noosense00

Based on what was stated about the RX350 and its new "advanced" AWD system, how much more advanced is it compared to the 04-06 AWD models? With the new advanced systems, what is more capable about this car that the 04-06 models cannot do.

"The AWD RX 350 model is improved with the addition of a viscous limited-slip center differential, which enhances drivability in all types of driving conditions. The full-time AWD system provides a constant 50/50 front-to-rear power split. If slippage occurs, the viscous differential directs torque to the wheels with the most traction. "

Todd

so don't understand what you have been told is new about that aspect of the vehicle.

Lexmex

Having the 99 AWD...the only way I ever know something has improved is after I drive it. I will take it from Lexus they have made changes, but I may or may not like them or may not even notice a difference.

Rockville

few times. The original RX had a viscous coupling center diff and a limited slip rear. This is a good combination for Lexmex as it would be good for traction when doing the quarter mile runs. In 2001 all of the differentials and driveshafts were lightened and left "open" and the Vehicle Stability Control was added. This used braking force to direct power to the side that was getting traction. The new RX330 in 2004 had a new elaborate traction control system that was very effective at getting power to the wheel(s) that were getting purchase. Again all differentials were the open type. Power distribution was normally left at 50%/50% front to rear. The GX470 was the first to use a limited slip center diff and allowed the power to normally be distributed 40% front and 60% rear. it has an electronic lock down that can keep it 50%/50% when mired in mud, heavy snow or sand. The RX350 will have more torque available so we are coming full circle back to a viscous coupling type center diff of the limited slip type. It is heavier but maybe Lexmex will like it. The transmission has some new software but retains the 5 speed format. The 0-60 time is just a few tenths of a second more than the RX400h and it will outperform some of the V8 luxury sport utes we are told....

Rock

noosense00

Thanks for all the responses. I am completely new to this and Lexus made it sound like a revolution based on what was published.

Lexmex

This sounds interesting. I was hoping that Toyota woud at least have the Rav4 AWD with the 3.5 L engine down here (no Lexus in Mexico) so I could get an idea of the power of one of these engines. I still like the PWR button on my 99 along with the overdrive (PWR on/overdrive off for 1/4 mile). I have tried out the RX330 so I have an idea about that. I have a turbo idea I have been floating around in my head, but I need to consult with a few of my partners before I give the go ahead to do it on my RX.

looknow12

From everything I've seen, it would seem traction control is only possible with open differentials, or with a viscous differential similar to the torsen on the GX.

When they added the traction control to the RX they probably needed to drop the limited slip diffs. You'll notice in the GX, as soon as you enable the center diff lock, the traction control becomes disabled. I also have a Tundra and as soon as you enable the part time 4WD (which always means center diff locked) the traction control is also disabled.

I suspect traction control can not function when any two wheels are locked together because braking actions to one wheel would in turn put too much load on that single brake.

I have a lot more questions in this area. It still would seem possible, although the potential benefit (from traction control) would be minimal to non existent with any differentials locked.

Broc

Update some. It seems that in Russia, Toyota has offered the Torsen posi diff in the rear of all Highlanders as a option (maybe RAV4's too ...). And there are plenty of used units available from salvage yards. That would imply that you can use a Torsen diff with Trac Control system.

Torsen diffs were also offered on select Ford Ranger pick-ups for many years. Some of those had Trac Control systems too. Ford offered clutch type posi's in Explorer's for ever. They had Trac Control too.

I think the brake loads are manageable as long as the diff can act as a normal unit ... Prolly not doable with a Detroit Locker style posi

Felix

Yeah, a Torsen/Quafie will work in a t/c equipped vehicle. I've install them in two of my cars & you'll find that the t/c hardy ever kicks in w/ a diff......

Broc

That's exactly what I expect. Same for various company vehicles I drove before retirement. TC and Posi get along OK as long as it's not a Detroit Locker style. And they are too rough for a Lexus

The issue I'm having is trying to define the guts of the RX300~350 rear differential ... On the build plates I have seen on vehicles we are looking at to buy, the Diff is "-02A" code. If you look at the attached PDF from Toyota, it's listed at the bottom of the page - RAV4. But it does not say whether it's a 6.7" diff or a 7.5" diff ...

Felix

Good question.....

Broc

Well, some more info for Lexmex. If you look at the doc I attached in the post a few up from here, it states Rav4 and Highlander got the -02A rear differential. But we know from other threads and research I have done, that the Lexus RX also uses the -02A differential out back. And we know that Toyota offered the limited slip differential (LSD) or Posi in the Russian market until quite recently.

And we know that in 2009 with potentially the same rear carrier and diff, the RX 350 was showing something like 275 HP. They may not knock back a Camero, but they are quicker than they have the right to be at 4000 lbs. Even with a 2.98 final gear in the diffs and parasitic losses through the auto trans ....

So, if you want to build a RAV4 hot rod, skip the turbo's and have a good used Lexus motor/tranny shipped down from USA and the ECU and wiring and have at it

And while you are about it, have an good used OEM Torsen LSD rear carrier sent down too

And the magic "advances" they did in 2007 was to go back to the viscous coupling center diff and move away from the complex TRAC system they used between 2004-2006 ...

Felix

Thats great they went back to a viscous center diff.......I was originally looking at both 330/350. What sold me was the grunt of the 35. btw, one of the last places I was at had a few of both 330's & 350's. I 1st one I drove was a 350 as it was easy to get out. A quick run on the 520 sold me on a 350.