it has to do with the piping diameter and the MAF mount location. Since the volume increased because of the bigger piping, the total velocity went down, so the MAF readings measure less air and compensates with the proper fuel/air ratio.
Nope, not really. I've learned a lot since that thread in the link.
The RMM Intake
(and just about every one out there except the old PHR CAI
) is 2.5" already, so it's not the piping. The MAFS location is also pretty much irrelevant. Easy_C tested a TPR CAI
without the fins (TPR has the best MAFS placement of any CAI
), and it still bogged about as bad as the Injen CAI
he borrowed for the dyno. I have the MAFS from my modded CAI
right on the end of a bend and it works fine. Even the AEM
Gen 2 has been known to bog with its updated MAFS location (only reason it was really made was because Gen 1 had hand-welded MAFS mounts, and they were misaligned), which is much improved over the original.
The fins are key to proper MAFS readings and safe fuel ratios, which leads to no bogging or CELs (and also a lot of power, shown in dyno comparisons). Even the Corolla and Matrix have similar fin or "strainer" setups before the MAFS to help out the airflow through it.