wwestwwest Posts: 10,706
    Just "free" advice..worth what you pay for it.

    Prior to 2010 the RX350 was predominatly FWD, torque dynamically apportioned to the rear ONLY with TC activation. 2010/+ has the Ford Escape's pre-emptive type F/awd, not nearly as good as the MDX but a step in the right direction.
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