Hi, I have 2.9 VR6 with 2.8 OBD1 ECU. Do I see improvement, if I change ECU to 2.9? Throttle is also from AAA. Is ABV throttle body much better?
Simply put, the ecu works off math - this math is calculated off a number of things but for example the volume of air in a cylinder can be 1 factor, if you change this then the math goes out of sync. So, generally, to change what the ecu is thinking about volume, i.e. the displacement differences, therefore needs changes in the ecu to sort the math out! However if the throttle body of both is the same diameter, I'll presume so in this instance, then the math is the same for the TB maps/functions so makes no real difference! So - same TB math/orifice diameter etc - pointless change! Different displacement or TB - different calcs so ecu needs modding. In short you'll be messing logical math up for a 2.8 to change it, only to modify it back again to some degree as the 2.9 maps vary due to displacement/math variances! Completely pointless! The only real differences in these ecu's apart from the obvious math changes, is the ignition changes that came into effect.
