Constant knock count, but no knock

jordancivic · Post by **jordancivic** » Mon Jun 29, 2009 5:06 am

Hi guys.

UK spec CTR k20 with JRSC @ 7psi.

Knock count is almost constantly increasing at all load rpm sites, but no knock is audible with my Phormula knock detection kit. The car has uprated motor mounts/insterts and i suspect that this is the cause of the high knock count? Is there any way to scale/calibrate/ relocate the knock sensor so that it can be used or should i just disable and tune with the Phormula on the dyno?

Post by **Hondata** » Mon Jun 29, 2009 7:11 am

This sounds similar to what we have seen with the JRSC, where we found that if you ran too little ignition timing on the low cam it would register knock. On the fuel here we found that we needed 14-16 degrees timing under full load, but it was very sensitive and even 1 degree too much timing caused real knock. Post your calibration and a datalog.

jordancivic · Post by **jordancivic** » Thu Jul 02, 2009 6:55 am

Attached, i dont have a log at 7psi as we soon changed out for the 10psi pulley. Please ignore the belt slip problem, we are working on this before mapping resumes.

Timing is VERY conservative at the moment until i resolve or get confirmation on this knock issue.

Car is using 99RON fuel.

Why isnt the ECU retarding timing as the knock goes above the threshold? Is the threshold and the amount of retard configerable? I cant seem to find this option or any mention in the help files.

I would assume that i should just disable the knock sensor and tune as i would normally. I have the facility to log an external knock sensor from the Phormula, with the dyno logger. The headphones are good, but the log gives a much clearer indication of knock at the higher ( louder ) rpms.

Thanks for the help

Post by **Hondata** » Thu Jul 02, 2009 10:06 am

I believe that you are running too little timing on the low cam. If you remove timing, and the knock count does not reduce, then this is a possibility.

The way the Honda knock control works is that it does not remove timing with knock - it just determines the fuel octane rating from the knock.

Post by **Spunkster** » Thu Jul 02, 2009 10:23 am

Try adding more timing and see if the knock count goes down.

jordancivic · Post by **jordancivic** » Thu Jul 02, 2009 11:27 am

I will log the knock through dyno and continue adding timing as normal, will report back with dyno logs when customer returns.

Hondata - I assume this means there is no active knock control, and the knock features are to be used as tuning tools only? That being the case why do we have a 'knock retard' log?

Is this something that Hondata are progressing? Solaris uses a clever knock detection which identifies which cylinder is knocking from the timing of the knock event in correlation to the cylinder firing. Surely it would be possible to add active knock control since we already have a 'knock threshold' and 'activity' data. If we could then customise the threshold and amount of retard we would have full knock control adaptable for things like forged pistons etc. There seems to be no point in identifying the octane rating of the fuel if the ECU doesnt have the facility to pull timing when knock is detected. I understand that we do not tune the engine to show knock activity, but an added safety margin for ' bad batch of fuel' etc is always nice to have.