Fix My ACD Problem and I will pay you!
I'm not confusing ACD with AYC. If you jack up the car and run the car while holding (while the pump is not functioning or when the hand brake lever is pulled) the rear wheels you will notice no AWD in the system; the front wheels simply spin while the rear wheels stay perfectly stationary.
You are correct in stating that the center differential remains a 50/50 torque split however, the only way the torque is even transferred is by the friction created from the clutch pack within the transfer case due to the hydraulic pressure which the pump produces. The lack of pressure will result in the clutch pack's inability to mate and create friction thus not being able to transfer power to the rear under conditions which produce reactive forces from the rear wheels. In other words, if you produce non-uniform torque from the front and rear wheels the torque will not be transferred. Therefore the ACD pump is required to provide hydraulic pressure to the clutch pack to provide the possible transfer of torque.
You are correct in stating that the center differential remains a 50/50 torque split however, the only way the torque is even transferred is by the friction created from the clutch pack within the transfer case due to the hydraulic pressure which the pump produces. The lack of pressure will result in the clutch pack's inability to mate and create friction thus not being able to transfer power to the rear under conditions which produce reactive forces from the rear wheels. In other words, if you produce non-uniform torque from the front and rear wheels the torque will not be transferred. Therefore the ACD pump is required to provide hydraulic pressure to the clutch pack to provide the possible transfer of torque.
Pulling the hand brake will deactivate the ACD by tell it to stop producing hydraulic pressure so that that clutch packs will disengage. That is the only way to stop the transfer of torque going to the rear wheels.
I'm not confusing ACD with AYC. If you jack up the car and run the car while holding (while the pump is not functioning or when the hand brake lever is pulled) the rear wheels you will notice no AWD in the system; the front wheels simply spin while the rear wheels stay perfectly stationary.
You are correct in stating that the center differential remains a 50/50 torque split however, the only way the torque is even transferred is by the friction created from the clutch pack within the transfer case due to the hydraulic pressure which the pump produces. The lack of pressure will result in the clutch pack's inability to mate and create friction thus not being able to transfer power to the rear under conditions which produce reactive forces from the rear wheels. In other words, if you produce non-uniform torque from the front and rear wheels the torque will not be transferred. Therefore the ACD pump is required to provide hydraulic pressure to the clutch pack to provide the possible transfer of torque.
You are correct in stating that the center differential remains a 50/50 torque split however, the only way the torque is even transferred is by the friction created from the clutch pack within the transfer case due to the hydraulic pressure which the pump produces. The lack of pressure will result in the clutch pack's inability to mate and create friction thus not being able to transfer power to the rear under conditions which produce reactive forces from the rear wheels. In other words, if you produce non-uniform torque from the front and rear wheels the torque will not be transferred. Therefore the ACD pump is required to provide hydraulic pressure to the clutch pack to provide the possible transfer of torque.
I do drive my car a bit hard on the street and take corners quicker than most, I definitely do feel a difference when my ACD did work.
Yes I have tried it. I was in the car when the two Mitsu Techs held the rear wheels in place. I remember last winter I tried getting up a hill infront of my house, the car wouldn't grip at all when set in Tarmac mode. Once I switched to Snow mode it gripped fine and I was able to get up the hill.
I do drive my car a bit hard on the street and take corners quicker than most, I definitely do feel a difference when my ACD did work.
I do drive my car a bit hard on the street and take corners quicker than most, I definitely do feel a difference when my ACD did work.
Once I switched to snow mode the torque transfer was just slow enough for the front wheels to grip first then it transfered the power to the rear and I noticed much less oversteer during turns above 10mph in the snow.
Last edited by timmiii; Aug 18, 2011 at 03:25 PM.
My ACD pump has recently become very very loud. Before it was not super noticeable and I always had one light as intended.
Now after start up and 1 minute on the road I get a very loud grumbling sound. Almost like bubbles popping. If this sound cuts off quickly (5 seconds or so it remains 1 light). If it does this sound for a minute or so then it cuts off and all three lights become illuminated.
Any ideas.
Now after start up and 1 minute on the road I get a very loud grumbling sound. Almost like bubbles popping. If this sound cuts off quickly (5 seconds or so it remains 1 light). If it does this sound for a minute or so then it cuts off and all three lights become illuminated.
Any ideas.
My ACD pump has recently become very very loud. Before it was not super noticeable and I always had one light as intended.
Now after start up and 1 minute on the road I get a very loud grumbling sound. Almost like bubbles popping. If this sound cuts off quickly (5 seconds or so it remains 1 light). If it does this sound for a minute or so then it cuts off and all three lights become illuminated.
Any ideas.
Now after start up and 1 minute on the road I get a very loud grumbling sound. Almost like bubbles popping. If this sound cuts off quickly (5 seconds or so it remains 1 light). If it does this sound for a minute or so then it cuts off and all three lights become illuminated.
Any ideas.
Then I tried launching the car this summer at the drag strip with the pump not working. Instant fail, there is video on youtube of my car just spinning the front wheels and smoking them. Car always ran 1.6x 60' but instead ran back to back 2.2 60' on the rev limiter entire time.
http://www.youtube.com/watch?v=trAp35U601U 2:22 in the video is a launch with a bad ACD pump.
Normal driving you wouldn't notice much and to be honest when I drove with three red lights I can still get some torque to the back wheels in snowy conditions.
Then I tried launching the car this summer at the drag strip with the pump not working. Instant fail, there is video on youtube of my car just spinning the front wheels and smoking them. Car always ran 1.6x 60' but instead ran back to back 2.2 60' on the rev limiter entire time.
http://www.youtube.com/watch?v=trAp35U601U 2:22 in the video is a launch with a bad ACD pump.
Then I tried launching the car this summer at the drag strip with the pump not working. Instant fail, there is video on youtube of my car just spinning the front wheels and smoking them. Car always ran 1.6x 60' but instead ran back to back 2.2 60' on the rev limiter entire time.
http://www.youtube.com/watch?v=trAp35U601U 2:22 in the video is a launch with a bad ACD pump.
Well considering it's been a problem since the Evo has had an ACD pump, I doubt they'll all of the sudden do something about it. This has been a problem for years....way before the evo was even available here.
ACD is such a pain in the A**. I had an 05 evo back in end of 04 and had problems with it and my solution was putting in a Built shep 04 RS t case. All 3 lights were on but the ACD was eliminated and I never had t case issues after that. This was after Island mitsu in lindenhurst NY didn't bleed my t case correctly and blew the pump