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anjuna · 02-11-2020, 10:28 AM

MISC.

Spot reserved for N20 TMAP conversion, disabling codes, engine cooling, and other misc documentation and explanation

N20 TMAP CONVERSION
For those of you who are not familiar with this concept, the N55 and N54 engine have TMAPs that only support "2.5" bar absolute. Since the N55 engine runs with VALVETRONIC enabled, there is very little vacuum, meaning this is effectively a 1.5bar sensor (21.75psi). If you want to read pressure greater than this, you must install the N20 TMAP. On N55 there is no re-pin required and the TMAP bolts and plugs right up with no changes. Further, the N20 TMAP is a 3.5bar, meaning that you get 2.5bar of positive pressure, allowing you to read up to 36.25psi. Is it overkill? maybe. It does allow us to read further than the 21psi, so if we are running ~20psi, we can get a nice safety net of area we can read, proper boost control, and work in additional safeties without worrying if the DME will just flatline the boost reading and never engage.

Now MHD does offer the ability to simply check a flash option for N20 TMAP, but let's go the extra mile and bake it into our tune. I am not sure all what else MHD does with the N20 TMAP option, so I like to know what I'm dealing with

On all most public XDFs, we have a section called "Sensor Calibrations" and two particular tables of concern.
PRESSURE SENSOR BEFORE THROTTLE OFFSET
This table simply defines our offset value. If we took the easiest linear line formula, Y=mx+b, this would be the "b" variable.
The publicly available XDF has a note - "set to 14.2 for N20 sensor" but I found that this was incorrect. It might have been my TMAP, I'm not sure... but I ALWAYS got readings about a psi greater than anywhere else (even when the engine was off, I was showing 1psi - not right).
As such, I will say that this value has worked out at 12.8203 for me.

PRESSURE SENSOR BEFORE THROTTLE GRADIENT
This would be the "m" variable in y=mx+b - we are scaling what the voltage multiplies by to give us our final value.
Public XDF is good enough for the girls I go out with. 72.3 works great.

02-11-2020, 10:28 AM	#10
anjuna First Lieutenant 307 Rep 394 Posts Drives: f25 Join Date: Feb 2017 Location: houston iTrader: (0)	MISC. Spot reserved for N20 TMAP conversion, disabling codes, engine cooling, and other misc documentation and explanation N20 TMAP CONVERSION For those of you who are not familiar with this concept, the N55 and N54 engine have TMAPs that only support "2.5" bar absolute. Since the N55 engine runs with VALVETRONIC enabled, there is very little vacuum, meaning this is effectively a 1.5bar sensor (21.75psi). If you want to read pressure greater than this, you must install the N20 TMAP. On N55 there is no re-pin required and the TMAP bolts and plugs right up with no changes. Further, the N20 TMAP is a 3.5bar, meaning that you get 2.5bar of positive pressure, allowing you to read up to 36.25psi. Is it overkill? maybe. It does allow us to read further than the 21psi, so if we are running ~20psi, we can get a nice safety net of area we can read, proper boost control, and work in additional safeties without worrying if the DME will just flatline the boost reading and never engage. Now MHD does offer the ability to simply check a flash option for N20 TMAP, but let's go the extra mile and bake it into our tune. I am not sure all what else MHD does with the N20 TMAP option, so I like to know what I'm dealing with On all most public XDFs, we have a section called "Sensor Calibrations" and two particular tables of concern. PRESSURE SENSOR BEFORE THROTTLE OFFSET This table simply defines our offset value. If we took the easiest linear line formula, Y=mx+b, this would be the "b" variable. The publicly available XDF has a note - "set to 14.2 for N20 sensor" but I found that this was incorrect. It might have been my TMAP, I'm not sure... but I ALWAYS got readings about a psi greater than anywhere else (even when the engine was off, I was showing 1psi - not right). As such, I will say that this value has worked out at 12.8203 for me. PRESSURE SENSOR BEFORE THROTTLE GRADIENT This would be the "m" variable in y=mx+b - we are scaling what the voltage multiplies by to give us our final value. Public XDF is good enough for the girls I go out with. 72.3 works great. Last edited by anjuna; 02-13-2020 at 08:53 AM..
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