ACD and AYC

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Mark_r33
Posts: 26
Joined: Sat Jan 18, 2014 7:14 pm

ACD and AYC

Post by Mark_r33 »

Hello chaps,

Have you guys played about with controlling the ACD and AYC on the Evo's 7-9 directly with your ecu yet?

Any thoughts on possible strategies etc?

I've got idea's of retrofitting the drivetrain elsewhere, and wondered if the chassis controllers needed to be used from the Evo, or if there were some possible control means via the Syvecs?

Bit of a thinking out loud thread this one, so please do throw out even your craziest of ideas for consideration!

I'm mainly after the centre diff control, as I would happily use mechanical LSD's front and rear. I'm feeling the Kaaz 35/65 split centre diff along with some locking up control I think.

Also, how good is the 4wd traction control that is based on the road speed radar at this moment in time? I doubt traction would be much of an issue in this build, but do love a bit of tech being applied to old school motors!

Links to things to read are as appreciated as direct input.

Thanks for any help - Mark
pavlo
Zen Performance
Posts: 407
Joined: Mon Aug 04, 2008 10:18 am

Re: ACD and AYC

Post by pavlo »

Done it on an R32 skyline for the centre diff control.

Pump motor controlled by a pressure switch (oem switch) to maintain system pressure.
Valve controlled using centre diff strategy using +12v, spare fuel injector output, Schoktty diode across the output, PWMed at 300hz like a mivec valve.

Good to add a brake pressure sensor so you can override on hard braking, although a brake pressure sensor is a good addition for datalogging on track anyway.
Mark_r33
Posts: 26
Joined: Sat Jan 18, 2014 7:14 pm

Re: ACD and AYC

Post by Mark_r33 »

Teaches me to look properly first, and I should have known that you guys would already have it figured!

I like that it is throttle and speed dependent, ever any need for lateral G or steering angle manipulation?

What about controlling the rear diff on an Evo, then? I'd probably just use a mechanical diff, but they are a rarer casing than the AYC ones, seemingly. If AYC could be nicely controlled then I'd definitely think about using it.
pavlo
Zen Performance
Posts: 407
Joined: Mon Aug 04, 2008 10:18 am

Re: ACD and AYC

Post by pavlo »

Lateral G input would be nice, an "open loop" system needs more tuning, although on the gtr it behaves quite well. The latest S8 firmware allows slip control via the traction control torque strategy, it's possible to stage the operation combined with TC torque reduction via fuel cut and ignition retard.

As for AYC control, that is much more complex I think, it's a two channel system for a start (there are two valves at least) and I think you need yaw input as a minimum. I think overall you would be better with a good LSD, although the R33 GTR vspec has an active rear diff with single channel control of preload, much like the centre diff. That is something worth looking at but you need two diff strategys available and there is only one. A dedicated controller may be more suitable if you wanted to do both.
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