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[DEcosse]

however. tune ecu readings start at 0, when bike is not running, which means that the readings shown are 'gauge' readings i.e. not absolute.
when you idle the engine the needles float about 600hpa (should be -600hpa if we are on the gauge and not absolute scale), and as you rev it up they get closer to 0.

having that - in front of the numbers would correct the readings to actual throttle pressure readings (on the gauge scale tune ECU uses), but the readings would not be raw readings as raw readings would be on the absolute scale.
tune ecu must do some simple maths to change the reading from 400hpa (absolute pressure at idle) to display the 600hpa. but of course it should be -600hpa to be correct.

That is incorrect
The simple reason that it displays 'zero' is because the engine is not running - there is only one single sensor and the software times the display measurement in concert with the cylinder on the intake to direct that reading to the appropriate display 'gauge'; i.e these readings are not constant per cylinder, each 'gauge' is only being updated by the software to report as the timing of the crank dictates - engine not rotating, there is no update to the display for any of those cylinders.
The pressure readings ARE absolute.

 

[EasTexRIII]

I'm glad I'm too stupid to understand all of that

 

[R-III-R Turbo]

That is incorrect
The simple reason that it displays 'zero' is because the engine is not running - there is only one single sensor and the software times the display measurement in concert with the cylinder on the intake to direct that reading to the appropriate display 'gauge'; i.e these readings are not constant per cylinder, each 'gauge' is only being updated by the software to report as the timing of the crank dictates - engine not rotating, there is no update to the display for any of those cylinders.
The pressure readings ARE absolute.

skip to 6:17 and learn

 

[DEcosse]

skip to 6:17 and learn

And that is teaching me what exactly?
Once again you are just talking rubbish and this time, I'm not getting into protracted debate with you - you're wrong, the end.

 

[Blackthou]

going off on a tangent, tune ecu is a bit confusing when it comes to throttle pressure readings.

since we're reading from a MAP sensor i.e. absolute pressure, the gauges should be reading about 1000hpa when the bike is not running.
and then when it is idling, the needles should be down around the 400hpa mark. when you rev it up, the needles would climb closer to 1000 mark. if you had a turbo or supercharger, as you rev it up more the needle would go past the 1000hpa mark and hit say 2000hpa if you were running 1 bar boost (and the scale went that far, of course).

however. tune ecu readings start at 0, when bike is not running, which means that the readings shown are 'gauge' readings i.e. not absolute.
when you idle the engine the needles float about 600hpa (should be -600hpa if we are on the gauge and not absolute scale), and as you rev it up they get closer to 0.

having that - in front of the numbers would correct the readings to actual throttle pressure readings (on the gauge scale tune ECU uses), but the readings would not be raw readings as raw readings would be on the absolute scale.
tune ecu must do some simple maths to change the reading from 400hpa (absolute pressure at idle) to display the 600hpa. but of course it should be -600hpa to be correct.

i understand nobody cares what the numbers are, as long as they are the same (why triumph's official gizmo for throttle balancing just says "they're grand" and don't give any numbers), but having gone this far with tune ecu why not have it absolutely (pun intended) correct

/end rant

Spot on explanantion

 

[EasTexRIII]

Oh Sh!t

 

[R-III-R Turbo]

And that is teaching me what exactly?
Once again you are just talking rubbish and this time, I'm not getting into protracted debate with you - you're wrong, the end.

ok tell us this - why does the needle shoot back up toward 0 when he revs the engine?

also tell us why a typical engine vacuum is about -19inHg (-9psi or -620hPa) gauge, when you say the tune ecu readings above are absolute values (i.e. 600hpa in absolute equals -400hpa in gauge)?

 

[Triple Trouble]

My understanding is that the higher the number the more vacuum therefore the middle cylinder showing a lower vacuum could indicate a leak.

 

[Claviger]

Full throttle shows a value of about 950 +/- ~50 (RPM dependent), local baro reads ~1010. Idle shows 540 +/- 10 for me on a warm engine.

That video shows only one thing, how slow TuneECU updates. The "going towards zero", so lowering of the number is when the motor is closed throttle coming down in RPM, or, the strongest vacuum area. You can see cylinder 3 pegged all the way on the right when he holds it open longer, that's the ONLY gauge that updated while he was holding the throttle open.

When going down the freeway, close the throttle and log the map sensor, its LOW value like 200 or 300, meaning very low pressure, or, very high vacuum.

It is an absolute value, referenced against the external barometric sensor on the bike to compensate for altitude and changing weather.

In the below, boxes are rough but convey my point.

Yellow - less than idle vacuum, e.g. closed throttle engine decelerating
Red - Cruise, part throttle, so higher air pressure than idle
White - open throttle, much higher pressure than idle, meaning more air pressure, so closer to atmospheric pressure.

 

[Claviger]

In the below, you can see where Throttle is big open, Map signal is high, 94kpa, when I roll the throttle closed, it pulls the map signal down to 27.9 kpa, the steps are because the ECU updates slllllllllllllllllowwwwwwwwww, and is nearly useless as a tuning tool.