Disabling knock control on noisy/tappety engines

[rexandy]

When mapping a car which has a 'loosely' built engine, maybe on solid lifters, the stock knock control settings would be way too sensitive and continually drag the octane value down... With aftermarket ECUs I would normally tune them with knock contol OFF then add in the knock control at a level i deem safe.

With the stock ecu, I appreciate how advanced the control is, yet I would like to map the car initially with it turned off (or at least minimised) what would be the best way to do this? I'm sure a few of you have heard some of the 'rally spec' engines slapping away merrily with duff lifters as well!

Many thanks in advance
Andy

[GrayW]

You can disable it using periphery code changes, kock adjustment is dependant rom ID.

[rexandy]

kock adjusting? :blink:

but seriously...lol this is where my knowledge runs out im afraid, the practical side of building, speccing and mapping all fine... but modifying the roms I'm still learning! Could anyone assist with this?

Many thanks
Andy

[jcsbanks]

There are many people that have now adjusted the knock control with success on strokers with forged pistons and stiff engine mounts etc. They usually only need about 10% increase in the background noise thresholds. It seems this is all that is required because you can accumulate impressive knock sums from just being slightly over the threshold but maintaining it for some time, whereas a timing responsive noise like knock would tend to be a sharper and short lived increase and dealt with better by the ECU without killing the whole pull through a gear and dropping the octane value. Noisy lifters I've not heard too much about people mapping around, but you can still run knock control on any setup where meaningful knock (after filtering and gating) is louder than the background noise level.

This thread describes the knock control system and adjustments available:

http://forums.evolutionm.net/ecuflash/382625-knock-control-load-vs-rpm-table-found.html

[rexandy]

ok... so can i add:

http://evoecu.logic.net/wiki/Periphery_Configuration

to any rom which will give me the option to change the bits.... then i just need to know which one affects the knock control?

ETA thank you John, I'll have a read! much appreciated

[rexandy]

or to adjust accordingly on 8mr: (in suitably Alan Partridge style 'A-ha!')

<table name="Knock Multiplier" category="Knock Control" address="5680" type="2D" level="2" scaling="uint8">
<table name="X" address="6cb4" type="X Axis" elements="14" scaling="RPM"/>
</table>

Thanks guys!