MAF CAL Use Case Example – 1.8T Big Turbo MAF Calibration
November 21, 2024In this video I show a use case for the MAF CAL MAF calibration product
The Engine
The engine is a 1.8T 20V from VW/Audi. It is running a big turbo which has meant a completely custom intake system was required, from turbo inlet to air filter. This entailed larger than stock piping and MAF relocation.
Why MAF CAL?
The “original” custom intake for this turbo had a few issues.
Maxed out MAF sensor
The MAF sensor seemed to be reaching it’s limit at 4.4 volts. To address this a larger MAF housing was used. The larger housing would effect the MAF signal so re-calibration would be needed.
MAF location after bend
The engine was probably mapped with the MAF sensor located immediately after a bend in the intake. The MAF signal quality was not consistent so the sensor was moved to a location where the air had a straight run into the sensor. This would need re-calibration of the MAF signal
Aftermarket Greddy Cone Filter
The filtration of aftermarket performance air filters is generally not as good as stock paper type filters. The Greddy filter was swapped out for a paper type filter from an RS6. Changing the filter medium can also affect the MAF signal slightly. This called for calibration of the MAF signal.
Rich Idle
With the “original” custom intake, idle was rich because the short-term fuel trims were maxed out. This suggests an issue with MAF calibration. MAF CAL can readjust the signal to get fuel trims within 5%.
Unstable/hard to modulate power
Engine was not smooth, it could be hard to modulate power. This could be due to bad MAF placement (see above)
All of these issues required a redesign on the intake and a method of re-calibrating the MAF signal so the signal accurately reflected the air going into the engine. This is a text-book case for using MAF CAL.
Adjustments – MAF Calibration
Using the Tune function the MAF signal was reduced by 5% at idle. This got the fuel trims to within 5% of zero.
From 2 volts MAF signal was increased by 5% and from 2.5 volts increase with 8%.
Results – MAF Calibration with MAF CAL and Intake Re-Design
With these changes short-term fuels trims were brought withing 5% of zero throughout the rev range. Engine was also now normal to drive with power being easy to modulate.
A big part of the improvements was down to the redesign of the intake and MAF relocation. But the benefits of these changes could not have been realised without re-calibrating the MAF sensor and in this case MAF CAL was the chosen product.
