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The Terminator
Engine/Tuning
Spark timing question
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<blockquote data-quote="ricksterman" data-source="post: 2986558" data-attributes="member: 35021"><p>I have screwed with this on my Mach1 for 6 months (of course I had knock sensors that I had to contend with too, totally worthless POS if you ask me). </p><p></p><p>In closed loop timing isn't relevant sine there is an active feedback. WOT is open loop and the spark timing is based on load and temperature. When you mod the vehicle you change the perceived load, and as a result the timing can change. The Predator has two ranges for timing, 2-4, 4-7K but these only adjust the existing timing curve in percent (10% is about 2 degrees max). Which is why, especially on forced induction motors, getting a good custom tune can make such a difference.</p><p></p><p>On my Mach with a custom tune I can pull 29 degrees advance (5200ft) without audible ping, but I doubt it makes much difference. The Cobra is at a safe 20 degrees WOT after 3K RPM. Since I am not allowed to post attachments I can't show you the dyno runs (w/ datalog overlay of load/spark) and the datalogs (Cobra), but doing this type of data collection and analysis will show you a lot, and also help you pinpoint deficiencies and potential problems (BOOM!). I know this information has probably already been presented numerous times, but it's always good to reiterate.</p></blockquote><p></p>
[QUOTE="ricksterman, post: 2986558, member: 35021"] I have screwed with this on my Mach1 for 6 months (of course I had knock sensors that I had to contend with too, totally worthless POS if you ask me). In closed loop timing isn't relevant sine there is an active feedback. WOT is open loop and the spark timing is based on load and temperature. When you mod the vehicle you change the perceived load, and as a result the timing can change. The Predator has two ranges for timing, 2-4, 4-7K but these only adjust the existing timing curve in percent (10% is about 2 degrees max). Which is why, especially on forced induction motors, getting a good custom tune can make such a difference. On my Mach with a custom tune I can pull 29 degrees advance (5200ft) without audible ping, but I doubt it makes much difference. The Cobra is at a safe 20 degrees WOT after 3K RPM. Since I am not allowed to post attachments I can't show you the dyno runs (w/ datalog overlay of load/spark) and the datalogs (Cobra), but doing this type of data collection and analysis will show you a lot, and also help you pinpoint deficiencies and potential problems (BOOM!). I know this information has probably already been presented numerous times, but it's always good to reiterate. [/QUOTE]
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Spark timing question
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