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Well just to put this subject to rest ... the MAF "IS" capable of being tuned up to atleast 15psi (as in my case) with what seems to be a lot more to go before hitting the max g/s on the table. BUT, this also required scaling the tables down. The issue we were having turned out to be the fuel pump tables that we forgot to scale as well. The fuel pump can boost rail pressure depending on the fuel flow rate, and since we scaled the injectors down, it was never getting to the fuel pump "high flow" table values. scaled the table down and we now have perfect fueling at the top end!
on a side note, I installed a Innovate SCG-1 (boost controller with wideband) that has some need safety features to cut boost by looking at AFR and Max boost pressure and I def saw it work when tuning as it kept cutting boost until the AFR got to a preset s ... best product ever!!!
See below graph, the BLUE is the commanded Lamba, the YELLOW is the AFR Lambda, the GREEN is manifold pressure and PURPLE is Injector duty cycle. This was before we realized the fueling never ramped up.
RPM's kept climbing as this was going on and finally reached a zone where fueling was good to stay below the 0.88 Lambda safety sett point ... until then, the controller kept pulling boost when it saw lean conditions ... really helps to dial in the tables without having to do too many runs.
Last edited by Mean Green z28; 06-26-2016 at 11:44 AM.
This is interesting. I didn't figure I would run into a problem, but it appears that I am maxing out at a MAF frequency of 12k on my tune right now around 5200 RPM and the AFR starts to drift high.
The way i tune the e38 is to disable the maf in the tune. Then tune the VVE up to abouy 4k inly. Then turn back on the maf and the tune the maf. Always works fine for me.
I am still running my maf in my 2011. I have had it up to 16lbs maxed out my fuel system and only hit 12,500HTZ out of the 15,000. I have had zero issues with lean spikes or MAF.
06-26-2016, 11:39 AM
