okay, i freely admit that i may be an idiot, but after searching for several hours i cannot find the answer to my question (with the exception of one post by jeff jeske)...

for you track drivers/autocrossers who have driven 03-04 evos with retrofitted front lsd, do you notice a definite benefit of acd-equipped cars versus the viscous center diff of the 03-04? essentially, is the acd better than the non-acd on the track all else being equal? this is assuming that all cars are equipped with front lsd.

thanks.

 

Good catch on the lsd front. I think that may have made for a bigger change on the 05 and 06 than the active center.

 

I don't. I prefer my '04 RS which has the viscous coupling unit. Another thing to consider is weight. My car weighed 3076 lbs with the OEM battery,OEM seats, full interior, an added radio, 19 lb wheels, a full tank, and a heavier than stock exhaust.

d

 

I prefer my non-ACD 04 RS as well.

 

I'm still not a fan of the ACD. It feels intrusive to me.

I like to think that Mitsu released ACD to make the EVO faster but I'm not sure if that holds true for track ****** that prefer a loose car or not.

The fact that they went as far as to add three pavement choices has me wondering if it was intended for the average driver.

The ACD is heavier. A bigger PITA to perform clutch jobs on. Expensive to repair. And as far as I can tell no stronger than the 03-04 LSD xfer cases.

All I know is I'm stuck with it.

 

ACD was originally developed to complement the AYC system. with the ACD only i believe its more of a toy/gadget. front lsd and rear lsd is nuff.

 

I agree with that.... its just odd that Mistu released it in the US without AYC. Expensive decision for a gadget.

 

I have run with and without the ACD working (3 lights of doom). If you taped up the display I wouldnt be able to tell you which was a working run and non-working run. But from what I know if it - the ACD goes open under braking and steering inputs and locks when the car is under accel and in a straight line (or braking in a straight line). So going into a turn or accel out it would be mostly open. And for winter stuff - I just leave it in Tarmac...get around fine.

The front diff would be a bigger difference.

 

For those who prefer the feel of the 03-04, have you ever messed with controllers for the ACD.

I'd agree that ACD was implemented to make the car faster (probably for the average driver), but I think like everything else on the car, there's room for improvement.

For those that drive on the dirt, active diff equiped cars are faster than those with mechanical diffs. Just look at WRC cars...

Dave

 

In wet it makes a lot of difference.

 

I've autocrossed both '05 and '06 US evos and and have tried the three factory settings. I've never tried the aftermarket ACD controllers, but they seem to be pretty rare.

Just to be clear, I _do_ think the front limited slip is an improvement, but don't care for the ACD. What do I know though? If you are into autocross, look at the results from SCCA nationals. The fastest Evos (Daddio, Berry, showcase) were all ACD cars. If you are going to do anything with this information other than just pass the time, they are the ones you should listen to.

I think it is unfair to compare the drivetrain of a production sedan to that of a $500k+ race car. The requirements are completely different as are the results.

d

 

Fair enough on the WRC cars, my point there was WRC is making everyone go back to non-active diffs for the front & rears (IIRC), and letting them keep the active centers. If there was no speed difference between the active and passive diffs, there'd be no reason for the change. If you don't like the WRC example, look at the US spec rally cars. Other than some safety gear and good suspension, the cars that are winning there are using GEMS & MOTEC ACD controllers (though they're driving subarus).

My real point is this, if you can properly optimize the settings for dirt and see big gains, I'm sure the same is possible for pavement. It seems like people here don't like the feel of the stock settings (who here likes anything stock) and haven't bothered to try modifying it to suit their tastes yet.

Dave

 

Here's an interesting article about diffs written by Andrew Comrie-Picard (ACP) who drives the SlowBoy Evo IX:

http://www.oldrallysport.on.ca/articles/diffs.html

 

The '04 RS was the first U.S. Evo with the helical (not viscous) front diff.

 

I think he ment the center diff.

I had a spool center diff in my 98 GSX and that was horrible for handling especially slow turns. It would drag a wheel everywhere.