m20b25 with 735 AFM

FastButBlind · Post by **FastButBlind** » Mon Aug 16, 2010 1:23 pm

Hi, what should I adjust if I want to tune a m20b25/173 ECU with 735 AFM? I don't know what the AFM part number, but its taken out of 735 BMW
Thanks

gavin · Post by **gavin** » Mon Aug 16, 2010 5:30 pm

Do you have AFR sensor?

FastButBlind · Post by **FastButBlind** » Mon Aug 16, 2010 9:21 pm

Sure I do

gavin · Post by **gavin** » Wed Aug 18, 2010 12:50 pm

install the AFM and wait for the ECU to adapt,look at the AFR on WOT run,if the AFR will go lean change the values in the WOT map to higher if to rich lower the values,but the bigger AFM will not do much if you will not have biger trottle

FastButBlind · Post by **FastButBlind** » Wed Aug 18, 2010 9:31 pm

thanks mate , will what happens

gavin · Post by **gavin** » Thu Aug 19, 2010 1:31 pm

the bether solution is to convert AFM to MAF it will give faster signal and increase the flow,there are kits like this one
http://picasaweb.google.com/tigrfan/Mil ... qE40XZlo3Q#

FastButBlind · Post by **FastButBlind** » Thu Aug 19, 2010 2:08 pm

I have seen some similar setups, just wanted to upgrade a friend car for better flow in short time, but currently am working on an emulator to convert AFM and MAF to MAP, much of work have been done with promising results, soon will be done with it, lots of functions based on aftermarket ECUs are included.
Thanks again

gavin · Post by **gavin** » Fri Aug 20, 2010 12:38 pm

i made many changes to m20 engines,i did instoll the biger AFM but the best results was after installing m30b35 injectors

DmcL · Post by **DmcL** » Wed Dec 08, 2010 12:47 pm

thought i read someone saying the values to set the AFM 1x8 to for the M30 AFM with stock injectors but cant find it if i did..

i can tell u AFM 1x8 values for M30 AFM/19lb injectors and stock AFM/19lb injectors tho. u could probably just work out the difference between the 2 sets of values below and apply the same difference for each of the 8 values in the stock AFM 1x8 tho, dont see why that wouldnt work or atleast get u in the right area.

tuning for M30 AFM w/19lb injectors:

open the 1x8 AFM map and change values to
184 173 163 154 242 225 210 196

tuning for 19lb injectors with stock AFM:

open the 1x8 AFM map and change values to
130 119 109 100 212 195 180 166

i have not tried this myself but i havent heard anyone saying it doesnt work right, etc, etc. i didnt bother with an M30 AFM, hard-ish to come by where i am and still old tech. i built a MAF conversion which worked well so might end up using that on my 325i. currently experimenting with a GM 1 bar map sensor, got the engine idling and free revving on it but MAP output was fluctuating. i fitted a little valve in the vacuum line to the sensor but that didnt really do anything. ive added a small capacitor and resistor to the wiring for the MAP sensor which should smooth the output signal into something tunable, dont think it will require an emulator or signal converter type device/curcuit tbh.. also starting to look into the possibility of using a variable TPS with a MAP sensor open to atmosphere for barometric correction, in theory it (and a MAP conversion) should work with tuning of the AFM 1x8 map and worst case also tweaking the other AFM map and then re-adjustment of fuel maps.