PE Enrich: Less than WOT vs WOT AFR Error not consistent with MAF, but is in SD Mode

[10_SS]

As the title explains, when I run the MAF at WOT (160kpa MAP), my ARF Error is very small, 1-2%, but when I run less than WOT, like 50% TPS but still in PE (125kpa MAP) then I run about 10% Richer than commanded.

When I disable MAF and run off the VE tables and do the same thing, I don't have this problem , I think simply because there's a MAP vs RPM table, at less than WOT MAP I've tuned those cells to give accurate AFR, so part throttle PE vs. full throttle PE both run around 1-2% error. There is no MAP table with the MAF, just vs. RPM. I think if it did have a vs. MAP table then I could tune this out.

Example: Normal MAF/SD mode: 7900hz on the MAF at less than WOT at 4000rpm (125kpa), and runs rich about 10%, if I go full WOT, then 7900hz is around 3200rpm, MAP 150kpa, and only 1% lean AFR error. So, WOT PE is more important than less than WOT PE so I tune the MAF to run good at WOT PE, but if I run less than WOT in PE which actually is more often than full WOT, it's rich.

Any idea's how to fix this in the tune some way?? Or.. could this be something to do with Injector Timing? Part Throttle PE mean less pressure in the cyl keeping more fuel in there and less blowing out of the exhaust as it's injected? At WOT, there's more pressure pushing unburned fuel out of the exhaust, so it needs more at WOT, but those same HZ cells at part throttle PE make it too rich? My Injection Timing is stock, not setup for boost. I just thought of this as I was typing.

I's always been like this, for 8yrs, ever since I started tuning it from stock, after I added the Whipple. Now I'm bored and wondering if there's any way to tune this up. I could just run in SD mode all the time but I don't want to do that, SD mode creates other problems like lean tip in, burst knock acts funny, etc.

I'm running the 2010 Camaro LS3 E38 2BAR OS, but a Whipple is on top. Could part throttle in PE (125kpa MAP) be possible to measure more air than is making into the engine compared to full throttle (160kpa)? If it's an Injection Timing issue, then yes??

Thanks

[SQUEEGIO]

I have noticed the exact same thing with mine. 11 Camaro LS3 with an LSA blower. 2BAR OS as well. Never been able to figure out how to fix that so I just ignore it 🤣

Sorry I'm no help.

[sgod1100]

Same with me as well.... 2014 ctsv with the LSA...there are two areas in my maf curve that I have small humps. Going WOT those are humps are needed otherwise i'll be slightly lean. If I go "part throttle PE" and pass through those areas they are pretty rich (around %10ish, similar to what you are experiencing). If I remove the fuel from those areas I will now be lean at WOT. So I ended up just leaving them alone. Rather have the fueling correct at WOT then part throttle PE. I'm sure there is a way to correct this, but me being a novice TOONER I'm not sure where to start

[10_SS]

Thanks for the feedback, I got nowhere with the injection timing, prob because I have a stock cam with no overlap. So I'll just live with it.

I think it's a MAF problem honestly, so I'll ignore. I do wonder if there's some air leaking at WOT though, PCV, gasket, other. I don't really think there is a way to tune it out with MAF since it's only 1 axis, you would need it setup like the VE tables to adjust for the difference. This is something I've always hoped the ECU would have, but still doesnt.

[sgod1100]

Thanks for the feedback, I got nowhere with the injection timing, prob because I have a stock cam with no overlap. So I'll just live with it.

I think it's a MAF problem honestly, so I'll ignore. I do wonder if there's some air leaking at WOT though, PCV, gasket, other. I don't really think there is a way to tune it out with MAF since it's only 1 axis, you would need it setup like the VE tables to adjust for the difference. This is something I've always hoped the ECU would have, but still doesnt.

Yeah, I went back and forth trying to get it perfect during both conditions but I was just chasing my tail so I left it "perfect" at WOT. Agree on the Maf only having one axis...because you hit the same frequencies at different rpms. Hopefully a more experience tuner can chime in and give some pointers