Need help tuning MAF on E38 ECU

[Z107]

I have a 2010 Camaro 6.2 m6 with a tsp bald eagle cam installed. I have been tuning my MAF for a little while and notice that occasionally the numbers don't make sense. For instance, when logging id grab alot of values near 3300Htz say at 1 or 1.5 and id flash them in, cold start flash fyi and percent half the whole table, then the new values are at 6 lean. why does it do this? I really would just like to know what values/procedures effect logs and how i should watch out for them. Attachment 124032Attachment 124033Attachment 124034Attachment 124035

[CaudleDynamicsLLC]

Maybe silly question but just covering basics first: is the tune file configured to be solely in MAF mode, i.e. RPM windows set as to not be referencing filtered/predicted dynamic flow? Also make sure the engine is operating as close to steady state as possible when logging and also apply transient rpm/throttle/etc filters to your logged data to omit any non-steady state points. Making sure the sensing element in the MAF is clean and oil-free is key also, as any contamination will affect the sensing wires response to airflow.

Not knowing the background of the engine/intake combo, the automotive engineering background in me also always wants to scrutinize the "recalibration" of an airflow measuring sensor, which regardless of how or why the air is flowing past it, was very accurately calibrated from the factory. Assuming you have changed the intake tube flow path around the sensor significantly, some adjustment may be needed. But bear in mind you are calibrating it against these assumptions: that your fuel/air mixture is being read exactly (which with good factory narrowband O2 sensors should be pretty darn accurate) and the biggest kicker of all: assuming the fuel injectors are actually injecting the exact amount of fuel that the ECM thinks they are. A stock calibrated MAF at steady state is more accurate and precise than fuel injector flow vs. predicted is, given the numerous variables they are exposed to. So, if there are discrepancies between MAF with stock calibration and fuel trims, make sure fuel rail pressure is correct (not sure if Camaro uses a fuel pressure sensor like trucks), if it's really erratic maybe even verify all injector spray patterns, and most importantly, all of the injector tables are appropriate for your injectors (stock injectors = absolutely stock, untouched injector data unless you have an injector flow bench to measure them on, and aftermarket injectors = their, hopefully, provided injector data)

[Z107]

So i have done no work to the intake whatsoever. Its stock from the filter to the heads, meaning its not even ported. I had assumed that since i had changed the way the engine breathes with the cam, the MAF was in need of some recalibration. Also yes i have it set to run MAF only under the parameters set, as i need to have it this way in order to get data from the maf only. As far as transient rpm/throttle/etc goes, im unsure as to what that means ill do some research right now but please if you have any input that would be fantastic.

[Stroked06Goat]

Hand smooth any anomaly values if need be this helps the transition through the range. The graph should be a smooth transition through. Also make sure you are filtering any transient data. Good Maf data relies on smooth driving which is tough sometimes in the real world.

[Alvin]

This cam is getting to the point where its better to go speed density just because the MAF can be so inconsistent at low RPM/load.

[CaudleDynamicsLLC]

As far as transient rpm/throttle/etc goes, im unsure as to what that means ill do some research right now but please if you have any input that would be fantastic.

Ah that's probably mostly, if not all, what was causing the apparent fuel trim swings ^ I think once you get those transients out the consistency will improve.

Not familiar with that camshaft, but as Alvin mentioned also, there may be a point where the airflow is just not "smooth" and has some pulsation even all the way back to the MAF (would imagine low rpm throttle blade open a fair bit?) If I recall, the lower flow/rpm range is where the factory strategy blended, or used primarily, speed density air calculations/fueling anyway. I personally always preferred pure Speed Density tuning on larger cams, but definitely enjoyed it much more on GenIII vs. the GenIV VVE stuff - takes a few more cracks to get it smoothed out correctly

[Z107]

Had no idea, thought the MAF was some genius invention that can do all things; At least from what im hearing from others. Ill try out SD only see how it works out, gotta start from scratch on the VVE. Also, just so i understand this completely, transients are what cause the lean and rich spikes on throttle adjustment right? Also from my experience, it cant just be as simple as disabling transients under the transient tab can it? Feels like theres always an extra parameter im forgetting when logging.

[CaudleDynamicsLLC]

Oh, sorry, there are a couple different definitions or usages of "transients" here. For clarification: The transient fuel parameters in your tune file provide the "makeup" needed to catch up and jump from the previous operating condition to the current or upcoming condition. They must be left active (and probably best stock until VE, VVE, MAF tuning is done) for the engine to run and respond correctly. They can later be fine-tuned, but only after the VVE and MAF are dialed in using steady state methods.

The "transients" that are being referred to in this thread are the points, or frames in your data log(s) during (and for maybe a second after) the throttle position, engine load, and/or RPM change, or transition, at decently quick rate. Tuning either SD or MAF is best done by datalogging many steady state operating conditions (i.e. 1500 rpm light load, then 2000rpm light load, then 1500 medium load, then 2000 medium load, etc.) until you get plenty of data points, or "counts" or "frames" at each condition (50-100 or so) and fill in as much of the operating condition range as possible. When someone mentions "getting rid of the transients" in your datalog they're referring to using the filtering function when you edit the 2D graph of your fuel trim data in VCM scanner. You can basically tell it to ignore any data points that were recorded when the throttle, engine load, and/or rpm was changing quickly. The remaining data in the 2D graph would be a more accurate representation of the adjustments needed.
I can't recall where the best walkthroughs were on these subjects, but there should be some good tutorials out there on the best way to set up the 2D graph, how to operate the vehicle for the best data, and then how to apply filters to the data. It takes some patience to get the process down, but then it becomes more science than art and well worth it.

[Tunercharged]

I replaced my intake and MAF tube so I had to retune my MAF. During this I also tuned my timing and switched to using only 93 octane pump gas. I first did some smooth runs to tune MAF and that was a good beginning. Then I hand tuned the MAF while doing WOT runs and also when doing some runs including part or heavy throttle runs data. I tuned for optimal power on WOT from 800 rpm to 6000 rpm. My MAF graph is not completely smooth. At areas where the engine is making best power there is a hump. Overall the graph is smooth but hand modified calibration is necessary I believe for better ride. To pinpoint data I would look at the graph in scanner and determine exactly what the fuel lambda vs MAF vs wide band are for the run by moving the slider by hand and taking notes for the MAF frequencies I would modify. It is a painstaking process like this but I love it and it only takes me about 15 minutes to go through the scanner’s run and fill out my best approximations on paper first and then in the editor. While filling in editor, MAF frequency table, I double check the viability of the numbers I am entering based on the trend of the graph picture. I agree with you that the MAF is amazing. Currently I run my tune with just MAF and no SD, keeping it all as simple as possible.

[Tunercharged]

I found tuning using these things helpful. Everyone uses different things and has their own style. I prefer looking at what I can in terms of cylinder grams of air.