You guys know that 4.062 "final drive" number is not the rear diff ratio right?


AYC is the rear diff on the GSR/MR

ACD is the front, in the transfer case. ACD and AYC share a seperate control unit (DCU) then the engine (ECU)

 

Well, I suppose the final drive is the important part of this correct? I'm not super great with my terminology so you'll have to pardon me, but the final drive should be how many turns it takes to the rear diff input shaft to make the rear wheels make a revolution or something like that. So if the front and rear are different, then either the front or rear set of wheels will turn faster and cause your drivetrain to lock up. (or you'll always be doing burnouts ) How is that different from the diff ratio? Also, I knew AYC was rear diff only on the 1-9, but I wasn't sure about the X. I'd rather know about what I'm talking about before I say anything haha. Thanks though.

 

Personnally, no... I just assumed that the person who brought up this info knew what he was talking about. I know my Firebird has a 3.23 and I want a 3.73.


I thought both the front and the rear shaft had a AYC. Just a question like that, do you think the AYC from the EVO would be a direct fit to replace the rear-diff of the ralliart? The logic to control a AYC should not be too complicated to reproduce using an external microcontroller with a CAN Bus and an ADC...

 

AYC is *only* on the Evo 10 GSR and MR in the USA.

No Evo's in the USA had AYC before this.

AYC is only on the rear, it is a totally different rear diff unit then the non AYC rear diff. AYC torque vectors between left / right rear wheels.

ACD is the center diff and located in the transfer case. This is on USA models, 2005 Evo 8 to 2006 Evo 9. 2008-2011 Evo 10's and 2009-2011 Lancer RA's.

Both AYC and ACD are hydraulic clutch pack type units. Controlled by the ACD/AYC ECU (seperate then the Engine ECU) and actuated by the hydraulic system.

 

I understand this, I'm not just talking about US models. I have a JDM Evo 4 rear end with all the AYC bits for sale because I don't want to mess with all the wiring. AYC isn't just the AYC ECU and the diff, it has many sensors all over the vehicle that I don't want to mess with tracking down, purchasing, importing, and if everything goes well with that then wiring all that crap in when I can just use an 8 diff in it's place. I imagine that anyone who would want to convert their Lancer to AWD or their RA to the X transmission wouldn't want to mess with finding all those parts and wiring it in either. I know what I'm talking about as far as the parts and systems go. If I didn't, I wouldn't have started this thread in the first place. You didn't answer my question by the way what's the difference between the final drive and diff ratio? I believe they're the same thing. At the very least, I didn't realize that the RA had the ACD, so that's good info for me as well.

 

No details about what all those sensors are? Are you sure they are not related to traction control rather than AYC?

I mean, a basic implementation of a AYC would just take into account steering position... A slightly more advanced should take into account the rotating speed of each of the 2 wheels to get some feedback and actively adjust clutch pressure...

 

It uses alot of different types of sensors. ABS sensors (which you already have), and some special sensors that can detect when you car isn't moving in the direction that the wheels are pointing. (drift) AYC is much more advanced than just adjusting the car using steering wheel position, though that is part of it. (2 sensors in the steering wheel on the Evo 4 I believe) I have the complete Evo 4 AYC wiring diagram somewhere, but I'd have to look for it. AYC has gotten even more complex since then though with the development of the S-AYC system.

 

Listen, I'm not challenging anybody here. I'm relaying information.

Final Drive Ratio:

ACD and AYC use input from sensors located in various places. Example being brake sensors, wheel speed sensors, G-sensors, Steering wheel sensor, etc etc.

If the car has ACD then it already has these sensors.

 

You're alright. I just don't like my knowledge of Mitsu's AWD systems being doubted as I've put alot of research into it. I realized you meant no offense, I was just stating that I know what I'm talking about when it comes to the subject (for the most part ) and if not, then I won't say something without researching it first. Still though, I don't see how the final drive and diff ratio are different, I think it's just different ways of saying the same thing. Interesting about already having the sensors as well. Are all of the needed AYC sensors there then or do we know for sure?