Originally Posted by Cheers!' post='920398' date='Apr 13 2009, 07:32 AM

So after 7 years of playing around with my car this is what I have before the original motor gave up.



SAFC wired to the Mazda pressure sensor

680cc GSL-SE injectors in the secondary fuel rail

10ohm resistors for getting the impedance of the injectors correct

Walboro Fuel pump

3" Turbo inlet duct

Racing Beat Turbo Back Exhaust

Paul Stokes DIY FCD with it wired after the safc so the voltage doesn't get clamped going into the safc



apexi AVCR for boost



What I noticed that if you use the SAFC to adjust for fuel by subtracting or adding you are also changing the timming. At 270 rwhp at 6000 rpm I recall my AFR being in the high 9s. I subtracted fuel from teh curve to get to 10s. When I subtracted the fuel I believed the timing actually advanced rather than retarded which is not what you want to do. This was at 11 psi(g).

Originally Posted by j9fd3s' post='920409' date='Apr 13 2009, 02:08 PM

the AFC goes in between the AFM and the ECU. since the ecu uses the afm to compute timing and fuel, changing the AFM changes both.



the AFM is a 5-0v sensor. key on car off its at 5v, idle is around 2-2.5v and 100% open is 0v

typically the AFM is 100% open over 5000rpms at full throttle, and since the voltage is 0, i'm not sure the AFC can ADD to that, as the voltage would have to go negative.



anyways to get back to the point, in theory a larger AFM opening (weather in reality or with the AFC) = more load, which = less timing and more fuel. a smaller AFM opening = less load which = less fuel and more timing.



so pulling fuel out with the AFC should also increase timing, but how much depends on where you are in the map, and how much correction you make with the AFC

Originally Posted by Cheers!' post='920410' date='Apr 13 2009, 11:27 AM

damn you mike. You are making me use my brain. It's been a while since I was so deep into rotaries and how rx7s worked. But that sounds about right, except that I thought full open (afm at 100%) occured at any manifold pressure about 5 psi regardless of RPM.

Originally Posted by Cheers!' post='920408' date='Apr 13 2009, 11:01 AM

I found the car most fun to drive when it was closer to stock.