a/f ratio question...
09-11-2005, 05:46 PM
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a/f ratio question... my car is near stock..only has a cutout and free ram air mod. I had it dynoed 291hp and 301lbs/ft now my a/f line on the graph is a little wobbly it goes up and down between 11.5 and 12 this is to rich isnt it? and its basically stock. what are some things to cause this to do that? Also i have an MAFT, can anyone tell me what setting to set it to to fix this? Sorry im new to all this. Any and all help is appreciated.
car is a 98ta a4 64k miles new plugs and wires and fuel filter.
car is a 98ta a4 64k miles new plugs and wires and fuel filter.
09-11-2005, 10:02 PM
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... thats the thing.....i dont have the MAFT on it. i wanna put it on and lean it out but dont know how. why would the car be so rich being stock (except the cutout) what could cause it to be rich like that?
09-11-2005, 11:15 PM
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On the Translator you want to first make sure all the switches at the bottom left corner of the box turned off (that means all of them down because none of them applys to your car), next there are tow knobes that you can turn to tune the A/F ratio. The first one is for low end and idle, and the second one is for wide open throttle (WOT). The first knobe goes in 5% incriments 1=+5% 2=+10% 3=+15% 4=+20% 5=+25% 6=+30% richer, then it turns into alphabets A=-5% B=-10% C=-15% D=-20% E=-25% F=-30%. For the second (WOT) knobe it is in 2% incriments 1=+2% 2=+4% 3=+6% 4=+20% 5=+8% 6=+10% and the alphabets goes A=-2% B=-4% C=-6% D=-8% E=-10% F=-12%. Use it according to your needs and dyno tune it as soon as possible.
09-12-2005, 01:25 PM
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Why it does that, is GM told it to. The factory PE
table commands a 1.25 fuel air multiplier from 3600RPM
to 4800RPM which is 11.8:1, and from 5200RPM on up
it's even fatter (at least on my '02 stock table, I don't
have an example from '98).
The good news is, you look to be getting pretty close
to commanded AFR. The bad news is, it's not -your-
command. But at least the system appears to be near
realistic, which is a nice basis for tuning.
If you choose to use the MAFT then you want to set
the high-RPM scale dealie to about -10% for a 13:1
AFR. A little richer would be a little safer. I wouldn't
recommend fooling with the "base" settings because
that will likely push your fuel trims and trans line
pressure around. Hopefully the WOT dial won't be
seen during closed loop operation and only where
you have enough "load" to make for adequate line
pressure.
table commands a 1.25 fuel air multiplier from 3600RPM
to 4800RPM which is 11.8:1, and from 5200RPM on up
it's even fatter (at least on my '02 stock table, I don't
have an example from '98).
The good news is, you look to be getting pretty close
to commanded AFR. The bad news is, it's not -your-
command. But at least the system appears to be near
realistic, which is a nice basis for tuning.
If you choose to use the MAFT then you want to set
the high-RPM scale dealie to about -10% for a 13:1
AFR. A little richer would be a little safer. I wouldn't
recommend fooling with the "base" settings because
that will likely push your fuel trims and trans line
pressure around. Hopefully the WOT dial won't be
seen during closed loop operation and only where
you have enough "load" to make for adequate line
pressure.
