One thing you guys should know about the ACD is that it has trouble coping with above stock boost levels vecause the pumps cannot run enough pressure to get them to react quickly enough, On our open class rally cars we replace the standard pump with one of two units, one sits in front of the co-driver the other is modified to fit in the standard location but it makes a huge difference especially if you run an active diff controller which allows you to customize the lock up characteristics of the differential. We run these on all of our rally cars as well as the subarus it changes the driving completely. Hope this helps you folks out.

 

On the US cars the pump is not in what is considered the standard location on the JDM cars. That spot is used for evaporitive emissions control equipment on the US cars and our ACD system components are mounted in the front drivers side (left hand drive car) corner of the engine bay.

Do you have the part numbers for the "normal" JDM pump and the upgraded one?

Thanks,

Keith

 

I can get them the upgraded pump is one that we purchase from Europe. There are three ways to do it, you can modify the existing stock pump, you can use a upgraded pump in the stock housing (this is not optimal because you will decrease the case life since it will have more internal pressure), or you can run one in the pasenger seat area which is the best but loud option. I can check on it and let you know when I get the part numbers for the JDM pump.

 

i had wondered if the pump would be a weak point in the system. upgraded pump would probably be the best idea. i dont know if putting a pump in the passener seat area is a great idea, although i could be wrong. introducing fluid into the cabin of the car, especially hyraulic fluid would make me leary. God forbid that pump or a line spring a leak there would be fluid everywhere, and when hydraulic fluid leaks its not pretty, ive seen what it does when greens mowers at golf courses do to entire greens when they leak. just a thought i had

 

THe problem is to cope with the increased power you need to run higher pressures to get the diff to react quickly enough or else the car becomes a bit difficult to drive. This is one place that the STi diff is better since it is electro manetic it uses resistor variance and current to change lock up.

 

Here is some info on using the Ralliart controller on the US Evo:
http://www.lancerregister.com/showth...threadid=65880 also FWIW there is a thread on this subject on this forum titled: Ralliart K1 ACD ECU

 

The K1 acd is effectivethough the Gems and Motec ones are better overall.

 

Bringing this one up from the dead, searched for a while and could not find a direct answer.

Its been 10 years since we have had ACD systems here in the US. Can anyone chime in on a torque level where the oem ACD clutch packs start to fail?

 

clutch packs rarely fail. Thing is.. the clutch pack doesnt transmit torque all the time, it just locks the front and rear axle togeather and the diff in the gearbox splits torque 50/50, so the clutch pack itself is not is not under so much stress... If anything the first thing you will break is the transfer gear itself and the diff output shaft (the large splined hollow shaft).... The splined output shaft being the weakest part... so I would say the ACD clutch pack is the least of your worries.