Discussion and questions related to the course Road Tuning
I would like some advice on tuning the MAF tables on my EVO X. I am using ECUFLASH and EVOScan. Attached are what the 2D tables look like. I am not sure how to convert units into load or air, or something I can understand. The issue I am having right now is my idle will lean out as far as 17-18 AFR, it wont quite die but it sure comes close. The car is stock injectors and stock tuning as far as the injectors go. It does have an aftermarket ETS intake and full exhaust.
Any help would be great!
If the injectors are still stock then you're in a pretty good place to dial in the MAF translation table. Particularly if the MAF tube is larger in diameter than stock then this can throw out the MAF calibration and have the engine running lean - Which sounds exactly like what you are experiencing.
A good place to start is by measuring the stock inlet pipe diameter and the new inlet pipe diameter. Calculate the area of each using (Area = pi x Radius^2) and then work out the percentage difference. If for example your new inlet pipe is 25% larger in cross sectional area I'd start by adding 25% to the entire table. From here you can log your fuel trims and adjust the MAF table up or down until you are as close to zero as possible (generally +/1 5% is acceptable).
When you are tuning the MAF table it is important to drive the car smoothly and not use any abrupt throttle application to ensure that no acceleration enrichment is upsetting your trims.
What about the MAF housing? The kit I have installed did not replace the MAF housing. So the intake system is ETS but I remove the Stock MAF housing and install it with the new intake pipe.
I would assume that because of the larger intake after the MAF housing that the air is passing through the MAF housing the same speed but somehow filling up the space after it, even with the MAF the same size diameter.
The way I am imaging this is a bottle of water. When you poor the water out, the neck is the MAF housing and the bottom is the new intake pipe. The water only comes out for how much can fit through the neck. Does this apply for the MAF housing and intake?
If the MAF housing is still stock then your calibration should still be close. From the factory though the intake system is calibrated in it's entirety. This means the intake pipe, MAF housing, air box, filter and intake to the filter. Changing any of these elements will have some impact on the accuracy of the MAF calibration. On LS2/3 V8's for example when we swap out the stock airbox for an over-the-radiator cold air intake, the accuracy of the MAF calibration can be out by as much as 25% at idle/low load even though the actual MAF sensor is still stock.