Air/Fuel ratios … what is best?

I have a 2007 VFR800 that has been upgraded with FMF titanium exhaust, modified air box, aftermarket air filter, new spark plugs, and a Power Commander V with AutoTune module. The Power Commander V has the air/fuel ratios set from the factory between 13.5:1 to 13.1:1 … with 13.5:1 being mostly at/around idle, 13.2:1 for 90% of the A/F chart, and 13.1:1 at WOT and above 9,000-ish rpm (regardless of throttle position).

My question is … for those Gen 6 VFR'ers out there who have spent extensive time on the dyno tuning their bikes, what is the air/fuel ratio that you have settled on to achieve the best power output? I'm not looking for a full race A/F setup, but rather a performance minded A/F ratio based on a bike with mild mods running on 91 octane pump fuel.

I know that (assuming no detonation/knocking/pinging occurs) the leaner the A/F ratio the more fuel economy will be realized while a richer A/F ratio will make more power. However, I don't want a cruising A/F ratio so lean as to be concerned about blowing up something.

So, I'm wondering how far I can stray (on the leaner side) from the factory settings that the Power Commander uses for its performance tune. Is the Power Commander's A/F ratios already on the edge or can I go to 13.3:1, 13.5:1, or what?

 

Based on the total lack of replies to this thread, Last night I decided to tinker around with the air/fuel ratio settings on the Power Commander V. In general, I changed each setting by 0.2 on the leaner side. Overall, the bike feels crisper.

In a similar manner, for the mid throttle and mid rpm settings I went 0.2 leaner. Thus, the 13.3:1 settings went to 13.5:1 and the 13.5:1 went to 13.7:1.

At this point I am just tinkering … but I would still like to hear from someone who has done extensive testing on the dyno for more advice on the best air/fuel ratios for a Gen 6 VFR800.

 

I think once you get into really fine adjustments as you are day to day things like humidity, fuel blend, ambient air temp, and altitude have as much affect on how your engine will react. Just my two pennies.

 

And speaking of fuel blend, here in California we have the best fuel available as we get the lowest octane "super unleaded" (91 octane versus 92 or 93 octane used in most other parts of the USA) and lots of items mixed with the fuel to promote cleaner air (oxygenation additives, alcohol, etc.).

 

Still tinkering, still looking for advice.

 

Well on a dynojet dyno, they generally fix the AF ratio at 13.2/1 across the board & then adjust the PC's map to add or remove x% from what the standard ECU sends, to achieve that. Personally, I think that is way to Rich an AF ratio, as witnessed by the amount of soot in my exhaust & the poor mpg I'm getting with my custom map, plus the bike runs much cooler too.

I'm toying with changing my PC3 for a PCV + autotune too allow my to play with the AF ratio. In the mean time, I've manually bully a couple of new maps to see if less fuel at cruise throttle will give better mpg, without affecting throttle response & acceleration.