Engine Load Calculator – From RPM, g/sec & Engine CC
This engine load calculator calculates engine load as used in the ME7 ECU. It gives the absolute engine load. The same calculation may be used by other ECUs. The formula in this calculator is from S4wiki. (The engine load calculated should be what you get in the “calculated engine load” channel from your car’s ECU)
The S4 wiki link above is a wealth of information for tuning the ME7 ECU.
MAF Sensor Trouble Shooting
As well as helping you tune or scale your MAF sensor/engine, this calculator can be used to diagnose the operation of MAF sensor.
For example
- Is the MAF sensor reading correctly?
- Has the MAF been scaled properly by the individual that tuned the ECU?
The video below is short and sweet. It illustrates the procedure perfectly. By logging the engine g/sec of air ingestion at WOT at various RPMs and entering those numbers into this calculator, you can see if the load result from the calculator, tallies with what your engine is actually doing.
NA Engines
For example, if you have a naturally aspirated engine, at full throttle (WOT) your engine load should be around 85% for most cars at 4000RPM+. If your car has variable valve timing eg VTEC or VVL, you could expect the load to be around 90-100%.
For this NA engine example, bolt into the calculator the g/sec the ECU is telling you at 4000 RPM, 4000 RPM and your engine capacity in CC. The engine load should be around 0.9
Turbo/Supercharged Engines
If your car is turbocharged and you are running 7 PSI of boost at 4000 RPM at WOT, you should expect an engine load of around 1.4.
Bolt into the calculator the g/sec numbers your ECU is getting at 4000 RPM, 4000RPM and the engine capacity in CC. The result should be around 1.4.
Engine Load Calculator – Summary
If the g/sec numbers you are getting from the MAF are not giving the expected result from the calculator (0.9 and 1.4 respectively for the two examples above), it could indicate an issue with the MAF sensor. Perhaps the MAF sensor needs to be cleaned.
There are probably other signs that your MAF sensor is not functioning correctly eg your short-term fuel trims are +/- more than a few percent.
Datalogging the MAF g/sec readings and using this calculator will help you narrow down why your fuel trims are so far out of whack.
Is it the MAF sensor readings or something else?
In this video the ECU is calculating the engine load for us. The calculated number it gives can be checked using this calculator by entering the g/sec,RPM and engine CC.
Testing a mass airflow sensor using calculated engine load – YouTube
