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By vilefly
#26081
It would be most useful to use either a custom MAF or a singular brand-specific MAF sensor with speeduino. It would speed up the adaptation tables and quicken the tuning process considerably. I can invade my gm ecm to pull up the lookup table for the MAF sensor to provide enough information to be of use in a feedback loop if an oxygen sensor cannot be installed (such as a marine application where the manifold is flooded with water to keep it cool).
This would help things along considerably for those applications without an oxygen sensor for feedback. I will see what I can dig up in terms of a MAF lookup table (frequency vs Grams per second). An interpolation formula will have to be implemented to fill the gaps, but I hope it won't slow down the system)
User avatar
By vilefly
#26083
This a MAF table for a 1995 LT-1 motor used in my station wagon. I imagine a 4 cylinder MAF would be more accurate for smaller engines. A more popular MAF sensor brand would also be more useful to others. I just don't have the MAF tables for those, but anyone using TUNERPRO with a 4 cylinder maf system should be able to pull it up.
Attachments
LT-1 MAF TABLE.png
LT-1 MAF TABLE.png (40.75 KiB) Viewed 2393 times
User avatar
By PSIG
#26085
Boats use anti-reversion elbows to keep water out of the inside of the engine manifolds, allowing O2, EGTs, etc. However, assuming there is an application that could not use feedback; how would you intend to tune the lookup table? I have some ideas, but have not tried them.

David
User avatar
By vilefly
#26086
If one could datalog the MAF g/sec output with calculated airflow, you could see which direction you need to adjust the VE table. Some code might have to be added to post the calculated airflow, though.
By klotzy_550
#26111
You could rescale it all to volumetric flow rate, then density doesn't affect it. Air density X volumetric flow rate = mass flow rate.

That being said, MAF isn't necessarily easier, yes in theory the math is more direct. MAF is susceptible as low engine speeds to reversion and skewed readings. Due diligence needs to be taken on MAF placement, and plumbing to ensure laminar flow. Quite a few GM ECU's use a blend of speed density and MAF until roughly 4000rpm (on LS truck engines) to where it switches entirely over to MAF. The reason It can do it here is that the intake pulsing has negligible effects on the reading at those volumetric flow rates.

TLDR; I would like to see this feature added, but it is not as easy as assumed.

Just my $0.02.
By JHolland
#26119
vilefly wrote:
Sat May 12, 2018 3:13 pm
This a MAF table for a 1995 LT-1 motor used in my station wagon. I imagine a 4 cylinder MAF would be more accurate for smaller engines. A more popular MAF sensor brand would also be more useful to others. I just don't have the MAF tables for those, but anyone using TUNERPRO with a 4 cylinder maf system should be able to pull it up.
A MAF with an analogue output may be easier to implement, I have data for a Suzuki MAF but that's not common either and wouldn't flow enough air for larger or blown engines.
User avatar
By vilefly
#26133
Since speeduino is better suited to 4 cylinder engines, it is probably more useful than my v8 MAF sensor data. I say we all post what data we have, and see who uses it later on.
By JHolland
#26210
This is from a Suzuki 58B00 MAF taken at 45C IAT.

Image

The red area is where the ECU applies a credibility check based on VE and limits the MAF value. The output from the MAF is actually a current source, a 1K resistor in the ECU converts the current to a voltage.

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