I'd really like to know.. especially since I recently had me car dyno tuned. It even smells different.
Take a look at this plot:
Opinions please.

 

your a little lean on the upper rpms. i like to keep it at 13:1 or 13.1:1 throughout. There is enough safety margin in there to compensate for different weather conditions. The 13.6:1 at the top is pushing the safety limit. If it gets real cold out and you push it hard it could possibly lean out. from 4.5-5.5k you could lean it out a tad, otherwise graph looks solid

 

Naw.. for a stock or mildly built (compression) motor... sitting at around 13.5:1 A/F is perfect for NA.

12.5:1 for boost.

 

Keep it under 14:1. Its alot safer..
The weather really effects the A/F.
The car will run abit richer in cooler weather.
and a little extra fuel really doesnt cost u alot of horse.

 

Most of the NA Hondas I have tuned have made the most power at 13.1:1...


Jason

 

OK, Help me out here.. According to this graph, I thought lean was closer to the top. After all, the tech did set the V-AFC from -5% - 8% on the second run.

Torque says richer in cold weather, Fast94gsr says leaner in the cold.
and... 13.6:1 is "pushing the safety limit" ?
I'm seeing conflicting info here.
A little help?
thanks!

 

keep it a little lean in the bottom rpm range and the higher the rpms go the closer you want to be around 13:1...you should be around 13:1 at 4500rpm or so...have the botton rpm range rich will actually slow the car a little bit

 

dude you misinterpret what i'm saying let me clarify..

13.6:1 is pretty lean for the upper high rpms. when it gets colder your car will lean out even more to a 14.something :1 af ratio and that is unsafe. so richen it up at the upper rpms.

at the lower rpms your running too rich, keep the rpm range consistent with 13.1 throughout. 13.1:1 has been proven to be the best af ratio to go with. hope that clears things up.

 

colder air will lean the car out slightly.

 

13.0-13.5:1 on NA.
12.5-12.8:1 on FI.

I've seen the best results with these ratios.