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Skyline Section Manager
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Discussion Starter #1
A while ago I fitted a pressure gauge to the R32 GTR ATTESA actuator cylinder on the rear of the transfer box. This was done as part of the Skylab Fusion development. If quickly became apparent what the ATTESA rapid start feature was all about and that hydraulic pressure and the torque split gauge didn't show the same thing.
I have mentioned before that between 0 and 20kph the ATTESA hydraulic pressure is proportional to TPS.
I have just fitted a gauge to a R33 GTR and video'd this feature.
It's also worth noting that the R32 has 0 psi line pressure at rest and the R33 GTR has 25 psi.


To do this test, i unplugged the TPS and plugged in a spare one so I could easily increase the TPS voltage without annoying the neighbors too much but revving the engine.
I started the engine, notice how the pressure drops from 85psi to 30 psi. The pressure rises when the engine is turned off. Perhaps to assist the handbrake?
I then turned the TPS to max and back to 0. The laptop shows the TPS voltage and the gauge shows the line pressure. All the time the torque split gauge showed nothing.
 

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That's wicked that is Andy!
:thumbsup:
Bob
 

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Well done Andy, does that mean the fittings are now available as I'd like to put a sensor in to send the pressure to the motec?
 

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Nice work Andy, I wonder if the torque split output only goes to the gauge once the ATTESSA ECU detects wheel speed?
 

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Skyline Section Manager
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Discussion Starter #5
Well done Andy, does that mean the fittings are now available as I'd like to put a sensor in to send the pressure to the motec?
They are all turned and heli coiled (12 off). I've not milled the hex on them or drilled/tapped the 1/8 npt holes yet.
I wanna run for a few days and check for leaks etc.
 

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Skyline Section Manager
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Discussion Starter #6
Nice work Andy, I wonder if the torque split output only goes to the gauge once the ATTESSA ECU detects wheel speed?
You are right, but I wonder why.
 

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Skyline Section Manager
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Discussion Starter #10
What's the voltage to the centre torque gauge again Andy? 0-5v?
.5-4.5v ideally. Gauge will run either PWM @ 5v or analogue 0-5v.

Basically, fit a .5-4.5v 0-300psi sensor in the adaptor, cut the wire on pin 50 of the ATTESA C/U. Wire the output of the sensor to the gauge and you will have a reading of sorts.
 

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Just out of curiosity, is the atessa driven by a pump or how does it make pressure exactly? An actuator in a cylinder or some such system?
 

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Skyline Section Manager
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Discussion Starter #13
It would appear that torque split is more than just a % of the pressure range for clamping pressure to the transfer box, is there some form of load cell in there?
There are no load cells, what do you mean?
 

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Ignore me that doesn't make sense, I was thinking the gauge reads torque which needs a load cell or torque arm rather than torque split which is just % of clamping pressure. Ignore me, I was having a moment :)
 

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Discussion Starter #15
Ignore me that doesn't make sense, I was thinking the gauge reads torque which needs a load cell or torque arm rather than torque split which is just % of clamping pressure. Ignore me, I was having a moment :)
The gauge reads in kg/f not %.
 

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Ignore me that doesn't make sense, I was thinking the gauge reads torque which needs a load cell or torque arm rather than torque split which is just % of clamping pressure. Ignore me, I was having a moment :)
But your an Evo man lol
 

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Discussion Starter #19
I am looking pressurising the system and putting a torque wrench on the front wheel output and seeing how accurate it is.
 

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Yeah that would be interesting, theoretically if you know the pressure and the area it is being applied to (transfer clutch area) then it could be calculated and compared.

I will be interested in seeing the results Andy.
 
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