Lean after boost mod?

[01yellercobra]

Has anyone else done the boost mod to their Eaton and found the A/F was leaner afterwards? I datalogged tonight and found my A/F had drifted into the low 12's. Before is was 11.5-11.7. I also did some timing adjustments before doing the mod. But that was mostly to have one set timing across the range.

My FPDC topped out at 82% and I added some fuel. I'll be doing another log in a little bit.

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[Zemedici]

Pardon my ignorance but what’s a boost mod?

 

[Bdubbs]

For some reason I was always advised not to do the "boost mod".

 

[03cobra#694]

Pardon my ignorance but what’s a boost mod?

Boost bypass mod. Thsere's a write up in how to.

For some reason I was always advised not to do the "boost mod".

Never did it on mine.

 

[Bdubbs]

Are you getting zero boost drop off now? Maybe you had some before doing the mod? And now it's not dropping off causing the a/f to be leaner?

 

[01yellercobra]

Are you getting zero boost drop off now? Maybe you had some before doing the mod? And now it's not dropping off causing the a/f to be leaner?

To be honest I couldn't tell you. My stock gauge is pegged from the smaller blower pulley. And I don't usually watch the boost level on the Aeroforce when I'm in it.

I had a couple thoughts last night before falling asleep. I think it's a combination of things I'm seeing. Initially I had my timing ramped in and I changed it to be one value across the board. So that's probably why I saw it leaning out on the lower in. Then the top end is it holding boost better.

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