Attn: Tuners-Low RPM AFR

[Ca_Silvia]

I just got my car retuned and at WOT it is a proper 11.3-11.6 all the way to red line. But when i am at 50% throttle, <5psi, <3500 rpm my AFR's are in the high 12's even seen a 13. As the revs/boost increases AFR do go down.

Is it normal to have higher then normal AFR at low rpm/low boost situations? It was my understanding that ANYTHING over high 11's is bad ANYWHERE while on boost.

[Nicksemianiw]

hmm well with my car its around a 11.-11.5 afr at WOT and it hits like 12ish for a second then drops down to 11ish. cruising at 4k rpm with no boost its 15ish but 13ish at 5psi sounds right cause if you mash it, it goes lower.

[progman]

sounds perfectly fine to me.

[Buddyworm]

Leaner mixtures on part throttle boost transition areas are normal. You don't want it to jump straight to 11-12 AFR once boost starts to build, it should transition smoothly.

[float_6969]

Sub 7psi boost pressures don't need that much fuel, and IMHO, I don't ever tune for any richer than 12:1 unless I am compensating for too much boost on too low octane fuel. If this is a stock compression CA, and you have 91 octane [(r+m)/2] they can lean that out some as long as you have a good intercooler.