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Knock retard

Posted: Sat Aug 01, 2009 1:32 pm
by accelguy
What is the relationship between knock retard and knock level?

First, I'd like to point out that there is absolutely no knock at WOT at vtec with its AFR running 13.5-13.0 at 5-7.5k rpm and AFR 12.5 at 7.5-8.5k rpm. Is this the optimum AFR for 93 RON fuel on a JDM FD2R?

How much knock retard before a K20A engine is hurt? e.g. T.pedal 25-40%, AFR 14.0-14.5, 2500rpm, VSS 70kph, 5th gear with knock retard=8 Is this a concern? What is the solution? reduce ign timing and run richer at 13.5 AFR?

Your input would be greatly appreciated.

Posted: Mon Aug 03, 2009 7:59 am
by Hondata
There is no relationship between knock level and knock retard - the knock retard is based on the 'knock sensitivity' tables, and not the actual knock. I know this does not make sense, but this is how the knock sensor works in this ECU.

You should run a flat AF 13.0-13.2:1.

Posted: Mon Aug 03, 2009 12:28 pm
by accelguy
Hi Hondata,

Thank you very much for the explanation on KR and KL.

May I ask how do I tell when there is a real knock from my datalog?

As for the AFR, flat AFR 13.0-13.2:1 from which rev range to which and at what engine load? Is it also the more stable AFR at 13:0-13:2:1 the better?

Much appreciate your input.

Posted: Mon Aug 03, 2009 12:44 pm
by Hondata
- May I ask how do I tell when there is a real knock from my datalog?
By the knock count.

- As for the AFR, flat AFR 13.0-13.2:1 from which rev range to which and at what engine load?
Any rpm, load 85 kPa or greater.

Posted: Mon Aug 03, 2009 2:31 pm
by accelguy
Hi Hondata,

Cheers for the answers again and sorry for my noobness.

As for the knock count, could you advise where I may find the right buttons in order to display it?

Am I right to think when you mentioned load 85 kPa or greater, you are talking about the value MAP(kPa)? Also, is this at WOT or part throttle?

As for AFR, what AFR below 85 kPa with 93 RON fuel?

Thank you very much