Pocketlogger & SAFC-II
spyderturbo007
08-02-2004, 12:22 PM
As some of you may remember, awhile back I posted about using the factory exhaust with a larger turbo setup (I was looking for ways to spend my bonus from work). Well after all of the excellent information I received from various members I ended up getting a new receiver for my home theater (Sorry!!!). Your information will not go unused (The turbo IS coming) I am just approaching things differently. I have purchased a Palm m105 (ebay for $16 :) ) and ordered the pocketlogger software from digital tuning (the stuff is in the mail). My wife is going to get me the SAFC-II for my birthday next week and I will be ready to tune. The problem is, I have read everything I can find on this site, RRE's site, dsmtalk.com, RacingKnowledge and truthfully I am still kind of lost :loser: . I have read that some people remove some of the honeycombs from the MAS?? Is this a good idea?? What is this about backing out the sensor screw??? Here are quotes and corresponding questions from the RacingKnowledge post.
Quote: When this is done, free rev to 1500 rpm and hold it there. Do the same thing, it will probably still be on the low fuel trim.
Why do this if we haven't set a NePoint for 1500rpms??
Quote in regards to STFT: Continue to do this at 2k, and 3k rpm. After you are done and are fairly confident they are close, take the car for a drive and see if they change.
How should I drive it? Like I was just going to the store or like I was cruising around on a warm Friday night with the top down???
Quote: Once they are within 5 or 10%, and they have stayed that way for a drive, you can carry the numbers across up to 7k rpm. So, if you have +5% at 3k and 4k rpm, use +5% at 4.5k, 5k, 6k, and 7k. Then, you will also want to use +5% on your high throttle table, all the way across, until we begin to tune it in the next issue
Huh?? :uhoh: Umm....Within 5 or 10%. What the STFT & LTFT? Carry what numbers across to 7k? Once they (ST & LTFT) level out, ie close to 0% for the 2g, you just use the same setting for the rest of the RPM range.
Quote: Also, this assumes that you have used the same correction factor that you used for the higher rpm's of the low table, all the way across the high table.
High & Low table? I am guessing this isn't the same as the FT's? Is this a different set of parameters you can change in the SAFC?
Quote: So, with that information, decide if the 3000 rpm point is rich, lean, or just right. Then, add or subtract just a couple % of correction,
% of correction....Is this for the FT's or the High or Low table?
As for Section 4, entitled Tuning: Advanced, I think I will wait on that one. :p . I realize that my last post resulted in you guys spending your time replying to my questions and then me deciding not to go with the turbo. And for that I apologize :disappoin I just hope no one thinks I am one of those people who ask questions with no intention of following through. Ok, enough ranting. If anyone happens to read this and immediately thinks...."this guy doesn't know enough to start screwing with an SAFC" I would like to know. That might push me in the direction of paying SlowBoyRacing, or someone else to do it for me. I really don't want to do that seeing as how I still have the T25 with stock injectors. Thanks again!!
Here is the write-up I was talking about:
http://www.racingknowledge.org/topic.asp?TOPIC_ID=1011
Quote: When this is done, free rev to 1500 rpm and hold it there. Do the same thing, it will probably still be on the low fuel trim.
Why do this if we haven't set a NePoint for 1500rpms??
Quote in regards to STFT: Continue to do this at 2k, and 3k rpm. After you are done and are fairly confident they are close, take the car for a drive and see if they change.
How should I drive it? Like I was just going to the store or like I was cruising around on a warm Friday night with the top down???
Quote: Once they are within 5 or 10%, and they have stayed that way for a drive, you can carry the numbers across up to 7k rpm. So, if you have +5% at 3k and 4k rpm, use +5% at 4.5k, 5k, 6k, and 7k. Then, you will also want to use +5% on your high throttle table, all the way across, until we begin to tune it in the next issue
Huh?? :uhoh: Umm....Within 5 or 10%. What the STFT & LTFT? Carry what numbers across to 7k? Once they (ST & LTFT) level out, ie close to 0% for the 2g, you just use the same setting for the rest of the RPM range.
Quote: Also, this assumes that you have used the same correction factor that you used for the higher rpm's of the low table, all the way across the high table.
High & Low table? I am guessing this isn't the same as the FT's? Is this a different set of parameters you can change in the SAFC?
Quote: So, with that information, decide if the 3000 rpm point is rich, lean, or just right. Then, add or subtract just a couple % of correction,
% of correction....Is this for the FT's or the High or Low table?
As for Section 4, entitled Tuning: Advanced, I think I will wait on that one. :p . I realize that my last post resulted in you guys spending your time replying to my questions and then me deciding not to go with the turbo. And for that I apologize :disappoin I just hope no one thinks I am one of those people who ask questions with no intention of following through. Ok, enough ranting. If anyone happens to read this and immediately thinks...."this guy doesn't know enough to start screwing with an SAFC" I would like to know. That might push me in the direction of paying SlowBoyRacing, or someone else to do it for me. I really don't want to do that seeing as how I still have the T25 with stock injectors. Thanks again!!
Here is the write-up I was talking about:
http://www.racingknowledge.org/topic.asp?TOPIC_ID=1011
Nayr747
08-02-2004, 01:37 PM
Do NOT remove the honeycomes! It srews up the airflow and causes the engine to stutter or something. I dont know maybe ur talking about different honecomes. Someone correct me if im wrong.
JoeWagon
08-02-2004, 08:57 PM
Honeycombs is only a mod for 1g cars, you shouldn't do it.
Make sure to read How the SAFC work, and How to use a pocketlogger on the tuning section of the tech articles, DSMtuners. http://www.dsmtuners.com/forums/forumdisplay.php?s=&forumid=39
I'm not going to guess at SAFC tuning since I have no desire to do it. DSMlink here I come. Hope you figure it out :)
Make sure to read How the SAFC work, and How to use a pocketlogger on the tuning section of the tech articles, DSMtuners. http://www.dsmtuners.com/forums/forumdisplay.php?s=&forumid=39
I'm not going to guess at SAFC tuning since I have no desire to do it. DSMlink here I come. Hope you figure it out :)
kjewer1
08-02-2004, 11:14 PM
Let me try to simplify the whole thing. This is how to go about setting this thing, but the basics you need to know to be able to set it.
The whole point of all this BS is twofold. Compensate for larger injectors and other mods, both while in closed loop (cruisng, idling) and open loop (WOT (wide open throttle). In closed loop you have done your job correctly when your fuel trims are 0%, plus or minus about 5. For open loop, you aim for the correct AFR, or indirectly, no knock and max power.
The AFC has two "maps" or "tables" you can tune. High and low. What that is refering to is throttle position. You have most likely set it up so anything below 30% throttle is low and anything over 80% throttle is high. In between, it will come up with an interpolated correction factor that will be somewhere between what you have set for your low and high correction factors at that rpm point. Same thing in between NE points, it will draw a line between the two correction factors and apply that correction factor. (For example, 5k rpm is +10%, and 6k rpm is +12%. at 5500 rpm, you will get a correction factor of 11%, etc)
You use the low maps to tune the closed lopp operation, or fuel trims. And you use the high map to tune for WOT. Low tuning should be very simple on stock injectors. With fuel mods things get a little more invovled, but the procedure is still the same. You shoot for 0 trims. Short term fuel trim (STFT) is what the ECU is doing RIGHT NOW. Long Term fuel trim (LTFT) is a running average of what the STFT has been doing over the last couple minutes or whatever. The LTFT takes a few minutes to adjust. So lets say STFT is bouncing around at roughly 0 as it should be, and LTFT is plus 10%. YOu make a change, and STFT becomes minus 10%. Add them up, you get zero. Give it enough time and that STFT will move over to the LTFT and they will both read zero. ;) Now, a positive fuel trim means the ECU is ADDING fuel. So you have to add some more with the AFC on the low maps. A Negative trim means the ECU is taking fuel out, so you have to take some out with the AFC. Do this as Kyle describes for each RPM point.
Once you have an idea of what your fuel system looks like using the trims, you would typically transfer those values over to your high maps to start with. Then use the logger to see if you are knocking, or if you can go leaner.
And keep in mind the basic principles are exactly the same when using DSMlink. We just have more tools available giving us a better chance of making the right decision. With a logger, you cant see knock on a 2g. You have to go by timing. IT takes some time to learn what is good timing, and what is lw timing (knock lowers timing). All I Can suggest is loging the car as often as possible until you get a feel for how your car behaves. Make small changes on the AFC, and dont stray too far from where it is supposed to be (with stock injectors, all zeros is "stock." YOu shouldnt have to go too far on the high map to get maximum performance). The stock ECU is very good at what it does I have found, only a little tweaking is necessary. The most common mistake people make is not trusting the ECU and goig to far with the AFC, or overtuning (messing with 1% changes for every single rpm point, etc).
Kyles tuning guide on RKO is pretty much spot on, just start slowly and you will understand it all eventually. Tuning is a learned skill, takes a while to get the hang of it. Some people never do ;)
The whole point of all this BS is twofold. Compensate for larger injectors and other mods, both while in closed loop (cruisng, idling) and open loop (WOT (wide open throttle). In closed loop you have done your job correctly when your fuel trims are 0%, plus or minus about 5. For open loop, you aim for the correct AFR, or indirectly, no knock and max power.
The AFC has two "maps" or "tables" you can tune. High and low. What that is refering to is throttle position. You have most likely set it up so anything below 30% throttle is low and anything over 80% throttle is high. In between, it will come up with an interpolated correction factor that will be somewhere between what you have set for your low and high correction factors at that rpm point. Same thing in between NE points, it will draw a line between the two correction factors and apply that correction factor. (For example, 5k rpm is +10%, and 6k rpm is +12%. at 5500 rpm, you will get a correction factor of 11%, etc)
You use the low maps to tune the closed lopp operation, or fuel trims. And you use the high map to tune for WOT. Low tuning should be very simple on stock injectors. With fuel mods things get a little more invovled, but the procedure is still the same. You shoot for 0 trims. Short term fuel trim (STFT) is what the ECU is doing RIGHT NOW. Long Term fuel trim (LTFT) is a running average of what the STFT has been doing over the last couple minutes or whatever. The LTFT takes a few minutes to adjust. So lets say STFT is bouncing around at roughly 0 as it should be, and LTFT is plus 10%. YOu make a change, and STFT becomes minus 10%. Add them up, you get zero. Give it enough time and that STFT will move over to the LTFT and they will both read zero. ;) Now, a positive fuel trim means the ECU is ADDING fuel. So you have to add some more with the AFC on the low maps. A Negative trim means the ECU is taking fuel out, so you have to take some out with the AFC. Do this as Kyle describes for each RPM point.
Once you have an idea of what your fuel system looks like using the trims, you would typically transfer those values over to your high maps to start with. Then use the logger to see if you are knocking, or if you can go leaner.
And keep in mind the basic principles are exactly the same when using DSMlink. We just have more tools available giving us a better chance of making the right decision. With a logger, you cant see knock on a 2g. You have to go by timing. IT takes some time to learn what is good timing, and what is lw timing (knock lowers timing). All I Can suggest is loging the car as often as possible until you get a feel for how your car behaves. Make small changes on the AFC, and dont stray too far from where it is supposed to be (with stock injectors, all zeros is "stock." YOu shouldnt have to go too far on the high map to get maximum performance). The stock ECU is very good at what it does I have found, only a little tweaking is necessary. The most common mistake people make is not trusting the ECU and goig to far with the AFC, or overtuning (messing with 1% changes for every single rpm point, etc).
Kyles tuning guide on RKO is pretty much spot on, just start slowly and you will understand it all eventually. Tuning is a learned skill, takes a while to get the hang of it. Some people never do ;)
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