2008 Acura RL SH-AWD Change?
09-11-2007, 02:51 PM
#1
Safety Car
Thread Starter
2008 Acura RL SH-AWD Change?
I just picked up a new 2008 RL brochure, and the most interesting thing to me was a completely different explanation of SH-AWD. For all the world, it looked like the specs of the MDX. The brochure is out of whack with the website and there is no 2008 press release yet.
Anyone know if there has been a gross software change, limiting front rear to 50/50? Of the 50 that goes to the rear, the brochures still says 0-100% can be directed to a single rear wheel. Gone is the careful mention of the 70-30 to 30-70 front to rear range etc.
Anyone know if there has been a gross software change, limiting front rear to 50/50? Of the 50 that goes to the rear, the brochures still says 0-100% can be directed to a single rear wheel. Gone is the careful mention of the 70-30 to 30-70 front to rear range etc.
09-11-2007, 03:05 PM
#3
Safety Car
Thread Starter
Yes, I had read that, in this forum also, but was never able to find it, although I never did pick up an 07 brochure. Anyway, the 08 brochure was quite a shock, so to speak.
09-11-2007, 03:20 PM
#4
Trolling Canuckistan
It's in the 08 brochure as well in 08 under the drivetrain stats. 08 model front:rear 80:20 or 30:70 (same set up as 07).
I believe 70:30 30:70 has been gone since the 06 model.
I believe 70:30 30:70 has been gone since the 06 model.
09-11-2007, 03:36 PM
#5
AcurAdmirer
Originally Posted by black label
It's in the 08 brochure as well in 08 under the drivetrain stats. 08 model front:rear 80:20 or 30:70 (same set up as 07).
I believe 70:30 30:70 has been gone since the 06 model.
I believe 70:30 30:70 has been gone since the 06 model.
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09-11-2007, 04:33 PM
#6
Safety Car
Thread Starter
Hopefully Black Label can do that.
You won't find numbers in the web site, but the SH-AWD video gives some numbers, including the 70-30 to 30-70 split. There is no parallelism in the website between the RL which gives no written power distribution numbers and the RDX/MDX which actually give some power distribution numbers.
When I have access to a scanner, I will attempt to scan and upload the 08 brochure page that shows the 50-50 for the RL. If I did not know any better, I would say they slipped the wrong graphic in the RL brochure pulling the 50-50 from the 2008 MDX brochure.
And even the 50-50 split for the MDX is only part of the story. At least according to the MDX 2007 technical press releases, the 50-50 only occurs in hard cornerning with 0-100 directable to a single wheel. Under certain heavy load conditions, SH-AWD can go 30-70, and in straight line cruising, no heavy loads, 90-10.
But Acura seems to have diminished the SH-AWD explanation each year, from 2005 which was most comprehensive to 2006 to 2008. I recall looking at a 2007, but do not recall exactly what is said with regards to SH-AWD.
That is particularly why I thought the 2008 brochure 50-50 explanation for the RL was so amazingly different.
The implementation of SH-AWD across the different vehicles is confusing. Speaking of which, does anyone know how I can upload an Excel spreadsheet to the site?
You won't find numbers in the web site, but the SH-AWD video gives some numbers, including the 70-30 to 30-70 split. There is no parallelism in the website between the RL which gives no written power distribution numbers and the RDX/MDX which actually give some power distribution numbers.
When I have access to a scanner, I will attempt to scan and upload the 08 brochure page that shows the 50-50 for the RL. If I did not know any better, I would say they slipped the wrong graphic in the RL brochure pulling the 50-50 from the 2008 MDX brochure.
And even the 50-50 split for the MDX is only part of the story. At least according to the MDX 2007 technical press releases, the 50-50 only occurs in hard cornerning with 0-100 directable to a single wheel. Under certain heavy load conditions, SH-AWD can go 30-70, and in straight line cruising, no heavy loads, 90-10.
But Acura seems to have diminished the SH-AWD explanation each year, from 2005 which was most comprehensive to 2006 to 2008. I recall looking at a 2007, but do not recall exactly what is said with regards to SH-AWD.
That is particularly why I thought the 2008 brochure 50-50 explanation for the RL was so amazingly different.
The implementation of SH-AWD across the different vehicles is confusing. Speaking of which, does anyone know how I can upload an Excel spreadsheet to the site?
09-11-2007, 04:40 PM
#7
Senior Moderator
Here's what Acura says about the 2007 RL:
http://www.hondanews.com/categories/757/releases/3772
The release for the 2005 RL has exactly the same information:
http://www.hondanews.com/categories/757/releases/2091
No info on the 2008 RL yet.
SUPER HANDLING ALL-WHEEL DRIVE SYSTEM™
Super Handling All-Wheel Drive™ (SH-AWD™) is an innovative all-wheel drive platform that distributes the optimum amount of torque not only between the front and rear wheels but also between the left and right rear wheels. SH-AWD™ goes a step beyond conventional all-wheel drive by actively controlling the torque delivered to each rear wheel during corning. The result is neutral, accurate steering when cornering under power that front-drive, rear-drive or conventional all-wheel-drive can't equal.
Torque splits are as follows:
During straight-line cruising and moderate cornering below about half throttle, up to 70 percent of the torque is delivered to the front wheels.
In full-throttle straight line acceleration, up to 40 percent of the power is sent to the rear axle.
In hard cornering, up to 70 percent of available torque goes to the rear wheels for enhanced chassis balance. Up to 100 percent of this torque can be applied to the outside rear wheel and that wheel can be overdriven up to five percent by the acceleration device if the situation dictates.
SH-AWD™ ingeniously varies the amount of torque to the left and right rear wheels. When cornering, a planetary gear set overdrives (or accelerates) the rear wheels while individual right and left clutch packs direct torque to either or both rear wheel, faster than the average of the front wheels to dramatically enhance the cornering, steering feel, overall handling and stability of the RL. The result is class leading cornering precision as well as enhanced traction.
Direct Yaw Control System Theory
SH-AWD™ counters understeer under power with the Direct Yaw Control System. Spinning the outside rear wheel faster than the average speed of the two front wheels allows the system to use engine power to yaw the vehicle while turning. By relieving the front tires of some of the work of turning the car, the system reduces understeer and the vehicle stays balanced and controllable. In addition, with the cornering load more evenly distributed between the front and rear tires, the total cornering grip is increased. In conventional cars, cornering is created almost entirely by the steering angle of the front tires; In the RL, cornering is created by steering angle of front tires combined with the extra drive torque supplied by the outside rear tire.
This is a significant advance over conventional drive systems. To deal with high power output, front- or rear-drive systems generally use some type of limited-slip device to maintain traction under power. The linking effect of the inside and outside drive wheels in these systems resists turning, however. This is a factor that works against the front tires as they attempt to turn the car. Conventional AWD systems have a similar linking effect between the inboard and outboard tires and front and rear axles, causing a similar resistance to turning. This is part of the reason why traditional AWD systems typically lack the more nimble feel of the best two-wheel drive systems. By using drive torque to actually help turn the car, the RL can be more responsive, neutral and predictable, while simultaneously offering all of the usual benefits of all-wheel drive.
Super Handling All-Wheel Drive™ (SH-AWD™) is an innovative all-wheel drive platform that distributes the optimum amount of torque not only between the front and rear wheels but also between the left and right rear wheels. SH-AWD™ goes a step beyond conventional all-wheel drive by actively controlling the torque delivered to each rear wheel during corning. The result is neutral, accurate steering when cornering under power that front-drive, rear-drive or conventional all-wheel-drive can't equal.
Torque splits are as follows:
During straight-line cruising and moderate cornering below about half throttle, up to 70 percent of the torque is delivered to the front wheels.
In full-throttle straight line acceleration, up to 40 percent of the power is sent to the rear axle.
In hard cornering, up to 70 percent of available torque goes to the rear wheels for enhanced chassis balance. Up to 100 percent of this torque can be applied to the outside rear wheel and that wheel can be overdriven up to five percent by the acceleration device if the situation dictates.
SH-AWD™ ingeniously varies the amount of torque to the left and right rear wheels. When cornering, a planetary gear set overdrives (or accelerates) the rear wheels while individual right and left clutch packs direct torque to either or both rear wheel, faster than the average of the front wheels to dramatically enhance the cornering, steering feel, overall handling and stability of the RL. The result is class leading cornering precision as well as enhanced traction.
Direct Yaw Control System Theory
SH-AWD™ counters understeer under power with the Direct Yaw Control System. Spinning the outside rear wheel faster than the average speed of the two front wheels allows the system to use engine power to yaw the vehicle while turning. By relieving the front tires of some of the work of turning the car, the system reduces understeer and the vehicle stays balanced and controllable. In addition, with the cornering load more evenly distributed between the front and rear tires, the total cornering grip is increased. In conventional cars, cornering is created almost entirely by the steering angle of the front tires; In the RL, cornering is created by steering angle of front tires combined with the extra drive torque supplied by the outside rear tire.
This is a significant advance over conventional drive systems. To deal with high power output, front- or rear-drive systems generally use some type of limited-slip device to maintain traction under power. The linking effect of the inside and outside drive wheels in these systems resists turning, however. This is a factor that works against the front tires as they attempt to turn the car. Conventional AWD systems have a similar linking effect between the inboard and outboard tires and front and rear axles, causing a similar resistance to turning. This is part of the reason why traditional AWD systems typically lack the more nimble feel of the best two-wheel drive systems. By using drive torque to actually help turn the car, the RL can be more responsive, neutral and predictable, while simultaneously offering all of the usual benefits of all-wheel drive.
The release for the 2005 RL has exactly the same information:
http://www.hondanews.com/categories/757/releases/2091
No info on the 2008 RL yet.
Trending Topics
09-11-2007, 05:13 PM
#8
AcurAdmirer
Boy, that tells me the MID display is nothing but a misleading toy. If a max of only 40% of the torque can go to the back in straight-line running, and that only under full-throttle acceleration, the display is flat wrong.
On my recent road trip, I spent some time watching the display just out of curiosity. When I was going straight down the interstate at 75-80 mph on cruise control, it was often showing an even 50-50 split. No full-throttle, just cruising. And I would swear there were times when it showed one more "bar" in the rear than in the front under certain kinds of acceleration situations (hills, downslopes, etc.). According to what Bob has posted, either scenario would be impossible.
In fact, in straight-line running, the rear should never show as many bars as the front if that's true. And mine certainly does.
So, I guess there's no point in paying any attention at all to the display.
.
.
On my recent road trip, I spent some time watching the display just out of curiosity. When I was going straight down the interstate at 75-80 mph on cruise control, it was often showing an even 50-50 split. No full-throttle, just cruising. And I would swear there were times when it showed one more "bar" in the rear than in the front under certain kinds of acceleration situations (hills, downslopes, etc.). According to what Bob has posted, either scenario would be impossible.
In fact, in straight-line running, the rear should never show as many bars as the front if that's true. And mine certainly does.
So, I guess there's no point in paying any attention at all to the display.
.
.
09-11-2007, 05:42 PM
#9
Go Big Blue!
Originally Posted by Mike_TX
Boy, that tells me the MID display is nothing but a misleading toy. If a max of only 40% of the torque can go to the back in straight-line running, and that only under full-throttle acceleration, the display is flat wrong.
On my recent road trip, I spent some time watching the display just out of curiosity. When I was going straight down the interstate at 75-80 mph on cruise control, it was often showing an even 50-50 split. No full-throttle, just cruising. And I would swear there were times when it showed one more "bar" in the rear than in the front under certain kinds of acceleration situations (hills, downslopes, etc.). According to what Bob has posted, either scenario would be impossible.
In fact, in straight-line running, the rear should never show as many bars as the front if that's true. And mine certainly does.
So, I guess there's no point in paying any attention at all to the display.
.
.
On my recent road trip, I spent some time watching the display just out of curiosity. When I was going straight down the interstate at 75-80 mph on cruise control, it was often showing an even 50-50 split. No full-throttle, just cruising. And I would swear there were times when it showed one more "bar" in the rear than in the front under certain kinds of acceleration situations (hills, downslopes, etc.). According to what Bob has posted, either scenario would be impossible.
In fact, in straight-line running, the rear should never show as many bars as the front if that's true. And mine certainly does.
So, I guess there's no point in paying any attention at all to the display.
.
.
Regardless, it works! Powering out of a curve feels confident. Plus, I've NEVER felt any sense of torque steer with my RL - no matter how hard I've punched it.
09-11-2007, 07:06 PM
#10
Torch & Pitchfork Posse
Originally Posted by Chas2
Anyone know if there has been a gross software change, limiting front rear to 50/50? Of the 50 that goes to the rear, the brochures still says 0-100% can be directed to a single rear wheel. Gone is the careful mention of the 70-30 to 30-70 front to rear range etc.
"as much as 70% power can be directed to the rear wheels"....and of the rear power "100% may be directed to either wheel".
09-11-2007, 07:52 PM
#11
Safety Car
Thread Starter
I wish I had access to a scanner. The full page graphic of the 2008 chassis and the notes are stunningly different than my 2005 and 2006 brochures.
09-12-2007, 05:08 PM
#13
AcurAdmirer
Originally Posted by Chas2
I wish I had access to a scanner. The full page graphic of the 2008 chassis and the notes are stunningly different than my 2005 and 2006 brochures.
You can get a really decent one for less than 50 bucks if you look around.
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09-13-2007, 10:29 AM
#14
Safety Car
Thread Starter
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
[img ] http://www.futerox.net/hostmypiconli...85641289361771 [/img]
In 2006 they had a smaller version of the same graphic
[img ] http://www.futerox.net/hostmypiconli...85641289461771 [/img]
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
[img ] http://www.futerox.net/hostmypiconli...85641289561771 [/img]
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
[img ] http://www.futerox.net/hostmypiconli...85641289361771 [/img]
In 2006 they had a smaller version of the same graphic
[img ] http://www.futerox.net/hostmypiconli...85641289461771 [/img]
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
[img ] http://www.futerox.net/hostmypiconli...85641289561771 [/img]
09-13-2007, 10:32 AM
#15
Safety Car
Thread Starter
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289361771[/img]
In 2006 they had a smaller version of the same graphic
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289461771[/img]
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289561771[/img]
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289361771[/img]
In 2006 they had a smaller version of the same graphic
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289461771[/img]
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
[img ]http://www.futerox.net/hostmypiconline/user_images.php?ID=985641289561771[/img]
09-13-2007, 10:36 AM
#16
Safety Car
Thread Starter
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
09-13-2007, 05:26 PM
#17
Safety Car
Thread Starter
Test
Originally Posted by Chas2
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
09-13-2007, 10:00 PM
#18
Senior Moderator
Chas, can you send me the pix so I can host them? Will PM my email addy.
09-13-2007, 10:28 PM
#19
Safety Car
Thread Starter
Let me try this again.
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
09-14-2007, 07:37 AM
#20
Trolling Canuckistan
Originally Posted by Mike_TX
Can you link to that? I've been all over the Acura website and can't find any specific mention of the front-rear torque split. It's not in Specifications, Features and Options or anywhere else I can find reference to SH-AWD.
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On the specs page under the category of "Drivetrain" the 3rd spec they list is "Maximum Torque Distribution Range" and as I said it is currently 80:20 to 30:70 for 07-08.
It doesn't go into specifics about how the system works. They gave you more info on that in the 2005 brochure when the car was introduced and they have sort of "dumbed down" their explanation of how the system works.
I don't think they have really changed anything mechanically on the RL SH-AWD system, my guess is that it's really a software change.
09-14-2007, 08:35 AM
#21
Go Big Blue!
Originally Posted by black label
I don't think they have really changed anything mechanically on the RL SH-AWD system, my guess is that it's really a software change.
09-14-2007, 09:04 AM
#22
Trolling Canuckistan
Originally Posted by SpicyMikey
Or its just a case of the "left hand not knowing what the right hand is doing". Design to development to marketing. Sometimes things change. Sometimes things get misrepresented or confused. In this case, if it was a mistake in marketing, it probably doesn't matter much. The system still appears to work as described regardless of 50/50, 70/30, or 80/20. Right?
It does mention the 70% max to the rear in the diagram above, but never goes into specifics about max % to the front.
As a side note (to further confuse the situation), the 07 RDX is listed as 90:10 to 30:70 for both 07 and 08.
With all of the people who complain that the SH-AWD is a front drive biased system, it doesn't suprise me that they don't brag that they do indeed have it set to send more power to the front wheels.
09-14-2007, 09:14 AM
#23
Trolling Canuckistan
Originally Posted by Chas2
Let me try this again.
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
I cannot for the life of me figure out why the images got distorted when I uploaded them, but it is all new to me.
Here is the 2005 version of SH-AWD that shows 70-30 to 30-70 FR distribution depending on the situation, and 60-40 for heavy straight line acceleration
In 2006 they had a smaller version of the same graphic
I do not have 2007 brochure, and cannot recall what it said. Here is 2008 which is much different. It shows 50-50 FR distribution, and dumbs down the presentation dramatically, skipping much of the drivetrain componentry, the 5% variable speed acceleration device, etc., and mentions the carbon fiber propellor shaft etc. In fact details such as the carbon fiber propeller shaft (terminology used in 2005 and 2006 and well highlighted) is now mentioned as a carbon fiber reinforced drive shaft, an example of the exotic materials used in the RL.
Of course we all knew that, they just described in in a strange way. They are not describing it as a "maximum torque distribution", just a general explanation of how it works to enhance steering.
09-14-2007, 09:43 AM
#24
AcurAdmirer
I don't know - maybe I'm just confused, but when 2 ratios are given (like the 80:20 to 30:70 black label quoted) what the hell does that mean?
I thought the two ratios would be either the front:rear / rear:front distribution, or the front:rear / (rear) side:side distribution. Since we know 100% of the rear torque can go to one rear wheel, shouldn't one of the ratios be 100:0 (left:right)?
But here's what confuses me, and makes me say the MID display must be wildly inaccurate. I have seen - with my own eyes - the display on my RL show MORE torque (more bars) to the rear than to the front. If a max of 30% goes to the rear, that would seem to be impossible, since 70% would still be going to the front.
This has happened in two different situations: one is steady highway cruising (on cruise control) and climbing a low hill, and the other is when highway cruising and coasting down a hill. About as confusing is that under these same cruising conditions, I saw the display showing an equal number of bars (50:50) a LOT of times.
So, can someone explain a.) exactly what the ratios mean, and b.) how in the world the rear wheels could EVER show more bars in the MID display than the fronts if a maximum of 30% goes to the rear.
(BTW, I thought it was really cool when I saw the rear wheels showing more bars when coasting down a grade ... it was like the car was "dragging" its rear wheels a bit to control the descent, which is brilliant.)
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I thought the two ratios would be either the front:rear / rear:front distribution, or the front:rear / (rear) side:side distribution. Since we know 100% of the rear torque can go to one rear wheel, shouldn't one of the ratios be 100:0 (left:right)?
But here's what confuses me, and makes me say the MID display must be wildly inaccurate. I have seen - with my own eyes - the display on my RL show MORE torque (more bars) to the rear than to the front. If a max of 30% goes to the rear, that would seem to be impossible, since 70% would still be going to the front.
This has happened in two different situations: one is steady highway cruising (on cruise control) and climbing a low hill, and the other is when highway cruising and coasting down a hill. About as confusing is that under these same cruising conditions, I saw the display showing an equal number of bars (50:50) a LOT of times.
So, can someone explain a.) exactly what the ratios mean, and b.) how in the world the rear wheels could EVER show more bars in the MID display than the fronts if a maximum of 30% goes to the rear.
(BTW, I thought it was really cool when I saw the rear wheels showing more bars when coasting down a grade ... it was like the car was "dragging" its rear wheels a bit to control the descent, which is brilliant.)
.
.
09-14-2007, 09:54 AM
#25
Burning Brakes
Originally Posted by Mike_TX
I don't know - maybe I'm just confused, but when 2 ratios are given (like the 80:20 to 30:70 black label quoted) what the hell does that mean?
I thought the two ratios would be either the front:rear / rear:front distribution, or the front:rear / (rear) side:side distribution. Since we know 100% of the rear torque can go to one rear wheel, shouldn't one of the ratios be 100:0 (left:right)?
But here's what confuses me, and makes me say the MID display must be wildly inaccurate. I have seen - with my own eyes - the display on my RL show MORE torque (more bars) to the rear than to the front. If a max of 30% goes to the rear, that would seem to be impossible, since 70% would still be going to the front.
This has happened in two different situations: one is steady highway cruising (on cruise control) and climbing a low hill, and the other is when highway cruising and coasting down a hill. About as confusing is that under these same cruising conditions, I saw the display showing an equal number of bars (50:50) a LOT of times.
So, can someone explain a.) exactly what the ratios mean, and b.) how in the world the rear wheels could EVER show more bars in the MID display than the fronts if a maximum of 30% goes to the rear.
(BTW, I thought it was really cool when I saw the rear wheels showing more bars when coasting down a grade ... it was like the car was "dragging" its rear wheels a bit to control the descent, which is brilliant.)
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I thought the two ratios would be either the front:rear / rear:front distribution, or the front:rear / (rear) side:side distribution. Since we know 100% of the rear torque can go to one rear wheel, shouldn't one of the ratios be 100:0 (left:right)?
But here's what confuses me, and makes me say the MID display must be wildly inaccurate. I have seen - with my own eyes - the display on my RL show MORE torque (more bars) to the rear than to the front. If a max of 30% goes to the rear, that would seem to be impossible, since 70% would still be going to the front.
This has happened in two different situations: one is steady highway cruising (on cruise control) and climbing a low hill, and the other is when highway cruising and coasting down a hill. About as confusing is that under these same cruising conditions, I saw the display showing an equal number of bars (50:50) a LOT of times.
So, can someone explain a.) exactly what the ratios mean, and b.) how in the world the rear wheels could EVER show more bars in the MID display than the fronts if a maximum of 30% goes to the rear.
(BTW, I thought it was really cool when I saw the rear wheels showing more bars when coasting down a grade ... it was like the car was "dragging" its rear wheels a bit to control the descent, which is brilliant.)
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I agree it's an awkward representation and leads to confusion.
09-14-2007, 10:31 AM
#26
Trolling Canuckistan
When I'm showing the Maximum torque distrubution it is front to rear potential values.
80:20 means a maximum of 80% to the front while the remaining 20% goes to the rear.
30:70 means a minimum of 30% to the front while the remaining 70% goes to the rear(essentially this is saying a maximum of 70% to the rear wheels).
In 05-06 it was essentially able to do the same thing front to rear (max 70%, min 30% in either direction), now it is definitely a "front drive bias" AWD system (meaning it has higer maximum levels for the front wheels than it does for the back).
These torque distributions have nothing to do with the transfer of power between the left and right rear wheels, only between the 2 front wheels and the 2 rear wheels.
What ever amount of power is being sent to the rear wheels (some where between 20% and 70% of the total engine power) can then be sent to either the left or right rear wheel to enhance cornering. A lot of the confusion is due to the fact that you are sending 100% of between 20% and 70% to the outside rear wheel during cornering, but not 100% of the total engine power.
80:20 means a maximum of 80% to the front while the remaining 20% goes to the rear.
30:70 means a minimum of 30% to the front while the remaining 70% goes to the rear(essentially this is saying a maximum of 70% to the rear wheels).
In 05-06 it was essentially able to do the same thing front to rear (max 70%, min 30% in either direction), now it is definitely a "front drive bias" AWD system (meaning it has higer maximum levels for the front wheels than it does for the back).
These torque distributions have nothing to do with the transfer of power between the left and right rear wheels, only between the 2 front wheels and the 2 rear wheels.
What ever amount of power is being sent to the rear wheels (some where between 20% and 70% of the total engine power) can then be sent to either the left or right rear wheel to enhance cornering. A lot of the confusion is due to the fact that you are sending 100% of between 20% and 70% to the outside rear wheel during cornering, but not 100% of the total engine power.
09-14-2007, 11:20 AM
#27
Burning Brakes
Originally Posted by Mike_TX
But here's what confuses me, and makes me say the MID display must be wildly inaccurate. I have seen - with my own eyes - the display on my RL show MORE torque (more bars) to the rear than to the front. If a max of 30% goes to the rear, that would seem to be impossible, since 70% would still be going to the front.
Rob144
09-14-2007, 01:00 PM
#28
AcurAdmirer
Originally Posted by black label
When I'm showing the Maximum torque distrubution it is front to rear potential values.
80:20 means a maximum of 80% to the front while the remaining 20% goes to the rear.
30:70 means a minimum of 30% to the front while the remaining 70% goes to the rear(essentially this is saying a maximum of 70% to the rear wheels).
In 05-06 it was essentially able to do the same thing front to rear (max 70%, min 30% in either direction), now it is definitely a "front drive bias" AWD system (meaning it has higer maximum levels for the front wheels than it does for the back).
These torque distributions have nothing to do with the transfer of power between the left and right rear wheels, only between the 2 front wheels and the 2 rear wheels.
What ever amount of power is being sent to the rear wheels (some where between 20% and 70% of the total engine power) can then be sent to either the left or right rear wheel to enhance cornering. A lot of the confusion is due to the fact that you are sending 100% of between 20% and 70% to the outside rear wheel during cornering, but not 100% of the total engine power.
80:20 means a maximum of 80% to the front while the remaining 20% goes to the rear.
30:70 means a minimum of 30% to the front while the remaining 70% goes to the rear(essentially this is saying a maximum of 70% to the rear wheels).
In 05-06 it was essentially able to do the same thing front to rear (max 70%, min 30% in either direction), now it is definitely a "front drive bias" AWD system (meaning it has higer maximum levels for the front wheels than it does for the back).
These torque distributions have nothing to do with the transfer of power between the left and right rear wheels, only between the 2 front wheels and the 2 rear wheels.
What ever amount of power is being sent to the rear wheels (some where between 20% and 70% of the total engine power) can then be sent to either the left or right rear wheel to enhance cornering. A lot of the confusion is due to the fact that you are sending 100% of between 20% and 70% to the outside rear wheel during cornering, but not 100% of the total engine power.
But I think you're saying that under the right circumstances, as much as 80% of the torque could be directed to the front, and under opposite circumstances, as much as 70% could be sent to the rear. I guess I can make that work in my thick head.
Thanks for the clarification, because that would explain why I've seem more bars at the rear than at the front at times.
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09-14-2007, 02:45 PM
#29
Trolling Canuckistan
Originally Posted by Mike_TX
I guess what confused me is when you showed both numbers - 80:20 and 30:70. It didn't seem like it could be both ways, because I was looking at it as having to be a nice symmetrical 70:30 / 30:70.
But I think you're saying that under the right circumstances, as much as 80% of the torque could be directed to the front, and under opposite circumstances, as much as 70% could be sent to the rear. I guess I can make that work in my thick head.
Thanks for the clarification, because that would explain why I've seem more bars at the rear than at the front at times.
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But I think you're saying that under the right circumstances, as much as 80% of the torque could be directed to the front, and under opposite circumstances, as much as 70% could be sent to the rear. I guess I can make that work in my thick head.
Thanks for the clarification, because that would explain why I've seem more bars at the rear than at the front at times.
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I've got to say, this is probably the most intelligent discussion I have ever taken part in here. It's all mature with no random flaming or name calling over here on the RL side of the world. If they only made it in a coupe with a manual transmission I'd buy today.
09-14-2007, 03:19 PM
#30
Banned
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I'm, like, totally with all this 70:30 / 30:70, 80:20 / 20:80 torque thingy. I get a headache everytime I try to understand it! So, um....I ain't coming back in here! 
with all this 70:30 / 30:70, 80:20 / 20:80 torque thingy. I get a headache everytime I try to understand it! So, um....I ain't coming back in here!
09-14-2007, 04:13 PM
#31
Safety Car
Thread Starter
Originally Posted by black label
Alright, I've stared at the diagram above and I've figured the 50/50 thing out. What they are saying is while 50% of the power can go to the front wheels while the other 50% can be directed exclusively to the outside rear wheel (or 100% of the rear wheel power). It doesn't actually say that it is limited at 50/50.
Of course we all knew that, they just described in in a strange way. They are not describing it as a "maximum torque distribution", just a general explanation of how it works to enhance steering.
Of course we all knew that, they just described in in a strange way. They are not describing it as a "maximum torque distribution", just a general explanation of how it works to enhance steering.
And Mikey, yes, I also think the left hand does not know what the right hand is doing. In the brochures, there appears to have been a slight change in the 2007/2008 RL software that allows the torque distribution range to be 80-20 to 30 70, versus the 70-30 to 30-70 range in the 2005/2006 RLs. However, the newly posted 2008 RL Acuranews.com writeups still say it is 70-30 to 30-70.
The 2008 MDX brochure explains what SH-AWD does in a much more clear fashion...
Straight line cruising: up to 90%-10% front-rear torque distribution
Heavy acceleration and/or heavy rear load: up to 30%-70%
High speed cornering: up to 50%-50% with up to 100% of the available rear 50% torque potentially distributed to the outside rear wheel
The RDX has yet again different numbers...
I guess in the end, whatever the range of max torque distribution turns out to be, it does not really matter. Honda is using that range to achieve certain handling targets for each vehicle, and the driver does not really need to worry about what the numbers are so long as the handling target is achieved...that is what all the computers and sensors are for...that is, except for us die hards, who like to know the intimate details of how the car works.
09-14-2007, 04:19 PM
#32
Go Big Blue!
Originally Posted by Chas2
I guess in the end, whatever the range of max torque distribution turns out to be, it does not really matter. Honda is using that range to achieve certain handling targets for each vehicle, and the driver does not really need to worry about what the numbers are so long as the handling target is achieved...that is what all the computers and sensors are for...that is, except for us die hards, who like to know the intimate details of how the car works.
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