AYC Flashing

merlin

Leaving Skid Marks
Location
Sydney, Australia
First Name
David
Drive
Evolution IX
I have decided to seriously investigate the possability of flashing the Evo6 AYC.
It is likley Mitu have used the same controller box in the VR4/Legnums as well.

I think I can borrow a E6 unit from Chris MEEK to start work on, but I would like to hear from you guys what the Mitsu part numbers you have for these to see if they are the same.
Does anyone have a donor unit they are willing to contribute?
And a pdf or jpg of the relevant pages from the factory field service manual would help.

Is there some interest in this? Some serious motivation is always useful.

Dave
 
i am so keen for this.

dave, pm me if you want a ayc ecu


macca, im sure dave will explain this better, but he changes the lock up/torque percentages of the diff,

so instead of 3bars lighting up and sending 90% torque to one wheel, and 10% to another; when flashed the max it will go to is 50/50, making it act more like a 2way LSD and more predictable.

dave has a fancy graph he might throw up
 
The stock system isn't capable of doing 90/10 anyway.

The only figures I've ever seen are approx 6% per bar, ie 44/56, 38/62, 32/68 for normal AYC. S-AYC does approx 50% extra, potentially as much as double normal AYC, so you could see 38/62, 26/74, 14/86 (if 12% each bar but I think this is unlikely) or if it is 50% better, 9% per bar, which is 41/59, 32/68, 23/77.
 
unclepaulies description is more or less what the aim of the project is, getting the diff to behave more like a clutch-pac diff but with programable control.

bradcs description of the available percentages may just be the bit of data I will need to decode the maps, many thanks.
This description sounds like it is a 2D table, rather than a 3D map. Hopefully we will find out.

Question: Does S-AYC drive worse on the track or better than AYC?
 
If you want a part number, my spare one has written on it in this arrangment:

MR368566
X4T71471
8605 T4

I assume the MR368566 is the part number. Thats for a pre-facelift if it makes any difference.
 
Dave, from what people have said from their experiences.. S-AYC does make you go around a corner faster and sharper..
 
Doesn't Josh have an S-AYC diff ?

I believe he does, plus I think at least 1 other person on here has one too?

The MEEK boys don't like them. They advise going LSD -> AYC -> S-AYC. Chris says there's too many parts in a SAYC to go wrong..
Be nice to have different AYC maps & switch between them! Kind of like a MOTEC controller lol..
 
The SAYC does move more power about when the car needs it, so yes the car feels better with SAYC as it is easier to keep neutral in more driving conditions.
 
Ive given christian a mild demo of SAYC when it was still fresh in my car. I just got all my diff mounts replaced (Finally, after nearly a year) and gave it a bit of a bootfull around a corner to remind myself why i got the SAYC. Its great, though i wouldnt be able to compare as i dont remember what regular AYC was like?
 
That's sweet sweet news to my ears Dave (as I read this aloud). Hopefully the AYC ecu is reflashable across all models, otherwise there will be a mad grab for FL ayc ecu's just like the 7202 chip sets!
 
How are the handeling setups different between an LSD and AYC?

More or less oversteer/understeer? Better grip/less slip?
 
How are the handeling setups different between an LSD and AYC?

More or less oversteer/understeer? Better grip/less slip?

An LSD makes it handle more like a RWD. Come in too hot and it'll understeer, you will get power on oversteer etc, far more predictable (The car does what you expect, ie more neutral)

Dave, will this setup make the diff more prone to breaking? I'm just thinking of the pressure placed on an LSD and how this may affect the diff centre in an AYC diff?
 
But ultimately lowers your cornering speed in a steady state corner where a VR-4 will naturally want to understeer.
 
I thought the AYC ecu was a separate unit to the engine ECU, just like the AT ECU; or for example the active centre diff ecu in an evo 8/9.
 
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