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GC8 MAP sensor wiring and scaling please

Old Feb 15, 2017 | 03:50 PM
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Default GC8 MAP sensor wiring and scaling please

I'm fitting a Subaru 2.5 bar map sensor to a BMW tomorrow to log it to build a VE table for SD conversion. I cannot find all my old Subaru data, I'm looking for the 5V, 0V and signal pins on the sensor as I have a plug and pigtail with it and accurate gradient/offset or a couple of values for various pressures. Thanks!
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Old Feb 15, 2017 | 04:06 PM
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I have the perameters for the 92-96 and the 97/98 sensor if they're any good to you.
Afaik the 92-96 is 2.26bar and the 97/98 is 2.86bar at maximum voltage.(Including baro pressure)


Last edited by ossett2k2; Feb 15, 2017 at 04:08 PM.
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Old Feb 15, 2017 | 04:54 PM
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Thanks. Gradient looks like hPa/V? Cannot work out units of the offset?
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Old Feb 15, 2017 | 05:15 PM
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I see the ESL manual with the same table. The MAP sensor is from a 95 WRX. So 5V = 2.26 bar. The offsets of 300 is tricky to understand though. It mentions 65535 as the basis but I cannot work that to a reasonable voltage at which there is a complete vacuum, or a pressure at 0V.
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Old Feb 15, 2017 | 05:24 PM
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As far as mapping goes I'm still learning the basics so haven't gone that deep into sensor scaling,the info I posted is from the ESL manual.
I did look into map sensor perameters recently as I'm unable to boost cut at my boost limit table(running SD)
As for wiring I have the GC8 ecu pin outs link but don't have time to check wire colours on my car atm so might be useless info for you?
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Old Feb 15, 2017 | 05:31 PM
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That is cool, thanks for the help. I think the Link V5 manual might have the connections in it. Assuming the 99/00 is the same as 92-96 for the MAP sensor plug.
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Old Feb 15, 2017 | 05:40 PM
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If you need any data logging I can do that tomorrow,not sure if that would give you the info you're looking for.
I have no option to log map sensor voltage.
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Old Feb 15, 2017 | 05:43 PM
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Thanks. I can always just see what the voltage is at atmospheric and work it out. I'm not planning to run the car from the sensor tomorrow as it is still normally aspirated so can just log the raw voltage and work it out later.
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Old Feb 16, 2017 | 09:23 AM
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Stuck as I don't know the pins and all the info I can find is 99/00 or later US models. It is a 95 WRX.
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Old Feb 16, 2017 | 12:09 PM
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Have you had a look through this:

http://ken-gilbert.com/wrx/mans/pre97/WiringDiag.pdf
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Old Feb 16, 2017 | 12:31 PM
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Perfect thanks!
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Old Feb 16, 2017 | 12:34 PM
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Think my MAP sensor wires are red, white, green. Apparently 5V, signal, ground from another source but doesn't match that manual.
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Old Feb 16, 2017 | 12:43 PM
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http://ken-gilbert.com/wrx/mans/1993-1996impreza.pdf agrees but funny colours!
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Old Feb 16, 2017 | 11:32 PM
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Red, white, green was correct.
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