S-AFC new users guide
Oct 17, 2003, 09:20 AM
#1
S-AFC new users guide
I posted this as a reply to a member who asked me about the S-AFC.. and I realised that this would probably make a very good 'How-To/Tech' article since nobody has posted a real guide.
I believe in the share with the community what i've learned
I have one more tech how-to to post once I verify that it works. (More to come!)
One observation about the S-AFC or any other MAf Intercept device.. because it intercepts the signal, the longer wires and its resistance causes the car to Idle a little lower than it would without it.. I used to think the car would 'learn it out' but it never did.. However if people find that they periodically stall, and they don't have a VTA Blowoff valve, this is probably the reason.. There is a setting for the BOV that lets it compensate, which might also work in that case, never tried it.. you can adjust the idle slightly at the Throttle body if needed.
Important configuration.. (I'm doing much of this from memory, so have the manual in hand as your configuring it so you can look up where these things are set)
Sensor type is Karmann, and the value of the sensor should be "Rising" (the diagonal up arrow, just means that its voltage reading increases as the karmann frequency rises, this is important because it will have a direct effect on how the correction compensation works)
TPS Sensor value should also be RISING since the value increases when throttle position increases.
for settings, EVERY car is different, and you really need to find a good baseline or have the car professionally tuned.. However I can offer a few base settings
(Assuming you have very few mods) You have to be very careful because leaning out your settings (A negative % correction) at the stock level, could be too lean for any other level..
If you are intent on tuning the car yourself, and going to road tune it.. you need an A/F Gauge, their essentially useless since their faily innacurate, but if your mixture is wildly off, you can at least get some indication.. You need a boost gauge, and an EGT (Exhaust gas temp) since by looking at the temp, you can see how lean the car is running, leaner mixture means more heat.. more heat is bad.. so its always a compromise.. The guys with an S-AFC-II Have the advantage of also being able to monitor knock.. I don't have one so I can't recommend a knock count since there will always be a small amount of knock, but I'm unaware at what count its considered detrimental or at what level the ECU begins to pull timing.
(Throttle points)
th-lo - most are running around 30-35%, for drivability's sake, I recommend going to 50% or 55%
th-hi - most run about 60%, I would go a little higher at about 70-75% (It improves drivability..)
Just so you know, 30% throttle is about when the car's ECU goes from closed loop to open loop.. open loop is when the fuel maps are used and therefore can be altered.. in closed loop, modifications to air flow generally get "Learned out" by the ECU so setting it lower than 30% is generally useless..
The th-lo and the th-hi settings are indications of when the corrections start, and when they are at their max settings, so if you keep the numbers fairly close,
you can get the curve to ramp up quicker, there are other ways to do that, but nobody currently uses it because it could effect other things.
your RPM Increments are generally every 500 rpm from 3500 to 7000, from about 3000 - 4500 rpm you want to try to ADD a little fuel to the car, NOT REMOVE.. so anywhere from +1 to +4% depending on the weather and typical engine load and if you find you get part throttle boost spikes at lower rpms..
5000 should be around -6% and 7000 should be around -12%... the rest of the values should fall in between and everything below 3500 will be 0% (no change) also these are the HI-TH
Correction point settings..
I cannot repeat this enough, THESE ARE ONLY GUIDELINES.. and although conservative, if you have alot of boost, or alot of mods, you might need MORE fuel, not less..
These are very conservative settings, and depending on the mods, you'll have to adjust them slightly.. These should be safe settings if your running a boost controller (at around 19-19.5psi through redline), but of course your not going to make the most power.. The problem is if you tune on the edge, you run the risk of detonation when weather conditions change.
For the monitor screen, you should watch the values for RPM, COR%, KAR, and THR
Karmann value should be around 30hz at idle (Just a little bit of trivia, when the engine is off, karmann reads 3hz, never zero), and can go way over 1200 at higher rpm's.. as long as it reads a value, and its going up, your sensor is connected correctly and configured..
COR% should start to move from 0 (Either positive or negative depending on which RPM Step your at) but the value will vary depending on your throttle position..
THR should of course read 0% when your not touching the gas, and 100% when your foot is about 3/4 to the floor.. (Hence my suggestion for raising the th-hi settings)
Hope this gets you started....
I am not responsible for damage if you go hog wild with your settings, so be VERY careful with what you do..
If anyone sees any GLARING innacuracies, PM me and I'll correct the post.. This might also be a good place for people to post their mod list, and AFC Settings for them..
The information I provided is accurate to the best of my knowledge..
I believe in the share with the community what i've learned
I have one more tech how-to to post once I verify that it works. (More to come!)
One observation about the S-AFC or any other MAf Intercept device.. because it intercepts the signal, the longer wires and its resistance causes the car to Idle a little lower than it would without it.. I used to think the car would 'learn it out' but it never did.. However if people find that they periodically stall, and they don't have a VTA Blowoff valve, this is probably the reason.. There is a setting for the BOV that lets it compensate, which might also work in that case, never tried it.. you can adjust the idle slightly at the Throttle body if needed.
Important configuration.. (I'm doing much of this from memory, so have the manual in hand as your configuring it so you can look up where these things are set)
Sensor type is Karmann, and the value of the sensor should be "Rising" (the diagonal up arrow, just means that its voltage reading increases as the karmann frequency rises, this is important because it will have a direct effect on how the correction compensation works)
TPS Sensor value should also be RISING since the value increases when throttle position increases.
for settings, EVERY car is different, and you really need to find a good baseline or have the car professionally tuned.. However I can offer a few base settings
(Assuming you have very few mods) You have to be very careful because leaning out your settings (A negative % correction) at the stock level, could be too lean for any other level..
If you are intent on tuning the car yourself, and going to road tune it.. you need an A/F Gauge, their essentially useless since their faily innacurate, but if your mixture is wildly off, you can at least get some indication.. You need a boost gauge, and an EGT (Exhaust gas temp) since by looking at the temp, you can see how lean the car is running, leaner mixture means more heat.. more heat is bad.. so its always a compromise.. The guys with an S-AFC-II Have the advantage of also being able to monitor knock.. I don't have one so I can't recommend a knock count since there will always be a small amount of knock, but I'm unaware at what count its considered detrimental or at what level the ECU begins to pull timing.
(Throttle points)
th-lo - most are running around 30-35%, for drivability's sake, I recommend going to 50% or 55%
th-hi - most run about 60%, I would go a little higher at about 70-75% (It improves drivability..)
Just so you know, 30% throttle is about when the car's ECU goes from closed loop to open loop.. open loop is when the fuel maps are used and therefore can be altered.. in closed loop, modifications to air flow generally get "Learned out" by the ECU so setting it lower than 30% is generally useless..
The th-lo and the th-hi settings are indications of when the corrections start, and when they are at their max settings, so if you keep the numbers fairly close,
you can get the curve to ramp up quicker, there are other ways to do that, but nobody currently uses it because it could effect other things.
your RPM Increments are generally every 500 rpm from 3500 to 7000, from about 3000 - 4500 rpm you want to try to ADD a little fuel to the car, NOT REMOVE.. so anywhere from +1 to +4% depending on the weather and typical engine load and if you find you get part throttle boost spikes at lower rpms..
5000 should be around -6% and 7000 should be around -12%... the rest of the values should fall in between and everything below 3500 will be 0% (no change) also these are the HI-TH
Correction point settings..
I cannot repeat this enough, THESE ARE ONLY GUIDELINES.. and although conservative, if you have alot of boost, or alot of mods, you might need MORE fuel, not less..
These are very conservative settings, and depending on the mods, you'll have to adjust them slightly.. These should be safe settings if your running a boost controller (at around 19-19.5psi through redline), but of course your not going to make the most power.. The problem is if you tune on the edge, you run the risk of detonation when weather conditions change.
For the monitor screen, you should watch the values for RPM, COR%, KAR, and THR
Karmann value should be around 30hz at idle (Just a little bit of trivia, when the engine is off, karmann reads 3hz, never zero), and can go way over 1200 at higher rpm's.. as long as it reads a value, and its going up, your sensor is connected correctly and configured..
COR% should start to move from 0 (Either positive or negative depending on which RPM Step your at) but the value will vary depending on your throttle position..
THR should of course read 0% when your not touching the gas, and 100% when your foot is about 3/4 to the floor.. (Hence my suggestion for raising the th-hi settings)
Hope this gets you started....
I am not responsible for damage if you go hog wild with your settings, so be VERY careful with what you do..
If anyone sees any GLARING innacuracies, PM me and I'll correct the post.. This might also be a good place for people to post their mod list, and AFC Settings for them..
The information I provided is accurate to the best of my knowledge..
Last edited by MalibuJack; Oct 17, 2003 at 12:45 PM.
Oct 17, 2003, 12:41 PM
#3
For the most part yes.. I'd back off 1 or 2 percent in very cold weather initially.. I'd also say that its dependent on your boost levels since high boost and more dense air means more fuel needed.. however, these are more conservative settings than most and should provide good gains through about 20 psi.. Its going to be trial and error to get something that works best for a persons car. I took into account part throttle spiking (especially in colder weather) which is why I recommended adding a little fuel in the RPM range where most of us might end up in when "Gassing to pass".. Downshifting or lugging and boosting usually is when I get the boost spiking, and it always seems to occur at lower rpms and at part throttle (60% or so)
Oct 17, 2003, 12:56 PM
#4
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The maximum of -12% correction is for a stock EVO? How about for EVOs with MBCs @20psi tapering to 18-19psi?
Avatar has an MBC with 20psi and he is running -19%. I think Buschur's is set max @ -17%.
Any more comments? Thanks guys. A lot of help in these forums.
Avatar has an MBC with 20psi and he is running -19%. I think Buschur's is set max @ -17%.
Any more comments? Thanks guys. A lot of help in these forums.
Oct 17, 2003, 01:07 PM
#5
I chose the most conservative values I could find that also gave decent gains.. -19% is risky when the air density changes because your "in the yellow" that is, on the border of going too lean in some circumstances. I've run -12% with 22psi of boost and made good gains, however I also hit fuel cut.
Truthfully I wanted to keep liability low by using conservative settings, and let a person "Sneak up" on their tune.. There's no doubt you can run 17%, but if you just create a linear ramp to 17 or 19% you'll find that there's a few very lean spots in the ramp.. and you need to go from a slightly positive value to add fuel in areas that might see boost spikes and higher loads, and optimum power at higher RPM's.. also keep in mind that 17 or 19% applies to WOT, but at part throttle, a large correction may introduce drivability bugaboos and leaning out if the turbo were to spike. I think everyone at some point has seen a 25psi spike when downshifting with a properly adjusted MBC..
My intention was to give everyone a safe start point, and dispell some of the mystery of this wacky device.. I'm hoping that you guys can contribute some of your own "Workable" settings that people with similar mods can start with.
Truthfully I wanted to keep liability low by using conservative settings, and let a person "Sneak up" on their tune.. There's no doubt you can run 17%, but if you just create a linear ramp to 17 or 19% you'll find that there's a few very lean spots in the ramp.. and you need to go from a slightly positive value to add fuel in areas that might see boost spikes and higher loads, and optimum power at higher RPM's.. also keep in mind that 17 or 19% applies to WOT, but at part throttle, a large correction may introduce drivability bugaboos and leaning out if the turbo were to spike. I think everyone at some point has seen a 25psi spike when downshifting with a properly adjusted MBC..
My intention was to give everyone a safe start point, and dispell some of the mystery of this wacky device.. I'm hoping that you guys can contribute some of your own "Workable" settings that people with similar mods can start with.
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Oct 19, 2003, 09:25 AM
#8
Yes, its safe, but I've found that below 3500 corrections aren't making much of a difference, and occasionally you can get a boost spike at 3000-3200 rpm if your downshifting causing a momentary lean condition..
The areas that are important for corrections are the places your PERSONAL car needs refinement.. The funny part is at about 3000-4000 I found I needed to ADD fuel because I was running a little lean..
Every car is different so every tuning set is going to be a little different. Guidelines are just that, guidelines.. and each of our cars will respond a little differently based on how it was broken in, how its driven on a daily basis, its modifications, air density, etc..
This isn't the be-all end-all for tuning parameters for the S-AFC.. Far from it, its a starting point. But everyone needs information, and everyone can benefit from sharing of info..
I'll keep saying this to everyone when they ask.. If you are uncertain of anything your doing, have a pro tuner do it with the right tools, you'll be alot happier because you won't have to go explain to the dealer how you melted something..
If your adventurous enough to do it, then always err to the side of caution and sneak up on your tune, and try to get the best tools you can afford to get the job done.. Even a pocket logger is a good tool although it lacks the resolution needed to "Do the job" 100%, the ability to log O2 voltage, Timing Corrections, and RPM will be invaluable in road tuning. It'll just take several attempts and you would need to always make small steps and sneak up on the tune.
The areas that are important for corrections are the places your PERSONAL car needs refinement.. The funny part is at about 3000-4000 I found I needed to ADD fuel because I was running a little lean..
Every car is different so every tuning set is going to be a little different. Guidelines are just that, guidelines.. and each of our cars will respond a little differently based on how it was broken in, how its driven on a daily basis, its modifications, air density, etc..
This isn't the be-all end-all for tuning parameters for the S-AFC.. Far from it, its a starting point. But everyone needs information, and everyone can benefit from sharing of info..
I'll keep saying this to everyone when they ask.. If you are uncertain of anything your doing, have a pro tuner do it with the right tools, you'll be alot happier because you won't have to go explain to the dealer how you melted something..
If your adventurous enough to do it, then always err to the side of caution and sneak up on your tune, and try to get the best tools you can afford to get the job done.. Even a pocket logger is a good tool although it lacks the resolution needed to "Do the job" 100%, the ability to log O2 voltage, Timing Corrections, and RPM will be invaluable in road tuning. It'll just take several attempts and you would need to always make small steps and sneak up on the tune.
Oct 19, 2003, 09:31 AM
#9
let me also add about the corrections below 3500 rpm.. Boost begins to ramp sharply at about 2800rpm, and will generally hit peak at about 3000-3200, this is where you may get boost spikes if your car is modified.. (even stock it could happen on occasion) Boost begins to taper (Even with an MBC) slightly at rpm's from 5500 through redline, thats why the correction settings on some peoples cars can be so dramatic at those RPM's.. The tapering (from what i can tell on my car) seems to be the stock blowoff valve leaking a little bit under boost (19psi seems to be about where it begins to leak on my car)
Ok I'm rambling and getting offtopic..
Ok I'm rambling and getting offtopic..
Oct 19, 2003, 09:35 AM
#10
Originally posted by BadBoyBeltran
The maximum of -12% correction is for a stock EVO? How about for EVOs with MBCs @20psi tapering to 18-19psi?
Avatar has an MBC with 20psi and he is running -19%. I think Buschur's is set max @ -17%.
Any more comments? Thanks guys. A lot of help in these forums.
The maximum of -12% correction is for a stock EVO? How about for EVOs with MBCs @20psi tapering to 18-19psi?
Avatar has an MBC with 20psi and he is running -19%. I think Buschur's is set max @ -17%.
Any more comments? Thanks guys. A lot of help in these forums.
Oh.. I feel the need to comment on this one again.. My car seems to run a bit stronger than most evo's.. and I found that even Buschur's settings were too lean! at 21psi I was backing off my settings until I hit about -12% and it seemed to be the magic number for my car.
Let me add that I had to remove my S-AFC and boost controller recently to troubleshoot my car's Fuel cut issue that I discovered in this cold dense air.. now you can understand why its best to be cautious about settings.
I just put 100 octane unleaded racing gas in my car yesterday, and did some road testing and STILL got fuel cut at 6000 rpm, with a fuel cut under load with part throttle at 3400-4500 rpm..
ITs obviously not a detonation issue with the gas I'm running.. It doesnt happen as frequently, but I do feel the stumble as if its a Miss.. I'm going to be checking the coils, wires, and plugs today to make sure their gapped correctly, its possible that I need to run a cooler plug though..
Last edited by MalibuJack; Oct 19, 2003 at 09:39 AM.
Oct 19, 2003, 09:57 PM
#11
with your mild mods you're probably hitting fuel cut because of excessive airflow detected by the MAF sensor. The s-afc actually tricks the ecu into thinking there is less/more air going thru. You may be hitting to much boost, even if for a split second, therefore hitting fuel cut. Try and back up the boost a bit, specially in this chilly weather were boost can be higher at times.
Oct 20, 2003, 04:40 AM
#12
my issue is unique to my car.... The point is offtopic so I'm not going to elaborate more other than I currently don't have an MBC or my S-AFC installed and it still does it from time to time... There's nothing saying that the same condition still exists without the S-AFC due to the need for extra fuel.. But its not a topic for this thread. Thanks for the info though..
Nov 26, 2003, 06:43 AM
#14
Hi,
I posted about a few weird items here:
https://www.evolutionm.net/forums/sh...threadid=50918
Most of these are resolved.
I hope that splicing the TPS better will fix the throttle readings. It's ~20% at closed and goes to 100% at like 1/2 throttle. I've adjusted my high and low points to compensate.
I know it's supposed to be pin 58, but on my car there is no wire in pin 58 and I had to use the pin "above" it. <goldmember>Isn't that weird?</goldmember>.
I just checked Karmann today in monitor, and it only reads 3hz (doesn't change), which it should read when the car is off. The correction factors seem to change as I go through the rpms. The sensor check shows diff values for "in" and "out". What wire corresponds to the karmann reading? If the fuel wire seems to be working, why isn't the karmann reading correctly? Car is performing better, so I think the correction is taking place. I don't have a wideband or dyno in the near future to make sure though...
Final point, I see other people get much lower knock readings. With my car fully warmed up, it reads like 720 at 800 rpm and 1600 rpm. I get 0 with it calibrated like this, but at idle I'll see readings of ~70-80. As I rev, it goes to 0. This seems to be working correctly, but why are these numbers so large?
Oh well, any input is appreciated. Could it be bad connections so my voltages aren't quite right? I'll take it out and rewire this weekend.
Thanks,
FB
I posted about a few weird items here:
https://www.evolutionm.net/forums/sh...threadid=50918
Most of these are resolved.
I hope that splicing the TPS better will fix the throttle readings. It's ~20% at closed and goes to 100% at like 1/2 throttle. I've adjusted my high and low points to compensate.
I know it's supposed to be pin 58, but on my car there is no wire in pin 58 and I had to use the pin "above" it. <goldmember>Isn't that weird?</goldmember>.
I just checked Karmann today in monitor, and it only reads 3hz (doesn't change), which it should read when the car is off. The correction factors seem to change as I go through the rpms. The sensor check shows diff values for "in" and "out". What wire corresponds to the karmann reading? If the fuel wire seems to be working, why isn't the karmann reading correctly? Car is performing better, so I think the correction is taking place. I don't have a wideband or dyno in the near future to make sure though...
Final point, I see other people get much lower knock readings. With my car fully warmed up, it reads like 720 at 800 rpm and 1600 rpm. I get 0 with it calibrated like this, but at idle I'll see readings of ~70-80. As I rev, it goes to 0. This seems to be working correctly, but why are these numbers so large?
Oh well, any input is appreciated. Could it be bad connections so my voltages aren't quite right? I'll take it out and rewire this weekend.
Thanks,
FB
Nov 26, 2003, 09:47 AM
#15
Well, I can tell you for certain that there's a pin 58.. If you don't have it, you may be looking on the wrong connector. I don't know about the knock readings only because I have an S-AFC and not the newer.
Double check your grounds, the symptoms your describing seem to be related to a bad ground.
Check to make sure that the in and the out of the sensor (the wire you cut) may be reversed. You should only see 3hz when the engine is off but the car's still on. (just not the accessory position, but the run position) Thats a clear indicator that its reversed because if your spliced into the right wire, and getting nothing. FYI, at idle Karman can read about 30-60hz and at high rpm, it can read several Khz
Also verify that your sensor type is definitely at Karmann, verify that your TPS setting is rising (the diagonal up arrow) If you spliced into the TACH lead make sure the RPM is set to 4, if you spliced into the Injector 1 wire, make sure its set to 1 (Otherwise it will read about 200 rpm at idle)
I'm not certain, but knock readings at idle may be false readings or something else rattling enough to trigger the sensor.
You need to double check your configuration and all of your wiring, SOLDER everything and make sure its insulated.
I'm a bit surprised to see your TPS value at about 20%, Depending on how good your solder joint is, you may see variations in where the TPS thinks WOT Is (I noticed this today when I tested my Apexi SAFC and SAVCR at the same time, at approx half throttle, one read 60% the other read 70% but both became 100% at 3/4, and both read 0 at idle..)
I took my hardware out to resolder everything with a better soldering iron..
Double check your grounds, the symptoms your describing seem to be related to a bad ground.
Check to make sure that the in and the out of the sensor (the wire you cut) may be reversed. You should only see 3hz when the engine is off but the car's still on. (just not the accessory position, but the run position) Thats a clear indicator that its reversed because if your spliced into the right wire, and getting nothing. FYI, at idle Karman can read about 30-60hz and at high rpm, it can read several Khz
Also verify that your sensor type is definitely at Karmann, verify that your TPS setting is rising (the diagonal up arrow) If you spliced into the TACH lead make sure the RPM is set to 4, if you spliced into the Injector 1 wire, make sure its set to 1 (Otherwise it will read about 200 rpm at idle)
I'm not certain, but knock readings at idle may be false readings or something else rattling enough to trigger the sensor.
You need to double check your configuration and all of your wiring, SOLDER everything and make sure its insulated.
I'm a bit surprised to see your TPS value at about 20%, Depending on how good your solder joint is, you may see variations in where the TPS thinks WOT Is (I noticed this today when I tested my Apexi SAFC and SAVCR at the same time, at approx half throttle, one read 60% the other read 70% but both became 100% at 3/4, and both read 0 at idle..)
I took my hardware out to resolder everything with a better soldering iron..
Last edited by MalibuJack; Nov 26, 2003 at 09:49 AM.