Originally Posted by RSCosworth
thats not correct.
the chip has nothing to do with the turbo.
if you have a big or a small blower the only thing different will be back pressure, boost temp and lag.
the only air information the chip gets is boost pressure, given by the MAP sensor and the air temprature.
a drop in boost temp caused by the increased A/R og the bigger turbo might cause your car to lean out at high rpm/boost if you already are on the limit of your injectors...
THE AIRFLOW at engine speeds with a t34 vs t3 is vastly different so needs a different chip as it is lean all over the boost range even on spool up its leaner
it is due to the ve of the engine and turbo that the chip needs changing