Warning, long post ahead

If you just want updated proper scalings to plug and play, skip to the tl;dr at the end!

First, I would not use the sensor scaling to "limit" boost (you should use the other appropriate tables for this). You should use the sensor scaling to reflect the max that your given sensor can have, scaled to the max that your rom version / trans type can allow.

For AT and 6MT, on the DME side, this is 1.50bar relative, while on the DCT it is 1.28 bar due to us not being able to make the same code change for MBoost in the TCU. This does not mean that the DCT is limited to a lower scaled max boost for a given sensor (let's say N20), but it does mean that the scaling will need to be different and it will require a scaling giving less resolution.

The initial N20 scaling (which was very slightly off since it was based on the numbers Cobb published for the N20 sensor, and not the sensor spec itself) was decided upon to report stock up to 10psi, and then scale from there up to 35psi as it gave a nice scaled boost of (X - 24.7)/2 + 24.7. 24.7 here is 10psi absolute, at sea level. If trying a scaling for yourself you should also use absolute numbers at sea level. 10psi was chosen as the middle breakpoint as it gave the nicer scaling equation, but you can go a few psi lower (I wouldn't go any lower than say 5-6psi), and certainly higher as well but then you lose scaled resolution.

Now comes setting the first two cells, and math for the third. You want to pick your first cell to be generally what the sensor spec publishes as it's min. For N20 it is 0.5V @ 7.30809 psi. For the common 4 bar, it is 0.4V @ 7.25189V. Do not worry about if this will set you under the voltage plausibility check for your altitude, as that should be disabled if need be the proper way with it's own byte. You DO NOT want to have scaled values in the first two cells, as it can effect idle, cruise, etc and hurt drivability.

For the second cell, you want to pick the psi you want to report stock up until, and add 14.7 to it. So we chose 10psi, which is then 24.7. You compute the voltage your sensor will have at this psi using y = mx + b. You can figure out variable M and B by using the equation for two points on a line from the sensor spec. For the N20 sensor, this is 2.15876V and for the 4 bar it is 1.861V.

Finally for the third cell. Setting the absolute psi in this cell is easier (and will never change!), so we'll start there. This value should be the max your rom version / trans type will allow, in absolute psi. So for AT and 6MT, this will be 2.56 bar absolute (hex max supported by DME, also seen in some places as 2559hPa). This comes out to 37.1x psi. However, to build a tiny margin in, we set it to 37.2psi. For the DCT, it is 1.28 bar relative (TCU limit) + 14.7 (pressure at sea level), which will be 33.26psi. Those absolute psi values will be the same no matter what sensor you are using, N20, 4bar, 5bar, etc.

Lastly, we need to figure out the voltage to go with either of our two psi values from above, 37.2 for non-DCT and 33.26 for DCT. If you don't care about having a nice scaling divisor like mentioned above in our (X - 24.7)/2 + 24.7 example (the scaling divisor here is "2"), you can simply enter the upper voltage from the sensor data sheet. However, that can make rescaling all your load axis trickier and does not give any headroom at the top end of the sensor before it can start reading non-linearly. For the N20 sensor however, our scaling divisor of "2" only works for

**non-DCT** cars. Here's how we picked that:

Stock sensor max: 22.5psi, scaling start: 10psi; N20 sensor max (that we want to scale to): 35psi, scaling start: 10psi;

stock: 22.5 - 10 = 12.5psi; N20: 35 - 10 = 25psi; 25 / 12.5 =

**2**;

Now to find your third cell voltage based on this, I setup two columns in excel and found first the real psi of the N20 sensor would give 37.2 scaled, using our formula of (X - 24.7) / DIVISOR + 24.7, here X is the real psi of the sensor, and 2 is our divisor. In this case it turns out to be 49.7psi gives a scaled 37.2. Now using y = mx + b again, we can get the voltage at 49.7psi, which is 4.543146V. And that would be our last voltage breakpoint!

If you're still following along you will see why the divisor of 2 will not work for DCT...because the DCT cannot report up the 22.5psi limit enabled with MBoost. It can only report up to the 1.28bar relative (18.5psi). So we will have to first find a new divisor. Here we will stretch the N20 sensor a bit more and use 35.5 as our max to scale to to give us a bit nicer divisor.

stock: 18.5 - 10 = 8.5psi; N20: 35.5 - 10 = 25psi; 25.5 / 8.5 =

**3;**
Now we need to solve for X in (X - 24.7) / 3 + 24.7 = 33.26psi (1.28bar + 1 atmosphere), gives X of 50.38psi. Lastly, we will use y = mx + b again to find the sensor voltage for that data point, which gives 4.608V. Done!

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tl;dr:

Proper N20 scaling for NON-DCT cars:

0.5V @ 7.30809 psi

2.15876V @ 24.7psi

4.543146V @ 37.2psi

and for DCT cars:

0.5V @ 7.30809 psi

2.15876V @ 24.7psi

4.608V @ 33.26psi

Hope this helps. Again, follow the same process for other sensors like 4bar / 5bar etc. I will work on getting the ambient pressure to voltage check toggle added to the XDFs so you high altitude folks don't run into that issue when scaling a larger sensor.