Quote:
Originally Posted by Tor
I only looked a little bit at it, but it seems to do the same as your formula? And then it's just comparing automatically instead of having to go over the curves manually, is that correct?
As far as I read ignition timing also affects the optimum AVCS timing. If I keed the changes fairly small, like not deviating from the shape of the original curve, wouldn't it be better to stay with the timing I intend to run and let the ECU pull timing? I understand if I opted to make flat tables and tried e.g. 40 deg intake advance at full throttle it might have a more profound impact on knock? This was in part my reasoning for sticking around Shivs curve.
My original plan was to make a flat curve from 5200 rpm to 7400 with 0 to 25 deg intake advance in intervals, which would equate to 6 tunes plus a baseline tune. With 4 pulls per tune, 28 pulls - bit much! Whereas sticking around Shiv's curve, seems to not only test out the most realistic option in the least amount of pulls but also offer the most safety without having to reduce timing?
Another thing, if I go down this route. Do the pulls even have to be made on a flat road or for that matter the same road? I would greatly reduce the chances of curious men in cars with blue lights on the roofs if I could do the pulls at different locations.
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First off caveat, I've done some studying with this and toyed*a bit* with AVCS timing, but novice here so take my advice with a grain of salt
From a string empirical approach, even on a dyno AVCS optimization takes time. Doing runs on a road takes even longer obviously. Create a handful of tunes, load them to your tablet, load one to your car (wait), log a run, load the next one (wait), make a run, and repeat for as many tunes as your table can hold. Analyze results, make new tunes, do it again. It's a fairly iterative process that can be shorted if you have some experience with this kind of tuning before (i.e. make educated guesses on next adjustments instead of the blanket +/- approach). I dabbled but gave up as I just don't have the time, and my wife thinks I've gone crazy. Cam timing and ignition timing do affect each other, although my typical approach is to tweak AVCS intake/exhaust first... get that right.... then go after timing. Ideally you'd probably make another AVCS pass after that, and then timing again... but that's an unrealistic amount of work for me. Also keep in mind that we're not just talking about pulling timing - AVCS changes can actually reduce compression in certain areas and allow advancing of timing - so you can just rely on tuning from watching where the ECU pulls timing via the knock sensor.
Again, I'm a newbie, so Kodename or anyone else feel free to correct me.