Originally Posted by kyoo

:::::::READ CAREFULLY:::::::


Now that there's been decent exposure about the benefits of modifying the rear differential (especially considering its not assembled properly from the factory), I'd like to turn some attention BACK to ACD Tuning - I'd like to reiterate a few points -

FIRST, Review this thread: https://www.evolutionm.net/forums/ev...everybody.html - ESPECIALLY the section C. How the ACD works


Motivation:

- Owners with evos overseas that come WITH AYC choose to disable the function in favor of a competent mechanical set up - think TRE or Cusco

- This is particularly helpful for USDM evos, that came with neither.

- In terms of our European and JDM counterparts, the main focus is not AYC, but ACD TUNING

- Tuning the ACD will actually complement the function of a competent mechanical rear differential, less and more lock up can dramatically improve both turn in and corner exit.

- I'm sure many people will doubt the benefit of this kind of mod, as they did with the rear differential mod in the beginning - however, if you consider how the factory would tune the ACD (for safety) and considering the dynamics of an AWD car, it should be pretty clear that there can be a lot of benefit from getting the ACD tuned.

- Some people, especially those with rear differentials, will wonder - do I need more? Won't I oversteer too much? The answer is no. If you think about it, that is dependent on setup. This will allow the car to exit out of corners faster, period.

- New options on the market allow for quick and easy turnaround time, and makes the ACD reflash a very simple modification.

- You can bet no serious time attack evo is running without the ACD modded. While most race teams went with the very expensive MoTeC or another equivalent custom map tuning system, there are now much more cost effective and efficient methods for anyone with an ACD to get it tuned.

- This may slip through as a "costless" mod in terms of points in certain motorsports classifications, if not many, as it is such a niche modification


With all that said, here are the options that I've been compiling for ACD tuning - it's come a long way since when I first made this post, and there are now even custom maps available for your particular driving.


ACD Tuning Options:

English Racing

Most recent shop to offer ACD tuning services. Things have 'evolved' quite a bit for the ACD scene in the recent years, and it seems the USA is just now catching up the realization that much of the handling magic in evos comes from ACD tuning, something they have been doing over seas for years upon years. Great to see a reputable shop like English Racing offer this service. More info here: https://www.evolutionm.net/forums/ve...cd-tuning.html


TSComptuned

TSComptuned is the most recent addition to the ACD tuning world. Please message him for more details.


Gruppe-S

This is the option that opened my eyes to ACD Reflash found here: https://www.evolutionm.net/forums/ev...available.html. Turn around time is quick and the difference is real. I at least suggest anyone who has seen it to give it a try. There was a thread about it, but it got thrown into service reviews, and ultimately not a large population of different people viewed it. Beyond this, at least for USDM evos, the options get a little less reasonable except for the more hardcore.


Ralliart

Next, there's the Ralliart ACD controller found here http://www.rhdjapan.com/ralliart-act...ion-viii-54389 . It is confirmed to work with the USDM cars, as discussed here https://www.evolutionm.net/forums/mo...ontroller.html and here https://www.evolutionm.net/forums/dr...t-acd-ecu.html . Unless you're doing rally, the second thread suggests that the Asphalt version, RMR-0728A, is the way to go for street driven USDM cars. Ralliart has had years more experience than anyone in the US when it comes to ACDs, so I think this is a great option for CT9A cars. This mod also disables AYC, had we had it anyway.


Motec

Finally, there is the MoTeC unit sold here http://www.worksevo.com/store/produc...roducts_id=664 . This is the priciest option by far, and while it offers many maps to choose from on the fly, this is most likely overkill for people who want something more like "high-speed map," "low-speed map" to set it and forget it. However, for the most hardcore and pro/semi-pro racers, this is probably the preferable option. It allows you to customize the maps how you'd like according to your personal driving, and it requires a lot of hours behind the wheel on the track to do so. It was pointed out later in the thread that the ability to have many different custom maps that you can switch between all on the fly can be a huge benefit in terms of rally driving, where you have a large variation in the types of surfaces you can come across, all within the same race.

Kaps

http://eng.kaps-transmissions.com/ne...ancer-934.html - seems to be rally oriented, plus a nice little video. However I'd like to iterate here that ACD tuning is not just beneficial for rally driving, as some may think. Please check out the video



Concluding:

There have been a lot of reviews generated already and it really makes a difference in how the Evo handles. I would say that between the rear diff and flash the ACD, it would be preferable to do the rear differential first, despite the simplicity of doing the ACD. This is because the rear diff is very gimped from the factory.

There's a question of either/or here - people asking "should I do the the ACD flash OR the Rear Diff?" and "I don't want TOO much oversteer" - both of these mods will compliment each other. The ACD reflash allows the center diff to lockup more efficiently, and the rear diff will manage that power better. Other handling characteristics of your car are related to setup. You can regard that both these mods will allow more power to get to the more efficient wheel. These differentials working together will allow the evo to rocket out of corners the way it was designed to.


Anyone with any of these systems please write a review here!