S-AFC alters Ignition Timing??
 

To all the ECU gurus out there .....

I came across a question while sitting on the throne the other day. It goes like this ....

The Apexi S-AFC increases injected fuel to the engine by intercepting the MAP sensor reading and then altering it to fool the ECU (say a standard FD3S type and not an aftermarket programmable master blaster) into thinking that there's more/less boost than ACTUAL, hence making the ECU increase/decrease boost. On the other hand, the ECU has maps that retard timing (upon higher boost) and advances timing (upon lower boost) ....... SO ....... would it be correct to say that everytime we adjust the fuel using the S-AFC, we are in actual fact altering the timing signal given out by the ECU (which itself is reading a false reading)???

Some side effects could be .... ignition timing advancing too much at high RPMs or retarding too much at low RPMs, causing blown engines and slow spool up respectively.

Appreciate any feed back.

Amendments to the above .......

main paragraph, line 3 ...

"........ , hence making the ECU increase/decrease FUEL ..."

I am new into the RX tuning, and have a slight idea of how it works on MAP sensors. But I can tell you that it does affect the timing on MAS sensor vehicles. I tuned my ex-Eclipse, and saw the timing curve go from -3 degrees to 20+ degrees when I upgraded the entire fuel system, which meant I had to go as far as -49 on the AFC settings.

it will put you in a different area of the "map" due to altering the signal. so i would say YES it will advance the timing....
as machinis stated, the 4g63 motor will run as much as 20+ degrees using the AFC. cant see how it would be any different for you.

btw, i am going to move this to the S-AFC forum. ;) :wavey:

Thanks for the input you guys.

I think it'll be important for anyone using the S-AFC to acknowledge the above information.

In my case, the S-AFC is good enough for decreasing the Knight Sports ECU (which is tuned for a sequential system) fuel map between 4000rpm and 6000rpm. Only -5% fuel decrease required.

I hope I've further contributed to the rotary community.

the s4 t2 primarily uses the afm for altering fuel only. The pressure sensor is used for timing.