What is the diameter of the stock MAF sample tube? Isn't it 2.5"? I just built a SRI with Spectre parts using the MAF adaptor #9405 and other people on the forums say to use the smallest calibration tube. The smallest tube though is only 2.25" diameter, effectively reducing what the MAF sensor sees and causing it to run wrong, right? I'll pop the 2.5" calibration tube in in the morning and see if it changes the AFR. With the 2.25 it goes pig rich (torque won't show richer than 10:1 and that's what it shows).
Mine is a 2008 1.8. It seems like it running richer than it used to, which would make sense if I used the wrong calibration tube. Too large a tube and the MAF sees less air, too small and it reads more air than normal right?
For anyone that needs to know the stock sample tube size on a 1.8L engine (2008 at least) is 2 3/8".. So anyone using Spectre part 9405 to build an intake should use the smallest (2.25 inch) calibration tube as the medium (2.5 inch) while only being slightly larger will cause issues (on mine it caused it to not want to accelerate from a dead stop)