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I've just finished fitting my Plex Knock Monitor to my NA 1995 b18c1 that previously had no knock detection and I'm pretty pleased with it. First time I've ever listened to an engine with headphones, not quite the same pleasing sound it makes without the headphones though haha.
Looking for guidance on what sort of expectations are realistic when it comes to knock. All I you ever hear or read is how bad knock is, and that's obviously undisputable. In a perfect world there would never be a single knock. However thinking from a realistic standpoint it must happen all the time in small amounts here and there no? Most all modern cars have knock detection and correction algorithms which I'm pretty sure on a regular basis detect some knock here and there and temporarily retard some timing here and there. Furthermore as I understand it the presence of a single knock is usually not enough to get a modern ecu to react and remove some timing, it would generally have to be over a certain count or limit or other measure.
So in running my car up and down the highway, doing some small pulls and so on amidst the what I assume was regular engine noise coming through the headphones I am fairly sure I heard a knock or two in there. Sure enough looking at the graph drawn by the Plex software there were a few outliers above the normal pattern it drew in the logs.
My car is running a tune done by a well respected tuner, with a worldwide reputation, several months ago who has quite the legacy tuning Hondas and he used no knock detection, and was pretty confident that was fine. Well, apparently it's not flawless.
I finally after watching hours of HPA webinars and courses go on the dyno myself next week (wish me luck). I'm looking for an understanding of what to realistically expect with knock? Is a few outlier dots on the Plex log here and there something to be extremely concerned about? Or should I really only be concerned with clusters of dot's in the knock zone? Furthermore, on the dyno vs on the road what are my tolerance levels for knock? I'm guessing on the dyno I should strive for a zero-knock, not even one stray dot on the log, result. However I'd guess if I take that tune and put down hundreds and thousands of miles on the road there are going to be some dots above the threshold line here and there and there's nothing I can do about it.
It's probably worth noting that my Hondata s300 can only read/log when it comes to the output from the Plex, so it cannot pull timing in a closed-loop type fashion when the Plex reports a knock. I'm assuming when tuning on the dyno I need to be more conservative because of this and allow extra wiggle room as there is no active knock protection other than the LEDs on the Plex once I take off the headphones and drive away.
So bottom line questions are, what is realistic for knock both when tuning on the dyno, and then when on the road. And given my ECU has no active defense against knock what's my best policy or strategy for where I tune my ignition timing in proximity to the knock limit on the dyno?
Hello the best advice i can give you here is to strive for no knock on the dyno and on the road, if you do see knock find the area remove some timing and do some fast transitions through it off and on the gas, and build the timing up in that area in small increments keeping in mind where you heard the knock and what the timing was when you heard it. leave it under the point of knock. you will find knock is higher when held in steady-state for long periods in a particular zone and when it is rapidly transitioned through that point, the hondata does not have transition ignition adjustment so staying on the safe side with timing is going to help the longevity of the engine.