LSA tuning, A/F ratio adjustments

[MikeOD]

Original poster asked this: "For example, if I have a flat A/F ratio of 13:1 from 3000-6000 RPM an I want to increase it to 12:1, what steps need to be taken? I can accomplish this in less than 30 seconds on an aftermarket EFI."

The correct answer to fix this in 30 seconds is: Adjust the PE enrich table.

Modify the MAF if you want to make the PE table match the calculated value 100%... but that's not what he asked, and there is no advantage to this time spent since his AF is flat (no real need to smooth or correct the MAF if it's flat, now is there?).

Adjusting the MAF, then dialing in the PE will only satisfy the anal, which I have done, but only in my free time to tidy things up when I have the urge to tidy things up. It wont do anything else. The best part is, your explaining how to rape the MAF table to make the PE table match. Whatever makes you happy.

MAF/airflow data is used in determining spark as well...and various other parts of the tune. Raping the PE table to bring the fuel inline means you're also hitting the wrong part of the spark table, and then you have to tune that too...it's really amazing how quickly the whole tune comes in line when you get the MAF and VE data correct.

Not to mention...tuning the MAF table when you have the wideband feedback coming into the software...is as simple as clicking copy and paste...and if you know how to setup the scanner to tell you the VE table based on the MAF, building the VE data correctly to match (for proper blending and redundancy) is as simple as copy and paste, then clicking "Generate Equations", and then copy and paste again...it literally takes seconds. Then when the weather changes, the spark/fuel corrections work as they should...when the fuel changes, the spark/fuel corrections work as they should...when you decide to try changing fuel compositions, it's as simple as changing the stoich AFR value (or hooking up an alcohol sensor and letting it do it itself).

If you don't know how to do it the right way as easily as it can be done, don't tell people to do it a hacked way while also trying to defend it as the best way.

[Area47]

Original poster asked this: "For example, if I have a flat A/F ratio of 13:1 from 3000-6000 RPM an I want to increase it to 12:1, what steps need to be taken? I can accomplish this in less than 30 seconds on an aftermarket EFI."

The correct answer to fix this in 30 seconds is: Adjust the PE enrich table.

Modify the MAF if you want to make the PE table match the calculated value 100%... but that's not what he asked, and there is no advantage to this time spent since his AF is flat (no real need to smooth or correct the MAF if it's flat, now is there?).

Adjusting the MAF, then dialing in the PE will only satisfy the anal, which I have done, but only in my free time to tidy things up when I have the urge to tidy things up. It wont do anything else. The best part is, your explaining how to rape the MAF table to make the PE table match. Whatever makes you happy.

do that and watch what happens when the temperature changes. you're not calculating for the air flow being added by modifications you have done. you commanded 1.30 in the pe table but you're only seeing "12.0" on the gauge. adjust the correct hz range in the maf scaling to achieve it. you will see the calc/cyl air go up. there is more to it than just this, or half assing the pe table to get it. in a pinch it works, IE between runs at the strip, or dyno pulls for power.

[Ben Charles]

do that and watch what happens when the temperature changes. you're not calculating for the air flow being added by modifications you have done. you commanded 1.30 in the pe table but you're only seeing "12.0" on the gauge. adjust the correct hz range in the maf scaling to achieve it. you will see the calc/cyl air go up. there is more to it than just this, or half assing the pe table to get it. in a pinch it works, IE between runs at the strip, or dyno pulls for power.

Yep seen boosted Lt1 guys rape the PE table for boost and when winter came around they made another 2-3 lbs of boost and the engine went lean.

[Mike@G-Force]

Everyone puts so much faith in their wide bands too. How far off the stock calibrations are. I had one of my personal cars on two different dynos 1 week apart with the dyno's wide band in a bung, not a tailpipe sniffer. Exactly the same tune on both dynos. The A/F was a full point different between the two wide bands.

Thats why I only tune with a ECM AFM1000 wideband all others are crap!