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Heya - next questions in my ongoing saga of "making it work" lol
in the elite 2500 ecu - you have knock detection - and its got a window it watches for knock
it uses "start angle btdc" and "duration", both in degrees
if the start angle is -10 and duration is 30deg, that means to me it starts listening for knock at 10deg before tdc and stops listening 30 deg later at 20 after tdc
if your timing map has 20deg of timing advance at some point doesn't that mean that the ecu wont start "listening" for knock for at least 10deg of crank rotation?
how soon does knock trigger when it happens - at the time of ignition? within a "few" degrees? As knock propagates really fast from what I've seen in the webinars - how many degrees between the ignition event and knock occurring?
Should I change the start angle to be "more" than the greatest timing advance I run? eg if I run 20 deg of timing at a place - should I make the knock window start listening "before" the highest timing advance used in the ignition map and keep listening until the 10deg past tdc the base map used?
Cheers in advance :)
Called Haltech when I got home and the support tech advised that knock was less likely to occur prior to the engine getting to 10 deg btc as there wouldn't be enough cylinder pressure to contribute towards provoking any knock (assuming the tune was done in a reasonable manner)
This was because the cyl pressure would normally peak after tdc (I think i remember Andre saying at one stage to aim for peak cyl somewhere around 16deg after tdc in a vid somewhere) so their range of 10 before tdc through to 20 after tdc should be fine for a factory engine in a decent state of tune.