so bigger injectors always means bigger MAF?
AGU / cable 1.8T / motronic 5 ecu / m3.8.* ecu
The AGU uses a narrow band ecu which every thing in the mapping ie primary fuel, timing and load is ALL based around the reading from the maf. The injection on-time is made up from maf reading, rpm and engine load. If you fit bigger injectors then the engine will run too rich and the ecu can only trim a small amount of the extra fuel by using the narrow band 02 readings.
If you change the MAF housing % size to the same % increase as the injectors then the ratio for injection ms and air drawn will be about spot on or within an ideal range for the ecu to trim by around 5-10%, then when is comes to mapping all we have to do is rescale the load axis on the ignition maps and fine tune the injection ms map, which can take a round a whole day to dial in from scratch. There is a way of just adding bigger injectors to the ecu but this mean changing the main global konstant ratio map, but doing this off sets all the map load axis and can take days of logging to rescale and get correct and will cost £100s.
AUM ARZ AUM ME7.5 ecu
These ecus allow just for the injectors to be fitted and just one map to be changed. The map KRKTE which means constant factor (K) for air flow (RK) to injection time (TE) just by changing this one map in the correct ratio to the injector size will allow the fuel to be near enough 100% bang on, The only other time the KRKTE map should be changed is when running a 4bar fuel reg, I would say 99.9% of all tuner who are mapping car with 4bar fuel regs are not doing changing this map which lead to high fuel trims and loss of power due to too much fuel lower down in the rpm range....
So dont just go and fit a 4bar reg... it wont work right unless its been added in the mapping (check with your tuner that the KRKTE is set for a 4 bar reg.
A lot of the Seat 1.8t boys are just wacking 4bars reg on there car and making less power..
. Going for 600cc+ injectors then a few more map need to be chnaged to get it bang on.
In theory.. a cheat just by adding 30% bigger injectors and MAF will give 30% more load request which could work out to be around to 30+bhp with just stock mapping. It wont kick like a remap and the N75% mapping wont change enough and the load map in the ecu is still on a linear scale.
I hope this helps..
sorry to bore you all
