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Knock sensing

Posted: Sun Dec 10, 2017 2:43 pm
by Cpur
I am currently installing an S100 to my Cosworth yb, The original ecu used to use a knock sensor. Unfortunatly DTA does not support knock.
Is it so important to use knock?
Also i found a GM module that converts knock frequency to analog voltage which on GM is used to retard timing. This can easily be inputed into the analog in , but can I make a table for retard or correction when knock is detected?



Thanks and regards

Cpur

Re: Knock sensing

Posted: Sun Dec 10, 2017 3:45 pm
by stevieturbo
Important ? Yes and No....depends how reliable that detection is, and what you want it to do.

Or if the tuning etc even warrants it in the first place.

You could use an analogue input to retard timing if your detection device offered a suitable 0-5v signal.
Would it really be fast and effective enough ? Who knows.

Build it right, tune it right and there shouldnt be any need for knock control, and even some systems that claim to offer it....they can vary hugely in their actual abilities. Some are crap, some are great.

Re: Knock sensing

Posted: Sun Dec 10, 2017 4:12 pm
by Rob Stevens
Yes as Stevie says tune it right in the first place, on the fuel you intend to use. I don't think that using an analog input would work very well as you have no damping or other 'detection windowing' features to help control the applied retard. In a simple setup you could probably use the ana input to help log any issues and review later.

Re: Knock sensing

Posted: Sun Dec 10, 2017 11:58 pm
by Cpur
Maybe if not fast enough, i would make it at least lower the boost and give out an alarm. I dont know how the original cosworth ecu was using it, if actually active or maybe long time adaptive, to adapt to the octane content.

Re: Knock sensing

Posted: Mon Dec 11, 2017 5:02 am
by Alex DTA
Rob Stevens wrote:Yes as Stevie says tune it right in the first place, on the fuel you intend to use. I don't think that using an analog input would work very well as you have no damping or other 'detection windowing' features to help control the applied retard. In a simple setup you could probably use the ana input to help log any issues and review later.
Roib

You can use a Plex Knock Monitor (or Phormula K) with an analogue output in to the ECU.
You can't connect the knock sensor directly, it requires all sorts of processing.

Re: Knock sensing

Posted: Mon Dec 11, 2017 6:14 am
by Rob Stevens
Indeed, I didn't think that I needed to mention that you couldn't connect it directly.

Re: Knock sensing

Posted: Mon Dec 11, 2017 8:20 am
by stevieturbo
As Rob says, just build it and tune it right and it shouldnt be a concern.

If you want an alarm of sorts, then the likes of Plex, Phormula, Knocklink and many other such devices can offer you a standalone alarm system.
Most will offer some ability to connect to the ecu which as you say could maybe reduce boost or timing etc. Not to say it would have no value doing this, but I wouldnt be relying on it and tuning close to the ragged edge.

Re: Knock sensing

Posted: Sat Jan 06, 2018 3:10 pm
by rocar