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ECU control of ATTESA

Gav
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Gav Mentor

Gav

Posted
Posted

I'm interested to talk with anyone who has successfully controlled the ATTESSA system with their ECU.

We are actually using a Motec 185 dash to control the system as we have already assigned the PID function from the M800 to boost control.  The intent is to control transfer case line pressure via PWM output from the dash.  This will set the amount of torque sent to the front wheels.

We have the following obvious parameters available on CAN bus available to set up the control logic:

 

* individual wheel speeds

* ground speed

* G force (longitudinal and latitudinal)

* torque request and TPS (using drive by wire)

* transfer case pressure

* front and rear brake line pressures

 

I'm envisaging we will use a 3D calibration table to set the required transfer case line pressure.  This will be similar to a boost table or perhaps a traction control table.  I know the Full Race controller only uses G force and TPS as inputs, but I'm thinking rear wheel slip would be a useful input as well as front brake line pressure.

Initially to get us going we could connect the Full Race controller and log parameters, but if someone has done this previously (and is willing to share), that will save us a lot of time end effort.

 

Cheers

Gav

 

 

 

 

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Duncan Grand Master

Duncan

Posted
Posted

I've never replaced the stock computer because I've found it fine with a piggyback controller modifying the lateral G sensor.  While I can't confirm the list you had above for fullrace, the standard one uses all those inputs + the 4 ABS/wheel speed sensors.

Generally the standard system gives more 4wd with throttle, much more with rear wheel spin. The main input seems to be the Long g sensor (more acceleration = more FWD, braking = less) modified by the Lat G sensor (less FWD with more cornering with the intention that it remains "balanced" like a rwd car in corners.  The standard system is a little slow (which the motec would fix) and too conservative with 4wd in corners (which we fixed with the piggyback). BTW the group A cars did not use the standard computer but I don't know what the actual technology was....it had multiple maps controlled by switches

It will be interesting to see what you think is effective in your mapping vs what Nissan did.

  • Like 1
Duncan Grand Master

Duncan

Posted
Posted

Oh its also a long shot, but I an ex-nissan engineer in contact also remapped an attessa ECU for us once (although that car is no more). It is likely there is a difference in the maps in standard vs N1 computers in R32s.  Again, I don't have exact details of what was changed

dr phil Collaborator

dr phil

Posted
Posted

Semi-related - i have an R34 GT FOUR, with a RB25DET conversion. I'm keen to understand if there is a difference in ATTESA maps between GTR and GT4 (I expect yes, given the difference in diff, suspension, wheels etc).
Where I am up to is trying to connect to the ATTESA ecu via consult. I have written some code to connect to the engine ecu successfully, still working on talking to ATTESA. With the engine ecu you can read the maps out via consult - hopefully this is possible with ATTESA also. Can at least monitor running values, according to the service manual, includes all the sensor values and the ETS solenoid current.

  • 4 weeks later...
alexj Contributor

alexj

Posted
Posted

If it helps I've been logging the transfer case solenoid pressure for a few track outings now so I have some data and will be collecting more.

I use the stock attesa ecu and Skylab Fusion to modify the lat and long G sensor output. 

The factory map/algorythm is fairly complex and I think tricky to reverse engineer from the inputs and outputs of the stock ecu. 

I have a m4 abs system and a full race ets pro going on at some point.

I've put a couple of simple videos on my youtube channel.

 

  • Like 2
  • 5 months later...

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