SAFC calculations help...

85celicasupra

spokane supra owner
Mar 9, 2008
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spokane,wa
forums.celicasupra.com
So I just got my mk2 boosted and up and running but it is running pretty rich on the RRFPR.
I knew it would, and that is why I bought an SAFC.

I have a wideband and know pretty much where I need to tune the fuel out, but dont know how much.
I know that the SAFC goes by a percentage, so is there a way I can calculate what percentage to pull by what my AFR is in that range...

Say just for examply I am running at 10.5 afr all the way through one adjustment point, how do I figure out the percentage of fuel to pull with the SAFC?

Also I know there are only 8 adjustment points for the SAFC. But can you choose from what RPM to what RPM?
I think I read somewhere they can only be in 500 RPM increments? Is this true??

ANY help is appreciated.

TIA
Scott.
 

mk3tattoos

New Member
Apr 12, 2008
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Bremerton, Wa
yep there are 8 points and at 500rpm. start it @ 3000-3500 and end the tune at 6000. you can not tune past 5500 rpm's due to the timing being pulled by the ecu. and you can only tune for WOT too. (that would be anything past 75% throttle) the best thing i found out is to set you afpr to the best running condition at idle and most important WOT. you should be able to get your a/f's close to 10.0 to 10.5. then the safc comes into play.
 

grimreaper

New Member
Jul 2, 2008
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Dallas
8% is roughly 1 point in af ratios. look at isnms charts (the man is good with excel!) and you can go from there.

Pleasing VF's at idle was not happening for me with fuel pressure, it caused me to have to pull to much fuel on the safc up top. I used the safc to please the vf's at idle and kept fuel pressure low enough that i could stay within the 20% safety range on the safc. I believe its because i have the stock lex afm screw in there and its not blocking any air what so ever. Your results may vary, good luck!

Tuning past 5500rpms may or may not be beneficial, i know for me thats when things slow down enough that i can actually look at my gauges (shift, and everything is a tunnel again). Ive read the timing being pulled bit and have searched endlessly for a 7m timing map to confirm. Only way to really know is stick it on a dyno. Maybe dr.j or supracentral have info on this and they can chime in.
 

85celicasupra

spokane supra owner
Mar 9, 2008
256
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spokane,wa
forums.celicasupra.com
Im not on a 7m here..
I am on a 5m...

The 8% was the answer I am looking for...
I will start with that basis (that 8% is roughly 1 pt of AFR)

but tuning out at idle and low rpms/ cruising is where i need to tune out some fuel cause I am running too rich there with my rising rate FPR. Under boost I am actually pretty good...
if I need an extra pound or so of boost I could always go for that...:evil2:
 

grimreaper

New Member
Jul 2, 2008
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Dallas
^ id pay for one! i have them for the 2j and 1j but the 7m got the cold shoulder. I was hopinig cp's ecu tear down would provide us with one shortly, still wishing....