been playing around with the car, adding timing. Whats a safe level for correction factor?
09-02-2006, 10:57 PM
#41
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Calling it a "Map" is a misnomer...
I'm no expert but I've learned quite a bit at ASP as well as through my own explorations.
There are quite a few factors which go into timing correction. There are a number look-up tables used to determine the requested values. There are also triggers which affect timing in the long-term(CF) Medium term (IAT) and short term (KV). When the ECU detects spurious (not predicted) knock, it applies a set amount of correction over a specified time... say, it pulls 5deg and waits 2/10ths of a second and listens again, if there is still knock it pulls again, usually an amount much higher than the first... 12deg. And it can do so again in another .2sec... I've seen negative timing (retard) during my homebrew times. Anyhow, once the knock has quelled it waits and ups timing at a rate of about half the amount it took away per step. This process is totally separate from CF and serves as another safeguard.
There are quite a few factors which go into timing correction. There are a number look-up tables used to determine the requested values. There are also triggers which affect timing in the long-term(CF) Medium term (IAT) and short term (KV). When the ECU detects spurious (not predicted) knock, it applies a set amount of correction over a specified time... say, it pulls 5deg and waits 2/10ths of a second and listens again, if there is still knock it pulls again, usually an amount much higher than the first... 12deg. And it can do so again in another .2sec... I've seen negative timing (retard) during my homebrew times. Anyhow, once the knock has quelled it waits and ups timing at a rate of about half the amount it took away per step. This process is totally separate from CF and serves as another safeguard.
09-02-2006, 11:06 PM
#43
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Yep...
Too many projects... work and car-wise. I'm feeding two S4's for the time being, lol.
I'll get another when I get a larger house (and larger garage) in a couple years, no biggie.
I'll get another when I get a larger house (and larger garage) in a couple years, no biggie.
09-02-2006, 11:09 PM
#44
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So you're saying this is independent of long term correction factors...interesting, thank you.
It somewhat reminds me of how Nye explained that LTFT and STFTs work together. If STFTs hit the limit in a certain direction, LTFT will bump up in the same direction. The process continues until STFTs are within the +/-25% limit. At least this is how I remember him explaining it...
09-02-2006, 11:17 PM
#45
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Indeed...
You're right. If you have consistent high KV activity, it'll bump your CF's in a similar way. The knock sensor circuits are also pretty smart. They know what signal pattern matches up with destructive knock and requires immediate attention (combination of cylinder and frequency/amplitude)and one that indicates insufficient octane (all cylinders and freq/amplitude). The second type results in a more rapid application of CF. KV's are just a shadow of the info the ECU gets from the knock sensors.
All of those variables are adjustable too. If you look at many chips, like X, you'll see the timing recovers on a 1:1 scale with the pull. Stock timing logic, like I'm running now, is much slower to recover. But since we're confident it's safe, that's gonna change bigtime
All of those variables are adjustable too. If you look at many chips, like X, you'll see the timing recovers on a 1:1 scale with the pull. Stock timing logic, like I'm running now, is much slower to recover. But since we're confident it's safe, that's gonna change bigtime
09-02-2006, 11:21 PM
#46
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Thanks for sharing 2 key points, differentiation of knock (CF effect) and manipulating variables.
I never would have thought you could manipulate the recovery time.
It's at times like these where I realize I just don't know anything.
It's at times like these where I realize I just don't know anything.
09-02-2006, 11:30 PM
#47
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Glad to help out... Good questions spawn useful answers :)
Honestly, it's really daunting what can be accomplished with these ECU's. There are so many ways to get the same desired effect, but like anything else in life, the most effective way is usually the most difficult.
If you have any other questions maybe I can provide an answer or two.
If you have any other questions maybe I can provide an answer or two.
09-02-2006, 11:33 PM
#48
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For now, I'll let this info marinate in my melon. You've been quite a help, kind sir.
Once all of this sinks in, I'm sure more questions will arise. The person you really need to answer questions for is Nye...throw that man a bone.
09-02-2006, 11:35 PM
#49
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and a 3rd key point, which myself and diego have long suspected
that logged absolute kv values are almost meaningless, the ECU does much more to distinguish between engine noise, normal ignition, pre-ignition, and detonation!
mike, thanks for confirming this.
mike, thanks for confirming this.
09-02-2006, 11:36 PM
#50
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hehe i always knew if we need to squeeze valueable data from knowledgeable individuals
we need to ask the right question!
It has been so much fun asking you the right question, i have learnt alot from the past couple of months. CJK's car is a very good example!
thank you sir!
It has been so much fun asking you the right question, i have learnt alot from the past couple of months. CJK's car is a very good example!
thank you sir!
