Best diff mode for each event...
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From: Eastern, Indiana
Best diff mode for each event...
I looked and couldn't find a thread where someone pinpointed the best setting...
I wanna know what's the best setting for drag racing? (snow?)
Best setting for autocross/track days (gravel?)
And I will assume daily driving is Tarmac....
If someone has input or a previous thread with the best answers that would be appreciated.
I wanna know what's the best setting for drag racing? (snow?)
Best setting for autocross/track days (gravel?)
And I will assume daily driving is Tarmac....
If someone has input or a previous thread with the best answers that would be appreciated.
ACD mode depends on surface you're driving on, not the event you're driving in. The labels should make this obvious enough.
Tarmac if you're on dry pavement.
Gravel if you're on gravel or wet pavement (reduced grip)
Snow if you're on snow/ice (very low grip)
Source: https://www.evolutionm.net/forums/ev...everybody.html
Tarmac if you're on dry pavement.
Gravel if you're on gravel or wet pavement (reduced grip)
Snow if you're on snow/ice (very low grip)
D. How the Tarmac/Gravel/Snow switch influences the ACD
Despite popular belief, this switch DOES NOT change the torque split. The differential is geared at 50:50 and cannot be changed by the push of a button. What this switch actually does is quite simple. Each setting determines how long the ACD will delay in freeing the center differential after a steering input is made. In addition, it will determine how much locking force the ACD will exhibit on the clutch pack and center differential. (10) (11)
Tarmac is the setting to be used in dry, paved conditions. In this setting, the ACD will almost immediately allow the center differential to go into a free state upon detecting a steering input. Additionally, this mode provides the strongest limited-slip clamping force of the three modes. (7) (12)
Gravel is the setting designed for wet or loose roads. In this setting, the ACD will delay in freeing the center differential for a moment (possibly 2-3 seconds). Of the three modes, this one has the second strongest clamping force. (7) (12)
Snow is the setting designed for, you guessed it, snow. In this setting, the ACD will delay in freeing the center differential for much longer than the other two settings (possibly 4-5 seconds). Of the three modes, this one also provides the least amount of clamping power. (7) (12)
Despite popular belief, this switch DOES NOT change the torque split. The differential is geared at 50:50 and cannot be changed by the push of a button. What this switch actually does is quite simple. Each setting determines how long the ACD will delay in freeing the center differential after a steering input is made. In addition, it will determine how much locking force the ACD will exhibit on the clutch pack and center differential. (10) (11)
Tarmac is the setting to be used in dry, paved conditions. In this setting, the ACD will almost immediately allow the center differential to go into a free state upon detecting a steering input. Additionally, this mode provides the strongest limited-slip clamping force of the three modes. (7) (12)
Gravel is the setting designed for wet or loose roads. In this setting, the ACD will delay in freeing the center differential for a moment (possibly 2-3 seconds). Of the three modes, this one has the second strongest clamping force. (7) (12)
Snow is the setting designed for, you guessed it, snow. In this setting, the ACD will delay in freeing the center differential for much longer than the other two settings (possibly 4-5 seconds). Of the three modes, this one also provides the least amount of clamping power. (7) (12)
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From: Eastern, Indiana
Yeah I know this. But in reality which one is best for grip and handling in each event.
I saw threads on here where people launch in snow mode and do their spirited driving in gravel mode. Just wasn't sure if anyone figured this out yet? I'm sure driving in anything but Tarmac accelerates diff wear.
I saw threads on here where people launch in snow mode and do their spirited driving in gravel mode. Just wasn't sure if anyone figured this out yet? I'm sure driving in anything but Tarmac accelerates diff wear.
Its a 50 /50 transfer front and back.....the ACD doesn't change this....you could drag race in Snow or Gravel its not gonna make a difference. The different settings are for the clutch packs inside the transfer case, how they release and such....there are numerous thread on how its works.
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Bad information, OP asked a serious question and just a bunch of nonsense answers. It's easy enough to answer the question for a USDM 9 with ACD only. The X and older Evo's with AYC make it more complicated.
Tarmac/Gravel/Snow modes deeply effect handling and there are big ways in which they can be utilized on different courses. The first thing to understand is that the modes are named by marketing people and are not really related to road surface conditions but rather to the locking time of the ACD.
Tarmac - This setting assumes the most amount of grip is available in terms of a road surface and the tires. The ACD does not activate until excessive front and rear delta occur, as much as 20% speed difference is allowed. Great for dry road courses and the street. Since the ACD does not activate heavily, this mode also allows for the least amount of power loss.
Gravel - The ACD governs slip more aggressively, around 10% front rear delta is allowed. This is great for rainy surfaces or a crappy road course with a poor surface condition. This is also the mode mose drag racers I talk to start with. When you launch, you want the most amount of power to transmit to the ground with the least slip. Tarmac will allow wheelspin in hard launches.
Snow - The ACD is a German Nanny on Steriods, basically a "locked" type condition where no front and rear wheel delta is allowed. This can be great for certain types of power sliding and road courses where conditions rapidly change from good traction to bad. Drag racers use this mode when the strip has bad traction or the car is not hooking up well. It sends a heavy jolt into the driveline so it's not the best for longevity of the ACD or the T-Case.
That's a basic synopsis of the modes. To really understand the ACD you have to comprehend that since it is completely electronically controlled it acts like a 1.5 way limited slip, meaning it can react differently in different states such as acceleration, braking, and cornering. For the most part the ACD acts similar during braking across all modes, meaning it locks. Accel and cornering settings are largely the areas where the modes differ.
Tarmac/Gravel/Snow modes deeply effect handling and there are big ways in which they can be utilized on different courses. The first thing to understand is that the modes are named by marketing people and are not really related to road surface conditions but rather to the locking time of the ACD.
Tarmac - This setting assumes the most amount of grip is available in terms of a road surface and the tires. The ACD does not activate until excessive front and rear delta occur, as much as 20% speed difference is allowed. Great for dry road courses and the street. Since the ACD does not activate heavily, this mode also allows for the least amount of power loss.
Gravel - The ACD governs slip more aggressively, around 10% front rear delta is allowed. This is great for rainy surfaces or a crappy road course with a poor surface condition. This is also the mode mose drag racers I talk to start with. When you launch, you want the most amount of power to transmit to the ground with the least slip. Tarmac will allow wheelspin in hard launches.
Snow - The ACD is a German Nanny on Steriods, basically a "locked" type condition where no front and rear wheel delta is allowed. This can be great for certain types of power sliding and road courses where conditions rapidly change from good traction to bad. Drag racers use this mode when the strip has bad traction or the car is not hooking up well. It sends a heavy jolt into the driveline so it's not the best for longevity of the ACD or the T-Case.
That's a basic synopsis of the modes. To really understand the ACD you have to comprehend that since it is completely electronically controlled it acts like a 1.5 way limited slip, meaning it can react differently in different states such as acceleration, braking, and cornering. For the most part the ACD acts similar during braking across all modes, meaning it locks. Accel and cornering settings are largely the areas where the modes differ.
Is there any solid evidence that different ACD settings affect launching? ive seen it tossed around that snow is better for launching but IIRC have never seen any data to back it up.
There has to be wheelspin in order for the ACD to make a difference, so it has to be a really serious launch with big power. If the wheels never slip then there will be no effect. But take a look at any legit Drag racing evo, there is slip.
You can produce and observe the evidence yourself. Log WSS with Evoscan during a launch. Do one in each mode. Plot the results of each WSS (split them into front and rear) and see the wheel speed differences. Compare WSS delta in each mode to your ET - RT.
You'll see a time difference for the mode that allowed the most wheelspin front rear delta, all else being equal. In fact, the time differences are related directly to the reaction time of the ACD locking.
But things like tire condition, track condition, etc. all become variables that can skew comparisons.
You can produce and observe the evidence yourself. Log WSS with Evoscan during a launch. Do one in each mode. Plot the results of each WSS (split them into front and rear) and see the wheel speed differences. Compare WSS delta in each mode to your ET - RT.
You'll see a time difference for the mode that allowed the most wheelspin front rear delta, all else being equal. In fact, the time differences are related directly to the reaction time of the ACD locking.
But things like tire condition, track condition, etc. all become variables that can skew comparisons.
Thread Starter
Evolving Member
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From: Eastern, Indiana
Thanks very much disco god father.
I seriously dont ask half of my questions I have on this forum due to people like that.
I thought it was a fairly in depth question and got all BS answers...
Well I'm glad I have some sort of idea now. I will continue not asking most of my questions on this forum. *sigh*....
Thanks again DiscoGodFather
I seriously dont ask half of my questions I have on this forum due to people like that.
I thought it was a fairly in depth question and got all BS answers...
Well I'm glad I have some sort of idea now. I will continue not asking most of my questions on this forum. *sigh*....
Thanks again DiscoGodFather
Bad information, OP asked a serious question and just a bunch of nonsense answers. It's easy enough to answer the question for a USDM 9 with ACD only. The X and older Evo's with AYC make it more complicated.
Tarmac/Gravel/Snow modes deeply effect handling and there are big ways in which they can be utilized on different courses. The first thing to understand is that the modes are named by marketing people and are not really related to road surface conditions but rather to the locking time of the ACD.
Tarmac - This setting assumes the most amount of grip is available in terms of a road surface and the tires. The ACD does not activate until excessive front and rear delta occur, as much as 20% speed difference is allowed. Great for dry road courses and the street. Since the ACD does not activate heavily, this mode also allows for the least amount of power loss.
Gravel - The ACD governs slip more aggressively, around 10% front rear delta is allowed. This is great for rainy surfaces or a crappy road course with a poor surface condition. This is also the mode mose drag racers I talk to start with. When you launch, you want the most amount of power to transmit to the ground with the least slip. Tarmac will allow wheelspin in hard launches.
Snow - The ACD is a German Nanny on Steriods, basically a "locked" type condition where no front and rear wheel delta is allowed. This can be great for certain types of power sliding and road courses where conditions rapidly change from good traction to bad. Drag racers use this mode when the strip has bad traction or the car is not hooking up well. It sends a heavy jolt into the driveline so it's not the best for longevity of the ACD or the T-Case.
That's a basic synopsis of the modes. To really understand the ACD you have to comprehend that since it is completely electronically controlled it acts like a 1.5 way limited slip, meaning it can react differently in different states such as acceleration, braking, and cornering. For the most part the ACD acts similar during braking across all modes, meaning it locks. Accel and cornering settings are largely the areas where the modes differ.
Tarmac/Gravel/Snow modes deeply effect handling and there are big ways in which they can be utilized on different courses. The first thing to understand is that the modes are named by marketing people and are not really related to road surface conditions but rather to the locking time of the ACD.
Tarmac - This setting assumes the most amount of grip is available in terms of a road surface and the tires. The ACD does not activate until excessive front and rear delta occur, as much as 20% speed difference is allowed. Great for dry road courses and the street. Since the ACD does not activate heavily, this mode also allows for the least amount of power loss.
Gravel - The ACD governs slip more aggressively, around 10% front rear delta is allowed. This is great for rainy surfaces or a crappy road course with a poor surface condition. This is also the mode mose drag racers I talk to start with. When you launch, you want the most amount of power to transmit to the ground with the least slip. Tarmac will allow wheelspin in hard launches.
Snow - The ACD is a German Nanny on Steriods, basically a "locked" type condition where no front and rear wheel delta is allowed. This can be great for certain types of power sliding and road courses where conditions rapidly change from good traction to bad. Drag racers use this mode when the strip has bad traction or the car is not hooking up well. It sends a heavy jolt into the driveline so it's not the best for longevity of the ACD or the T-Case.
That's a basic synopsis of the modes. To really understand the ACD you have to comprehend that since it is completely electronically controlled it acts like a 1.5 way limited slip, meaning it can react differently in different states such as acceleration, braking, and cornering. For the most part the ACD acts similar during braking across all modes, meaning it locks. Accel and cornering settings are largely the areas where the modes differ.
P.S ACD info is stickied....not hard to find
Last edited by Teal2nnr; Nov 25, 2011 at 10:11 AM.
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