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Can anyone explain this

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Old 07-29-2016, 08:26 PM
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Can anyone explain this

What would explain different AFR numbers at WOT between 2nd and 3rd gear?

I've consistently logged an AFR of 11.8 at MAP97-100 between 3500 and 5000 RPMs in 2nd gear. However in 3rd gear at the same RPM and MAP the AFR is a near perfect 12.8.

How can I lean out the 2nd gear values without effecting what happens in 3rd gear?
Old 07-30-2016, 12:12 AM
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Car: 92 Trans Am Conv
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Re: Can anyone explain this

It's normal to have a difference due to length of time at the rpm but usually not so extreme.

What ecu/car are you working with?
I plan on writing a per gear fueling setup for 7730 ecu. But that's a ways out.
Old 07-30-2016, 11:14 AM
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Re: Can anyone explain this

Originally Posted by Vanilla Ice
It's normal to have a difference due to length of time at the rpm but usually not so extreme.

What ecu/car are you working with?
I am using EBL. It works great. I just have a lot to learn. The engine is a Pontiac SD4. Similar to the old iron duke, but about double the horsepower.
Old 07-30-2016, 02:49 PM
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Re: Can anyone explain this

Interesting engine. Not knowing the conditions of getting to 2nd gear and flooring it. There may be too much AE, or that AE lasts too long that is adding to the richness.

As for 3rd being 1 AFR leaner then 2nd, that does seem to be a bit high. However, if the AE is correct you can use the enrichment over time logic. Will need to reduce fueling via the VE table to get 2nd OK.

Then attack in the enrichment over time so that as higher vehicle speeds are attained, the AFR is commanded richer:

PE - AFR Attack Enrich Over Time

RBob.
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