This is a very common question that we get here at East Coast Customs, so we will do our best to answer it without going into a hour-long diatribe.
Firstly, the MAF is a vehicles Mass Air Flow meter (also commonly referred to as an AFM or Air Flow Meter) – this is a sensor that provides feedback to the engine control unit (ecu) to indicate the volume of air being consumed by the engine. Generally, from this feedback, the main source of engine ‘load’ can be determined and subsequent calculations for fuel, timing and countless other variables can be manipulated. MAF simply refers to tuning a vehicle that still retains its MAF meter. Conversely, MAFLESS refers to tuning a vehicle in which the MAF has been removed.
Why would someone remove the MAF you ask? In certain circumstances, once a vehicle has been modified, it may have the capacity to consume more air than the MAF sensor is capable of accurately reading. When this situation arises, the ecu is provided with inaccurate information to determine load, and hence, many resulting calculations suffer and our ability to derive an optimal state of tune is compromised (often so severely to the point that sever engine damage can occur). One may also remove the MAF if the physical size of the unit becomes a restriction to airflow into the engine. Once one reaches this point, there are generally two options; Firstly, one can upgrade to a different MAF sensor that has the ability to accurately measure and / or support the air flow requirements of the engine, or alternatively, one may look towards removing the MAF and adopting a different strategy for the ecu to calculate and measure load and airflow – this is normally achieved by referencing manifold absolute pressure in relation to rpm to determine load.
Depending on the vehicle / engine setup we are working on this may be done in different ways. When opting down this path, some vehicles are required to change over to a full stand-alone engine management system to do this job correctly. Some vehicles have the luxury of being able to support MAFLESS tuning in factory form, some run a somewhat maf and mafless system concurrently, whilst others require us to make some modifications to the ecu and software to support this method of tuning.
The question as to which one is ‘better’ is a tough one though, as it is fairly subjective and no two individual circumstances are the same. So rather than say which one is ‘better’, I will simply list some of the pros and cons, and when it comes to deciding what is ‘better’ for your car – give us a call!
In favour of the MAF, there is a lot to be said for not over complicating things. If the factory ecu was designed to measure and calculate load via the MAF, then it makes a lot of sense to retain the MAF in order to keep things working the way they should. As the old saying goes, ‘there is more than one way to skin a cat’, and whilst this is true, if you can do it via the ‘technically correct’ way, or the way it was intended, then this is invariably the path of choice. Secondly, removal of the MAF is technically illegal, in the sense that it is an obvious flag to someone that knows what they are looking for, to indicate a defective vehicle that is running in a somewhat form of altered emissions output from factory conditions – depending on location, differing consequences may apply.
Where some of the confusion I believe stems from, is that many people remove the MAF unnecessarily. If the MAF is still completing its job efficiently, then the concept of removal must be based upon a few other factors.
Luckily, in favour of the MAFLESS brigade, there exist many amazing options that allow MAFLESS tuning that also come with a whole bunch of extra features and benefits. If this means changing to a stand-alone unit, with it comes all the extra features and functionality (if required). If this means changing to a different operating system in the factory pcm, it also brings with it some other impressive features that are not available when retaining the MAF. These differ car to car and setup to setup so it would be pointless to elaborate now – but I think the point is clear that unless there are other reasons involved, whether it be maxing out the old MAF, or wanting the extra features available in some of the MAFLESS options, removing the MAF for the sake of removing the MAF is pointless. If the removal is warranted, in the case of desire for extra features, and functionality, size or flow restrictions, or incompatibility with the setup (eg – large camshaft vehicles with lots of overlap at idle and low rpm conditions or will provide false MAF readings compromising the state of tune and drivability in the affected areas).
So, if you’re contemplating taking the next step into a custom tune with your vehicle, hopefully this will help at least clarify some of information involved. As I stated earlier, every setup is unique and ideally, give us a call and we can discuss in some depth exactly what they best option for your individual setup, goals and needs are to ensure optimal results and satisfaction.