Hello, its my first post here.

I recently acquired my Canadian 2017 IS350 F-Sport, which means the only drive train option is AWD, and I've heard a couple different explanations about how the AWD system works. I've heard that it is RWD bias, sending 70 to the rear and 30 to the front with up to 50/50, or FWD bias with the same power splits. So how does the AWD system really work in the 2017 IS350?

Thanks!

 

Its a rear biased AWD system. Roughly 70% of power goes to the rear and it can split power 50/50 when detecting slippage.

Heres some more info quoted from a thread on here...

“Full-Time All-Wheel Drive
This traction-enhancing system distributes power to the front and rear axles during normal driving, and resists sending power to an axle that encounters a low-grip surface.
• A planetary-type center differential and chain drive provide robust, reliable power transfer.
• A wet clutch helps keep an axle from spinning if the front or rear tires encounter slick pavement.
• The clutch engages smoothly and avoids binding when making tight turns.
• Traction control is specially tuned to work in concert with the all-wheel-drive system.

• A robust differential continually delivers power to the front and rear axles.
• The planetary gear design eliminates binding when making sharp turns.
• The wet-clutch limited-slip device helps to keep wheels from spinning on very slippery surfaces.
• Electronic controls help the system respond quickly to changing road and driving conditions

VDIM with Sport Mode:
• One of the high-performance features included on IS 250 and IS 350 F SPORT sedans.
• When VDIM Sport Mode is selected, the VSC and TRAC programming switch to a high-performance mode that raises the threshold at which the systems intervene.
• VDIM Sport Mode allows the driver to accelerate, corner and, in some cases brake more aggressively, without activating VSC.
• VDIM Sport Mode allows the driver to accelerate from a corner or pull away from a dead stop with TRAC operating in A-LSD mode—simulating a limited-slip differential.
• Each time the vehicle is started, VDIM defaults to normal mode”

 

Thanks for posting. I know this is not a recent thread, but I just got my car so I'm interested in how the AWD system works.
The info posted above is probably accurate but it's a bit vague. I'm interested in more detail. I'm looking for a more thorough description of the powerflow from the engine to the wheels. Can anyone refer me to a source with diagrams etc.? Thanks very much. Jim

 

I know I might be a tad late, but hopefully this is helpful too you.

https://toyota-club.net/files/faq/11..._ifour_eng.htm

 

THANK YOU! The material was very helpful. I'm very glad you responded. Cheers. JC

 

I've had my Lexus now for just over 2 years, and I like driving it, although I've only put 4000 km on it, all in good weather. I don't drive it in the winter..
The car is a '17 IS 350 AWD and I bought it at Performance Lexus in St. Catherines, Ontario. (I live in Ancaster, part of Hamilton.)
It was in very nice condition with 38,000 km. At the time, it was the only 350 IS available and I was happy with the car and the dealer was very good to work with.
I replaced all the rotors and pads. What's visible is all good. There are two things I don't like, and I am a fussbudget. I don't think I have OCD but my wife might beg to differ.
The previous owner must have parked the car outdoors as the underside is quite rusty. I'm not sure if I had known that whether it would have deterred me from buying. Other wise the car was pretty much perfect for a 5 year old car (at the time). The engine revs at about 1400 rpm on startup when it's cold and takes quite a while to settle down. I don't like putting it into reverse with high revs, so I usually wait, but it seems to take too long to me.. Are they all like this? I disconnected the battery and cleaned the throttle body which was moderately dirty and it seems slightly better. I'm not sure if I will keep this car forever. That was the plan, but I haven't really fallen in love with it so far. JC

 

The engine revving at 1400 and taking ~30 seconds to drop down from High Idle is normal. It's mostly an emissions thing where cars want to warm up the catalytic converter as quickly as possible. This takes longer on this engine compared to other cars. Even other cars from Toyota. My mom's RAV4 goes off high idle and will even get fully warm much faster than mine will. But that probably has to do with how big the actual engine block of these V6 engines are. These engines hold a lot of coolant and oil compared to newer engines, even those of the same or bigger size.

Newer engines do this for environmental impact, government regulations and fuel economy reasons. The car might be 2017, but remember, the engine itself has been used in the IS from 2006 onwards. Its an old school motor. That has its upsides, highly reliable, very well built, and very linear power delivery. But yes, not so fuel efficient, not as powerful as newer turbocharged ones and a by product of its age is how long it takes to warm up. Newer engines do things like valve overlap to a far more aggressive level, to meet those newer emission levels.

As for rust, well the previous owner must've driven it in the winter, and being from Ontario you guys salt the road like crazy, not to mention the large bodies of water, that not helping.
We have a rule here (Alberta): Never buy a car from the eastern provinces.

But, regardless, unless its seriously bad, it should all be surface rust, and is normal in that case.

 

Hey, George42, thanks again for the info. I am knowledgeable about cars and I used to be a licensed mechanic, back in the early 1980's. But I don't know all the details about newer cars.
I have a pretty good understanding of the basic systems and I have worked on auto and manual transmissions, clutches, axles, brakes, etc. My previous car was a 2012 135i BMW 6MT. Extremely nice car. I've also owned a 2010 G4 FWD Acura TL with the J series 3.5L and I loved that car. That engine is fantastic. I had a 1999 Integra for 13 years from new, and it was also awesome. 5MT. I do all my own maintenance that I can do without a lift. Unfortunately (?) I left the business before OBD came in, Back in the day I also owned a 1969 340 Dart Swinger with a 4 speed, 3.90 gears etc. It was fast but it had so many flaws I vowed never to own another Chrysler product. The Lexus is very different of course, and I've never previously had a vehicle with AWD. When I bought this car I specifically wanted the 2GR engine. I would have preferred a RWD car but they are not readily available in Canada.