In order to use 440cc injectors I know we will need to use a SAFC. How does the SAFC make it work in our cars? I would like know and understand.

thanks!



l e o n

DIGITAL SUPER AFC
Piggyback Fuel Computer

Modifies air-flow meter signal
(pressure signal in some vehicles) to
optimize fuel-air ratio; Vacuum
Fluorescent Display (VFD).


The second-generation S-AFC is a
fuel computer that adjusts fuel/air
ratio by modifying the air-flow
meter/MAP sensor signal. The
S-AFC features a user-definable,
eight-point, adjustable fuel curve that
can be set in 500 RPM increments.
The range of fuel adjustment is +/-
50% at each of the user-defined
setting points. On hot-wire vehicles,
the Deceleration Air Flow Correction
function is capable of curing the
erratic idle and stall problems
associated with open-atmosphere
blow-off valves on hot-wire air-flow
meter systems. The S-AFC is
capable of monitoring and replaying
the following data channels in
Numerical, Analog Meter and Graph
displays: Intake Manifold
Vacuum/Boost Pressure, Air Flow
Capacity, Intake Manifold Pressure,
Karmann Frequency, Engine RPM,
Throttle Position, and Air Flow
Correction %.

How do you know at what RPM to set the settings?

Also, since our map sensors don't read boost, is it possilbe to replace the sensor so that the AFC can see boost?


l e o n

Messing with an S-AFC is not for the timid, IMHO, but you must know a little about how to use your gauges and meters. You will need at least a Voltmeter to read your O2 sensor and EGT gauge to measure how hot the gases are, shooting out of one of your exhaust runners(the hottest is number 1 I believe). HRC's site has a little info about how to tune and so does RRE.

Skrilla
'97 Base Talon NA
"Technology is the Only Substitute for Displacment"
"Peace and Turbo Grease"

Actually cylinder number 4 runs hottest. Also, the AFC allows you to read many sensor voltages including the O2 sensor.

yeah I got my guages..

is it cylinder 1 or 4 that runs the hottest?

I have my EGT probe taped on the far right side..


l e o n

Driver's side Cylinder is number four. If you are looking at the front of your car it is the cylinder/runner closest to both the battery and PCM. I see it on my hotshot header and it is number four. The driver's cylinder. It is also the cylinder last(obviously) on the rail

Skrilla
'97 Base Talon NA
"Technology is the Only Substitute for Displacment"
"Peace and Turbo Grease"

yup, that's where I tapped my probe..

why is it that that cylinder runs the hottest?


l e o n

I've heard a few different explanations. One being that its so far on the fuel rail that it doesnt get enough fuel. Etc etc. Its just a good safe idea to monitor your hottest cylinder. If that one is in check, then you know the others are fine.

One question:

would it not be better to monitor it at the collector (where all four runners meet)?

l e o n

Then you would be getting the average temperature of all four cylinders. We know for a fact that #4 runs the hottest, so why not get the reading from the hottest cylinder? That cylinder could run dangerously hot while the other three are within acceptable ranges. It's just safer that way.

-DarkOne
I'm so bad, i should be in detention.

Are we sure the temperatures are averaged and not cummulative?

I don't see how they are averaged...the temperature probe just measures temperature; it doesn't do any division!


l e o n

1st off heat is not exactly commulative. If it were commulative then taking 12* of heat and 150* would equal 162* when that's not the case at all, especially since 12* is actually cold air, the same applies for all "heat". 600* plus 600* doesn't equal 1200* but just helps to sustain the heat, sure it may be a little higher but certainly not twice the heat.

-to answer an earlier question: who would really want an average where all the heat is combined. Like Darkone said while 1 cylinder is lean the other could be rich, so I would you take the worst of the pick #4. Ideally(if you had $$) you would get 4 EGT's for each exhaust runner(monitor each cylinder).

Skrilla
'97 Base Talon NA
"Technology is the Only Substitute for Displacment"
"Peace and Turbo Grease"

Heat isn't cumlative at all. Measuring temp at runner #4 vs at the collector is like measuring the temp at my house and the temp at your house. Your not measuring the same place. No such thing as 150C+150C. If you take a 30deg F block of ice and put it next to another 30deg F they dont cumulate. You still have 30deg F. The four individual runners cannot heat the collector any hotter than the hottest runner (turn your stove to 400deg you cant heat the chicken to 420deg). Putting the probe at the collector would allow the exhaust to cool by the time it reached there. Not only would you not know which cyl is the hottest you couldn't measure exh temp as accurately as you should. The closer to the exhaust port the better.


Stan2gnt
Stan2va@aol.com
95 Talon ES-I-NOS
http://members.nbci.com/FlyEsi/home.htm
You too can have a never updated site complete with old info and dated pics!

http://smkn95eclipsemwc.homestead.com/mainpage.html