selanne8

just entered in my low throttle settings and i was wondering if i'm cruising at about 2800-2900 rpm, am i using the 2500rpm setting or the 3000rpm setting?

just wondering...

thanks,
john

bcty

i would say 2500.. use 3000 when u go over 3000

GsX2Rx7

its alot more complicated thatn that. i dont even get the basics of it. you know (hi-thrtl/lo-thrtl/ne point/air-dec) dont know what to set them at. got any ideas or basic settings. what mods you have done selanne8. can you please explain how to use the s-afs, the manual is confusing.

eddie

GsX2Rx7

oops s-afc

Bambam7

Adjust them both... the S-AFC extrapolates, and determines the condition between them based on their positions...

rx7_turbo2

OK

Air/Dec- Don't touch that it's for turbo cars that have problems with stalling when using a blow off valve vented to atmosphere, our cars don't have this problem.

Hi throttle/Low throttle- This just tells the SAFC when to do what. If you have an s4 car then the TPS is like an on off switch set the SAFC to Hi Throttle=99% Low Throttle=98% if you have an S5 the full range TPS lets you play around with it a bit more.

My RPM points are as follows I believe.

1000
2000
3000
3500
4000
5000
6000
7000

S4 cars= 05in 05 out
S5 cars= 06in 06 out

Flaper Door setting

4cylinder

Arrow points up to the right.

I think that covers it. Sorry if theres any mistakes correct me if I'm wrong

Anderson

HI, I'm lookign for a thread with English in it, ahve you guys seen one?? J/K

Excuse my S-AFC Ingorance.

Seeing how I don't have one, I was wondering how thsoe things are tunned, what kidn of options do they have, and do you need an experience person to tune one??

rx7_turbo2

No you don't need a pro to tune them. A pro and a dyno might be the best way but I know of many myself included who have tuned them succesfully by themselves with nothing more than an autometer a/f gauge. The key is to always locate your tunning on the side of rich rather than lean. Unless you have a dyno and wide band O2 sensor don't be trying to tune every last pony out of the fueling or you will blow your motor. Fine tuning must be done on the dyno, but very succesfull rough tuning can be done on the street.

The SAFC works great with the stock ECU. It's probably the best way to contol fuel while still using the stock ECU. The only downside to the S4 cars is the stupid TPS. The second generation SAFC allow for all sorts of different settings and senarios. The settings I qouted would sound like jibberish to most but if you've read the SAFC manual it would all make sense.

selanne8

sorry gsx2rx7, but when i said that the settings were just entered, i took it to my local rx7 guru who recomended it to me. i did the install myself, but you're right, the manual is confusing and i didn't want to screw with it until i had at least some clue as to what i was doing.

here's what i got out of it when we were chitchatting about the s-afc: the low throttle are the points to set when you're car is under 3k rpm. the low throttle points that he set for me were as follows:
1000 rpm = -8%
1500 rpm = -15%
2000 rpm = -18%
2500 rpm = -18%
3000 rpm = -8%

the high throttle points would be from 3500 up, but those were not set for me as he didn't have a dyno. he suggested that i could go find a nice strip of road and mess with the settings +- 2% at a time with a stop watch. not the most scientific way to set the high points, but better than stock most likely.

there's two reasons why my settings are so low - 1) i've got an n/a (so i don't need to worry as much as you turbo guys about pinging) and 2) i needed to pass smog (i was off the charts in terms of pollution). a word of caution that he gave me - it would probably be a good idea to run 91 octane while messing with the settings, that way if you do go too lean accidently, the octane will help prevent damage. most likely though, you'll see a decrease in speed/power before the pinging starts.

disclaimer - i do know a little about my car, but i don't completely understand how the s-afc works. i'm only trying to repeat what i was told, so if i've got it wrong, please jump in and save me.

when i figure out how to adjust the high throttle, i'll post a sample walk through.

john

mods - heavy street port on a 91 n/a, pineapple sleeves, k&n drop in filter. right now i have the stock exhaust on so i can pass smog tomorrow. after that, the bonez high-flow cat goes back on.

RXSETH

I was wondering if any of you get vacuum pressure on your super afc. I can't get a reading and was wondering if anyone knew how to rig it up.

Chris Ng

Ummm, okay.. there's some confusion about how the s-afc works and is set... Let's see if we can clear it up abit

One of the factors in determining the ammount of fueling your car is to recieves from the ecu is measured by the signal the ECU recieves from the AFM.. The S-afc works by changing this AFM signal at a given point to either make the ECU belive the AFM door is either opened more or less then it actually is.. In turn the ECU either adds or subtracts fueling..

How are these points set? Well the S-afc is basically set up with 3 diffrent fuel maps.. You have a low throttle map, a high throttle map, and an interpolated map that is somewhere in between the lo and hi throttle settings..

What determines with map you are using? The s-afc will determine which map point it is using by reading your Throttle position and compariing it to how you have the LO and HI throttle settings set up.. Example: If you set the LO throttle setting to 50% and the HI setting to 75%, then anytime your TPS is reading 50% or lower, you are going to be using the LO throttle map, If your TPS is reading 75% or higher the S-afc will switch over to the HI throttle map... But what if you are at 60% throttle? This is where the S-afc will interpolate between the low and high throttle maps.. It will find a correction value inbetween the high and low throttle maps at that given RPM and use it..

Series 4 cars use a narrow range TPS, and this can lead to some confusion for some people.. the TPS will read 100% even before your push your gas pedal down halfway.. unless you are willing to use a little creativity in rigging up a full throttle TPS, generally it's a good rule of thumb to set the HI throttle setting to 99% and the LOW throttle settings between 90-95%..

Selanne8's interpretation of the S-afc is unfortunately wrong.. Your LO throttle and high throttle fuel maps are not determined by what RPM you are at.. it's entirely based on what your throttle position you have set..

Hmmm. I hope this clears some things up and doesn't cause any more confusion.. If you guys with Turbos want to find out how to hook up the S-afc to determine fueling based on boost pressure, rather then throttle position, read the thread marked "FCD" you'll find a link to another thread in there that we had going concerning this.. or else you can just do a search for my name concerning the s-afc

selanne8

thanks chris, it makes more sense now...not yet crystal clear, but i'm getting there :-)

out of curiosity, anyone know why there's two settings (low/high throttle) and then from there it's keyed off rpms? why not just have everything off rpm?

john

Bambam7

Well, do you want the engine to be leaned out by 10% when you are just touching the gas, and ALSO when you are at full throttle?? No, not really.
The LO throttle map is to adjust for drivability, and fuel economy. If you have fuel system mods and things that cause your car to run richer than normal at part throttle, but fine at full throttle, you want the S-AFC correcting more at part throttle and less at full throttle.
Typically, the LO throttle settings (which are dependant on GAS PEDAL POSITION not RPM) are MUCH leaner than full throttle settings. This allows the car to be more fuel effecient while cruising, and still be able to give max fuel or whatever is required whenever you mash the pedal and go into the HI settings.

DON't try and measure these with a stopwatch!!!
If you have an N/A, you will only gain about 5-10 peak HP MAX, but maybe 15 in the midrange.... you won't easily be able to register those small increases, 1 or 2 hp at a time with adjusting, with a stopwatch!!
You at least need to use the voltage output from your O2 sensor, to determine what ratio you are running at, and arent going to lean to blow your motor!!
The more your car is modified, the richer it will run, and need correction by the S-AFC (leaning out)...
For your N/A, they run best at about 12.5:1 in low range, 13:1 midrange going up to 13.5:1 -14:1 at redline.
I have one on my car, and one it was set (o2 sensor only) It was easily the single most HP gain I have gotten from any one bolt on.

Anderson

This statement doesn make sense.

Unless I have been reading the wrong info about a free flowing exhaust, its supposed to give but 15 HP, which is already more that what you said the S-AFC will give.

I think the HP numbers for the S-AFC you gave are a lil bit low.

But I wouldnt know for sure either way, I'm jsut assuming by what I've read ont his forum.

rx7_turbo2

Chris, and Bambam cleared it up nicely.

The fuel requirments at any given RPM point are different depending on what type of driving your doing. You need less fuel at 4000rpm if your cruising, than you would need if you stomp the gas at or through 4000rpm. On turbo cars this is mainly because on cruising the engine is operating under vacuum and of course when you get on it the boost comes up and more fuel is need, it is this reason why many people have attempted with varying degrees of success hooking the SAFC to become boost dependant instead of throttle position dependant.