Not sure with Skyline, but with the Evo the Maf is next to the filter and therefore does not read the air that is recirculated by the DV so if you use VTA there is less airflow than is expected, whereas a MAP sensor, as you said reads manifold pressure and works out airflow from that.`With a Map sensor it sits in the inlet manifold so what it reads is what the engine recieves no assumptions for recirculated air.`
With MAF sensors you directly measure mass air flow into the engine. With MAP you measure manifold pressure and the ECU calculates mass air flow based on its air path model. So much misinformation about MAP Vs MAF.
MAP based systems will not give you as repeatable AFR as MAF (I`m talking aftermarket ECU`s here, not OEM). Driveability can usually be optimized further over MAP as well.
Only real advantage of D-jetro on GTR is it saves the cost of two MAF upgrades when you saturate the std ones.......
Manual boost controllers can work very well if they're installed correctly and you don't mind a couple psi of overshoot. Manual boost controllers can't anticipate when when the wastegate actuator will need a bump, but the electronic ones can.Thanks for the replies,.,
and what do you think about having a manual boost controller or does the jetro do all of that as well