I'm so confused on all the information that honda is releasing on how its SH-AWD distributes the ratio of power to the front and rear wheels. Lets first state the obvious:
If the rear diff locked both of its electromagnetic clutches the system would then be 50:50. Meaning 50% torque to front wheels 50% to rear. This is because the car has no center diff so all locked up would mean every wheel gets equal power assuming all have traction.
Now lets talk about what acura says: They say that on the 2014 TL up to 70% of the power can be directed to the rear of the vehicle if need be. I was SO CONFUSED on how this is possible till I read that the rear is constantly overdriven by 1.7%. AAAAHHHHH ok. So the rear diff is geared 1.7% faster than the front. NOW HOLD ON. So a 1.7% over gearing causing 70% of the torque to then want to go to the rear wheels? I guess. I 'm sure you can't just add 1.7% to the torque split because the over drive would make those wheels drive slightly easier which would naturally send power more towards those wheels which could account for the 30:70 possible torque split acura is talking about if its rear clutches in the diff were FULLY LOCKED.
BUT WAIT! THE STORY GETS CONFUSSING. Acura in its release of the first SH awd in 2005 on the acura rl said that in straight line acceleration the max amount of power available to the rear wheels was 40%. OK I buy that. The RL does have the 1.7% gear increase but they are just not locking the rear diff all the way to get a full 50/50 during acceleration. Now the RL has a front "acceleration device" that actually can increase the rear over drive up to 5.8% in cornering situations, BUT LETS NOT BRING THAT INTO THE CONVERSATION AT THIS POINT. Instead lets go back to the TL.
Ok so the Tl in 2014 is said to allow up to 70% of available torque to go to the rear wheels which we assume is from the 1.7% overdrive of the rear with a FULL LOCK of the diff.
WELL HERE COMES THE CRASHING DOWN ON MY PARTY.
For the 2015 TLX acura has released that with the new design of the SH AWD rear diff it is ditching the electromagnetic clutch packs for hydraulically controlled clutches that work the exact same but are able to shed 30% of the weight of the rear diff. GREAT. Also the rear over drive is being increased from 1.7% to 2.7% to allow even more control and power to be directed to the rear wheels. They state that up to 70% of available engine torque can now be sent to the rear wheels.
WAIT WAIT WAIT. WHAT THE HELL? with a 1.7% you said up to 70 % could be driven to the rear wheels and now you say even more can be driven to the rear wheels with a 2.7% overdrive yet you state that as 70%?
And then you go and quote that the new TLX can supply up to 885 ftlbs of torque to one wheel in a cornering situation. WHAT THE HELL?!?!?! The car is rated at like 270 lbs of torque and your saying a 2.7% overdrive gets me to 885 lbs of torque to a wheel? You must be using some
Help me understand this people. Where am i going wrong in my thought process?
Let me throw some quotes in:
2010 acura TL:
SH-AWD® operating parameters include:
Up to 90-percent of available torque can be transferred to the front wheels during normal cruising.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics.
Up to 100-percent of the torque sent to the rear axle can be applied to either rear wheel, depending on conditions.
The TL SH-AWD® rear drive unit is constantly overdriven by 1.7-percent and the resulting overdrive effect is regulated by left and right electromagnetic clutch packs which independently control the power delivered to each rear wheel.
2015 TLX :
Up to 90-percent of available torque can be transferred to the front wheels during normal cruising.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics.
Up to 100-percent of the torque sent to the rear axle can be applied to either the left or right rear wheel, depending on conditions.
The TLX's new, more lightweight (25 percent reduction) SH-AWD rear drive unit is constantly overdriven by 2.7-percent (the previous generation TL system was overdriven by 1.7-percent). The resulting overdrive effect is regulated by left- and right-side clutch packs (located in the rear differential) that independently control the power delivered to each rear wheel. The increased overdrive percentage in the new TLX means that the torque vectoring effect is more pronounced and effective even in corners with a radius of as little as 49.2 feet (15 meters). This means that torque vectoring can be felt more often, such as when accelerating aggressively through a standard corner. Up to 885 lb.-ft. of torque can be delivered to either rear wheel, which gives the system the unique ability to yaw the TLX into turns for superior handling.
2009 Acura RL:
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 that can also be overdriven up to 5.7-percent by a built-in acceleration device.
If the rear diff locked both of its electromagnetic clutches the system would then be 50:50. Meaning 50% torque to front wheels 50% to rear. This is because the car has no center diff so all locked up would mean every wheel gets equal power assuming all have traction.
Now lets talk about what acura says: They say that on the 2014 TL up to 70% of the power can be directed to the rear of the vehicle if need be. I was SO CONFUSED on how this is possible till I read that the rear is constantly overdriven by 1.7%. AAAAHHHHH ok. So the rear diff is geared 1.7% faster than the front. NOW HOLD ON. So a 1.7% over gearing causing 70% of the torque to then want to go to the rear wheels? I guess. I 'm sure you can't just add 1.7% to the torque split because the over drive would make those wheels drive slightly easier which would naturally send power more towards those wheels which could account for the 30:70 possible torque split acura is talking about if its rear clutches in the diff were FULLY LOCKED.
BUT WAIT! THE STORY GETS CONFUSSING. Acura in its release of the first SH awd in 2005 on the acura rl said that in straight line acceleration the max amount of power available to the rear wheels was 40%. OK I buy that. The RL does have the 1.7% gear increase but they are just not locking the rear diff all the way to get a full 50/50 during acceleration. Now the RL has a front "acceleration device" that actually can increase the rear over drive up to 5.8% in cornering situations, BUT LETS NOT BRING THAT INTO THE CONVERSATION AT THIS POINT. Instead lets go back to the TL.
Ok so the Tl in 2014 is said to allow up to 70% of available torque to go to the rear wheels which we assume is from the 1.7% overdrive of the rear with a FULL LOCK of the diff.
WELL HERE COMES THE CRASHING DOWN ON MY PARTY.
For the 2015 TLX acura has released that with the new design of the SH AWD rear diff it is ditching the electromagnetic clutch packs for hydraulically controlled clutches that work the exact same but are able to shed 30% of the weight of the rear diff. GREAT. Also the rear over drive is being increased from 1.7% to 2.7% to allow even more control and power to be directed to the rear wheels. They state that up to 70% of available engine torque can now be sent to the rear wheels.
WAIT WAIT WAIT. WHAT THE HELL? with a 1.7% you said up to 70 % could be driven to the rear wheels and now you say even more can be driven to the rear wheels with a 2.7% overdrive yet you state that as 70%?
And then you go and quote that the new TLX can supply up to 885 ftlbs of torque to one wheel in a cornering situation. WHAT THE HELL?!?!?! The car is rated at like 270 lbs of torque and your saying a 2.7% overdrive gets me to 885 lbs of torque to a wheel? You must be using some
Help me understand this people. Where am i going wrong in my thought process?
Let me throw some quotes in:
2010 acura TL:
SH-AWD® operating parameters include:
Up to 90-percent of available torque can be transferred to the front wheels during normal cruising.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics.
Up to 100-percent of the torque sent to the rear axle can be applied to either rear wheel, depending on conditions.
The TL SH-AWD® rear drive unit is constantly overdriven by 1.7-percent and the resulting overdrive effect is regulated by left and right electromagnetic clutch packs which independently control the power delivered to each rear wheel.
2015 TLX :
Up to 90-percent of available torque can be transferred to the front wheels during normal cruising.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics.
Up to 100-percent of the torque sent to the rear axle can be applied to either the left or right rear wheel, depending on conditions.
The TLX's new, more lightweight (25 percent reduction) SH-AWD rear drive unit is constantly overdriven by 2.7-percent (the previous generation TL system was overdriven by 1.7-percent). The resulting overdrive effect is regulated by left- and right-side clutch packs (located in the rear differential) that independently control the power delivered to each rear wheel. The increased overdrive percentage in the new TLX means that the torque vectoring effect is more pronounced and effective even in corners with a radius of as little as 49.2 feet (15 meters). This means that torque vectoring can be felt more often, such as when accelerating aggressively through a standard corner. Up to 885 lb.-ft. of torque can be delivered to either rear wheel, which gives the system the unique ability to yaw the TLX into turns for superior handling.
2009 Acura RL:
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 that can also be overdriven up to 5.7-percent by a built-in acceleration device.