Motec ACD Controller = AWESOME
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From: San Mateo, CA
Motec ACD Controller = AWESOME
So at one of the Works Evo T/A tests we got to play around with the new Motec ACD controller... I don't know why everyone doesn't have one of these! The thing is so simple, yet super effective.
Basically the stock one just adjusts pump pressure going to the transfer case which adds or decreases the amount of lockup in the center diff. This does not mean more or less power goes to the back wheels, but it changes the amount of chance that the front and rear wheels work independently. Its quite a dynamic science, and super confusing (I'm not 100% clear on it myself).
The Motec unit allows the user to create custom maps to fine tune the power on/off dynamic of their Evo. You can set the lockup in the center diff based on throttle position, brake position (under throttle), and speed. I believe there also might be a slip angle compensation in there as well (I didn't play with it).
The basic idea is that less lockup on braking will cause the car to be a little less stable (usually in the rear) and thus (usually) helping turn in with trail braking. More lockup will stabilize the rear end (often on both acceleration and braking).
The other BIG thing this unit allows is to put more pump pressure into the ACD to compensate for power. Because the stock unit is limited (to around 27psi), more crank power changes the amount of lockup and therefore essentially creates a more open diff under power. The Motec unit can put up to 34psi of pressure [safely] to lock up the diff more effectively.
The one thing I'm still unclear on is the true dynamic of what openning the center diff does for an Evo. Someone was mentioning that because its a transaxle w/ a transfer case to the back wheels (v. a U.S./BMW style system where its an inline transmission with transfer case to the front wheels), the front set will always get 100% torque, and the locking is adjusting how much bias the rear wheels get at a maximum of 50%. I'm no expert on drivetrains, but looking at the Evo front/center diff, it looks like its one set of splines INSIDE the other, allowing EITHER set of wheels to get 100% of the torque. If this is the case, and the center diff was full open, would the set with least resistance get all the torque-- so with oversteer, would the car go all drifto and get all the power to the rear? If this is the case, this Motec unit is invaluable!...
Let me know if there are any drivetrain experts floating around!
Basically the stock one just adjusts pump pressure going to the transfer case which adds or decreases the amount of lockup in the center diff. This does not mean more or less power goes to the back wheels, but it changes the amount of chance that the front and rear wheels work independently. Its quite a dynamic science, and super confusing (I'm not 100% clear on it myself).
The Motec unit allows the user to create custom maps to fine tune the power on/off dynamic of their Evo. You can set the lockup in the center diff based on throttle position, brake position (under throttle), and speed. I believe there also might be a slip angle compensation in there as well (I didn't play with it).
The basic idea is that less lockup on braking will cause the car to be a little less stable (usually in the rear) and thus (usually) helping turn in with trail braking. More lockup will stabilize the rear end (often on both acceleration and braking).
The other BIG thing this unit allows is to put more pump pressure into the ACD to compensate for power. Because the stock unit is limited (to around 27psi), more crank power changes the amount of lockup and therefore essentially creates a more open diff under power. The Motec unit can put up to 34psi of pressure [safely] to lock up the diff more effectively.
The one thing I'm still unclear on is the true dynamic of what openning the center diff does for an Evo. Someone was mentioning that because its a transaxle w/ a transfer case to the back wheels (v. a U.S./BMW style system where its an inline transmission with transfer case to the front wheels), the front set will always get 100% torque, and the locking is adjusting how much bias the rear wheels get at a maximum of 50%. I'm no expert on drivetrains, but looking at the Evo front/center diff, it looks like its one set of splines INSIDE the other, allowing EITHER set of wheels to get 100% of the torque. If this is the case, and the center diff was full open, would the set with least resistance get all the torque-- so with oversteer, would the car go all drifto and get all the power to the rear? If this is the case, this Motec unit is invaluable!...
Let me know if there are any drivetrain experts floating around!
