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Webinar 057 knock frequency

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Ask questions about webinar lessons here. To see the Previous Webinars for a complete list of archives tuning webinars. 

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Hi guys , I’ve been trying to set my knock frequency on my elite 2500 and I’m having a little tough time understanding where the frequency should be set based on this webinar explanation in regards to all the little lines everywhere and where to determine is the center point of all that ... I do understand there is a formula and that it is rather accurate .. in my case I have 86mm bore and that equates from what I understand to 6700hz.. should I just double that and make it 13400hz and call it good ? Or should I be doing this spectrograph test and setting it to a specific spot ?... I think I’m having false knock readings .... SR20DET , 10:1 compression running OneR 117 octane E90 would anyone suggest this setup is NOT knock limited ?

How much boost do you run? Most likely you are not experiencing any knock on e90...

I’m running 30psi up top ... as I was tuning on the dyno trying to find MBT I ended up seeing great power gains every time I added timing all the way to 20 degrees at 30psi .. sounds a bit hi right ? Well I checked the plugs and everything seems perfect without any signs of detonation and I decided to stop adding timing because I exceeded my power goal of 500whp... but later down the road after a lot of beating on the car I did a data log on the knock detection and it’s picking up knock at 24 degrees at 1 bar and says it’s knocking all the way up from there and that just didn’t seem right to me as there isn’t any physical signs of it ... so here I am trying to tune the knock detection correctly to make sure this is actually not happening ... car runs great and strong by the way

It is very easy to check. Retard 5 degrees of ignition in that area and check if the knock signal would go away. If it stays - most likely it is false knock.

I tune quite many SR20 motors on Ethanol, higher compression and some on NOS and at that level I would be very doubtful you're getting knock.

On 30psi we are seeing around 19-21 degrees peak but only about 13-14 mid range. This is dependent on setup obviously.

You will find as you increase things like boost, rpm etc your knock level/noise will increase. While pulling out 5 degrees could show if you're getting knock, you can also get false information as you will reduce cylinder pressure which will also reduce noise and show lower levels.

Ideally you need to confirm you're getting knock, which the best way is to listen yourself by using some knock gear.

Thanks for the reply’s guys .... I’m pretty confident that I’m not getting knock but I think I will get some knock gear and give it a listen anyways ... I’m still fairly new at tuning and trying to learn as much as I can