Knock sensors

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Wade
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Knock sensors

Post by Wade »

Been reading up on knock. hp academy mention you can use the second order knock frequency which drowned out the background noise. Are the ecotec v6 a tuned frequency knock sensor and can you use a knock sensor that picks up the second order knock frequency or is there more to it than that.
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vlad01
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Re: Knock sensors

Post by vlad01 »

I always use proper knock ears as electronic knock detection is hit and miss at the very best. On the average day it doesn't work at all on the delco ECUs.

Hearing it yourself with the knock ears is definitive, you can't miss it as the human brain is sooo much better at picking out patterns and sounds from otherwise to electronics an ocean of sounds.
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Wade
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Re: Knock sensors

Post by Wade »

My plan is to get a plex knock detection kit. But with that said I’d still like to know if using a second order tuned knock sensors will work. The v6’s pick up knock even with no timing or boost. So even if it’s tuned correctly the factory knock sensors will still be pulling timing. I’d like to have it still doing its job, just seeing if there’s a way you can minimise background noise
immortality
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Re: Knock sensors

Post by immortality »

I was under the impression the knock sensors on the ecotec where better than the earlier models.

I've come across one engine that showed knock on the dyno no matter what we did but the engine was mechanically very noisy.
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Re: Knock sensors

Post by delcowizzid »

Even headers can set of stock ones you used to be able to buy little insulating baggies to go on them that stopped the outer shell of the sensor ringing from vibration
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Re: Knock sensors

Post by vlad01 »

Wade wrote:My plan is to get a plex knock detection kit. But with that said I’d still like to know if using a second order tuned knock sensors will work. The v6’s pick up knock even with no timing or boost. So even if it’s tuned correctly the factory knock sensors will still be pulling timing. I’d like to have it still doing its job, just seeing if there’s a way you can minimise background noise

This is a consistent issue with the knock filtering and detection on the delco. Not only that but I also have proven consistently that when actual knock occurs it fails to respond to it at all. This is bad!!!

Yes the plex is a good bit of gear, the important thing is it's got audio out and headphones so you can actually verify and tune the plex to get reasonable results for a digital knock triggering.
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vlad01
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Re: Knock sensors

Post by vlad01 »

immortality wrote:I was under the impression the knock sensors on the ecotec where better than the earlier models.

I've come across one engine that showed knock on the dyno no matter what we did but the engine was mechanically very noisy.
Not really. Seen a heap of destroyed stock ecotec engines and obviously the detection failed. First hand experience with a guy who blew 4 stock ecotec engines is a row. All the pistons just shattered minutes to less than few hours of driving. Was a dodgy fake walbro pump that caused it from fuel starvation but also most certainly the knock retard doing jack all.

The way its handled in the code is better but I am not convinced on it being better filtering wise as I see the same failed detection.
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vlad01
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Re: Knock sensors

Post by vlad01 »

delcowizzid wrote:Even headers can set of stock ones you used to be able to buy little insulating baggies to go on them that stopped the outer shell of the sensor ringing from vibration

Mine was being triggered by the rear axle juddering over rippled bitumen on hard acceleration. Did it without fail every time haha.

I turned it off and just tuned on the dyno with knock ears to be sure it was safe.


This is also the cause of the classical V6 power loss seen with age and the huge variation from car to car even when all are the same setup. Turning it off makes a huge improvement. My old vacationer was the perfect example of this. fast when I installed a fresh engine, by the time I added another 200-250k to it, it lost about 3 sec to 100 taking bit over 10 sec to get to 100.

Disabled knock in the tune and immediately it got to 100 in 7 sec flat lol It actually ended up a little faster than when I installed the 90k fresh engine in the fist place. About .5 sec quicker even though the engine was well and truly worn by that stage. If I only had known back then I could of enjoyed the full benefit.
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immortality
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Re: Knock sensors

Post by immortality »

The ones I've played with when they have detected knock you see retard. On our L67 I had some weird knock retard, since replacing the injectors and now the plugs I'm no longer seeing that knock retard, no doubt a lean pot and possibly coupled with poor ignition.

Knock retard can only do so much, if the tune is bad or in the case above extremely lean than knock retard isn't going to save the engine and TBH, if the guy is willing to detonate 4 engines before looking deeper than really he needs to re-think his strategy.

For a daily driver a little retard is much better than a burnt piston/blown engine.
immortality
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Re: Knock sensors

Post by immortality »

I wonder if The1's enhanced code has made any difference to the knock retard or just the way it is logged?

I was hoping to get a hold of Festy's knock box but unfortunately they are no longer available.
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