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Discussion Starter · #1 ·
Since the torque meter is a "synthetic" signal from the ETS brain there's no way of really telling what it translates to in terms of the amount of pressure on the transfer case clutches.

So using R32Combat's excellent adapter I've rigged up an external pressure transducer on the hydraulic line to the transfer case.



And hooked that up to a Aubers multimeter gauge (can be configured to use sensors of various types: resistance, voltage, k-type thermocouple etc and can relay the value out to a logger). The one on the right is the hydraulic pressure peak value after a brisk country drive with my skylab fusion turned up to full. The camera doesn't pick up the LCD well but that says 6.12 bar. I guess on the stock gauge that would have been just under "10kgm". The gauge seems to sit a 1bar when you are just cruising (only tried this with the skylab on "full" though) and the pressure twitches around between 1 and 2 bar a fair amount without the factory gauge moving noticably.



Next step will be to actually log some of the data during some track action instead of just displaying it.

Unlike the other sub gauges for oil pressure and water temp which are resistance based (Wheatstone bridge), the front torque meter is a basically 0-5v voltmeter. Since I had the clocks out to change the faces and all the traces on the back of the clocks are nicely labelled I thought I'd have a play. Sure enough while the oil and water ones just have +12v, GND and signal (basically varying resistance to earth) the torque meter has +12v, GND and a +v and -v

So I powered up the clocks with a regulated 12v supply set to a low current so I couldn't do any damage and powered the torque meter with a separate 0-5v supply. Here's what a sweep 0-5v looks like.


Anyway fairly nerdy stuff but maybe someone will find it interesting....
 

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Good work Alex. I hope it all goes well.:bowdown1:
 

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Good nerdy thread .:thumbsup:

Did you repeat on the oil press gauge too ?
 

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Discussion Starter · #6 ·
Yeah I tested the engine oil pressure and water temp gauges. Both are fairly heavily damped so a given resistance in the sensor will show as anywhere in a range on the gauge, mostly depending on whether the needle is on the way up or down, and there is a fair delay before the needle responds to a change. The water temp is especially inaccurate, it is almost designed as an idiot light; there is about 45deg central sweep which is "normal", above that or below it the needle quickly pegs in either direction.
 

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Discussion Starter · #9 ·
Looks good, would be interesting to measure that pressure and also voltage to the original gauge and plot them over each other, or is that what you were doing?
Yeah that's the idea... when I pull my finger out, I'll pull both signals into my data logger. Although the initial test was to confirm the gauge is not telling the whole story and that's been done.

Hi Alex, any idea whether the pressure sensor for the Defi ZD Advance can fit the adapter?

Seems the picture didn't come out well, the pitch at the screw part of the sensor is 1/8PT and the length is 10mm
View attachment 90978

Thanks
I think that will be 1/8BSPT which is handy for fitting to the stock oil pressure sensor location because that the correct thread. 1/8BSPT is not popular in the UK or US though and most aftermarket pressure transducers will be 1/8NPT. Andy tapped my adapter to 1/8NPT for me, I have 1/8NPT tap but hand tapping taper threads isn't much fun so it was much easier for him to do it for me.

You also need a higher pressure sensor like this one :18 Bar (260 PSI) fuel/oil pressure sender, 1/8 NPT. [AUBER-P218] - $67.00 : auberins.com, Temperature control solutions for home and industry because the ATTESA runs much higher pressure than the engine oil.
 

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I love this!!!
:)
bob
 

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Hooked up a oil pressure sensor to my Defi Advance ZD and did a short trial...

How do i post the video?? Can't seem to be able to do it...

Sent from my SM-N910G using Tapatalk
 

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Discussion Starter · #16 ·
Nice work

It looks like your attesa system normally sits at about 1.5bar, mine tends to sit around 1bar.

I've totally got to pull my finger out and connect this up to my logger!
I pulled my finger out at last, i now have the correct pressure transducer (18bar) fitted, the 1-5v output from the gauge plumbed into one of the analog inputs on the link ecu. The plan then is to output that data on the can bus transmitting to my diy can bus multigauge and also to my data logger. i have moved all the other sensor inputs to the data logger onto can bus so everything can be shared with logger/ecu/gauges.

there is a small hitch, the link isn't letting me setup custom can bus streams at the moment so i am stuck with pre defined ones, none of which include the extra input which is understandable. i've put in a support email to link so we should have that sorted fairly soon, hopefully in time for Silverstone at the weekend.
 

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Discussion Starter · #17 · (Edited)
Finally some logs of the ATTESA transfer case pressure. In the dry at Silverstone with pretty decent grip levels. Skylab controller in the "neutral" position so having no effect.

This is as it was logged in the Link G4+, I didn't get time to upgrade the firmware to retransmit the data to the video logger so I had to cross reference the data to understand where the centre diff is actuating.

The ATTESA log is the white one at the bottom, input is a simple voltage with no translation but the "background" level of 1.5v is equivalent to 14psi or atmospheric pressure basically. The big peaks of 3v are 260psi which would be fully locked 50/50 split assuming the transfer case clutches are capable of fully locking.

Throttle and Boost are shown to help understand what's going on, but I've annotated the main places the system engages (at least on my car): full throttle, full boost, fairly high speed in roughly a straight line.

There's no real oversteer in this lap or launch "traction control" situations so it doesn't demonstrate the behaviour in those conditions.



Track map for reference

 

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Good work Alex.
Can you confirm 260psi equates to 50kgf of the front torque split gauge?
 

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Discussion Starter · #19 ·
Good work Alex.
Can you confirm 260psi equates to 50kgf of the front torque split gauge?
That question remains as I've not setup logging for the standard gauge driven by the ets ecu.

I would guess in most cases ~260psi equals full scale on the standard gauge also, and that the gauge is pretty linear with the actual pressure. What will be interesting to see is if there are conditions in which the standard gauge deviates from the measured pressure.

I'll also look at the logs for wet vs dry road, and with various adjustment positions for the Skylab.

Plenty more to learn :) interesting to see the basic "magic GTR 4wd" as it functions on track though.
 
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