Ralliart Active Center Differential Controller
 

It's been a while since I posted on the forums, but I've got something good to share to make my absence worthwhile. ;) I tested a Ralliart ACD controller in my Evo IX RS over the weekend, and I thought you all might be interested in seeing what I found out:

http://evolvedperformance.com/?p=52

Overall I am really happy with the Ralliart part, and would recommend it to anyone who tracks their Evo.

Let me know if you have any questions and I'll do my best to answer.

I think this is probably what you meant to post: http://evolvedperformance.com/

I'm very curious about this as it's the one bit of the drivetrain I've yet to address on my car that I'd still like to tackle in the near future. I see you did some testing in the various modes, but I'm a bit confused. I was under the impression that when you bought a ralliart diff controller, you specified if you wanted a tarmac controller or a gravel controller...and that the settings were just more or less aggressive.

I had held off on buying one of these controllers as my goal was to have an aggressive tarmac map and two different gravel maps, so as I headed up the hill, I could swap back & forth. These requirements had me thinking a programmable setup is the only option, but now you've got me wondering. The ralliart controller is signifigantly cheaper than the programmable ones.

Dave

Please post link of where to purchase? I assume Works does not stock it? How does price compare to the $$$ Motec unit?

Also, I've heard word of a Cyber Evo version of the ACD controller, with mapping tested and tuned by the Cyber Evo crew. Anyone have info on this?

http://www.evasivemotorsports.com/me...code=cyber_ecu

EVasive Motorsports sells the Cyber Evo ACD Controller

http://www.rallispec.com/raparts_retail.pdf

Go to the "Gearbox" heading on page 2.

About the Evasive link, it looks like a loosely translated product description, and I can't make much sense of it:

Circuit mode: Adjustable for track conditions.
Sport mode: By installing a high grip radial tire, it optimizes street driving.
Lane mode: Adjust to wet road conditions.

Is it supposed to say it has one dry tarmac map for race rubber, one for lower grip street tires, and one for wet conditions? :confused:

Dave

Theres two different ACD Controller one is meant for mostly street use with
occasional track time

and

the other is meant for track only?

Thats how I interpreted it

I'd agree that one is marketed as a street upgrade and the other is a track upgrade but they're leaving out a ton of details about what's being changed IMO. i.e. they talk about how these were optimized thru tracking thier time attack cars...but their time attack cars are lightyears ahead of what most people are running here, so will the lack of aero enhancments, widebody cars with huge rubber make these diff setting less than optimal for the 'weekend warrior' trackday enthusiast? Do these units up the clamping pressure? Also, how might these compare to the ralliart tarmac ones available?

Hopefully someone might be able to chime in with more info. :)

Dave

I don't think these parts are the same one as I am running.

According to ACP (who is the only one I have spoken to on this, so I'm trusting his inout), there are two ACD controllers with selectable modes. One is for high performance use in a street car, the other is for racing applications (K1 and K2).

The modes on the K2 are still selectable, and the switch between tarmac and gravel on the K2 controller that I ran doesn't feel all that different from the switch between tarmac and gravel on the stock controller. What I mean by that is that when in gravel mode in both controllers, you can feel the diff react similarly when left-foot braking mid-corner, and you can feel the pump acting more slowly relative to tarmac. That says to me that what ACP shared is probably true -- that these still really are tarmac, gravel, and snow modes, but just with more aggressive maps designed for racing applications.

ACP did mention that there are controllers then designed specifically for tarmac and gravel, which are yet again more aggressive, but then require you to switch out the ECUs between surface types. I'll dig in a little more and ask him if he knows anything else about these options.

I did consider the Motec or Pectel units, especially being that WORKS has one that i could have borrowed. That said, you have to start with the stock maps (which, BTW, in tarmac mode will only do a 35% lock-up in the center diff at all times -- explains why the stock maps suck) and then fine tune it yourself from there. As I can't replicate the road conditions at Targa, I'm very wary of doing my own map tuning during a couple of test days, only to end up with a mode that really only works well on very smooth surface closed course tracks. Add to that fact that the Motec and pectel units are 4X as expensive as the Ralliart controller ($500 vs. $2000), and for me it was a no-brainer.

If I were building an open class rally car, or if I were building a dedicated road racer or time attack car, I'd go programmable and spend the extra time and money to tune it precisely. For my purposes, I'm really happy with the Ralliart unit.

This is a Garage HRS part -- probably a custom flash on a stock unit. You are basically just updating 3D maps on this like you do with an ECU, so i can't imagine that this would be all that difficult for a real tuner.

With that, I have to wonder what the Garage HRS maps look like. Anyone speak Japanese that can call them up?

I read your entire article, and it sounds like you have a very similar driving style as to me in my IX with the very same gripes on it's understeer. Are these things hard to get your hands on? Works just HAPPENED to have one laying around, where would I find one?

Great info Peter, thanks for the post. Any way you can grab the part# off the unit you have? Looking at the Ralliart sheet I am trying to ID which one you have.

Thanks!
Rob now with an IX SE.

Talk with Robert/RobiSpec. I believe he may have experience with the CyberEvo/HRS unit. . .

double post FTL!

Try calling WORKS and see if they can get it for you. If not, they can recommend somewhere else to look.

The part number on the controller is RA580728K2, and can be seen here: http://flickr.com/photos/peter_g/256...n/photostream/