lexus114

if they would have turned off the vsc. there would have been a totally different outcome.

vlad_a

The center diff would have overheated and it would have limped into the FWD mode.
If anything, you want to apply brakes to transfer some torque over from the spinning wheels to the one with traction. I will tell you, it doesn't work in extreme situations, such as digging out of sand.

ericsan13

Everything else looks like it's been answered

The issues is more about left/right torque distribution as opposed to front/back. Even with VSC turned off, either one wheel in the front will spin or one wheel in the back will spin.

The 4RX is supposed to fix this with brake-based limited-slip, which is still not as good as a mechanical system. Not sure if the 3RX VDIM does this.

450h is a different beast with the E-Four system. Who knows how that works!

If only someone would put their VDIM models on the hill test we would know for sure!

carguy75

I bet it would handle just fine.

All these videos are with the RX in snow which most FWD can manage with snow tires.

The RX only failed tests that put it on no traction surfaces like pure ice or rollers which gives one side of tires/axles no traction at all which most people will not encounter often unless they live somewhere that need snow chains anyway in the winter.

Plus, in the real world a person would turn off the traction control to get up a slippery slope in the RX if needed unlike the tests.

The Acura test was just showing off that the SH-AWD system can be used with the traction control turned on.

Nice system though, but the RX AWD works just fine for my light winters in the South.

ericsan13

There are actually several threads from disappointed RX owners who, like myself, beached their car in the snow due to the lack of side-to-side torque distribution. Not a fun surprise to have when you're in the snow with the false pretense of an advanced AWD system. Oops, let's hope F-Sport fixes that...

Marqevans

Have not read all 6 pages of this thread, but I hope they put the same tires on all the cars for comparison sake.

carguy75

Sorry to hear that you actually got stuck in the snow with your RX.

It does seem like the RX with its low ground clearance(7.3in) and simple AWD system is better in areas that do not get much snow/ice like in my area or Texas.

The RX (350 at least)is not really a rugged or sporty SUV at all, however it is nice to drive on normal roads.

Hence why my wife likes to drive it, and myself on long trips.

If I lived in an area that gets real snow accumulation yearly then I would not have bought the RX in all honestly.

Every SUV/crossover has its advantage or strong point, apparently off-road/limited traction use is not one of the RX advantages.

CanadianRX

Reiterating, never had a huge problem with fwd and snow tires so the RX with awd, snow tires and VDIM make snow/slush easy. Don't over think just drive, it'll be fine lol.

lexus114

what? where do you get that information from?

vlad_a

I've read about it in an off-road test by an auto publication. The AWD system is identical to RAV4.
Here's the best description I found:
http://rav4world.com/pdf/2006/2006_4wdsystem.pdf

lexus114

but our rx 350 has what they call all weather drive. not sure it is the exact same system as the rav 4. the rav 4 seems to indicate a 4wd system.

vlad_a

It's just marketing terms being thrown around. Rav 4 is not a 4x4 either, which usually implies a transfer case.

vlad_a

The more I read into this, the more I realize the simple truth - RX350 does not have a center differential. Active Torque Control means the rear wheels get engaged and disengaged by an electric coupling. And they have to stay disengaged most of the time as it can't compensate for the front and rear wheels rotating at different speeds. In other words, it works like a clutch in a manual car. It can take some slip, but will overheat rather quickly if it has to.

33pilot

lol at the rx with SNOW CHAINS going through snow. Lexus needs to build a better awd system. Subaru builds it's car's around the AWD system and has very good software programming that is why most car's here in Alaska are Subaru's - they perform flawlessly in dangerous snowy conditions, uphills, you name it.

The current RX is not on the same level as Subaru, Audi, BMW's Xdrive, Lexus step your game up. I think Lexus is getting rid of the GX and going with a 7 seat RX - hopefully that one will get a redesigned AWD system with a Torsen Center Diff. Otherwise will have to buy a Subaru or go with 4runner limited, gx, or lx.

vlad_a

Wrong architecture, my friend. Not going to happen. RX has no place in Alaska.

We already know the 7-seat RX was a failure from the start, which all of competitors realized was a must. Now, 4RX has all the futuristic designs few of the old-timers buying a Lexus desire. Have they even looked at their demographics? Lexus is as confused as ever.

I need a 7-seater and I'm eyeing either a 4Runner Limited or an Audi Q7. Can't help myself wanting a full time AWD system with RWD bias. RX is getting a bit boring, especially having an amazing AWD sedan in my garage as well.