MoTeC Global Forum

hi. long story short - i bought an m84 without realising there was no knock monitor function on it.
what are my options as i really want to monitor knock?

simply monitor knock, or actually log it's occurrence ?

There are various external add-ons to allow both.

Or maybe Motec's own SKM can be used with the M84 ? ( Sequential Knock Module )

enable the ecu to see and log it ideally

last time i asked the SKM was £600. abit steep IMO

If the SKM is £600, then it allows you to run knock monitoring and knock control ( assuming same as M800 etc )

There are plenty of other products to give you visual or audible alarms, and some do have 0-5v outputs to allow logging as well. But you're still talking a few hundred quid.

Phormula's KS-4 is one such device.

Just google knock detection etc. Various companies make products. Suitability is down to you to decide.

The M84 cannot do proper knock monitoring. By "proper" I mean that you have a gated signal (like and Ignition signal) to the Knock device to tell when a particular cylinder is firing. This way you can close the window when nothing is happening so that it cuts down on noise that you are really not interested in in the first place. Secondly you can pin point which cylinder is detonating so that you only retard ignition advance to the cylinder that is weak.....why would you hinder the other cylinders and go down in HP for no reason? Hence 600 quid and an M400, M600, M800.

can i swap my 84 for a 600 please?

So just to clarify for everyone reading, that a MoTeC SKM (Standalone knock module) cannot be used with an M84. It can only be used with the 'hundred' series ECUs such as M400/M600/M800/M880.