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greasemonkey
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3,123 Posts
Discussion Starter #1
im not sure if any of you know this or not but i figured id share the info. you can hook up an s-afc to tune the fuel by boost instead of throttle position. what you do is get a map sensor that has a 0-5v output, such as the stock map sensor(only measures up to ~15psi). but a 3 bar would be best. you hook the 5v power to the 5v power of the stock map sensor, or to another 5v power source such as the maf or the tps. then you hook the ground to the ground of the same device you took power from. then you hook the output of the map sensor to the tps signal wire on the s-afc. now it will allow you to adjust by boost instead of throttle position since the boost wont always be the same for a given throttle position, this will yeild better day to day drivability and a more accurate fuel curve. i know gm has a 3 bar map sensor that is readily available but am not positive if it is 0-5v output or not. i will try to find out and let everyone know. hth.
william
 

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Moderator, l337 M0d3r4t0r
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12,149 Posts
Yeah I've heard that before... Is quite a good mod, you can also hook up the blue wire to the o2 sensor to get 02 voltage and keep a eye on the 02 a/f's
 

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Can't wait for Spring!
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2,364 Posts
:drooling: thats so cool! wait wait wait. what about adding a toggle switch, that switched the input signals so you could tune for throttle, OR for boost. or toggle that O2 thing. hmmmmm....

how accurately does this work? so you would be tuning the safc for low/high boost conditions still based on the engine rpm? and you would configure the high/low boost settings under the throttle post. menu right? this is pretty cool. i' might consider this.
 
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3,796 Posts
Have you done this to your car or know someone who has? This sounds very interesting. What about off boost situations? I think this will cause promlems at lower rpm/throttle positions, where there is no boost or vacuum though.
 

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greasemonkey
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3,123 Posts
Discussion Starter #6
why would it cause problems? the map sensor measures vacum too.
william
 

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greasemonkey
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3,123 Posts
Discussion Starter #7
oh, and yes, it would be shown as throttle position even though its boost.
william
 
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Good info slim
 
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