How to account for commonly upgraded components
For a method to calibrate injectors: http://m44.wikia.com/wiki/Tuning_the_Injector_constant_and_dead_times
Calibrating for injectors requires setting the 'Injection Basic Adjustment Factor' and the 'Injector Opening Time by Voltage'.
The formula for the 'basic adjustment factor' is:
(Old injector size)/(New injector size)*(the current adjustment factor).
This formula is only an approximation and will need some fine tuning.
Adjustment factors for known flow rates:
Basic Adjustment Factor
|Constant for Consumption Display|
|Bosch 750cc (ev14)||3bar||750cc||.3907 or .3985||13.13|
Voltage Correction Tables
In order for the injectors to work correctly the 'Injector Opening Time by Voltage' must be set correctly. These values can usually be obtained from the manufacturer. Here are a few samples for common injectors:
(Important: in this example Basic Adjustment is set to .7188)
The stock MAF can only measure flow up to 826Kg/h, this limit can be reached on a stock 850 with a 15g fairly easily. In order to maintain accurate fueling calculations past this rather low limit it is recommended to upgrade the size of the MAF by placing the stock sensor in a larger housing. Here are a couple of housings that are a direct fit for the original MAF sensor:
- 2.75" ID S90/960 Volvo Part#9146483 Bosch 0280217511
- 3.25" ID 540i BMW Part#13621702078 Bosch 0280217800
It is very important the increase in airflow is accounted for in your bin!
Accounting for the increase
The ECU uses a lookup table to correlate MAF output voltage to airmass. There is actually a linear relationship between the diameter of the housing and flow rate. This means we can multiply each cell in our MAF table by a single factor to account for the difference in flow provided by the larger MAF housing. However, this table is not available for editing directly in TunerPro. The solution:
MAF Table Editor
available here (alternate mirror1)
==== Instructions: ====
- Open your Bin
- Select all of the Air Mass Values in the table
- Change the Function to: Multiply
- Type in the desired correction factor (see below)
- Click Execute to apply the factor
- Save your modified Bin and flash your new Bin!
The factors needed:
|Inner Diameter||Originally equipped||Multiplier||Max Airflow|
|2.5"||Volvo 850/S/V/C70||Stock||826 kg/h|
|2.75"||Volvo S90/960||1.34||1107 kg/h|
|3.25"||BMW E39||1.94||1612 kg/h|
|3.5"||BMW 3,5,7 series||2.24||1850 kg/h|
|3.75"||citation needed||2.57||2123 kg/h|
(you may need to use a comma instead of a decimal as a separator depending on your regional settings)
Alternative Mafconverter: here
(for simply changing your MAF table into a Standard 2.5" ID, 2.75" ID, 3.25"ID or 3.75" ID table at the push of a button)