amused

Ok, just spent an entire night wiring it up nice and purty.

On the advice of a rotorhead I know who i believe knows his stuff, I attached the TPS (grey) wire to the MAP sensor. Supposedly in the long run this is better for me because it's adjusting fuel for boost, not throttle positon.

I attached the o2 sensor too, but it doesn't really seem to do anything for me.

There is a built in pressure sensor in the SAFC, but it doesn't seem to be picking up any readings. There are two wires left that I did not use, a pink and an orange, but I tried hooking those to the MAP as well and it didn't change the dead reading of -760

These is my wire setup - suggestions/thoughts?
Red - Pwr
Green - RPM
White - Airflow In
Yellow - Airflow Out
Blue - o2
Grey - MAP Sensor
Brown - Ground
Black - Ground
Pink - ?
Orange - ?

Now, it's all setup. 4cyl, Flap 6, setup, etc. I'm planning on running 720s but right now I"m on the stock fuel setup plus a Walboro. Should I bother bringing the car to the dyno before I drastically change my fuel delivery or are there basic fuel maps I can set up myself that will be a little stronger? I already adjusted the idle mixture to make up for a phantom vac. leak.

With the TPS wire hooked to the MAP sensor, under WOT the TPS reads 65% at best. Any way to get the AFC to recognize that as 100%?

Anyway, I'm really having fun now. I love my car. I'm getting that rush feeling that happens after every new mod.

Fingers

Initialize the SAFC... (like, reset it). not by unplugging it, by actually going into the "initialize" menu

good luck
-Ross

SonicRaT

iTrader: (6)

How's your S-AFC doing running off the MAP? I'm hoping to be doing this soon instead of running off the TPS. Have any issues at all?

Scott 89t2

if you have an 89 stick the TPS wire onto the TPS. the map trick is for 86-88.

Cheers!

2nd gens do not have MAP (mass air pressure sensors) we have MAF mass aiflow sensor via flap type.

You will get no reading from pressure on the safc. Since we don't have a MAP sensor. We have a MAF sensor.

The method you have just describe is hooking the throttle input to the Pressure sensor on the car.

You throttle now monitors 0 to 5V output of the pressure sensor.

Please check teamfc3s.org for the paul stokes FCD. Paul stokes detemerined the relationship between the pressure and voltage output of the Turbo II pressure sensor.

Basically at 14 psi you get 5V at -640mmHG you get 0 V

however setting up the safc on the pressure sensor is very very diffcult.

My original plan was to have the safc control boost over 8 psi (which is stock max boost for S5 TII cars) to accomplish this the safc would have been set such that the low throttle point percentage would have been set to the throttle % corresponding to the voltage at 8.2 psig.

so from paul stokes we know

Out(V) = 0.169V/psi*P(psi) + 2.318V

P(psi) = (Out(V) - 2.318V)/0.169V/psi

Pluggin in some numbers:
14.7 psig = 4.8023V (which i belive is the max pressure of the pressure sensor)

8.2 psig = 3.7038 V

3.708V / 4.8023 V = 0.77

or 77 percent.

Therefore if i set the safc low thorttle point to 77%, and thing below 77% will have fixed fuel adjustments. I then set hi - throttle point to 100%. Therefore anything over 100% throttle point (ie 14.7 psi) will also get fixed fuel enrichment.

So anything between 77% and 100% is then corrected/average by the safc.

The problem now comes.

How to calibrate the safc. The safc is self learning. Apexi knows that not all automolbile sensors can give 0 to 5V output. Maybe hte carpet is too thick... whoknow.

So when you hook up the thorttle wire to teh pressure sensor lead (before the FCD) of the ECU harness, the max voltage the safc now sees is 3.7038V which is 8.2 or max stock psi.

So it thinks that 3.7038 V is 100% throttle.

Now you see why it's a bitch to set it up? i ahven't set it up correctly.

Right now iknow that at 0.27 kg/cm^2 which is 3.84 psig my safc says i'm at 100% throttle. I want the safc to read full range but the safc only learns when it has RPM and air flow and throttle tied in. You can't just put a compressor with a check valve and start trying to go from vac to 14.7 psig on the rx7 pressure sensor.

I'm now thinking of hooking the wire back over to the throttle for 0 to 5 V operation, have it learn on that. then reattach it to the pressure sensor lead.

So that hte safc calibrates over a wider voltage range.

Good luck.

ViRuS

Hey guys! I have a ? How can I tell for sure if the s-afc is gen 1 or gen 2? I thought the one with the **** was ver.2 (or limited edition?)But i am not to sure. Thanx sorry this has nothing to do with your thread. But you guys sound like you would know. Thanx again.

vectorminds

the one with the **** is the second version

gsracer

Maybe on a s5 I would hook into the TPS, but I definitely tied my safc into the pressure sensor.

It really doesn't matter what percent it's reading as long as it's under 100 percent. Let me explain. Let's say at 8 pounds of boost the TPS (which is actually a voltage coming from the pressure sensor) reads 60 percent. Up until 8 pounds I feel more than confident in the factory ecu to take care of fuel. All you need to do then is set the hi-thrtle map at 60, and set the lo-thrtle at 59. So in essence you have the stock fuel map up until 8 pounds of boost at which point it switches over to what figures you have plugged into the safc.

With my safc tied into the pressure sensor it originally ran into 100 percent throttle at 4 pounds. Since this is way to small of a pressure to set as a high map switch over I just did a little thinking. All the safc reads is a voltage coming from the pressure sensor. So then therefore if you lower the voltage, you lower the throttle reading. A quick trip to radioshack and 2 bucks later I soldered in some resistors inline between pressure sensor voltage line and my safc. Now I hit 100 percent around 8-9 pounds. I have 99percent set as the high-thrl map switch over and I love how it works. No, it's not nearly as good as a 3d fuel map ecu, but for a 200 dollar hack it will hold it's own on the stock turbo all day long.

Scott 89t2

the one with one **** and blue sceen is the S-afc II. the one with arrows and blue screen is the S-afc.

there was one even before that with 4 or 5 ***** and no screen. so just because it has a **** doesn't make it the new one