This is what it does :

 

Folks, we have been through this so much times before, its all wonderful technology, but the benefit is not worth the purchase/service expen$e and headache!!

 

Thumbs Up Jemm. U rock! You just keep churning out more interesting info about our cars. Iam guilty of the "I just want to drive it as fast as it can. I dont know how exactly it works but It sure as hell works!"

 

Jemm correct me if iam wrong, but doesnt setting the ACD to gravel or snow effectively bring power distribution more to a FWD bias? thus understeering characteristics? Isnt tarmac mode mean power distribution is something like 70% rear and 30% front? on throttle? though this is actively adjusted by the ACD ECU depending on traction?

 

nice info jemm, can someone effectively explain the viscious system?

 

Jemm amazing information. This is an incredible help.

 

Unlike a viscous coupled center differential, the ACD is mechanically geared to a 50:50 torque spilt. This is only seen when the diff is in 100% lock mode (typically in straight line driving on tarmac). What changes is the opening/slippage between the clutch plates in the diff itself, varing from a fully open diff (no power to rear wheels) to fully locked.

In Tarmac mode ... which has the highest locking force and least slip of the three, the diff opens up (i.e. slips) instantly on turning the wheel allowing for increased steering response.

In Gravel mode (recommended for wet tarmac) ... which has a lower ultimate locking force value, the diff takes 2-3 secs to unlock. Thus sending more power to the 4 wheels on gravel, but still enabling good steering feedback.

In Snow mode ... the locking force is lowest and takes around 5 secs to release.

Get this : the system behaves differently on different surfaces. CCC magazine once said it was as if the electronics know that you are trying to trick it! For example, putting it into Gravel on Dry Tarmac causes the center diff to remain locked for longer and thus sending more power to the REAR wheels... thus causing the oversteer. On wet pavement, putting the car into Gravel mode (as is recommended) quiets the car down and glues it to the road!

The coolest thing about ACD, is that it unlocks the center diff immediately on application of the handbrake, just like a WRC diff.... no need to dip the clutch for handbrake turns!

 

Thanks Jemm for the info! Hmmm... no wonder my friend said the same thing ("switch to Gravel, get ready to oversteer"). I gotta try it on the track one of these days...

One of the most common misconceptions of ACD is the "power distribution". Throughout all the ACD modes, torque split is always 50:50. Good thing you brought it up.

 

Btw to any cost issues jemm; when you buy a performance vehicle you should also have performance pockets if you catch me drift.

 

For those hell bent on doing this conversion .... your best bet is to contact one of the japanese auction sites e.g:

http://www.providecars.com/shuppin/s...carname=Lancer

http://www.gcar.co.jp/parts/index.htm

http://www.idirect.co.jp/

and have them source a wrecked Evo 7 or 8 chassis. These go for cheap. I have no idea how you would get that into the states... maybe they can give you info on a shop in Japan that will take out the parts and ship those alone....

Only you will know if having active diffs is worth all that time and money..

I don't think it is.. but that is my opinion.

 

I was the one that posted about RMR's car. When I enquired about the ACD, I was told they had an ACD and a spare Evo VII dash and ACD control unit (no AYC). The conversion can be done, but it would cost a pretty penny. And before you ask, it is from a Euro VII, so it is LHD. You can always call them and ask about it.

To me, I would rather wait until Cusco comes out with some diffs for our cars. 1-way front, stock center, 2-way rear...

 

i couldn't agree more with Chris. for a better example why, just take a look at most of the EVOs that race in Japan and you will see that most of them dump the ACD and AYC for the cusco setup

 

Cusco diffs are the best - too bad there are no USDM Evo diffs yet... There are 29 different ones for the Evo VII alone.

 

Your probably right that most Evos in Japan that race are RS versions w/o the AYC and ACD. But have u seen the best motoring review of the evo 8 versus the evo 7? They had a full race advan evo 7 RS against the Puma evo 8 GSR with ayc and acd. The puma evo had much less horsepower than the Advan car. But in the end, the Puma started like 1 min later and thoroughly trounced the advan car in a race around the track. The advan driver also tested out the Puma car and at the end and they all surmised that the Super AYC made a huge difference in handling. The advan race driver even said he is going to put AYC on his car.

Good or bad, i guess at the end of the day, it all boils down to your driving style and opinion. Or more like whose opinion you agree most with.

 

Thanks for that translation. I have watched that video (downloaded) and always wondered what was going on

AYC/SAYC rocks at the track!
ACD rocks on the gravel stages man!

We just had one of our many island-wide rallies this weekend... the Evo 8 RS (preped in Japan by Plaza Motorsports) won.. This is the second rally car in Jamaica (group N spec) with ACD diffs... and the drivers have given it :


http://www.wheelsjamaica.com/wheels_...;threadid=9090