If i were trying to lean out my car via an safc, and I just wanted it in the general "stoich" area, will my autometer AF guage fit the bill?

 

Not in this lifetime.

 

thought so, then what is a safe percentage of fuel I can take out to help my emissions test? My HC and CO readings are through the roof.

 

I don't agree with J-rat...In the middle ranges, or stoich area if you will, the narrow band is just as accurate as the wide as far as I'm concerned. If this were not the case, all new cars would have wide bands on them for the closed-loop operation to save fuel.

A narrow band's bounce will look the same as a wide band's bounce around the stoich point in closed loop...

 

^^^^ I concur. If you are looking for around 14.7 AFR then narrow band O2 is fine. Wide bands can measure from 9.0:1 to 15.0:1 AFR.

 

One word..

Dithering..

 

They have an idle test and a load test usually. Under load, you don't want to tune for 'stoich', at idle, tune the bitch until it stalls or starts hunting.

 

It's OK, Rat, it's a very rare thing indeed when I disagree with you

Dithering, I haven't been called THAT before...

 

Well the test goes up to 3k, so I was just gonna lean the hell out of it, but I dont want to go too low.

 

Run a shitload of alcohol and baby it.

 

Yea that too,

My HC readings where like 100 above the limit at 25mph and 50 above at 15mph

CO % was about double at 25 and 1.5 times more at 15mph.


So my plan will be about 10% less fuel up to 3500 and a gallon of alky-haul and a 1.4 tank of gas.

 

so what is the range for a narrow o2?

 

narrow band is simply not going to do it if youre tuning for any power. word on the street is that the stock o2 sensor pretty much just tells whether your rich or lean.. just a lack of accuracy. for a low rpm test though im sure you could probably get some correction #s from a forum member if anyone could volunteer an approximate amount that he can cut. being a turbo car though.. its tricky. my na .. ive run it -25% and it never detonated.

 

Yeah but make sure your running an upgraded fuel pump because you would be going dangerously low if you adjusted with a syock fuel pump.
I did this to pass my emissions test way back, i lowered the 1k to like -15% all the way through till 3k. Of course i had a walboro so i was flowing a little more fuel than normal.
It worked though i passed perfectly once i got rid of some of that fuel.