wjbecker

Hi guys I put a procharger 9psi
on my 89 gta it works great.how lean is
too lean for idle??? I have @16:1
in open loop and i lowered it from 18:1
should i go to 15:1 or 15.5:1????

thanks in advance

scottland

14.7:1

TexasLT1

As lean as you want and the engine can handle. 16:1 sounds way too lean though. I wouldn't go any higher than 15:1, but since its just idle, is there really a point to go any higher than 14.7? You're not going to gain anything by doing that.

wjbecker

thanks for reply
I have read posts in the past
that someone said a lean idle is desireable and I think ihave seen it multiple times. once my car goes into closed loop it modulates between 14.3:1
and 15.4:1 but it hangs around 14.7.
open loop hangs around 15.1:1 to 16:1.
I can adjust the maf to get closer to 14.7
but it runs and idles so good.
I will get it to 14.7 at idle to have something to compare to.
this car is a weekend daily driver
and I want it to be happy in all weather.

thanks

25THRSS

that is fine. Some cars only get around 17:1 afr during highway mode.

Tony89GTA

iTrader: (7)

Are you getting your numbers from a WB02 setup or are you just looking at what the scantool is putting out.

wjbecker

I am using a techedge wb02
it is very relyable so far --3 wks.

biggtime

I'm 14:1. Thats what my combo likes. You need to find what your engine wants. Different Idle speeds will dictate different mixtures.

gta324

Big cam engines may like richer A/F at idle to stabilize it......

I think GM has richen up the idle some in the chip......