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Injection Timing

Practical Diesel Tuning

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Hi can someone confirm please that in the attached photo that the negative numbers are before top dead centre thank you

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It looks like the data in that map is represented in ATDC, not BTDC like you're expecting. The (-) data is more advanced and would be an injection event starting BTDC. The (+) value is one more retarded, starting ATDC.

What vehicle is the map from, out of curiosity?


Thanks for the reply. It’s a stock map from a 2012 Mazda bt50. So a larger negative number would be advancing the timing? Also these numbers are SOI numbers?

That's correct from what I can tell. -10* would indicate SOI 10* BTDC


I´d like to add a little bit of wisdom here. Don´t believe every number in those maps. They have to be taken with a grain of salt. Not uncommon for the drivers (definition files) to be wrong.