Air Fuel ratios...

freyguy_412 · Post by **freyguy_412** » August 16th, 2005, 6:56 pm

Ok... I got my Autometer A/F guage installed this weekend and just wanted to know if I could compare it's readings to someone elses. I got a K/N filter on the intake hose and a cat back exhaust done to it so far.

At WOT, it dances from about mid lean to the rich side of stoich under 3300-3500 rpm. After that, it usually pegs itself rich about 4 bars down. When I'm decelerating in gear, or the engine is coming down off a rev, the meter goes off the scale on the lean side (I assume cause it cuts fuel to lower the rpms to idle...) I just wanted to see if anyone else can verify these kind of readings so I can establish a base line before I start tuning (Ordering a SAFC in a few months... and yes I know that an A/F guage is only really an approx...) Thanks

facko · Post by **facko** » August 16th, 2005, 9:04 pm

that sounds about like how mine is, and ive got the bigger bp injectors in too. from slight to mid throttle its jumps around the richer side of stoich and when im @ WOT it just barely goes into the rich side, like 3 bars i think. when i had my stock injectors in it was about the same too so, im guessing thats where things should be? lol

nos92mx3 · Post by **nos92mx3** » August 16th, 2005, 9:12 pm

Lol, not to sound mean but you guys are comparing dancing lights..
A Narrowband o2 sensor Dosent tell you very much afr wise. its like 0-1v while a wideband is 0-5v(?)

facko · Post by **facko** » August 16th, 2005, 9:22 pm

yea but when ur a broke 17yr old the $60 guage is alot more reasonable than the $300 wideband

freyguy_412 · Post by **freyguy_412** » August 16th, 2005, 9:25 pm

I totally agree, but it's something rather than nothing. I want to run it with the piggy back just to have an idea of where she's runnin at a glance. That's all.

broke 17 yo

More done to his car than mine... lol

nos92mx3 · Post by **nos92mx3** » August 16th, 2005, 10:03 pm

Well get atleast an egt gauge as well, I just wouldnt want to see one of you guys posting something up along the lines of It smokes alot and has no power and is making funny sounds...
Oh and btw Im not spoiled and rich i work my arse off or everything i bought on my car including a 7$ an hour job which took me a month to save up for the wideband.
im Not harshing or trying to start a fight but i know your pain.

facko · Post by **facko** » August 16th, 2005, 10:08 pm

yea i know what you mean, im not planning on using the a/f guage to tune my whole turbo project off of tho...and im sure freyguy isnt either. id probably have a wideband by now but school started again so

cant work as much

nos92mx3 · Post by **nos92mx3** » August 16th, 2005, 10:30 pm

another thing to remember that 3 bars rich may be lean on a turbo motor.
Stoich on those AFR gauges are 14.7 which is very lean ona turbo motor.
What im trying to say is be careful guys.