Larger MAF Housing + Bigger Injectors

[Chipmunk]

This appears to be a common modification amongst the VAG engines especially the 1.8t In order to run bigger injectors the ecu either needs to be reprogrammed (if you can get into the relevant maps) or by modifying the sensor inputs in order for the ecu to cope. Bigger housing means more air which means lean so larger injectors will offset by throwing in more fuel... it's kinda crude but appears to work. My question is how does this affect idle, throttle enrichment, closed loop etc or does it all work great if done correctly? The open loop maps and timing can be tweaked for perfect fueling but it's the annoying stuff like idling lumpy or even stalling due to overfueling that I am worried about.

 

[Sim]

If you use the correct size injectors for the correct MAF ID, it may work out quite well (perfect idle, perfect closed loop). Throttle enrichment does not seem to get modified however (on the second thought - why would it be), but using "moderate" (f.eg 386cc) sized injectors you won't go extremely rich, especially if you also have increased on the boost pressure. If you are really into tweaking maps (i assume) you can "easily" modify the MAF calibration map (easy to find) so you can set the car up with practically any sized MAF. Anyway lowering the MAF values will affect other data too (you also wrote), but as we know our MAF-s are sadly not known for their preciseness and reliability and the ME7 is clever enough to compensate minor "glitches" .

These are based on my own experinments, would be nice if somebody esle could back me up.

 

[t18con]

mine ran ok for 2 years with 3 inch maf and tt injectors. youll not get full potential without remap though.