I have a 2014 ZL1 and i created a "calculated AFR" math channel and histogram. I'd like someone who can compare it to a wide band to see if its close to being accurate. I cannot install a wide band at the moment, and the local tuner shop only works on Mustangs. So im looking for a way to see my AFR using the math and it seems to be pretty good, but I have no comparison. It even shows the lean area when applying full throttle like ive seen on wide bands. Any help would be greatly appreciated.
Last edited by Dark Sun; 01-15-2024 at 10:18 AM.
From his post on Camaro5 he is using “ Mass Airflow SAE divided by Instantaneous Fuel Flow Est. both in Grams per Second.”
Did you look at the files?Originally Posted by gtstorey
No, on my phone. And don’t need to to know what you are trying to do won’t work. If only it was that simple.
The reason I posted what I did from Camaro5 is because the odds of someone loading your math in and comparing is pretty remote. There are plenty of people on here that can you why it doesn’t work and maybe they can explain better than I did on Camaro5.
I put your math (purple) into my scanner and lined it up with my wideband output (green). The flexfuel sensor was reading 9.9% so stoich would be 14.11:1 (and I put a purple reference line in there to represent that). This is really zoomed out on a 27 minute log, so kinda wacky lines all over the place). Surprisingly the math is close in places, but a lot of times does deviate from the wideband.
test.jpg
Overall, the calculated value always reads lean. You can see the wideband dances over the 14.11 stoich line the entire time.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
Oh man that?s great to see. I may be able to tweak the math now and dial it in with that information. I?ve been comparing it with the MAF airflow and frequencies trying to see and do comparisons for it. I figured out today my MAF is not exactly where it should be on readings. It?s a stock air box so I?ll look at that first and see what it does for this.
I just wanted to double check, your plan is to use this calc'd value to dial in your mass air flow table? In both closed and open loop?
No, Im just playing with the math channels and trying to look at different information. But I?m also comparing different data that?s being collected vs the set parameters in the stock tune. I know it?s hard for most to understand, but there?s more than one way to measure AFR without a wide band if you know the information needed. They did it in the 1940?s with 3500-4000 HP aircraft piston engines, and on the fastest engines ever made on the SR-71, all done with pencil and paper with gauges and levers. This HP Tuners has a multitude of information I?m looking at and learning using my past experience. I?ve been scolded by a lot of people already on my way of doing things. I?ve had this car for 2 months and put about 2500 miles on it. I have not done any ECM tuning or even bought the credits yet. It has everything stock but I have done a few things to it and basically been scream at by others that I?m ignorant. Example: the supercharger is a fixed displacement and boost cannot be changed without a pulley change and the airflow/psi is not adjustable. Well I raised the boost from the stock 6-7 psi to 9. Did more research and math, and I put a 10% lower pulley on two days ago, (8.625 lower, stock 3? upper, 2.87 ratio) and now I?m at 13.2 psi and hitting the torque management boost disable and 115% injector duty and my catalyst temps are still normal at 1700 degrees. So I ADJUSTED the boost down to 11.5 psi and the injector duty is 102%. Now on my AFR math channel for my stock ECM, it?s reading perfectly with the command lambda and the PE ratio table within a few 10ths of a percent. My MAF readings are just one column axis apart (airflow vs frequency) at WOT. So am I not understanding something? I am getting a wide band soon along with injectors, cam, springs, and other work.
How did you get the boost from 6-7 to 9 without a pulley change? Did you fit an interchiller?
https://www.camaro5.com/forums/showthread.php?t=621746
The best I can tell is shimming the bypass spring.
At best, this calculates commanded AFR with measurement noise and transient effects introduced. If your MAF or VVE are underestimating, fuel flow will follow suit and yield the same calculated result, despite being leaner. Not really doing much for you.
Another kingtal0n type. I've been trying to tell him.
https://www.camaro5.com/forums/showt...8#post11396608
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