Ideal timing for coolest engine at idle?
if you're using a wideband or any oxygen based system than youre dead wrong. Your post about injection timing is all fine and well but if you're using a wideband to tune A/F it absolutely does impact it. You live in a world of theory....remind me of Chuck Cow blinding potential customers with all this gibberish and double talk.
You calling me out?" because I will start filling the thread with pics of videos of turbo cars I tuned
thats all I tune, and there are hundreds of engines out there idling around 14.5 and 14.9:1 that I took the extra time and care to ensure wouldn't wander into the 13's at idle. And the plugs come out lookin clean as they went in, the engines sound and smell great. And that is what matters to me.
thats all I tune, and there are hundreds of engines out there idling around 14.5 and 14.9:1 that I took the extra time and care to ensure wouldn't wander into the 13's at idle. And the plugs come out lookin clean as they went in, the engines sound and smell great. And that is what matters to me.
if you want to find out what your engine likes for fuel/spark at idle, try the following: Turn off Closed Loop, Idle Spark and IAC. Ignore your AFR as it is most likely skewed by the overlap of your cam. Adjust fuel for highest idle/ lowest MAP and do the same for spark. I would drop the MBT spark by about 5 degrees to give your Idle Spark some torque reserve for A/C, fans coming on etc.
Mike
Mike
stoichiometric is where fuel is burned for cleanest emissions (C0 and NOX) and that is it. Saying all engines idle cleanest at 14.7 afr is a joke and shows your lack of experience. Some engines with a lot of overlap won't even think about idling at stoich.
To get back on topic this is the correct way to tune for best idle spark.
To get back on topic this is the correct way to tune for best idle spark.
Please don't pretend I care about emissions lol
if you're using a wideband or any oxygen based system than youre dead wrong. Your post about injection timing is all fine and well but if you're using a wideband to tune A/F it absolutely does impact it. You live in a world of theory....remind me of Chuck Cow blinding potential customers with all this gibberish and double talk.
Wideband gauge will read 16:1 or 18:1 if you have enough fuel to flood the cylinder and dampen the spark (very very rich condition). This misfire condition still reads lean because a wideband is not perfect. It is with the essence of that example you must see that the number on a wideband cannot be trusted, therefore you are never really supposed to "tune with it" based on what it says. You tune based on what you know, instead. What you know is that the computer says that 11.255ms of fuel was injected, and you know that the speed of the injector at 13.8volts was .414ms, so you have 11.255 - .414 worth of on-time at 68psi of fuel pressure which is some exact quantity of fuel, that you happen to know is somewhere near 70% duty cycle of an injector capable of supporting 100horsepower per cylinder, so if this was a V8 you should be nearing the 600-700 horsepower region depending on the a/f ratio. We also know that our VE/MAF table is within 5% of accurate (you flow benched it first and acquired the true voltage cuve) giving us within 5% of actual airflow, which enables us to calculate the true air fuel ratio without looking at the wideband. The wideband could read 0 or -.- and we can still find the air/fuel ratio in theory by using the computers information, never depend on a wideband fully. Just because the number wanders around doesn't make it true. That fuel is there... and stuck there, if it injected post EVC.
there is a very simple scientific way to tackle these sorts of questions.
Datalog with:
10*
20*
30*
Compare vacuum, idle speed, EGT, for some number of minutes.
Then adjust Air/fuel ratio and repeat the test for reasonable ratios (14+ usually)
You can do the same thing for fuel economy cruise situations:
data-log EGT, vacuum, Injector duty;
Increase or Decrease timing using 5* increments
Compare data-logs. You want the highest vacuum with the lowest injector duty and lowest EGT in most situations for cruising at normal speeds, you MUST USE CRUISE CONTROL. Higher speed cruising (100mph+) throw all this out the window and keep the air fuel reasonable near the low 14's to high 13's for safety (as you tip in at those speeds the engine is much more likely to lean misfire)
IMO Idle timing I tend to keep say 15-22*. Alot of engines have idle timing control which constantly jumps the timing around to help steady the idle, making it much less of an "ordeal" when deciding what number to actually put into the map. Some ECU will even over-ride the users input number for some static hard-wired starting value (apexi Power FC does this). The Cruise timing is much more important for keeping an engine cool than the idle timing; you should not be throwing off enough temp rise during idle to cause an issue. The engine BTU/joules output around idle is minimal compared to say, high RPM at WOT.
Datalog with:
10*
20*
30*
Compare vacuum, idle speed, EGT, for some number of minutes.
Then adjust Air/fuel ratio and repeat the test for reasonable ratios (14+ usually)
You can do the same thing for fuel economy cruise situations:
data-log EGT, vacuum, Injector duty;
Increase or Decrease timing using 5* increments
Compare data-logs. You want the highest vacuum with the lowest injector duty and lowest EGT in most situations for cruising at normal speeds, you MUST USE CRUISE CONTROL. Higher speed cruising (100mph+) throw all this out the window and keep the air fuel reasonable near the low 14's to high 13's for safety (as you tip in at those speeds the engine is much more likely to lean misfire)
IMO Idle timing I tend to keep say 15-22*. Alot of engines have idle timing control which constantly jumps the timing around to help steady the idle, making it much less of an "ordeal" when deciding what number to actually put into the map. Some ECU will even over-ride the users input number for some static hard-wired starting value (apexi Power FC does this). The Cruise timing is much more important for keeping an engine cool than the idle timing; you should not be throwing off enough temp rise during idle to cause an issue. The engine BTU/joules output around idle is minimal compared to say, high RPM at WOT.
Also, trying idling a big cam at 14.7 AFR. Good luck.
There you go again spouting off stuff you read somewhere else and not in the real world. Your "real world example" using math to calculate AFR doesn't take into account things like reversion, injector dead time, and component tolerances. You're guessing and claiming it as the truth......I'm done replying to your ignorant post in this thread. I must resist the urge to feed the trolls.
The main idea if I were to shorten to one sentence:
Overlap and long duration camshafts may influence the wideband sensor read, but not the actual a/f ratio which was determined elsewhere, you cannot trust the wideband as you remove fuel at idle and the engine starts to skip/hop/jump around so instead you look at the injector PW and use intuition / common sense.
Would you like a video of an LSx 5.3L turbo engine with a long duration (beyond 230* @ 0.050) camshaft idle between 14.6 and 15:1? I bet I can find or make one...
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Verdad Gallardo No, sorry, you are missing the point still. The idea isn't that we know some exact number or perform any calculations. The idea is, if you are running the engine hard, and the spark blows out, who are you going to believe: the wideband that reads 16:1+ or the computer which says you have 70%DC correlated with the power output just before the engine stumbles? It is a lesson in wideband sensor readings, nothing more.
The main idea if I were to shorten to one sentence:
Overlap and long duration camshafts may influence the wideband sensor read, but not the actual a/f ratio which was determined elsewhere, you cannot trust the wideband as you remove fuel at idle and the engine starts to skip/hop/jump around so instead you look at the injector PW and use intuition / common sense.
The main idea if I were to shorten to one sentence:
Overlap and long duration camshafts may influence the wideband sensor read, but not the actual a/f ratio which was determined elsewhere, you cannot trust the wideband as you remove fuel at idle and the engine starts to skip/hop/jump around so instead you look at the injector PW and use intuition / common sense.
http://www.hotrod.com/articles/ctrp-...ine-reversion/
QUOTE- Just keep in mind the process tends to blend exhaust gas with fresh air/fuel mixtures. Plus, it also represents a portion of the combustion ingredients that take up space in the place where combustion occurs. By displacing some of the space that could be occupied by combustible material, it further reduces power as evidenced by lower exhaust gas temperature. It’s like a built-in EGR (exhaust gas recirculation) system.- END QUOTE
By DEFINITION- when you have things like reversion you CANNOT use a math equation based on injector pulse width to determine actual air fuel ratio in the chamber.......NOW IM DONE.
Last edited by ddnspider; Sep 26, 2016 at 03:43 PM.
The purpose of a log is to establish steady-state conditions. In order to find steady state, a system must have a 4th dimension of time at the very least. SO you log the system as long as necessary to ensure that you have hit a steady state for every variable (found their ranges). Then, adjust the conditions (both initial and after the fact) and repeat the tests. This is an engineering principle, not a tuning specific one.
Would you like a video of an LSx 5.3L turbo engine with a long duration (beyond 230* @ 0.050) camshaft idle between 14.6 and 15:1? I bet I can find or make one...
Would you like a video of an LSx 5.3L turbo engine with a long duration (beyond 230* @ 0.050) camshaft idle between 14.6 and 15:1? I bet I can find or make one...
Anyways for the original question yes a bit more timing at idle will increase vacuum, clean up combustion, and drop engine temps to a certain extent. It can also make the spark timing idle control function much less effective so I would never just ramp up timing at idle until the MAP stopped decreasing. At that point you have effectively neutered the PCM's ability to increase rpms by increasing timing taking away a very effective idle control method that the factory PCM uses.
Holy hell, what a load of ****. Your very first comment about how a "misfire condition still reads lean because a wideband is not perfect" shows a complete lack of understanding. A misfire can show lean on a wideband because it reads unburned oxygen and you don't have complete combustion, not because it's not perfect. The rest of your diatribe is absolutely ridiculous and I hope nobody listens to it.
Wideband gauge will read 16:1 or 18:1 if you have enough fuel to flood the cylinder and dampen the spark (very very rich condition). This misfire condition still reads lean because a wideband is not perfect. It is with the essence of that example you must see that the number on a wideband cannot be trusted, therefore you are never really supposed to "tune with it" based on what it says. You tune based on what you know, instead. What you know is that the computer says that 11.255ms of fuel was injected, and you know that the speed of the injector at 13.8volts was .414ms, so you have 11.255 - .414 worth of on-time at 68psi of fuel pressure which is some exact quantity of fuel, that you happen to know is somewhere near 70% duty cycle of an injector capable of supporting 100horsepower per cylinder, so if this was a V8 you should be nearing the 600-700 horsepower region depending on the a/f ratio. We also know that our VE/MAF table is within 5% of accurate (you flow benched it first and acquired the true voltage cuve) giving us within 5% of actual airflow, which enables us to calculate the true air fuel ratio without looking at the wideband. The wideband could read 0 or -.- and we can still find the air/fuel ratio in theory by using the computers information, never depend on a wideband fully. Just because the number wanders around doesn't make it true. That fuel is there... and stuck there, if it injected post EVC.
Anyways for the original question yes a bit more timing at idle will increase vacuum, clean up combustion, and drop engine temps to a certain extent. It can also make the spark timing idle control function much less effective so I would never just ramp up timing at idle until the MAP stopped decreasing. At that point you have effectively neutered the PCM's ability to increase rpms by increasing timing taking away a very effective idle control method that the factory PCM uses.
Holy hell, what a load of ****. Your very first comment about how a "misfire condition still reads lean because a wideband is not perfect" shows a complete lack of understanding. A misfire can show lean on a wideband because it reads unburned oxygen and you don't have complete combustion, not because it's not perfect. The rest of your diatribe is absolutely ridiculous and I hope nobody listens to it.
Holy hell, what a load of ****. Your very first comment about how a "misfire condition still reads lean because a wideband is not perfect" shows a complete lack of understanding. A misfire can show lean on a wideband because it reads unburned oxygen and you don't have complete combustion, not because it's not perfect. The rest of your diatribe is absolutely ridiculous and I hope nobody listens to it.
Anyways for the original question yes a bit more timing at idle will increase vacuum, clean up combustion, and drop engine temps to a certain extent. It can also make the spark timing idle control function much less effective so I would never just ramp up timing at idle until the MAP stopped decreasing. At that point you have effectively neutered the PCM's ability to increase rpms by increasing timing taking away a very effective idle control method that the factory PCM uses.
Holy hell, what a load of ****. Your very first comment about how a "misfire condition still reads lean because a wideband is not perfect" shows a complete lack of understanding. A misfire can show lean on a wideband because it reads unburned oxygen and you don't have complete combustion, not because it's not perfect. The rest of your diatribe is absolutely ridiculous and I hope nobody listens to it.
Holy hell, what a load of ****. Your very first comment about how a "misfire condition still reads lean because a wideband is not perfect" shows a complete lack of understanding. A misfire can show lean on a wideband because it reads unburned oxygen and you don't have complete combustion, not because it's not perfect. The rest of your diatribe is absolutely ridiculous and I hope nobody listens to it.
1. actually the real reason is because of the design of the circuit and it's components, and there is an even more specific reason after that involving programming, and again, another even deeper one involving electrons and atomic theory, and then finally quantum physics and observations and whatever god wants. The real reason is simple: it isn't perfect. Your reason is no better.
2. Who cares why it reads wrong? Does that change anything? No. You argue a futile point because at the endof the day: The wideband is still wrong. Which was my only point. I don't give a **** how you quantify that. It's wrong and you have to stop using it, and use your head.
Seriously.....just stop posting. I get exactly what you're saying and you're wrong. EDIT........I'll just go ahead and leave this here:
http://www.hotrod.com/articles/ctrp-...ine-reversion/
QUOTE- Just keep in mind the process tends to blend exhaust gas with fresh air/fuel mixtures. Plus, it also represents a portion of the combustion ingredients that take up space in the place where combustion occurs. By displacing some of the space that could be occupied by combustible material, it further reduces power as evidenced by lower exhaust gas temperature. It’s like a built-in EGR (exhaust gas recirculation) system.- END QUOTE
By DEFINITION- when you have things like reversion you CANNOT use a math equation based on injector pulse width to determine actual air fuel ratio in the chamber.......NOW IM DONE.
http://www.hotrod.com/articles/ctrp-...ine-reversion/
QUOTE- Just keep in mind the process tends to blend exhaust gas with fresh air/fuel mixtures. Plus, it also represents a portion of the combustion ingredients that take up space in the place where combustion occurs. By displacing some of the space that could be occupied by combustible material, it further reduces power as evidenced by lower exhaust gas temperature. It’s like a built-in EGR (exhaust gas recirculation) system.- END QUOTE
By DEFINITION- when you have things like reversion you CANNOT use a math equation based on injector pulse width to determine actual air fuel ratio in the chamber.......NOW IM DONE.
Lets work backwards from the IVC. IVC = intake valve close. Going backwards, it starts to open. Fuel is washing in because this is where you phased idle injection to occur. Now keep moving the piston up towards overlap position. What's that? We are moving backwards in time so the fuel is never exposed to overlap conditions?
Lets try it forward. Exhaust is being pushed out and the piston is moving up. The Intake valve starts to open as the engine is approaching overlap. Still no fuel hanging around because the injector is phased shut. The overlap occurs, air goes where it wants, then the exhaust valve shuts. NOW the injector opens. Fuel Cannot escape into the exhaust system because the valve was never open for that to occur. Overlap therefore has no effect on air fuel ratio in this situation as our MAF/MAP VE programming is "100%". As VE changes within a range because of overlap situation this will cause the air/fuel to vary cylinder to cylinder, but there is no way to "tune that out" so we deal with whatever range appears, regardless of what the wideband says. It isn't appropriate to say that it 'affects air fuel ratio because VE varies'- it does so in all applications, all camshafts, because no cylinder ever fully balances 100% with the next one in any engine, all the time.
Originally Posted by kingtal0n
1. actually the real reason is because of the design of the circuit and it's components, and there is an even more specific reason after that involving programming, and again, another even deeper one involving electrons and atomic theory, and then finally quantum physics and observations and whatever god wants. The real reason is simple: it isn't perfect. Your reason is no better.
2. Who cares why it reads wrong? Does that change anything? No. You argue a futile point because at the endof the day: The wideband is still wrong. Which was my only point. I don't give a **** how you quantify that. It's wrong and you have to stop using it, and use your head.
2. Who cares why it reads wrong? Does that change anything? No. You argue a futile point because at the endof the day: The wideband is still wrong. Which was my only point. I don't give a **** how you quantify that. It's wrong and you have to stop using it, and use your head.
TLDR cause you literally posted about quantum theory in a prior post in a thread about idle timing. Stop Googling crap and regurgitating text book crap. Stop trying to "help" cause your way of going about it is entirely wrong. Perhaps you should analyze your approach to providing info and making posts of public forums.
Im going to keep trying to help you until you get it.
Lets work backwards from the IVC. IVC = intake valve close. Going backwards, it starts to open. Fuel is washing in because this is where you phased idle injection to occur. Now keep moving the piston up towards overlap position. What's that? We are moving backwards in time so the fuel is never exposed to overlap conditions?
Lets try it forward. Exhaust is being pushed out and the piston is moving up. The Intake valve starts to open as the engine is approaching overlap. Still no fuel hanging around because the injector is phased shut. The overlap occurs, air goes where it wants, then the exhaust valve shuts. NOW the injector opens. Fuel Cannot escape into the exhaust system because the valve was never open for that to occur. Overlap therefore has no effect on air fuel ratio in this situation as our MAF/MAP VE programming is "100%". As VE changes within a range because of overlap situation this will cause the air/fuel to vary cylinder to cylinder, but there is no way to "tune that out" so we deal with whatever range appears, regardless of what the wideband says. It isn't appropriate to say that it 'affects air fuel ratio because VE varies'- it does so in all applications, all camshafts, because no cylinder ever fully balances 100% with the next one in any engine, all the time.
Lets work backwards from the IVC. IVC = intake valve close. Going backwards, it starts to open. Fuel is washing in because this is where you phased idle injection to occur. Now keep moving the piston up towards overlap position. What's that? We are moving backwards in time so the fuel is never exposed to overlap conditions?
Lets try it forward. Exhaust is being pushed out and the piston is moving up. The Intake valve starts to open as the engine is approaching overlap. Still no fuel hanging around because the injector is phased shut. The overlap occurs, air goes where it wants, then the exhaust valve shuts. NOW the injector opens. Fuel Cannot escape into the exhaust system because the valve was never open for that to occur. Overlap therefore has no effect on air fuel ratio in this situation as our MAF/MAP VE programming is "100%". As VE changes within a range because of overlap situation this will cause the air/fuel to vary cylinder to cylinder, but there is no way to "tune that out" so we deal with whatever range appears, regardless of what the wideband says. It isn't appropriate to say that it 'affects air fuel ratio because VE varies'- it does so in all applications, all camshafts, because no cylinder ever fully balances 100% with the next one in any engine, all the time.
Legitimate question, what is wrong with you? That isnt out of a textbook or PowerPoint by a reputable source, that's your own crap. I literally posted a hotrod article disproving your theory and you respond with a picture you made. When you post factual data from a reputable source (aka not from your head) maybe your post will hold weight. I'll try this 1 more time for you, read it slow, than stop and reread it and realize it completely disproves your theory.
QUOTE- Just keep in mind the process tends to blend exhaust gas with fresh air/fuel mixtures. Plus, it also represents a portion of the combustion ingredients that take up space in the place where combustion occurs. By displacing some of the space that could be occupied by combustible material, it further reduces power as evidenced by lower exhaust gas temperature. It’s like a built-in EGR (exhaust gas recirculation) system.- END QUOTE.
QUOTE- Just keep in mind the process tends to blend exhaust gas with fresh air/fuel mixtures. Plus, it also represents a portion of the combustion ingredients that take up space in the place where combustion occurs. By displacing some of the space that could be occupied by combustible material, it further reduces power as evidenced by lower exhaust gas temperature. It’s like a built-in EGR (exhaust gas recirculation) system.- END QUOTE.
every word you type is 'your own crap'
I just put my words into a picture cause im sick of typing.
Now, you either find something wrong with it, or ask a question to get clarification, or step off. Every new thing that somebody invents is 'their own crap'- when a scientist doing research or a PHD creates a paper about Ebola virus or whatever its 'their own crap'. Just because it winds up in some kind of online journal or a book about viruses doesn't make it any more or less legitimate. Its up to the reader/observer to determine what is being presented and draw their own conclusions.
I updated it to include an xample for even more clarification. Hope it helps.
consider that even if a misfire occurs and the wideband jumps, that doesn't change the a/f ratio. It just means the hydrocarbons passed through un-reacted and might even react later in the hot exhaust tube. Also I probably had a stand-alone on a V8 before anyone in this thread, and have written software to control it.
here it is, my first stand-alone ECU, I think 2001? I don't primarily tune 4-cylinders, that is a myth. Ironically I mostly tune 6's, for whatever reason. Everybody has a 2jz
http://s9.photobucket.com/user/kingt...zzsfl.mp4.html
I just put my words into a picture cause im sick of typing.
Now, you either find something wrong with it, or ask a question to get clarification, or step off. Every new thing that somebody invents is 'their own crap'- when a scientist doing research or a PHD creates a paper about Ebola virus or whatever its 'their own crap'. Just because it winds up in some kind of online journal or a book about viruses doesn't make it any more or less legitimate. Its up to the reader/observer to determine what is being presented and draw their own conclusions.
I updated it to include an xample for even more clarification. Hope it helps.
consider that even if a misfire occurs and the wideband jumps, that doesn't change the a/f ratio. It just means the hydrocarbons passed through un-reacted and might even react later in the hot exhaust tube. Also I probably had a stand-alone on a V8 before anyone in this thread, and have written software to control it.
here it is, my first stand-alone ECU, I think 2001? I don't primarily tune 4-cylinders, that is a myth. Ironically I mostly tune 6's, for whatever reason. Everybody has a 2jz
http://s9.photobucket.com/user/kingt...zzsfl.mp4.html
Last edited by kingtal0n; Sep 26, 2016 at 08:18 PM.
