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Knock Noise from Valvetrain or Actual Knock?

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Good day, folks long time no write!!!!! I was doing some prepping the other day on my daily for a track day event and I thought to richen and advance a little bit my maps as they are fairly retarded due to the fact that the car has never been dyno tuned! The setup is like the B20/Vtec motor running upgraded headers and full exhaust plus ITBs! the compression ratio is quite low as 9:1 and all the other parts are stock! I mounted my Knock monitor on quite a high place as it was difficult for me to access the car on the proper spot and hit the road! (Pic for the mounting position of knock sensor). What I noticed was that after the Vtec point was engaged I was having too much indicated detonation and the same went with the audio! (Running plex V1 on the Hipass filter and its setup to read RPM) Can anyone with experience on with Honda motors tell me if this is normal during V-tec engagement to hear knocking? Thanks in advance guys!

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Hey mate, is the ecu registering knock? What ecu are you using also?

That location looks to be quite high on the cyclinder head. On the engine block near to where the combustion takes place should give a better indication, and there should be much less valvetrain noise. Andre does a webinar on knock sensor placement, be worth a watch.

I do find it can be quite fiddly and time consuming to fit knock sensors in the ideal place especially in a compact engine bay but if it saves an engine surly its worth the effort.

The Ecu Is a Honda P30 with a Demon daughter board tuned on Neptune so no Knock sensor for me on the ecu. Looking to go for a haltech but the price tag is a little bit high for now. As for the sensor placement it was for me a quick on and off position!

I know that location is super convenient, however it hasn't proven to be that effective in my own experience on the Honda B-series engines. I'd spend the time and get it onto the block personally.

To answer your question though, yes, it's quite normal to hear a sound that is very similar to knock at the VTEC engagement point. There is a mechanical noise associated with the VTEC system engaging and the sensor will detect this, particularly in the location you have the sensor mounted. It shouldn't however continue beyond the VTEC point - it should be a sudden and short crack and then nothing more. If your CR is geuninley 9:1 and you're running on a decent quality pump gas then you should be relatively immune from knock at high rpm and should be able to tune to MBT. From my experience that's likely to be in the high 20's on this sort of engine.

Thank you guys for the support! I will take the time to mount the sensor properly!

Andre if by the high 20's you mean degrees of advance at some point I'm with 32-33 degrees of advance with a base timing of 16 degrees

Yes, I meant degrees of advance. 32-33 degrees under full load isn't unusual but I seldom find that the B series needs to be in the 30's. I'll assume you're not meaning 32-33 degrees PLUS 16 degrees though? That would be a problem...

From my understanding of the ECU the main map acts as target degrees and timing is added or subtracted from the base timing. So I might be way way over advenved. Thanks for your support I'm going to make a new ignition timing map from the beginning!