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2008 Cadillac CTS DI AWD Thunder Gray Chromaflair/Ebony
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AWD System Information

I think the CTS offers a nice balance with its AWD system with the normal 75/25 split. That being said, not much info has been posted online about its capabilities.

AUBURN HILLS, Mich., Aug. 3—The all-new 2008 Cadillac CTS will offer BorgWarner’s all-wheel drive (AWD) technology as optional equipment for the first time, beginning later this summer. The new InterActive Torque Management Transfer Case (ITM tc) system uses sophisticated controls and algorithms to augment vehicle handling and traction by optimally using grip at both the front and rear wheels. In addition, the ITM tc system uses BorgWarner’s Vehicle Dynamics Control (VDC) software, which is designed to work in cooperation with other vehicle systems like anti- lock brakes and electronic stability programs to further improve traction, stability, and performance.

“We are proud to launch another all-wheel drive application with Cadillac and General Motors,” said Cindy Niekamp, President and General Manager, BorgWarner TorqTransfer Systems. “Adapting this technology to the passenger car market was the next progression. As a global leader in all-wheel drive technology, we are pleased to provide the next generation of CTS drivers with the enhanced vehicle traction, stability and handling that the system offers.”

The Cadillac CTS uses the latest generation of interactive transfer case technology available as part of BorgWarner’s torque management portfolio. BorgWarner’s portfolio consists of a full line of active torque management devices focused on the needs of the expanding all-wheel drive market. In the new CTS, the active transfer case from BorgWarner can shift up to 100% of available torque to the front axle if needed. In addition to providing the transfer case hardware, BorgWarner will also supply the software controls and electronics for vehicle level integration support. These capabilities are core competencies of BorgWarner and provide automakers like General Motors with outstanding vehicle performance.

Auburn Hills, Michigan-based BorgWarner Inc. is a product leader in highly engineered components and systems for vehicle powertrain applications worldwide. The FORTUNE 500 company operates manufacturing and technical facilities in 64 locations in 17 countries. Customers include VW/Audi, DaimlerChrysler, Ford, General Motors, Toyota, Renault/Nissan, Hyundai/Kia, Honda, BMW, Caterpillar, Navistar International, and Peugeot. The Internet address for BorgWarner is: http://www.borgwarner.com/
 

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07 300C-SRT8 - Looking at 08 AWD CTS
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Re: AWD System Information

I have been looking for something like this.

Thanks for posting
 

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Cadillacs: '13 CTS Cpe, '71 Eldo Conv
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Re: AWD System Information

It would be nice to have one of those indicators that lets you know which wheels are working/engaged--I saw this on a friend's Acura RL. Not necessary, but it is a neat gauge! Maybe Cadillac will add one? :yup:
 

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2008 Cadillac CTS DI AWD Thunder Gray Chromaflair/Ebony
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Discussion Starter #4
Re: AWD System Information

Some additional information about ITM:

"The InterActive Differential Control(TM) system also uses BorgWarner-developed electronic sensors and controls, in this case to deliver optimal biasing torque across the center differential automatically. When the system senses that the wheels are slipping, it automatically transfers power to the tractive wheels through the center differential. When the slipping stops, biasing to the tractive wheels is reduced or eliminated -- again, enhancing vehicle handling and traction through the management of power between the front and rear wheels.

Both systems deliver the requested amount of torque in response to electronic signals provided by one or more of the vehicle's traction and/or stability control systems. They are both fully interactive with, and work in conjunction with, other vehicle systems including antilock braking systems (ABS), electronic traction control (ETC), electronic stability programs (ESP), and active suspension programs. Both systems are pre-tested, and offer the customer benefits such as improved vehicle integration with no separate electronics to package, as well as reduced wiring harness complexity."

I was surprised how many manufacturers use Borg Warner:

 

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Re: AWD System Information

If anyone has any questions concerning the AWD system on the CTS feel free to ask as I am the responsible Development Engineer for that system. :thumbsup:
 

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2008 Cadillac CTS DI AWD Thunder Gray Chromaflair/Ebony
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Discussion Starter #7
Re: AWD System Information

If anyone has any questions concerning the AWD system on the CTS feel free to ask as I am the responsible Development Engineer for that system. :thumbsup:

As a proud new owner of a CTS I like to learn about interesting technical enhancements or features that are not in the GM press releases or most Auto reviews. Anything you can share would be welcome!

- For instance, the 2009 brochure mentions the 75/25 ratio as the normal torque distribution. Although other reviews imply it only send power to the rear wheels by default. Please confirm.

- Assuming my first statement was true. What made you decide that 75/25 was the best ratio in the CTS? I believe the Infinity G35 uses 95/5 and I know the new Audi A4 is 60/40. I could speculate this is somewhat dictated by the G35 and CTS already having rear biased drivetrains (vs Audi), so this makes sense. However, with you here, why speculate.;)

- How did Cadillac manage to do so much better than competitors in regards to gas mileage? BMW and Infinity seemed to have big dropoffs in fuel economy compared to Cadillac on their AWD variants. Is this simply due to the different drive ratio in the rear end?

- From what I can tell, it appears synthetic oil is also used in the transfer case to minimize maintenance. Is there any thing we should know from a maintenance perspective?

--
Doug
 

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Re: AWD System Information

Doug I had a detailed lengthy response wrote last Friday and somehow it got blown away. I'll try again. The 25/75 front/rear torque split in our marketing literature can be confusing because of the type of AWD system on the CTS. Let me digress a second. There are many different AWD systems with different manufacturers and until lately the most popular was a transfer case with an open center differential. This system by design involves a fixed front/rear torque split of typically 40/60 but can really be tailored to the desired characteristics of the vehicle as you noted with as little as 5/95. The Borg Warner active transfer case in the CTS uses a clutch pack instead of a differential which allows an infinitely variable front/rear ratio with the ability to transfer 100% of available torque to the front axle in conditions where the rear wheels may be slipping. It would take me pages to explain the control algorithms but in a nutshell, the system is continually monitoring and adjusting the clutch pack based on the input of sensors such as the throttle, steering wheel angle, yaw sensor, wheel speed sensors, engine torque, transmission gear state, etc. There are many advantages this system has over open center differentials although it is far more complex.

Now back to your 25/75 question.....the transfer case in the CTS is ONLY 25/75 DURING STEADY STATE DRIVING. This split was derived from a lot of development testing to determine what ratio provides optimum traction and handling on both high and low coefficient surfaces without transmitting so much torque to the front axle that fuel economy suffers. I'm not qualified to answer why we're so much better than AWD competitors on fuel economy but as you pointed out the 3.23 axle ratio certainly helps. Additionally, as you can imagine in this time of high cost fuel, we are constantly being challenged to improve component/driveline efficiency. The oil used in the transfer case is Mobil LT and is not synthetic but has been designed to provide great service life and performance under extreme conditions. Hope this helps and if there's something more specific you're wondering about let me know.
 

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Re: AWD System Information

Doug I had a detailed lengthy response wrote last Friday and somehow it got blown away. I'll try again. The 25/75 front/rear torque split in our marketing literature can be confusing because of the type of AWD system on the CTS. Let me digress a second. There are many different AWD systems with different manufacturers and until lately the most popular was a transfer case with an open center differential. This system by design involves a fixed front/rear torque split of typically 40/60 but can really be tailored to the desired characteristics of the vehicle as you noted with as little as 5/95. The Borg Warner active transfer case in the CTS uses a clutch pack instead of a differential which allows an infinitely variable front/rear ratio with the ability to transfer 100% of available torque to the front axle in conditions where the rear wheels may be slipping. It would take me pages to explain the control algorithms but in a nutshell, the system is continually monitoring and adjusting the clutch pack based on the input of sensors such as the throttle, steering wheel angle, yaw sensor, wheel speed sensors, engine torque, transmission gear state, etc. There are many advantages this system has over open center differentials although it is far more complex.

Now back to your 25/75 question.....the transfer case in the CTS is ONLY 25/75 DURING STEADY STATE DRIVING. This split was derived from a lot of development testing to determine what ratio provides optimum traction and handling on both high and low coefficient surfaces without transmitting so much torque to the front axle that fuel economy suffers. I'm not qualified to answer why we're so much better than AWD competitors on fuel economy but as you pointed out the 3.23 axle ratio certainly helps. Additionally, as you can imagine in this time of high cost fuel, we are constantly being challenged to improve component/driveline efficiency. The oil used in the transfer case is Mobil LT and is not synthetic but has been designed to provide great service life and performance under extreme conditions. Hope this helps and if there's something more specific you're wondering about let me know.
jjab4444,

Thanks for the additional info. I learn something new every day on this forum. Your participation is appreciated.!
 

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Re: AWD System Information

jjab4444; having owned my CTS4 for over a year, and having driven it through one of the toughest Iowa winters in years, I can't say how much I appreciated the handling of the car; far superior to my previous '05 STS with RWD. The AWD makes a world of difference in winter conditions.
 

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Re: AWD System Information

Thanks for the kind remarks guys. We're proud of the way that system was integrated and performs. Admittedly AWD is not for everyone but my biased opinion is that if you live where it snows, the traction and handling benefits of AWD are far superior to RWD and provide peace of mind.:thumbsup:
 

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Re: AWD System Information

Sorry for re-opening an old ass thread but...is there anyway possible to make is a 5/95 split??
 

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Re: AWD System Information

Thanks for the kind remarks guys. We're proud of the way that system was integrated and performs. Admittedly AWD is not for everyone but my biased opinion is that if you live where it snows, the traction and handling benefits of AWD are far superior to RWD and provide peace of mind.:thumbsup:
Absolutely agree.....under one conditon - the drivers need to know their limits and use winter tires ;)

Unfortunately too many car owners think that AWD is a sunstitute for they ignorance....
 

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Re: AWD System Information

No, but by pulling the fuse for AWD on a CTS4 it becomes a 0/100 split (i.e. 100% RWD).

Reference thread/post: http://www.cadillacforums.com/forums/2008-cadillac-cts-general-discussion/280164-didnt-know-i-could-turn-4wd.html#post3206488
Do we know if anyone from the states not dealing with snow and ice has tried pulling the fuse? I wonder if that would adversely affect the AWD drive system (premature wear on some components reducing their longevity) by having the power removed from the system. What about a CEL and storing codes, thereby possibly masking a real condition where the CEL should be on? Ah, the questions.
 

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Re: AWD System Information

^ HurstGN, if there was any adverse affect to the AWD system, the GM development engineer ..[responsible for developing the AWD system on the CTS4 and who recently provided me this information that 100% RWD is the result after pulling the AWD fuse].. would have certainly advised this. He mentioned that with some other vehicle brand vehicles, there's a facility inside the car to disconnect the 2nd axle, converting the vehicle from AWD (or 4WD) to RWD. Anyone doing this would do so primarily for fuel savings.
In the spring, when the snow and ice are gone, I intend to pull the fuse and try that for a while and see what sort of fuel savings are realised. I'll no doubt be seeing a message in the DIC about All Wheel Drive being off. I can live with that.

If I'm pleased with the result I may later install wiring and a switch to remotely enable/disable AWD, from inside the car. There's an available switch location on the IP center stack (there's currently a 'faux' switch there) where the heated windshield washer fluid control switch once resided (2008-09 cars).
 

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Re: AWD System Information

^ RAB, as your friend at GM states, there will be negligible gains in terms of fuel economy "due to inertia and spin losses associated with the front driveline components". Even with the clutch pack "disengaged" the front drive system is still spinning. The front tires are still linked to the half shafts / differential / prop shaft, all of which is still spinning as you move. Remove the ~300lbs of AWD technology if you maybe want to see an improvement. 1-2mpg is only a savings of $250USD/year (15k miles, $4USD/gal gas).

Here's an EPA comparison between 2011 3.6L AWD, 3.6L RWD auto, 3.0L RWD, 3.0L AWD. http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=30386&id=30378&id=30389&id=30390 . As you can see, RWD and AWD are the same/close in terms of fuel economy.

Just my opinion, but it really isn't worth the risk of drivetrain damage for $250/year. And no disrespect to your friend at GM, but the engineers at the Tier 1 supplier usually have more intimate knowledge of the systems they have to design/validate for the OEM.
 

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Re: AWD System Information

somedaycts, the points you make are good ones... however I still plan to proceed later this year in seeing what the mpg differences are between AWD enabled and AWD disabled (i.e. 100% RWD) on my '11 CTS4.
Don't get me wrong... I'm very happy to have a CTS equipped with AWD - when I drive the car during winter.

A lot has been discussed in various threads about EPA mpg numbers, and how far-off they can be from real world fuel mileage results. Personally I don't trust the EPA's mpg numbers. Before my current 2011 CTS 3.6 DI AWD I owned a 2009 CTS 3.6 DI RWD for over 2 years, and I KNOW FOR A FACT the two cars are not the same in terms of fuel economy. And yet according to the EPA they are.

BTW.. to be precise - gasoline prices north of the border (in Ontario) currently hover between $4.90-$5.25 USD per US gallon, and have been close to $6.00 USD per US gallon at times. That's where the typical price of regular gasoline will be heading in the not-too-distant future, at least here in Canada. I think I'll be looking for a turbo-diesel engine in my next vehicle.

I have been assured there is zero risk of drivetrain damage with AWD disabled on the CTS4. My engineer friend at GM is extremely knowledgeable and was a key player in the development and qualification of the AWD system on the 2nd gen CTS.
 
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