Megasquirt MAT CLT correction table tuning (intake air charge temperature correction)
Автокөліктер мен көлік құралдары
Megasquirt MAT CLT correction table tuning (intake air charge temperature correction)
The ITB system I am running on my Datsun 240Z L28 stroker draws air from the engine bay. I was experiencing large changes in AFR when MAT and CLT temperatures would change which should not happen.
There are a lot of resources that suggest you should alter the MAT correction factor for air temperature density away from the default (based on the ideal gas law) and ignore other corrections. I do not agree with this strategy.
The missing link that assisted my tuning was using the MAT/CLT correction table which by default is all zero’d out. Just about all only aftermarket ECUs have self learning algorithms in the firmware. Megasquirt ECUs are about the only ECU which the user has to program this table.
Follow the video to see what I came up with for my build (everyone’s build will be different) and be sure to watch Andy’s video below!
Andy Wyatt’s video: • Video
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**CHAPTERS**
0:00 Intro
1:03 Air charge temperature theory and Megasquirt
2:39 My tuning challenges
3:38 I had some help
4:13 My solution and table
6:22 Validation of the solution
7:05 Outro
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DISCLAIMER: I am not a mechanic or tuner. This video is for entertainment purposes only and is not to be used an instruction or a guide for your own activities. Copying modifications described in this video is at your own risk.
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Пікірлер: 10
I'm keen for feedback from Megasquirt users how you might address air charge temperatures. Let me know with a comment 👍
Hey Aaron, can you please provide a link to Andy Wyatt's video that talks about intake air charge temperature correction. Thank you, and keep up the great work!
Great result Aaron, I bet that's a big load off your mind..lol🤣 Looks like she's getting very close to the perfect tune at last....Speaking of tunes, I always look forward to the outro music...Has been one of my favourite V.H songs forever🤣👍🇦🇺
@kyushaspeed
2 жыл бұрын
Thanks Simon 👍 It certainly feels like it was that missing link that stopped everything from working properly.
thanks for a inside! FYI Ecumaster has this as a 3D Table and it also needs to be tuned by hand
for some reason I can't find the clt/iat correction table. I have the tunerstudio MS ultra with mspnp2 ecu. Any idea why I don't have this option?
Could you help me with the data needed to complete this
You cant add fuel using the air flow mat correction table. The ms3 manual says to use the mat density table to make it richer. If the air intake sensor is subject to heat soak you most likely have to add fuel unti, the heat soak is gone.
@kyushaspeed
2 жыл бұрын
That is incorrect. The manual is poorly written in this regard which is why I prepared this video. The MAT table is a function of the ideal gas law which is fixed by nature and changing that table is a band aid fix. I am not sure why it is adjustable in the first instance as all big brand ECUs have this fixed as part of the fuelling algorithm. The MAT CLT correction table is to allow for heating of the air post IAT sensor as it moves through the heated intake manifold and approaches the intake valve. Watch Andy Wyatt's video linked in the description for better context. Most after market ECUs have this correction already integrated into the fuelling algorithm normally called intake charge correction and is a 3D table. Megasquirt only has a 2D table which is a little illogical but better than none. The amount of correction varies on the amount of flow through the manifold as slower air has opportunity to absorb more heat than faster moving area.
@marks93cobra
2 жыл бұрын
@@kyushaspeed Hi, I found your video because I am desperately trying to figure out how to populate the correction table. I have a v8 ford 5.0 pushrod engine, and the IAT is literally about 3-4 inches from the intake valve. I find it highly unlikely that the air temp would increase much (if at all) in that small of a distance before it gets into the cylinders, so I am trying to figure out how to basically fill out that correction table so it does not take the coolant temperature in effect at all. I could see this being an issue if the IAT is mounted, say, in the filter box, which would read (essentially) ambient, but I believe in my case, I want the megasquirt to take the IAT AS IS and don't fudge it against the coolant temp. Thanks for any advice you can give me!