filmteknik

What kind of AWD (4WD) is the RX350 (2008)? How is the power split? Is it 50/50 or do the front wheels do most of the work when there's no slippage detected?

jgr7

iTrader: (1)

Mostly front. Not sure of the % but I've heard it is around 95/5.
Jeff

draco

AWD and 4WD are different in some key things, namely a low range gearbox etc. etc. I thought the AWD on the RX330 is all-wheel-drive all of the time (i.e. constant). I may be wrong, but I don't think there was much of a change to the 350's from a design point of view.

lexus114

"AWD on the RX330 is all-wheel-drive all of the time" yep,that is my understanding as well.

Boognish

It is my understanding that the RX350 has a viscous center differential (VCD). What this means is that when the front and rear axles are spinning at different speeds, the fluid in the coupling heats up, causing clutch packs in the coupling to grab in an attempt to equalize the speed of the axles. A VCD is not as strong as a mechanical transfer case, but a pretty good solution for a car based awd vehicle intended for snow/rain traction. I think we all know the RX was never intended to go off road - it's based on a Camry chasis.

Iowa330

I'm confused. I've heard that the 2nd generation has both the Camry and Highlander chassis. So which is it?

kitlz

I thought the RX300 was the Camry, RX330/350 the Highlander.

Iowa330

That makes sense, but until an expert chimes in we'll never know

LexFather

These vehicles share the same chassis. It's not the "Camry" chassis per-se, they have different wheelbases and drive-trains (no Camry AWD).
Camry
Avalon
Highlander
Venza
ES
RX

Also the 400h AWD system is different than the 330/350. The hybrid gets its power from the rear hybrid battery.

The systems are FWD biased until slippage is detected and power is shifted to where its needed.

https://www.clublexus.com/forums/car...d-systems.html

MerlinT

Here's the press release on the 08 RX from March 07.

Lexus Announces
Prices for 2008 Model Year RX 350 Luxury SUV
01/26/2007 Torrance,
CA
Revised: 04/02/2007

March 29, 2007 – Torrance, CA - Lexus
has announced manufacturers suggested retail prices (MSRP) for the2008 RX 350,
the top-selling luxury sport utility vehicle (SUV). For 2008, the RX 350
receives exterior enhancements that include a freshened front-grille design and
new exterior chrome door handles. New seven-spoke 18-inch alloy wheels with a
Liquid Graphite finish are available as an option. The 2008 RX 350 also adds two
new exterior colors: Brandy Wine Mica and Desert Sage Metallic. Inside, the RX
350 offers an additional wood trim color, Black Bird’s-Eye Maple, on units with
a light gray interior.

The RX 350 retains its excellent value as the MSRP
will remain unchanged from 2007. Prices for the RX 350 will remain at $37,400
for the front-wheel-drive model and $38,800 for the all-wheel-drive model. All
optional equipment prices also remain unchanged.

Powerful
Performance
Powered by a 3.5-liter V6 engine, the RX 350 produces 270
horsepower and 251 lb.-ft. of torque. Featuring all-aluminum construction, the
V6 harnesses the benefits of advanced technologies to optimize performance, fuel
economy and low emissions. The V6 enables the RX 350 to sprint from zero to 60
mph in just 7.3 seconds for the FWD model and 7.4 seconds for the AWD model.

The performance of the RX 350 is
comparable to the output of some competitive V8 engines while still providing a
fuel-economy rating among the best in class for nonhybrids.

Its
five-speed electronically controlled automatic transmission is tuned for refined
drivability as well as excellent fuel efficiency. EPA-estimated combined fuel
economy rating for the RX 350 is 20 mpg (18 mpg city/23 mpg highway) for the
FWD
model and 19 mpg (17 mpg city/22 mpg highway) for the AWD. The RX 350 retains its ULEV II emissions
certification.

The highly sophisticated engine uses electronically
controlled sequential fuel injection, which optimizes the fuel mixture and
creates a precise burn, higher output and lower emissions to aid drivability. In
addition, an electronic throttle control presides over several systems to
maintain superior control of power flow. This system, Electronic
Throttle
Control with intelligence (ETC-i), helps manage idle speed, cruise control,
Traction Control (TRAC) and Vehicle Stability Control (VSC). The result is
engine efficiency with excellent power and impressive fuel
economy.

Refined Comfort and Luxury Features
The RX 350 produces
minimal cabin noise, allowing for a very quite interior that provides an
exceptional listening environment for its standard premium,
satellite-ready,eight-speaker AM/FM/CD audio player with in-dash six-CD
autochanger. The audio system is compatible with MP3/WPA-formatted CDs and
includes Automatic Sound Levelizer (ASL), Radio Data System (RDS) and a digital
signal processor. Commonly used audio functions are accessible via
steering-wheel-mounted controls.

For true audiophiles, a Mark Levinson®
Premium Audio System is optionally available. This 11-speaker system features an
in-dash six-disc DVD/CD autochangeR, DVD-audio and DVD-video playback as well as
remarkable sound clarity at all volumes (with 210 watts at 0.1% THD, 20-20,000
Hz). An available factory-installed, rear-seat DVD entertainment system features
a nine-inch fold-away video screen for convenient viewing.

The Lexus DVD
Navigation System is optionally available on the RX 350 and includes voice
recognition that allows the driver to input a desired destination by voice
command while driving.

Like other Lexus navigation systems, the system is
offered in conjunction with a rear back-up camera to supplement the driver’s
visibility of the area behind the vehicle. The camera provides the driver a view
of what the camera lens can detect behind the vehicle, automatically projecting
a color image on the navigation system’s seven-inch VGA screen when the reverse
gear is engaged.

In addition to English, the navigation system includes
Spanish and French text display options. The user can select the language
preference at system start-up.

Lexus’ craftsmanship and renowned
attention to detail provide sumptuous comfort by design. Standard dual-zone
automatic climate control, 10-way power front seats with available memory, a
sliding center console, adjustable light in the visor vanity mirrors, and wood
interior trim set the tone for luxury in the RX 350. Luxury extends to the
smallest details, such as illuminated front cup holders and a wood- and
leather-trimmed steering wheel with integrated audio-system and trip-computer
controls.

Premium options include a power-tilt/telescoping steering wheel
with memory, and an illuminated entry system that lights the door handles, scuff
plates, and front footwells.

A unique, wide-opening multipanel moonroof
is an optional alternative to the optional conventional moonroof. With an open
area that is 150-percent larger than a normal moonroof and a 250-percent larger
illumination area, the multipanel moonroof is made of three separate glass
panels. The small front panel is angled to reduce wind noise, the rear panel
slides backwards on top of the vehicle, while the middle glass panel slides
backwards on top of the rear panel.

Advanced All-Wheel Drive
The AWD RX 350 model features 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.

A direct-type Tire
Pressure Monitor (TPM) system alerts the driver via a warning light on the
instrument panel if a significant drop in tire pressure is detected in any of
the tires.

Produced in Kyushu, Japan, and Cambridge in southern Ontario,
Canada, the 2008 RX 350 begins arriving at Lexus dealerships in early February.

lexus114

2004-5 dont use a vsc. It works from the wheel sensors,and uses the center diff. Not exactly sure how,but it`s simpler/and lighter than the other set up. And very effective. I have not been stuck yet,and I`v even driven on ice.

willyb0b

so 50/50 on my 2009... thanks for that posting

on another note, here's a blurb pulled from wikipedia about the longevity of a VSC differential. though a portion of it is not cited, it's still interesting

""Viscous LSDs are less efficient than mechanical types, that is, they "lose" some power. In particular, any sustained load which overheats the silicone results in sudden permanent loss of the differential effect.[4] They do have the virtue of failing gracefully, reverting to semi-open differential behaviour. Typically a visco-differential that has covered 60,000 miles (97,000 km) or more will be functioning largely as an open differential;[citation needed] this is a known weakness of the original Mazda MX-5 (a.k.a. Miata) sports car. The silicone oil is factory sealed in a separate chamber from the gear oil surrounding the rest of the differential. This is not serviceable and when the differential's behaviour deteriorates, the VLSD centre is replaced.""

kiwi

mines a 2004, and i got stuck a few days ago.

about 2 feet of snow did it, trouble was there was ice under the snow.

additional trouble was the fact that the rear wheels would not spin at all. (yes it is AWD). and i have no idea why, i am assuming the power took the path of least resistance and just let the front wheels spin.

only after shovelling for 20 minutes and a friend pushing did i get free.

Iowa330

2 feet of snow? You needed a hummer not a Lexus. Never bring a knife to a gunfight

kiwi

my surprise wasnt that i got stuck, it was that the rear wheels werent moving.

i had made it through 50 feet of the 2 feet deep snow, it was only the last 5 that for some reason gave me trouble.