LT1 8051 EE 1240A Mass Air Cylinder Coefficient vs Map vs RPM

[Terminal_Crazy]

Can anyone confirm what this table does ?

I guessed it's a scalar for VE calculation? A bigger number calcs more air & adds more fuel per the VE number?

I increased the low rpm / high kpa and the tune went richer in that area.
Raised the med & High rpm / high kpa and the tune seems to have leaned out.

Thanks
Mitch

[kur4o]

This table is only used with MAF, it smooth down the rapid transition of maf reading, so you got more flat curve instead of steep peaks.

Usage is still unknown even after I have played it with it realtime. You can also control it realtime to see best settings.

Main usage is to compensate on rapid acceleration and deceleration, something like a maf pumpshot. Or modded engine with stock settings, when you nail it you got lean stump very often. Playing with this table help alot for that condition.

On SD tune it is never used by any form.

[Terminal_Crazy]

Ah OK. Thanks Kur4o, I don't need to persue that avenue then.

Another question then. OL SD Tune still.
Have you got any info on Intake Temp compensation.
I've still got the '95 Z28. I've got an aluminum intake elbow right behind the radiator & it heatsoaks.
I've moved the IAT sensor down to the side of the Cold Air Intake so it still seems engine bay temps.
Normally the car intake is running around 20C. The last run out was a hot sunny day, air temps near 30ish. It seemed to run leaner as the temps got hotter.
Idle also goes lean still but that's down to the 3" header collectors and pipe & lack of flow there.

How would I richen up the tune with a rising intake temp ? or is my issue else where?

Thanks
Mitch

[steveo]

you want the iat right at the throttle body but isolated from conducting heat. if its heat soaking from the elbow you need s bigger grommet
i consider a -/+ 5% seasonal variance in fueling with speed density acceptable and unavoidable

[Terminal_Crazy]

Thanks Steveo.

Why would it tend to lean out when the intake temp goes up?

I'm using all the stock temp settings and have played with them without any consistant results.

[MO LS Noobie]

If you are concerned with heat soak you could try wrapping the elbow in some kind of thermal wrap. Heat soak is typically is thought of when you shut off the hot engine the heat soaks into everything, not a running engine. As the temperature goes up less fuel is needed for proper AFR, but less horsepower is the result. That's the way it's programmed, and why that parameter is in the tune. Some of the older EFI system actually had the IAT in the intake manifold, it was compensated for in the programming.

[In-Tech]

you want the iat right at the throttle body but isolated from conducting heat. if its heat soaking from the elbow you need s bigger grommet
i consider a -/+ 5% seasonal variance in fueling with speed density acceptable and unavoidable

Yes, Not trying to interrupt but I would like to throw in that some aftermarket IAT sensors are copper or brass like an ECT sensor, all bad when used as an IAT sensor. The factory one's use a faster response element. These pictures are of the correct type.