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Lexus RX 350 versus Toyota Highlander Limited?

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Comments

  • steverstever Viva Las CrucesPosts: 41,582
    Let's get back to comparing the 350 and the Highlander, and I don't mean the minutia of AWD systems that are only of interest to one or two gearheads out there.

    Thanks!

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • luckysevenluckyseven Posts: 134
    I feel this is enough too. Just sad to see how wwest turns every discussion on this board into baseless bashing of Toyota AWD and misleads people into thinking that it is inferior based on his own theoretical conclusions.
  • wwestwwest Posts: 10,706
    This discussion is about purchasing a new RX350 versus a HL Limited.

    Other than the up-pricing due to the upscale features, heated/memory/leather seats, HID headlamps, etc, etc, just what are the differences???

    3rd row seating and the F/awd system.

    You either need or want that third row, so question answered.

    I do find myself puzzled that Toyota has used, adopted the new, more functional F/awd system across the product line with the sole exception of the HL. I fully expected that as of the new model year the HL would also be so equipped.

    Maybe we can get someone from Toyota to chime in and tell us why the HL is being left out in the cold...?

    So, nuff said, bye.
  • johnxyzjohnxyz Posts: 94
    "I do find myself puzzled that Toyota has used, adopted the new, more functional F/awd system across the product line with the sole exception of the HL. I fully expected that as of the new model year the HL would also be so equipped."

    Hi again wwest - Would you expand on the improved Toyota system. Is it in the RX/ 4Runner /RAV4/Toyota trucks but not the '10/'11 HL? Interested in purchasing a Lexus RX or Toyota crossover this year. Thanks.

    What's your opinion on the Honda Pilot and CR-V? Any idea if Honda/Acura is going to upgrade their somewhat dated 5 speed automatic transmission?
  • wwestwwest Posts: 10,706
    edited March 2011
    For quite a few years now, going back to the '01 F/awd RX300 and the F/awd HL, the F/awd system has been basically a ONE-WHEEL drive system. Three simple, fully "open" differentials. Meaning if any one wheel begins slipping then it gets all the "drive", sapping the torque level down to just enough to keep that slipping wheel or wheels spinning.

    Care of wording must be exerted here, as one should realize that even as above ALL four wheels are still getting EQUAL torque. It's just that for the wheel(s) remaining with traction the torque is now so low that no motion results.

    The "legacy" technique, TC(TDC IMMHO) technique, that was in use, moderately (ABS "style" "pulse" moderation) brakes the slipping wheel(s) to simulate traction. But that could easily result in over-heating of the brake components so the engine was always dethrottled just as quickly.

    While that proved to be satisfactory in some cases, maybe even most, there was enough public outcry about one serious shortcoming that it was addressed via adding a manual TC(TDC) disable feature.

    Basically this legacy system was a REACTIVE, after-the-fact, F/awd system. Prior to a wheelspin/slip the system was, by default, a ONE-WHEEL drive system.

    The new systems are "pre-emptive", "before-the-fact"...! So, has Toyota found a way to predict the future..."

    Not at all.

    The new system engages the rear drive capability in situations that are most likely to result in loss of traction on the primary drive wheels, the FRONT wheels.

    That is:

    A) During acceleration from a stop or from a relatively low speed, below 25 MPH. The higher the acceleration level, the more engine torque will be routed, coupled, to the rear.

    B) When turning a F/awd vehicle then engine drive torque will oftentimes overcome the front tires' roadbed traction capabilities needed to provide enough lateral traction for maintaining or sustaining directional control. This, in effect, is what results in FWD vehicles becoming so patently UNSAFE on adverse roadbed conditions, and F/awd systems slightly less so.

    With a R/awd system one might simply reduce the torque coupling level to the front, entirely so if the need should arise, a tight accelerating turn, for instance.

    F/awd systems have a HARD, non-modulateable, front drive coupling. So all torque re-apportionment, F/R torque re-apportionment, must be toward the rear drive.

    The obvious shortcoming of this new pre-emptive F/awd system is that unless the roadbed happens to be slippery enough to not incur driveline windup and/or tire scrubbing/hopping the driveline components might be subject to premature failures.

    Your can see that in the long history of the use of this new F/awd design approach in the Ford Escape and Mariner, and more recently in the Acura MDX VTM-4 system. Both fraught with failures historically.

    IMMHO the proper design approach would have been to have these new systems default to "reactive" mode but allow the driver to manually switch into "pre-emptive" mode when roadbed conditions are recognizably. In either case should the system not encounter a "slip" condition within a given time period or # of miles it would automatically switch back into reactive mode.

    The Ford AeroStar R/awd system runs by default with 30/70 torque distribution. When wheelspin/slip occurs it automatically switches into 50/50 F/R torque delivery mode. It will UNCONDITIONALLY switch back in 50/50 mode in 3-4 minutes. The if wheelspin/slip repeats.....
  • luckysevenluckyseven Posts: 134
    This is really a moot point since this could be only applicable to the vehicle having difficulties to get moving from a dead stop position under very specific road conditions that most Non Off-Road drivers will never experience in their life time. Real life experience proves that AWD HL or RX300 handle good under demanding road conditions.
  • wwestwwest Posts: 10,706
    "..will never experience..."

    Boy, you sure live in fantasyland.

    Why do you think the public outcry was so "loud" and widespread that most "ONE-WHEEL" F/awd manufacturers have added a TDC "off" funtion...?
  • luckysevenluckyseven Posts: 134
    edited March 2011
    "public outcry".... I don't think so. TC off function was added for the same reason hundreds of new functions added to any new car model. One of my friends owns a 1st gen HL, another owns RX300. I asked them if they would ever benefit from such an improvement and they didn't have a single time they'd need it. I have TC off functionality in my HL but like the most people never needed it going through 4 fierce Ohio winters. Frankly, 99% of the drivers wouldn't even know about it, even though their cars have such an option.
  • I am researching the Lexus RX350 and the Toyota Highlander Limited. Have driven the HL and really liked it but noticed some road noise which is something that bothers me. Would anyone like to weigh in on the comparison of road noise on the 2012 models of these two?
  • wwestwwest Posts: 10,706
    Differing road noise is more often than otherwise the result of different tires being fitted.
  • nit2nit2 Posts: 29
    Did quite a bit of reading-up on the Web before we narrowed down to the Highlander Limited with 4WD and the Lexus RX 350 AWD. Test-drove both vehicles on (unfortunately only) dry roads but within 1 hour of each other.
    My impression re big differences:
    The HL seats 7 (third row is somewhat cramped, but it's there); the RX350: seats 5. The HL has more clearance from the ground; the RX 350 is not really meant for off-road use - more aimed at comfort & safe driving. On the HL we tested, with less money we could have gotten the NAV system. But the HL ride was quite noisy (almost as much as my 4Runner) and a little bouncy. Also, the labelling on some of the controls and the quality of the chrome pieces on the HL Limited were not up-to-par. The SE trim level didnt suffer the chrome pieces, but you lost some of the options.
    The real clincher for us was absolutely top-notch quality of material used and design on the RX 350 and the ride was super-quiet and cushioned. The interior quality on the RX 350 is several grades above the HL.
    Once we test-drove the RX350, we could not bring ourselves to settle for the HL. Have had the RX350 for 4 days now and we just simply love it! If you are down to these two, then test-drive both, in close succession, if possible.
    Good luck!
  • There is a reason why RX350 has much nicer interior and better tuned suspension then a HL. Toyota want's you to shell out more $$$$ for a Lexus and these $$$$ need to be well justified in the buyers eyes. It's up to the buyer to decide if it worth to spend significantly more for luxury RX350 vs significantly less for more practical HL.
  • typesixtypesix Posts: 314
    Neither is meant for real off road use. Would compare RX350 to Venza instead of Highlander since Venza has similar hatchback body style.
  • wwestwwest Posts: 10,706
    Could we possibly, FINALLY, put this "not for off-road use" issue to BED...??!!

    F/awd, R/AWD, RWD, these are all about SAFETY, SAFE on-road driving but in adverse or wintertime surface conditions.

    The few who are interested in off-road have their own choices to make....4WD/4X4, etc.

    The "world" was perfectly satisfied with the state of affairs until the switch was made to FWD, FWD market dominance.
  • we did a brief test drive of both. we diced to go with the highlander because of the softer ride . however we liked the rx but the ride appeared to be a little stiff.?!??
  • steverstever Viva Las CrucesPosts: 41,582
    edited February 2012
    Tire pressures in new cars are overinflated for shipping and sometimes dealers forget to air them down to spec when they prep them for the lot, making for a bouncy test drive. You may want to try another one.

    Either way, a longer test drive is a good idea before buying.

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • mgrodymgrody Posts: 2
    I'm a long time 4Runner owner but am thinking of switching to a Highlander. Haven't driven one yet, but have been doing a lot of research. I'm confused by the different descriptions of it's performance in the Edminds ratings and the Edmunds review. The Edmunds rating says with the 3.5 V6, it "has only enough power to allow for adequate acceleration". That kind of turned me off, but then I read the Edmunds review. There the Highlander with the 3.5 V6 "has especially brisk acceleration". Guess I'll take Edmunds ratings and reviews with a grain of salt from now on. What do owners think about it's performance with the V6?

    Thanks
  • wwestwwest Posts: 10,706
    Going from a RWD "based" AWD/4WD/4X4 4runner to a FWD based F/awd vehicle might be fraught with peril unless you truly understand, KNOW, the tradeoffs.

    And I do NOT mean the availability of a mostly useless 4X4 mode.

    Both of the vehicles you mention are primarily FWD vehicles with only PART-TIME. AUTOMATIC PART-TIME "awd" systems.

    I would suggest you consider the base Porsche Cayenne, R/awd, instead, especially if you are in an area of harsh wintertime road conditions.
    Decidedly more safe than ANY F/awd system, inclusive of even the best of the best, the SH-AWD system.
  • titancrewtitancrew Posts: 17
    I don't know about the RX350, but the Highlander uses 3 open differentials (front, center, and rear). So it is not primarily FWD with only "AUTOMATIC PART-TIME "awd" systems". As long as traction/friction is equal on all four wheels, power is sent to all four wheels equally, hence "full-time" awd. But as you know with open diffs, power always wants to go to the wheel with less resistance (i.e. traction). This is true regardless if the vehicle is f/awd or r/awd if there are open diffs involved. Hence the use of electronic traction control (i.e. applying brake pressure to the slipping wheel to increase resistance, thus sending power else where).

    The notion that r/awd are better than f/awd is false. Without traction aids, any type of awd system (regardless if its fwd based or rwd based) with three open different are really one-wheel drive. A f/awd vehicle with traction aids (e.g. diff lockers, limited slip diff, etc.) will perform better than a r/awd with open differentials.
  • wwestwwest Posts: 10,706
    edited March 2012
    You are NOT incorrect, clearly...

    "..As long as traction/friction is equal..."

    Exactly....!

    But just since when is that of any real matter with the wintertime adverse roadbed conditions for which many (most?) of us purchase AWD systems...?

    It's when traction is NOT equal, or so extremely low that EQUAL matters not, that the need for a TRUE AWD system, a R/awd, arises.

    "..power always wants to go to the wheel with less resistance.."

    Yes, and that results, directly, in the engine output torque level dropping to ZILCH.

    "...Hence..."

    TC braking, the method used to re-apportion engine torque to wheels other than the one(s) having lost traction will only be, can ONLY be AUTOMATICALLY activated AFTER, POST the initial wheelspin/slip event.

    Should that initial wheelspin/slip event happen to occur at the front (a F/awd virtual CERTAINTY IMO) then the driver, at this instant in time, has lost directional control of the vehicle. Obviously that would not be the case with a rear biased, R/awd, system.

    "..The notion that R/awd are better than F/awd is false.."

    Absolutely NOT..!!!!

    Modern day R/awd systems automatically reduce or completely CUT engine torque to the front drive at times of expected need to dedicate more front traction coefficienct for the use of lateral control. Those times are pretty much restricted to turning or correction of direction if the need arises.

    Modern day F/awd systems operate in the inverse of that. Under low speed acceleration engine torque is automatically re-apportioned to the rear in to make optimal/best use of ALL available roadbed traction. On the other hand, if turning, turning tightly, or accelerating into a turn, F/awd systems will attempt to more heavily BIAS the engine torque to the rear in order to allot more roadbed traction to the front for lateral control, maintaining directional control of the vehicle.

    With F/awd, make the turn a tad too tight, or accelerate a bit too hard into a turn, and VSC will activate pre-emptively. VSC will activate since absent doing so the system has predicted a HIGH probability of not enough front traction being available to support the maneuver the driver wishes. The result will be FULL engine dethrottling. To regain control over the throttle the accelerator pedal must first be fully released.

    With an otherwise equivalent R/awd vehicle and in the same above circumstance the front traction coefficient WOULD BE, in the worse case, TOTALLY dedicated to maintaining or asserting directional control. Should the system judge, compute, that to much lateral force is required at the rear for the current maneuver, and the driver does not quickly react on their own via cranking in the appropriate level of counter-steering, the same result would occur. The engine would instantly be fully dethrottled.

    Oh, and finally, is there a F/awd system manufacturer, even inclusive of the SH-AWD system, that does not advise that the system is FRONT TORQUE BIASED...??
  • wwestwwest Posts: 10,706
    In the past 10 years or so Lexus factory representatives have attempted to explain to me on numerous ocassions, phone and face to face, just how and why the RX and HL series have front torque biasing, most definitely so.

    All I have ever gotten out of those explanations is that it has something to do with the mechanics of the center diff'l vs the front diff'l vs the rear diff'l configuration. Number of side, spider, gears in each..?
  • mgrodymgrody Posts: 2
    That's very interesting and I hadn't given it any thought. Thank you!
  • titancrewtitancrew Posts: 17
    "Should that initial wheelspin/slip event happen to occur at the front (a F/awd virtual CERTAINTY IMO) then the driver, at this instant in time, has lost directional control of the vehicle. Obviously that would not be the case with a rear biased, R/awd, system. "

    The same thing would occur with a R/awd system too because if the wheel spin occurs a the front, power will be routed to the slipping wheel unless you have an active (i.e. Torsen or equivalent) center diff because power will ALWAYS go to the wheel of least resistance (i.e. slipping wheel). If the F/awd system has an active center diff, it will send the power to rear wheel this situation just like the R/awd. Even your explanation for the different awd system concede this. So I don't know how you can conclude that a R/awd system is better.

    Hence, it doesn't matter whether you have a F/awd or R/awd system, it all depends on the type of front, center, and rear differentials. If they are all open, then you have a essentially one-wheel drive vehicle. Very few car-based vehicles come with Torsen center diff or locking/limited slip front and rear diffs anymore. Most use TC ABS to simulate resistance/friction.

    Here's an interesting article on why FWD and AWD system based on FWD are better than RWD and AWD system based on RWD in low speed low traction situation.

    http://www.thetruthaboutcars.com/2012/02/avoidable-contact-color-my-world-the-ca- se-for-front-wheel-drive/
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