GolfRS
Banned
- Location
- Europe-Greece
I though its time for a bit more technical discussion and some views from experts on the actual effects aftermarket intakes
might or DO have on the way the ECU "adapts" aftermarket software, based on its readings.
The idea is that most of the aftermarket intakes "try" to maintain an OEM MAF housing size to keep the readings as
OEM as possible, so as to assure the ECU responds well to what the performance software is asking of it.
The fact is though that even though people might not understand it, and there hasn't been any talk about it, MAF readings effect the cars performance A LOT.
One recent example is STAULKOR's who was literary tortured by -12 timing pull, without being able to find out what exactly was causing this issue.But a timing pull of that magnitude sure isn't the rule, but rather the exception.Does that mean that if you don't have -12 your car is running fine ?Well yes and no.Timing pull even in the area of -4,-6 or more might also be bad, from the point of view of power loss.Your car might not actually need to cut that much timing, but its trying to adapt to what its reading.
Differences in MAF sizes from OEM can also be monitored through the fuel trims, with the Long term trim being the most important in this case.A highly positive fuel trim might show deviations from what the ECU is expecting to see, and from my knowledge and experience, a simple increase in LTFT should be considered an increase in air flow IF it actually zeros down after the car adapts to the new intake.But a constant LTFT that just refuses to zero, possible means there is a problem.
Now most of the aftermarket intakes claim to have a MAF housing that approaches OEM dimensions, but i haven't found that to be true AT ALL.Most of the intakes run a 2.75'' or 3'' MAF housing that is in reality MUCH MUCH larger than stock.With the OEM housing being oval shaped, i did a few measurements , and figured out that for a round intake tube to have actual OEM dimensions, it should be in the 2.55'' (65mm) diameter area.That actually means OEM MAF dimensions (in a circular intake) correspond to
Circumference of :204.2
Area of:3.318
Now in an intake with a MAF housing of 70mm (2.75'') the following is true:
Circumference of :219.91
Area of :3.848
And with 76mm (3'') :
Circumference of :238.76
Area of: 4.536 !!
So in the first case there is an increase of about ~8% and in the second an increase of ~17% !!!
Now some have claimed the ECU can adapt to small changes in the measurements, but somehow i don't see 8% and 17% as being that subtle....
As for what effect these changes have on the cars performance ??Possible "theories" will be presented in the my second post sometime later...
Feel free to discuss...
might or DO have on the way the ECU "adapts" aftermarket software, based on its readings.
The idea is that most of the aftermarket intakes "try" to maintain an OEM MAF housing size to keep the readings as
OEM as possible, so as to assure the ECU responds well to what the performance software is asking of it.
The fact is though that even though people might not understand it, and there hasn't been any talk about it, MAF readings effect the cars performance A LOT.
One recent example is STAULKOR's who was literary tortured by -12 timing pull, without being able to find out what exactly was causing this issue.But a timing pull of that magnitude sure isn't the rule, but rather the exception.Does that mean that if you don't have -12 your car is running fine ?Well yes and no.Timing pull even in the area of -4,-6 or more might also be bad, from the point of view of power loss.Your car might not actually need to cut that much timing, but its trying to adapt to what its reading.
Differences in MAF sizes from OEM can also be monitored through the fuel trims, with the Long term trim being the most important in this case.A highly positive fuel trim might show deviations from what the ECU is expecting to see, and from my knowledge and experience, a simple increase in LTFT should be considered an increase in air flow IF it actually zeros down after the car adapts to the new intake.But a constant LTFT that just refuses to zero, possible means there is a problem.
Now most of the aftermarket intakes claim to have a MAF housing that approaches OEM dimensions, but i haven't found that to be true AT ALL.Most of the intakes run a 2.75'' or 3'' MAF housing that is in reality MUCH MUCH larger than stock.With the OEM housing being oval shaped, i did a few measurements , and figured out that for a round intake tube to have actual OEM dimensions, it should be in the 2.55'' (65mm) diameter area.That actually means OEM MAF dimensions (in a circular intake) correspond to
Circumference of :204.2
Area of:3.318
Now in an intake with a MAF housing of 70mm (2.75'') the following is true:
Circumference of :219.91
Area of :3.848
And with 76mm (3'') :
Circumference of :238.76
Area of: 4.536 !!
So in the first case there is an increase of about ~8% and in the second an increase of ~17% !!!
Now some have claimed the ECU can adapt to small changes in the measurements, but somehow i don't see 8% and 17% as being that subtle....
As for what effect these changes have on the cars performance ??Possible "theories" will be presented in the my second post sometime later...
Feel free to discuss...