Topic: A/F mix for power

[flatlander]

here's the dyno graph for my 550:


the A/F mixture is between 12 and 13 throughout the rpm range. this is where i was also before the current engine mods but i wonder if this is good, or if it can be improved for squeezing a bit more power out of it?

what's done on the engine:
wiseco 59mm pistons
mike rieck stage 2/3 with +1mm intake valves
megacycle 126-00 cam
stock 069a carbs with stock jetting
stock airbox with stock paper filter
more details here: http://forums.sohc4.net/index.php/topic,134863.0.html

[TurboD]

My experience on track is that around 12.5 to even 13.2 is where you make the most power and best ET. So I would say you're really good.

[flatlander]

thanks, that's good to know.

[MRieck]

Roughly 13:1

[Bill/BentON Racing]

Samauto on the dyno!! Always liked this pic! K, Bill

[flatlander]

i guess i could try getting it a tad richer, closer to 13. but that is a really small adjustment. any guesses on how to get there, with jets or needle adjustment?

[TurboD]

If you are wanting to richen during WOT, you would install a larger main jet.

[MRieck]

Unless I am seeing incorrectly you are just a bit rich now at 12:1

[scottly]

i guess i could try getting it a tad richer, closer to 13. but that is a really small adjustment. any guesses on how to get there, with jets or needle adjustment?

The A/F ratio means the parts of air, by weight, to 1 part fuel. A larger number is more air, so 13:1 is leaner than 12:1.

[flatlander]

ah yes, thanks for setting me straight.

[Jerry Rxman Griffin aka MuthaF'er]

Try a K & N air filter for better flow. May lean it out that little bit.

[flatlander]

does.k&n still make them for the 550? i mean the one replacing the original filter, not the pods.