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Link MXS Strada Street Dash wiring


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Yeah in the old days about 2"Hg is about all you could get - in fact we would usually measure in inches of h2o and I remember 20-30" being a common aim.  

Nowadays with multiple Roots scavenge sections that has climbed.  Depending on boost levels though I suspect you wont maintain -ve press under high boost (especially a subaru!)

We can fix your calibration and use a math channel in the dash if we need to scale that channel to read in the units you want  i.e -ve numbers for vac or whatever. 

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 Right now in logs it seems to maintain vacuum everywhere, but its only on 50Kpa boost 400hp, I certainly do want to be able to see if and what positive pressure happens under high power, How would I go about getting dash readout to show -ve and positive numbers when crankcase gets pressurised ?

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could you just fudge the calibration on the crankcase "MAP" sensor to make it read in "MGP"? change the axis so instead of 1.5v or whatever it is being 100kpa, this is 0kpa, and set 0.5v to be -100kpa.

It wont help your conversion to imperial as the maths is different for inHg vs +psi but in kpa that would give you a straight forward readout. 

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45 minutes ago, cj said:

could you just fudge the calibration on the crankcase "MAP" sensor to make it read in "MGP"? change the axis so instead of 1.5v or whatever it is being 100kpa, this is 0kpa, and set 0.5v to be -100kpa.

The GP pressure runtimes in the G4+ firmware is stored as an unsigned integer so you cant do "-ve" pressure calibrations.  So unfortunately there is no way to make it display both +ve and -ve pressures in PC Link, we are going to have to put up with it reading in absolute in there.

However the dash I think can be manipulated to display it as gauge pressure.  There are many ways to skin the cat but I would do it like this:

Set the PC link calibration correctly like this:

KBtIDPP.png

 

In RS3, add a simple operation math channel, "Crankcase press - Baro Press", then use this new channel to display on the screen.  It should show -ve for press below atmosphere and +ve numbers for above atmosphere.  This example below would result in Kpa units, if you want psi or inhg then you would add a further math channel to multiply this channel to give the correct scale and units.

ohYIc2q.png

 

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I put the crankcase pressure sensor calibration back to 3 bar, then did as you suggested and used a math channel to -baro, which now gives correct -ve and +ve vac numbers in Kpa, but adding another math channel to convert Kpa to InHg seemed to screw that up and convert that to absolute where atmo is 30 InHg lol, guess that's technically correct, I'll live with +ve and -ve Kpa numbers.

Everything is working pretty well, had to add math channel for lambda's as they needed multiplying by 10 to display correctly.

Only other thing is Rev gear is displaying as "15" !, used to just show a " -" in reverse...anyway of making that show an R ?

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1 hour ago, oversteer said:

Only other thing is Rev gear is displaying as "15" !, used to just show a " -" in reverse...anyway of making that show an R ?

There is an encoding feature in the CAN config where you can convert received values into text but I have never tried it for the gear channel.  This is normally used for bit field" type data such as the "limit flag word" where 1 = RPM limit, 2 = MAP limit, etc.  Can you attach your latest dash config and I will give it a go.  

Note in your ECU config you have your Reverse set to gear 15 (-) so I would suggest you also change that to gear 10(R) and I will code the dash to match.  

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