Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Did you get a great deal? Let us know in the Values & Prices Paid section!
Meet your fellow owners in our Owners Clubs

Lexus RX 350 versus Toyota Highlander Limited?

srisssriss Posts: 2
I've been researching the Lexus for a couple of months now. I want a 2009 and even rode in a friends 2008 last week. I liked everything but the front dash. I don't like the navagation system (big square right in the middle of the dash). Anyway I started comparing the RX350 with the Highlander Limited and they don't seem too different, except of course the Lexus is a "step above". I'm wondering if any of you thought about the Highlander before you bought the Lexus? I have also heard the Lexus will be re-tooled in 2010 and look more like the Highlander...shape wise. I appreciate any and all replies. As you can see I'm on the fence! Thanks, Suzq
«1

Comments

  • player4player4 Posts: 362
    I really dont see any major diffs between the two, other than the 3rd row seat and the wood steering wheel and the HID's?? Oh and the L in the grille and hatch haha.
    The RX is getting a full redisign for 2010 so when it comes out we will see more differences but till then if you are debating between the two and $ is a factor, go for the HL but if $ is not an issue then why not go for the RX?
  • I have priced leases out on both and currently the Lexus is cheaper to lease than the Highlander hybrid (by quite a bit). I got $495/mo on the rx and $719/mo on the highlander.
  • Gosh, I hope the shape of the next RX doesn't look like the Highlander. I still like the shape of the current RX over the Highlander.
  • banxbanx Posts: 6
    The Rx 350 now has a $5K manufacturer to dealer incentive until 2 weeks from now, according to Edmunds. I just bought an '09 RX350 awd with various options (no navigation) for $34.6K and that was $950 under Edmunds' TMV for this vehicle. What I paid was only $200 over the TMV for a similarly equipped Highlander Limited awd w/options. The Lexus also has a better warranty at 4 yrs, 50K miles. As "player4" noted, you may want that 3rd row seat that the Lexus doesn't have. Another costly difference may be the octane requirement. The '09 Lexus manual states use only 91 octane - there's nothing about using anything lower. Edmunds states the Highlander uses regular fuel, even though both vehicles use a 3.5L engine with 270 hp. The Lexus has 3 more ft-lbs of torque which is negligible. The Lexus curb weight is 4090 lbs while Highlander Limited is 4321 lbs, so the Toyota may get worse mileage in the real world due to the extra weight, despite the EPA estimates. The Lexus awd has a viscous center differential while the Toyota's is mechanical. I got the 18 in wheels on the Lexus while the Toyota has 19 inch wheels - a larger wheel tends to make the ride worse. The Toyota allows you to manually open the rear hatch window (Edmunds features), but the Lexus window is fixed. The Lexus has 3/4" less front leg room and 10 cu ft less cargo room than the Toyota. The Lexus is smaller in many dimensions than the Toyota crossover, hence the Toyota has more cargo space, payload, ground clearance, and a wider turning circle than the Lexus.
  • srisssriss Posts: 2
    Thanks to all who posted. I have some research and I have an idea that I will be buying the 09 Highlander Sport. The reasons I think it's a better deal (and the right car for me) is: I am not getting the 3rd row seats. There is an option to have them removed and a credit lowers the price, I LOVE the idea that I can use regular fuel in it, the design (I finally have gotten use to it) looks "simular" to the new design on the new 2010 Lexus (of course I've only seen pictures), and from everything I've read I can have exactly the same features and options for an overall lower price. I road in a friends Lexus and hated that big navigation screen in front...and I really don't need that anyway. And finally I think the resale value will hold as good or better than the Lexus in the future.

    I'm one of those people who has very low miles on their car and keeps a car for many years (5-10) and since this will be my car right before retirement I hopefully will hold on to it for awhile. So my reasons for my choice may not be like others.

    I can only hope that Totota comes out with a sweet deal in the next month or so. I'm planning on my purchase in the next 2 months.
  • wwestwwest Posts: 10,706
    I would be really surprised if somewhere in the owners manual it doesn't say fueling with regular is not, will not be harmful. Almost modern day vehicles use the newer wideband knock sensors which allow for the mixture being enriched slightly with the use of 87 octane.

    Viscous Clutch vs not.....

    The '99 & 2000 F/awd RX300's had a VC and actually relied on it for partial, rubber-bandish, locking of the otherwise full open center diff'l. By '01 VSC and TC were added to the RX300 thereby, with TC, making the VC virtually non-functional. Although marketing contended otherwise the VC was dropped altogether for the entire RX330 model run. The RX350 is supposed to have a VC but none of the Lexus shop/repair manuals indicate so.

    If you read the factory information on TC it will be pretty obvious that a VC would be pretty much non-functional even if installed.

    But for the 2010 the RX center diff'l is being dropped in favor of an automatic PART-TIME engagement of rear drive using an electric clutch as is used in the new Venza and in past years in the Ford Escape and Mercury Mariner.
  • I own both. BIG difference for me in the Highlander advantages over RX is driver's seat ... I hit my head on the roof (with moon roof) on RX, whereas I have plenty of headroom in the Highlander - plenty. I'm 6' 1". Also, the Limited Highlander has a driver's seat option that lifts up the front of the seat for better leg support - RX doesn't (at least mine doesn't). Hence, driving for me is more comfortable in the Highlander. I would bet both are fixed in the 2010 RX ... if they don't they will miss the mark for many drivers. In the end, they are both good vehicles and well built. Lexus has the better warranty - no doubt. BTW - I run 89 E-10 in both - NO knocking, no problems.
  • If you don't mind a little more road noise and the red circlular display light color for the speedometer, i'd say the highlander definitely provides better bang for the buck. cargo space really sux on the RX350. the only thing that it's got going for it is that its appearance/styling is preferred by many soccer moms and grannies. sure, the sales and service dept at lexus might kiss your [non-permissible content removed] better and cookies/water may be free, but for the best return per $, i'd choose the highlander.
  • I currently own a 04Rx and a 05HL. I find the seats/interior better in the RX and the extra Lexus features a plus. I don't have Nav in either so you can get one without one pretty easy. My next purchase will be a used Lexus certified to get the extended warranty. Since my RX has 107K miles on it, I had a major tuneup; belts, plugs, brakes, etc. at my local Toyota dealer at less cost. I expect to get another 4-5 years on it.
  • bob259bob259 Posts: 280
    I looked in 06 and again recently when I bought an 08 left over. While it appears the price delta seems to have decreased both times I chose the Highlander Limited (Hybrid). I didn't think the HID's and different audio system were worth the difference, as both are real close. I was considering the 2010 Lexus when I was looking this time and noticed the wheel base remained the same as before, the longer wheel base gives a nicer ride in the new Highlander. All in all been real happy with the Highlander.

    The seats in the 08 and 09 Highlander Limited I would say are as good and the Lexus as they now adjust to make the seat cushion longer. This was one of the things I was looking for as my 06 Highlander seats and distance from the pedals and my back did not get along on trips over 45 min.
  • We own a 2000 RX300 (same body) and I have rented a Highlander (2005) for a road trip in Oregon.

    BIG DIFFERENCE. The top-3 problems with our RX300 are : turning radius, cargo space, and flakiness of (lights, driver's visor, cup holders atop console.)

    CARGO SPACE IS ROTTEN ON THE RX300. We have gone camping 10x times. It's just tiny enough that our 7-year old kids have to put up with sleeping bags under their feet and/or a cooler on the floor between them !! When they turn 10 we're gonna be OUT OF LUCK !! My wife often has a backpack and/or paper bag under her legs in the front seat, or both !! And this is with the rear of the car PACKED with stuff, and we have a tiny tent, you can only fit 3 full-sized cardboard boxes in the rear of the car before you're in trouble !! I would love to have the ~7 cu ft extra cargo space in the Highlander !!

    If you camp with a family, STAY AWAY from the RX300, RX330, RX350, and RX400 series of cars !! STAY AWAY !! This is the greatest flaw in the RX3/4 series of cars ...
  • la4meadla4mead Posts: 347
    Wow! Sounds like you need a bigger car, and you need it now!

    (FWIW, there are great deals on Suburbans and trailers right now. ;)

    Personally, I really like the smaller size RX300, but it's not for everyone. It's a little more spacious than I normally need, and I appreciate a car that's more nimble than any of these. I value the RX's features that "spoil" my tastes like the much better sunroof, etc. I've gone camping with many different cars, but I usually take the motorhome when I need that much stuff. I've even camped out of the RX and slept inside. The load floor is flat and long, a Toyota wagon trademark it seems. So I've never ran out of room in the RX; never even used the roof rails I took off when I first bought the car new.

    The Highlander may share a common platform, but it's not the same as an RX, and I'm sure that's by design. The Lexus models have some really nice useful features that become endearing which are not available on cars like the HL. Little things that I use everyday, like the auto up and auto down on all windows and moonroof simultaneously remotely or activated inside and (via the lock) outside, to name one of many little tricks. I do miss the little extras when I'm not driving the RX. The newer RX's have many other tricks, too. But if you prefer a lower price and a little bit more cargo space and are annoyed by extra gadgets and don't care about things like an obviously better stereo with stock subwoofer, I can understand how the HL would be a better fit for you.

    If you need that much more cargo space than the RX provides, you may run out with the HL, too. If that happened to me, I'd look at minivans, which can hold lots more, and attain about as high MPG. But the RX is roomier than expected, and in no way cramped, even for larger people.

    I guess the Venza (with it's standard direct-injected 4 cylinder) is not even enough space??
  • wwestwwest Posts: 10,706
    It was a big surprise to me to find that the new Venza 4 cylinder does not use DFI.
  • typesixtypesix Posts: 321
    The RX series and Venza have a hatchback style while Highlanders have a wagon rear end for the extra cargo room. I'm happy that I didn't have to buy Lexus for Highlander rear end, but in your case, no Highlanders were around for 2000 model year.
  • jerry116jerry116 Posts: 13
    The different between RX350 and Highlander limisted is that RX350 is a luxury car brand but Highlander not. Class different, not much comparsion. Even many luxury brand can't offer real wood interior but Lexus can. It just like how you want to dress yourself. You can pay $100 for a famous brand Tshirt or $20 for the same thing which made in the same factory with almost the same material. RX350 wasn't designed as big SUV. Many people dont like big SUV otherwise they should choice LX470. if your compare current RX350 vs BMW X3 or Audi Q5, you will find RX350 have more room. You drive Lexus means you have used a luxury brand as your transportation tool otherwise you just use common tool which doing the same thing (transfer you and your family from one place to another ).
  • berriberri Posts: 10,166
    I don't think most luxury cars are a big deal any more because so many people can lease them - you don't really have to make that much to lease mid level Lexus, MB or BMW, so I don't really think it has all that much status.
  • jiaminjiamin Posts: 556
    RX does not lift up the front of the driver's seat? My 2000 RX does (part of 8-way power driver's seat). On the power seat switch, do you see the up-and-down arrow?
  • umn65umn65 Posts: 2
    The Lexus has one of the best retained value histories in the industry, and that's why it is generally cheaper to own or lease the Lexus vs. the Highlander. If you like both cars, I'd go for the Lexus, cuz in reality it's cheaper to own.
  • I am considering both these cars now. I was wondering if anyone had any more recent comments on the comparison of the 2011 RX 350 and 2011 Highlander Limited?
  • I am the extremely happy owner of a 2001 Highlander with 220K miles. It is easily the best vehicle I have ever owned. My son will be driving in Sept this year so I'm casually looking at a new car for my wife. I will be giving him my 2008 Element and was considering the RX 350 for my wife with me driving the 2001 Highlander. I will not pay 40k for a car so a new RX350 is not an option but looking at 2 year old RX350's the price drops all the way down to the same as a 2 year old Highlander. I am now torn between the new Highlander or a 2 year old RX350. leaning towards the new Highlander. I really do not need the gadjets or style points as I have a gorgeous classic car in the garage. I am a dealers worst nightmare.
  • And don't forget you can't get the memory seats, memory mirrors and the power telescoping steering wheel on the Highlander. I have to have the memory seats. But, certainly, if you need a little bit more cargo room, then the Highlander will suit your needs better.
  • wwestwwest Posts: 10,706
    While far from acceptable by my standards the newer RX350's (2010+{?}) have a much more functional F/awd system vs the HL. The Honda/Acura SH-AWD system is the best of the best for vehicles with sideways mounted engines.
  • luckysevenluckyseven Posts: 134
    edited March 2011
    We already know that Highlander's AWD works extremely well and owners more then happy with it's performance

    http://townhall-talk.edmunds.com/direct/view/.f21ebcd!make=Toyota&model=Highland- - er&ed_makeindex=.f21ebcd

    stop beating a dead horse...
  • wwestwwest Posts: 10,706
    Then why does it need a TDC "off" function to quickly convert it into the old style ONE-WHEEL drive system for getting unstuck or initially in motion..?
  • luckysevenluckyseven Posts: 134
    Only if you stuck and can't move, not in motion. it takes special skills or really abnormal road conditions to get stuck in this vehicle. Since it is not an off-road vehicle you really need to be looking for troubles to get it stuck. It never got me stuck even going through last three Ohio winters.
  • wwestwwest Posts: 10,706
    "..Only if stuck and can't move, not in motion.."

    In the general case once you are "in motion" there is NO requirement for both front and rear drive. Most true 4WD owners will tell you that it is HIGHLY inadviseable, even DANGEROUS, to have both front and rear drives engaged when/once in motion.
  • wwestwwest Posts: 10,706
    You're obviously not considering the fairly common "stuck" situation wherein you're trying to start up, initially, from a stop, a slight incline that is icy or slippery.
  • luckysevenluckyseven Posts: 134
    edited March 2011
    I can't comment on "the fairly common "stuck" situation wherein you're trying to start up, initially, from a stop, a slight incline that is icy or slippery" for a simple reason that MY Highlander never got stuck in this situation and started moving with ease. As a matter of fact MY Highlander didn't get stuck even once since the time I purchased it back in 2008.

    I can see that you have wast theoretical knowledge about AWD but it worth zilch to me. I'm not a Toyota transmission engineer to go over AWD design implementation, it's shortcomings and advantages. Toyota doesn't engineer and manufacture vehicles that are "DANGEROUS" too drive (at list no one was able to get any credible proof too this date). You'll have very hard time finding a second Gen Highlander owner being unhappy with it's AWD performance under severe weather conditions. You on the contrary never bothered to drive the vehicle and trying to prove that it has inferior design based purely on your own theoretical conclusions. Real life experience proves you wrong! Read here:
    http://townhall-talk.edmunds.com/WebX/.f21ebcd/21!make=Toyota&model=Highlander&e- - - - - - - d_makeindex=.f21ebcd
  • wwestwwest Posts: 10,706
    Sorry, but is well understood that FWD vehicles and F/awd vehicles are patently dangerous to life and limb on an adverse, slippery, roadbed. That's why TDC is so important and has become horribly aggressive, it needs to be in order to sunstantually lower the potential for an accident resulting from loss of directional control.
  • luckysevenluckyseven Posts: 134
    Any car is dangerous on "an adverse, slippery, roadbed". Any 4WD/AWD/FWD design has it's limits. You can go over this hundred of times but Highlander AWD works well in real life. Read here:

    http://townhall-talk.edmunds.com/WebX/.f21ebcd/21!make=Toyota&model=Highlander&e- d_makeindex=.f21ebcd
  • steverstever Posts: 52,462
    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!
  • 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: 40
    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: 321
    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 Posts: 52,462
    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.
  • 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...??
Sign In or Register to comment.