Advice about 2011 Highlander and AWD
biosmonkey
Member Posts: 2
I am in the market to move from my Tundra back to an SUV, mainly due to kids and the desire to have a better ride for commuting. I need a foldable 3rd row seat, and would strongly prefer a vehicle with 4wd capability for camping/beach/ski purposes, and the very occasional snow. I live in Atlanta, though, so the need for 4wd in bad weather will be minimal. However, when I need it, well, I really need it. Given the large discrepancies in AWD capability that I have read, I am leery about getting a vehicle with full-time awd.
The 4runner sounds like a good option also, but I have read that it is very truck like, which is kindof what I want to get away from?
The Highlander sounds like what I need, if it only had a 4wd on-demand option, which it doesn't.
I also saw this video on youtube
http://www.youtube.com/watch?v=ooQRxlChvMw
around 3:10 they test a 2007 AWD Highlander, and the results are concerning. Not sure how much the awd system has been changed up to 2011.
I will be test driving both of these soon, but wanted some advice/opinions on getting AWD in my situation, and how well it works in 2011 Highlander for snow and sand.
I should also mention that I am concerned about extra maintenance and care that goes with AWD and tire rotation/inflation/differential servicing. I have never owned an awd car, and a lot of the info I have read talks about possibly damaging the system with even a difference in tire tread height??
The 4runner sounds like a good option also, but I have read that it is very truck like, which is kindof what I want to get away from?
The Highlander sounds like what I need, if it only had a 4wd on-demand option, which it doesn't.
I also saw this video on youtube
http://www.youtube.com/watch?v=ooQRxlChvMw
around 3:10 they test a 2007 AWD Highlander, and the results are concerning. Not sure how much the awd system has been changed up to 2011.
I will be test driving both of these soon, but wanted some advice/opinions on getting AWD in my situation, and how well it works in 2011 Highlander for snow and sand.
I should also mention that I am concerned about extra maintenance and care that goes with AWD and tire rotation/inflation/differential servicing. I have never owned an awd car, and a lot of the info I have read talks about possibly damaging the system with even a difference in tire tread height??
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The HL was/is and remains a ONE-WHEEL drive system, there fully open diff'ls, front, center, and rear. It can be called AWD since when a wheel begins slipping Traction Control will activate, braking the slipping wheel(s) to apportion torque to wheels remaining with traction. The sad part, but a SERIOUS SAFETY aspect, is that it will also instantly dethrottle the engine.
The "backup" is the ability to switch TC off thereby returning the vehicle once again to ONE-WHEEL drive system but allowing unlimited wheelspin.
What we have out there in the marketplace today, "base" FWD marketplace, is both reactive F/awd systems, and pre-emptive F/awd systems. The reactive type, VC (Viscous Clutch/coupling) or TC (Traction Control), is fading away due to their poor performance in the real time wintertime environment.
There are now many versions of pre-emptive F/awd systems, the Honda/Acura SH-AWD system being the best of the best of those IMMHO. The idea is to ALWAYS bring on the rear drive capability, engage the rear drive in the instances most likely to result in loss of traction, and thereby loss of directional control, due to too much engine torque being used for roadbed conditions.
So, these systems engage the rear drive, in effect locking the "virtual" center differential even in highly tractive conditions. All of these systems seem to be incurring premature drive train component failures.
Were I in your shoes I would probably purchase an Acura MDX but disable the rear drive coupling(***) control circuit except in time of KNOWN need.
*** Remove fuses or add a manual switch.
The currently accepted, seemingly accepted, design fix is to provide a method for disabling the TC, Traction Control, system temporarily.
I also wanted to comment on the youtube video you linked... It's all true- traction control will take over in this situation on HL, and you'd get stuck in the deep snow or ice because of that. What Subaru's PR video conveniently "forgot" to mention that you can temporary disable traction control. Current HLs have a button for that by the knee and that would get you un-stuck and moving. So this is not a real life scenario. Subaru's 4WD is very good, but it comes at fuel economy price. There is always a trade-off in car designs.
TC, Traction Control, is the only means the HL has for re-apportioning engine torque to non-slipping wheels. To do that it applies braking to any slipping wheel(s) in order to sustain engine torque to a level higher than would be required for just freely spinning that slipping wheel(s).
Since this is a F/awd it will more likely than otherwise be the front wheel(s) that lose traction first. Since that is such a DIRE matter, often leading directly to loss of directional control, engine dethrottling is applied simultaneously with TC braking in order to URGENCY return your front wheels/tires to a tractive state.
There is also the potential for brake component overheating and rotor warpage if engine torque control is left to an unknowledgeable or inexperienced driver. It is for this reason that even RWD or R/awd TC systems will also dethrottle the engine but shortly after, typically a second or so, beginning braking the slipping wheel(s) should the driver not immediately "feather" the throttle.
And take a look about at how many owner without the TC off function are trying to find a substitute.
A halfway decent R/awd system would NOT require that.
It's merely to keep the ABS from kicking in, to stop wheelspin... You need a little wheelspin to get out of deep snow.. Even my RWD sedan has the T/C disable function..
I don't see what that has to do with FWD based vehicles?
regards,
kyfdx
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First of all, the 4wd Highlander does use 3 open differentials, and traction control (ie braking) to redirect the torque to the non-spinning wheel. In this sense, it really is a 1WD vehicle I suppose. I will not comment on the safety factor of throttling the engine, but considering that a high rpm freely spinning wheel is typically going to happen in a low-speed "get me out of the mud/snow" situation I don't really see how that's an issue.
So I purchased a 2011 4wd Highlander, and have put around 700 miles on it so far. Very, very pleased with it.
I live in an area that saw a big winter storm dump 5-6 inches of snow on us last night. So after shoveling a path for the wheels, I had an opportunity to test the very reason I bought 4wd.
My driveway has a decline to it, so when backing out I am actually going uphill backwards. My neighbor has a similar situation, however, he has a 2wd Tundra. He spun his wheels most of the time, eventually making his way out after inching backward over the course of an hour. A few times, he started sliding forward and almost hit his house. I was a little hesitant to try, considering that if my car lost traction and I slid forward, I would fall off of a small cliff and plummet into the woods (no convenient house to stop me).
But, this was the reason I bought it right?
My neighbor, anxious to see how much trouble I would have, had asked if he could watch, so I knew I had an audience too (I think I saw popcorn?).
So I warmed up the car, engaged the Snow button, and put her in reverse.
I backed out of my driveway with absolutely no problem. If a tire slipped, or the tc engaged, I didn't know it. Even when I got to the street, and was driving in 5 inches of snow, I felt pretty much in control. Admittedly, I did not drive around the neighborhood for fun, so I can't say how well it would have done in a driving situation, but I didn't need to do that anyway.
My neighbor was pleased I did not plummet into the woods, although I think he was a bit disappointed in the lack of entertainment.
Nonetheless I am very pleased. Time will tell, but overall a great car, and highly recommended.
Last Saturday I drove to Snowshoe, WV (from the Washington, DC area) on a ski trip. Snowshoe is about 4,500 feet higher in altitude than DC so it gets a lot more snow up there. I drove there in the middle of a snowstorm and the last 20 miles up to Snowshoe are all steep mountain switchback roads. Through sometimes near zero visibility and about 6-8" of snow, I had absolutely no problem taking the Highlander up the hills. Never once did I get stuck and I confidently made my way up the mountain (on crappy OEM tires, no less). We got another snowstorm on Tuesday (12" this time) while in Snowshoe and I decided to use the "Snow" setting while driving around the mountain. It worked out well! The "Snow" setting altered shifting points beyond just starting in 2nd gear and it just worked. At the end of the day that's all I really care about - it just works. I'm never going to do anything extreme with the Highlander and I'll never try to make the Highlander do anything that it wasn't designed to do... it seems like a very capable vehicle.
So 1 month later and about 3 + hours of driving up and down steep mountain roads covered in 4-8" of snow, I can say that I'm very pleased with the real world performance of my Highlander.
By the way, "snow mode" is just another "nanny" helping you "feather" the throttle so you can more easily get up and going initially. Some earlier snow modes result in the transaxle never starting out in 1st gear, 2nd only. Others, mostly DBW, lower the "gain" of the throttle control servo.
That's why many new vehicles now have a TC off function so that you can get around by simply feathering the throttle. Many of us are old enough that we HAD to learn "feathering" the throttle as only RWD vehicles were around.
Bottom line...buy the FWD for FE but carry a good set of tire chains, for the FRONT, for the seemingly RARE occassions of need.
As I have said, modern day "snow mode" systems simply detune the engine's throttle response in reaction to acceleration position, simply making it more difficult to lose directional control on the slippery stuff. Most driver's of "my" era learned to use "snow mode" long before such an item existed. Start off in second gear, and/or pretend you have an egg between your foot and the accelerator pedal.
Also, learning to drive a Porsche 911 over our nearby mountain passes during the wintertime simply adds to the level of knowledge for wintertime survival.
"..loves bashing..."
No, I simply think driver/owners should be well educated as to the capability/functionality/limitations of their vehicles.
The HL's, and the pre-2010 RX', TC implemented F/awd system is strickly of the passive type, only reacts, "engages", POST wheelspin/slip development.
Prior to TC activation it is, and forever remains, a simple ONE-WHEEL drive system, THREE fully OPEN differentials, front/center/rear.
I have a 4runner awd that has differential lock and a 08 HL awd. Having driven both in bad Neast ohio weather I am pleased with the HL in deep snow and slush. My wife feels quite safe using snow mode, prevents lead foot on ice. Again in real life situations the HL does really well. I know I can turn off the traction control but have never found it necessary, even in 10-12 inches of unplowed road. I do obsess about wanting true 4wd in the highlander but have never needed it.
Not sure why luckyseven is so defensive about Toyota's AWD system. WWest wasn't critical, he just described how it worked. I'm sure that Toyota's goal was to give consumers an "easy" experience that was mostly dependable. But, as with all things that involve engineering, the outcome in unusual situations can be unpredictable, and dangerous.