Defi and Syvecs 4bar disagreement!

[stevieturbo]

Whilst I agree manual calibration should not be necessary....when there is any doubt about the readings, the only answer is to test.

There may be no problem, there may be a problem with plumbing, wiring or other. But testing as installed in the car is the only true way to find out if it is working as expected or not.

[TimH]

Testing and calibration are not the same thing

[stevieturbo]

Testing and calibration are not the same thing

Cant calibrate without testing !

[RICE RACING]

.....and 'calibration' needs to be against a certified suitable test capable instrument (with current certificate of accuracy)

how exact (anal) about it you want to be or need to be is another topic for sure

[stevieturbo]

Cheap Mityvac does me for now lol

[RICE RACING]

We need to start a topic on GPS accuracy/precision I just got my Race Logic VBOX (VB3i and IMU) re certified then there is NTK sensors as well need to set up a laboratory

Fit for purpose, as you say the Mightvac was handy, for me too till I broke the gauge

[TimH]

My point is that with a quality sensor, with a known specification and a calibration sheet, for most of us, a simple linearisation of (in the case of KA) 0bar = 0.5V and 4.5V=FS is quite adequate. A 20mBar error at any point in the range is of no consequence, and only a very anal calibrator would check a sensor every 20mBar over the 4 bar range, surely!?

Yes, you need to *test* that the sensor works (!) and that it really is a 4 bar (had a customer buy 2 sensors recalibrated to 6 bar...but turns out they were recalibrated to 3 bar in error ). And if anomalies are seen, then test, sure. Or an unknown sensor (and this topic suggests the Syvecs 4 bar is an unknown )

If you are doing a bleeding-edge tune, squeezing the last 10ths of ignition timing out of it, and pushing boost as close to the limits as you dare, yes, be "anal" - you have to be!

NTKs are a different matter as they do vary and the corrections 100% depend on this value being right. I suspect part of the problem is that the NTK calibration resistor is not taken account of by the Syvecs hardware so the linearisation is only an approximation. These really should be checked against a known reference (usually the dyno wideband, or the mapper's known-good-reference). The LSU 4.9 interface on S6plus and our MEU *does* use the calibration resistor so ought to be much closer. Also, the Bosch documentation is much more thorough.

And, with all of this, "I am not a mapper" (maybe IANOM should be this forums equivalent of the old "YMMV" or "IANAL", for those that used forums in the 90's!)

[Ryan.g]

Gents,

Over the years we have had 2 different versions of the 4bar Map sensors after having some issues with transducer suppliers a while back. The output between the 2 sensors are slightly different and hence why the voltage point is supplied with the sensor.

I will remove the 4Bar from the Sensor DB to stop any confusion and ensure users check the sensor data provided

Ryan

[dr_jones]

Thanks Ryan - can you tell me - is the sensor data published anywhere? - mine came without anything...

[Ryan.g]

0mbar = 0v
1000mbar = 1.20v
4000mbar = 4.75v