Internal Knock vs. Knockblock

[Josh Burt]

As I understand the knockblock is needed for individual cylinder 'closed loop' knock control. If that is the case, then what does the internal knock function do? Does it just process the raw knock signal from the sensor and retard spark across all cylinders? Thanks

[Dtech Motorsport]

What ecu are you using ?

If it is the G4 Extreme then it does closed loop knock off its own dedicated knock inputs.

if you are using the G4 Storm or any other G4 pluggin ecu then you will need the Knock block to interface with the ecu as they do not have dedicated knock inputs and required circuitry.     this is only required if you want knock control and are preppared to set it up correctly.

Regards

Dave

[email protected]

 

[Josh Burt]

Ok thanks, that's where the confusion was for me. I'll be going with the Xtreme, so no problem.

[Jurgen Biggelaar]

Hi Josh.

Just so you are aware.  If you are using the G4 Xtreme knock control that is built in to the device, it is analogue knock control as opposed to digital.  Don't get me wrong, this is still very good knock control, but digital is just that little bit more accurate. 

The only reason I am saying this is I don't know if you are doing a 100HP or a 2000HP vehicle, and looking for the perfect knock system.  If this was the perfect scenario, I would still go digital.

PS.  Individual cylinder knock control is a current feature with the Xtreme system natively.

Jurgen

[Josh Burt]

Thanks Jurgen, well it is more like a 400hp turbo high compression 6cyl. I want to run right at the edge of knock while at full boost if possible. I am having trouble wrapping my head around why the digital is better? Will the analog potentially miss some knock events? Or does it falsly detect knock events? If so is it because it doesn't process the knock signal as good as the knockblock can? I am probably confused because I'm not sure what makes one analog and the other digital. Thanks Josh

[Jurgen Biggelaar]

Hi Josh.

Then I would totally go the new G4 Knock Block!  I am also currently in the same boat... mid-build on an SR20 high compression that I am turbo'n, and want to see a few KW so will defo be on the edge too   I will not consider anything else but the new G4KB for this reason.

The main reason for increased accuracy is the way the signal is processed.  I can't explain with all the really fancy words and reasons, but in short I believe it is to do with the filtering of this signal.  The analogue can clip parts of the signal that may be important (unlikely but not impossible), where as the digital signal processing is much better at manipulating the signal for filtering.

One really good example is the difference between Analogue TV and Digital TV.  The old TV worked just fine really, and you don't notice anything crap about it... Until the advent of the Digital TV's & transmission system; and now you note how much CLEARER they are!  Same thing, the result is just that much more improved.

Hope this helps in your understanding.

Jurgen

 

[Josh Burt]

Clear as mudd! My next question is if the digital is so accurate, how come the knock Advance Delay has a minimum value of 2sec? I have tuned a road race car using Motec's digital knock device and M800. The software allows you to be real aggressive retarding spark and you can advance it all back in within a few firing events if you so desire. I have found that if you are real aggressive pulling spark out when the knock event happens, you can be aggressive putting it back in and see no immediate loss in hp nor do you have engine damage. This feature would be real nice in PCLink, really just having the option to have the advance delay be 0sec would accomplish this.

[Jurgen Biggelaar]

Josh.

It has nothing to do with accuracy, and everything to do with a valid reason it has been done like this... However.  The minimum could be a bit lower in reality, so I have talked to our engineers to advise of what you suggest.  They are happy with your comments, and will be adding to the next firmware update, a minimum of 0.5 seconds, as with all of our R&D, we still think it is not a very good idea to start re-introducing the timing so quickly after det.

Jurgen

[Josh Burt]

Thanks Jurgen .5sec should work great, it might not be ideal for all applications but it works well for what I am doing.

[Josh Burt]

I figured I would give an update. I am running the G4 with internal detection with a microphone mounted in the engine bay ran into my stereo to listen for actual pings. The G4 seems to do a good job of detecting knock but if I induce it on a single cylinder (ie. have a very conservative base spark map and add 10deg to a single cylinder), it detects it on all cylinders. I know Motec ecus have the same problem which is where their digital box comes in which does a great job of individual cylinder detection, I'm guessing the same applies here.

 

Down the road I'll probably pick up a knockblock to really push the limits.