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    Vishnu Procede N54 misfire mystery solved? CPS offsetting to blame?

    Click here to enlarge

    With all the discussion on the CPS offsetting lately, I have been delving deeper into this topic and contacting various tuners to get to the bottom of it. Now, we all know the Procede has had and still has misfire problems and the JB has not had this problem. As I have learned more about the impact of this system I have spoken to a couple tuners who pointed me in the right direction.

    What is the major difference between the two? CPS offsetting.

    Why would CPS offsetting cause misfires? Well, if the CPS offsetting is based on load and not static it will wreak havoc with the misfire detection of the DME. Here is how the Procede does CPS offsetting:

    Click here to enlarge Originally Posted by Shiv@Vishnu
    Not sure I follow but yes, the Procede only retards timing under load. Or more specifically, when load is greater than stock. The more extra engine load, the more extra retard.
    So, the more load the more offset. Why is this a problem? The ECU uses the CPS signal to mesaure the acceleration of the crankshaft. If the acceleration value is outside what the DME expects, it is interpreted as a misfire. So when the ECU goes to measure the crank speed and this signal is changed, boom, misfire.

    Why has this been difficult to pin down? Because the Procede varies the offset and it isn't static. CPS offsetting isn't the right way to reduce ignition timing but the only option the Procede really has, as do all N54 piggybacks. Since the number isn't static misfires will happen based on a ton of variables that affect the ECU, load, weather, rpm, VANOS, etc. This is why there is no rhyme or reason to it only the constant of CPS offset.

    Further evidence that supports this theory is that Terry of BMS has recently been doing CPS Offset Testing and has been able to induce misfires with the CPS offsetting. So, hopefully this clears things up for people and to be noted a static offset may be best to prevent misfires. Ideally though, tuners we have contacted stated they believe such a vital part of the way the factory DME functions should not be messed with due to its impact on VANOS and the knock detection system.

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    spell check

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
    spell check
    Thanks.

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    I hope your tuner sources aren't the same ones who told you the compression cycle is 60 degrees.

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    Click here to enlarge Originally Posted by Jimefam Click here to enlarge
    I hope your tuner sources aren't the same ones who told you the compression cycle is 60 degrees.
    You misunderstood, calibration window, not compression cycle.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    You misunderstood, calibration window, not compression cycle.

    Originally Posted by shiv@vishnu
    The compression stroke window is 180 degrees wide. If you think offsetting to the tune of 2-4 degrees is going to have an appreciable effect on knock control effectiveness, VANOS mapping or injection timing, that's you're call. But at least be educated.

    Shiv

    I find this post rather amusing as I have been told the window is typically 60 degrees... interesting.

    I didn't misunderstand you misspoke.

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    Click here to enlarge Originally Posted by Jimefam Click here to enlarge
    I didn't misunderstand you misspoke.
    You still are misunderstanding. He implies the window is 180 degrees because the compression stroke is. The adjustment window is only about 60 degrees which he conveniently omits. Hope that clarifies it for you.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    You still are misunderstanding. He implies the window is 180 degrees because the compression stroke is. The adjustment window is only about 60 degrees which he conveniently omits. Hope that clarifies it for you.
    Lol I got it the first time but you should have just corrected his info(which your right is misleading) I was being sarcastic. It just made you sound clueless.

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    Click here to enlarge Originally Posted by Jimefam Click here to enlarge
    Lol I got it the first time but you should have just corrected his info(which your right is misleading) I was being sarcastic. It just made you sound clueless.
    I thought I was clear but if not no big deal should be clear to everyone now.

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    4 out of 4 members liked this post. Yes Reputation No
    Honestly, the JB3/4 holds it's own against the Proceed, and just as much (if not more) reliability; so what's the advantage of CPS offsetting on the N54? Shiv has mentioned that the JB rides the knock sensors... I'm pretty damn sure the factory DME does too. How else would it know where the timing advance limit is? These aren't the same computers auto manufacturers were using 20 years ago. They have MUCH faster response times, and rely much more on real time data, than they used to. Those very outdated computers relied more on the base programming, and incorporated miniscule changes to improve performance as long as conditions permitted over a period of time. These days, the base program is simply a starting point for the car to quickly adapt from. One great example, is the N54's amazing ability to tune itself to a dry shot of nitrous, or heavy doses of meth injection. I think the DME is going to target as much advance as it safely can based on the conditions, without us having to dick with timing.

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    Click here to enlarge Originally Posted by Eleventeen Click here to enlarge
    Shiv has mentioned that the JB rides the knock sensors... I'm pretty damn sure the factory DME does too. How else would it know where the timing advance limit is?
    Exactly. The DME works in the same fashion and that is good enough for BMW yet not good enough for Vishnu who is trying to create a "safety" marketing ploy. And.. they have pulled it off for the most part as look at how many people really believe this illusion of safety.

    Click here to enlarge Originally Posted by Eleventeen Click here to enlarge
    One great example, is the N54's amazing ability to tune itself to a dry shot of nitrous, or heavy doses of meth injection. I think the DME is going to target as much advance as it safely can based on the conditions, without having to dick with timing.
    I feel the exact same way and what the DME has done thus far with mods as you mention seems to support this.

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    Can we get an adult/mature type comment from Shiv?

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    Click here to enlarge Originally Posted by alpinedevil335 Click here to enlarge
    Can we get an adult/mature type comment from Shiv?
    He is free to refute or address anything posted.

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    Poor choice of words....I meant "will" we?

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    Click here to enlarge Originally Posted by alpinedevil335 Click here to enlarge
    Poor choice of words....I meant "will" we?
    Ah, I doubt it due to this all being correct and that it can not be spun or removed. We will interpret lack of response as confirmation since the parties in question have already read the thread.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Ah, I doubt it due to this all being correct and that it can not be spun or removed. We will interpret lack of response as confirmation since the parties in question have already read the thread.
    Yes we will.

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    2 out of 2 members liked this post. Yes Reputation No
    lol... wrong. The theoretical compression stroke in a 4 cycle internal combustion engine is 180deg. But with real-world valve timing dynamics, it's closer to 145 degrees. Of course, this will vary from engine to engine.

    Static vs. dynamic CPS offsetting isn't the key to avoiding misfire diagnostics. Our CPS offsetting is more dynamic now than it's ever been and we are supporting up to the limits of the factory ignition system misfire-free Click here to enlarge
    Last edited by shiv@vishnu; 03-23-2011 at 11:41 PM.

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    So if the guys at vishnu know more about controlling timing than BMW, why dont they just make their own car?
    Click here to enlarge


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    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    The theoretical compression stroke in a 4 cycle internal combustion engine is 180deg. But with real-world valve timing dynamics, it's closer to 145 degrees. Of course, this will vary from engine to engine.
    What is the adjustment window? Is it 180 degrees? 145 degrees? Forget the compression stroke, how many degrees of adjustment do you have?

    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    Static vs. dynamic CPS offsetting isn't the key to avoiding misfire diagnostics. Our CPS offsetting is more dynamic now than it's ever been and we are supporting up to the limits of the factory ignition system misfire-free
    What are the limits of the factory ignition system?

    Thank you for confirming the CPS offset / misfire connection and I hope your new offsetting (not sure how it differs) solves any issues.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    What is the adjustment window? Is it 180 degrees? 145 degrees? Forget the compression stroke, how many degrees of adjustment do you have?
    The adjustment range is +/- 15 degrees.

    What are the limits of the factory ignition system?
    Oh right around 500whp, you will run into high rpm misfire from time to time.

    Thank you for confirming the CPS offset / misfire issues and I hope your new offsetting (not sure how it differs) solves any issues.
    It wasn't the offset that caused the misfire. For those cars that misfired, even running an offset of 0 deg (no offset) resulted in misfire. So there goes your theory, huh?

    Shiv

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    I still want to know how bad your CPS resolution had to have been all these years to suddenly be able to improve it 800%. It sounds like that was the mistake all along...

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    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    It wasn't the offset that caused the misfire. For those cars that misfired, even running an offset of 0 deg (no offset) resulted in misfire. So there goes your theory, huh?
    No, because you haven't proved that is the case and it would not be beyond you to simply say so in order to save face.

    If anything, the correlation between the CPS offset and misfiring has been strengthened. How else do you explain JB's without CPS not having this problem? What proof do you have? Haven't cars that have changed hardware still had misfire problems after the change? Isn't the constant the tune? So...

    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    The adjustment range is +/- 15 degrees.
    How much of this range is it that you use?

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    Click here to enlarge Originally Posted by Terry@BMS Click here to enlarge
    I still want to know how bad your CPS resolution had to have been all these years to suddenly be able to improve it 800%. It sounds like that was the mistake all along...
    Lmfao I was thinking the same thing when I read that
    JB4LIFE

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    No, because you haven't proved that is the case and it would not be beyond you to simply say so in order to save face.

    If anything, the correlation between the CPS offset and misfiring has been strengthened. How else do you explain JB's without CPS not having this problem? What proof do you have? Haven't cars that have changed hardware still had misfire problems after the change? Isn't the constant the tune? So...
    I think their new claim is that Adrian Vos made a programming mistake and was not catching/updating edges with enough precision to avoid a false misfire detection. The problem with a troubleshooting misfire code is you have many possible causes all giving the same symptom.

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    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    Oh right around 500whp, you will run into high rpm misfire from time to time.
    Click here to enlarge Originally Posted by shiv@vishnu Click here to enlarge
    It wasn't the offset that caused the misfire. For those cars that misfired, even running an offset of 0 deg (no offset) resulted in misfire. So there goes your theory, huh? Shiv
    maybe on your cars Click here to enlarge so maybe that DOES support his theory Click here to enlarge


    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    If anything, the correlation between the CPS offset and misfiring has been strengthened. How else do you explain JB's without CPS not having this problem? What proof do you have? Haven't cars that have changed hardware still had misfire problems after the change? Isn't the constant the tune? So...
    I seem to recall another 500hp range car dyno'ing the same time frame as his, but no CPS offset, and did NOT have a misfire,even going ALL......THE..........WAY............THROUGH...... .....REDLINE...............
    Cheers,

    LM

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