The V8 Owners Forum -

why does it get knock when you go WOT while cruising and not from standing start mate?

Coops wrote:why does it get knock when you go WOT while cruising and not from standing start mate?

Usually knock detection is turned off below certain thresholds. Could be rpm, throttle, map etc.

But as I say...it probably isnt knock, it's just the knock sensor has not been calibrated or fine tuned correctly to your engine.

So it's hearing noise and this noise is loud, but you need to tell it this noise is just noise ( after manually confirming of course ) and not detonation.

Every engine is different, so there is no generic setting that a noise is detonation. You need to do this yourself.

But with such low timing, there is no way it can be detonation. ( assuming timing on screen is confirmed as accurate )

IMO you could easily have another 5-8 degrees in there which will massively improve performance.
It immediately drops to 15deg even at lower rpm and almost no boost. Essentially still a n/a engine at that point, so could be running timing akin to a n/a engine circa 28-30deg

Sent the datalog over to Shaun ( www.ms2tuning.com ) who mapped the car last December and set it all up correctly timing etc,
he says it is detecting knock and has advised to take a couple of degrees out in the problem spot and try again,
will let you know how things go if the rain stops and I can get out and try it after changes made.

IMO with 15deg of timing it should be impossible for there to be knock.

The knock sensor is hearing noise, the ecu just has not been told correctly what noise is just noise, and what noise is actually knock.

You can try pulling timing but I dont see it making any difference, but it will verify what I'm saying.

If less timing does change it, I would be checking again that timing on screen is what you're seeing at the plug. But it's a quick easy and free test. But pulling 8deg is also a strangely huge amount.

What compression ratio are you using ? For timing to need to be anywhere near that low, you would need to be in the high 10's range.

And certainly there is no reason for timing to be so low at such low boost/rpm where it drops to 15deg and just stays there.

Possibly at maximum boost and rpm it could have dropped to there, but certainly not at say 3000rpm and almost no boost...as said, it's still virtually normally aspirated at that point, so would run timing appropriate to n/a

Coops wrote:http://www.sendspace.com/filegroup/kf%2 ... 8HGl7oMjkQ

has the file gone ? not at home and trying to download it again, webpage doesnt seem to work or something ?

OK had another look.

Even after the ecu has pulled some 7-8 deg of timing on your logs, there is still "noise" on the "Knock in" which I assume is the knock signal input.

So it's removed 8 deg of timing and still hearing things. Detonation is not the problem, because there is none

what is it then???
what ever it is its making the knock unit take timing out briefly

Coops wrote:what is it then???
what ever it is its making the knock unit take timing out briefly

Ive already explained what it is.

Noise, and knock sensor setup not set up correctly for your engine

engines are noisy.

ok will see what happens if I turn the sensitivity down a fraction on the knock unit,

Coops wrote:ok will see what happens if I turn the sensitivity down a fraction on the knock unit,

No idea what way the MS Knock works.

But basically yes you'd need to run the engine with known safe timing etc, then adjust any knock thresholds to tell the ecu this is safe. Dial it in until the ecu thinks the noise is knock, then you know it's went too far

But noise may be louder at various rpm's, so depends how fine or crude any adjustment is, how sensitive you can make it.

If it starts to hear excessive noise or possibly knock, it can do no harm to verify this manually with det cans, stethoscope, whatever you want to use.

But you cant just simply bolt a knock sensor to an engine and assume generically it will work as the name suggests. It just isnt as easy as that.
It takes some effort from the installer/tuner to actually make it work correctly.

Glad to say we are dialling ignition back in as the fault has been traced to a faulty knock box.
for some reason it has gone mega sensitive and shut down one channel,
new unit on its way to me to fit later this week,