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Lean on load trip - Trip Enable Manifold Pressure

Posted: Mon Jan 09, 2017 1:08 pm
by dr_jones
Apologies for the - newbie question here - I just want to be absolutely sure as these trip values are so critical as engine savers.

The "Trip Enable Manifold Pressure" value - can anyone confirm its an absolute value - IE 1000 mbar is roughly atmospheric pressure - or to dumb it down - 1000 mbar is ZERO boost.

IE - A 'Trip Enable Manifold Pressure' setting of 1500 mbar here would be 0.5 bar of boost?

Cheers,

-Ed.

Re: Lean on load trip - Trip Enable Manifold Pressure

Posted: Wed Jan 11, 2017 1:55 pm
by pat
You will struggle to find references to manifold relative pressure anywhere in the calibration, so it should come as no surprise that here too you are looking at absolute pressure. It makes sense to allow a trip to be activated if you are too lean even before you get onto boost, simply because there may not be any boost, ever. There is no requirement from the ECU that there be a turbocharger or a supercharger, but you would want to allow the trip to be activated if you were at full throttle and at or just below atmospheric on an naturally aspirated engine. The fact that the axis stops at 0mbar then is a clue that you could not achieve the above unless the pressure reading was absolute.

Hope this helps,

Pat.

Re: Lean on load trip - Trip Enable Manifold Pressure

Posted: Wed Jan 11, 2017 2:07 pm
by stevieturbo
Or...look at your MAP sensor reading lol.

Key on, engine off will be around 1000mbar.