Detonation & Knock Sensing
Discussion
Seems to be the topic of the moment so I was wondering what can be done to protect against it. Has anyone used something like this? www.motec.com.au/skm/skmoverview/
It would be interesting to find something that can reduce boost in FI applications when knock occurs.
It would be interesting to find something that can reduce boost in FI applications when knock occurs.
Edited by anonymous-user on Thursday 12th November 11:38
i dont think ive ever experianced knock
what does it 'feel' like when your driving? i know the timing is retarded to help prevent it.
is it just like a hesitation/missfire or is it audible aswell?
im not talking about your engine being in piecies, just the ecu retarding it.
what does it 'feel' like when your driving? i know the timing is retarded to help prevent it.
is it just like a hesitation/missfire or is it audible aswell?
im not talking about your engine being in piecies, just the ecu retarding it.
Edited by k15tox on Thursday 12th November 13:08
Trailermasher said:
stigmundfreud said:
a decent engine map will help prevent knock 
Wont help against a bad batch of fuel.89RON - 99RON, it ain't always what it says on the tin!
Still, only so much you can do, if you get too much knock something somewhere is wrong.
That SKM is only for Motec ecu's.
I'd have thought that if your happy with the mapping. Then you'd just need to monitor det, to detect either a bad batch of fuel or other issue.
I've used this in the past but not sure if its suitable for the LS2:
http://www.phormula.co.uk/KnockDetection-KS-3.aspx...
I'd have thought that if your happy with the mapping. Then you'd just need to monitor det, to detect either a bad batch of fuel or other issue.
I've used this in the past but not sure if its suitable for the LS2:
http://www.phormula.co.uk/KnockDetection-KS-3.aspx...
have a chat with Richard for capability or Harry/Jez as i believe they have variable boost controllers but whether they are statically mapped or able to trigger based on KR is another question.
Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
I'm sure Mark usually maps for 95 to combat such issues anyway so worth chatting with him to see which he mapped for. Also if you are Mafless depending on ecu you might be forced into a single spark map anyway
Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
I'm sure Mark usually maps for 95 to combat such issues anyway so worth chatting with him to see which he mapped for. Also if you are Mafless depending on ecu you might be forced into a single spark map anyway
Edited by stigmundfreud on Thursday 12th November 15:59
stigmundfreud said:
have a chat with Richard for capability or Harry/Jez as i believe they have variable boost controllers but whether they are statically mapped or able to trigger based on KR is another question.
Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
The boost controllers won't be mapped unless they interface with the ECU which I doubt they are, and unless stand alone ECU's are being used, then generally it is a solenoid controlled via the ECU, in which case it can be mappable. Anyway using a boost controller would only reduce the boost to the wastegate spring pressure at best. I am not sure dumping boost would be either the best or fastest way to achieve protection with what is available on the market at present.Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
Edited by stigmundfreud on Thursday 12th November 15:59
TerryS said:
stigmundfreud said:
have a chat with Richard for capability or Harry/Jez as i believe they have variable boost controllers but whether they are statically mapped or able to trigger based on KR is another question.
Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
The boost controllers won't be mapped unless they interface with the ECU which I doubt they are, and unless stand alone ECU's are being used, then generally it is a solenoid controlled via the ECU, in which case it can be mappable. Anyway using a boost controller would only reduce the boost to the wastegate spring pressure at best. I am not sure dumping boost would be either the best or fastest way to achieve protection with what is available on the market at present.Possibly a custom OS from EFI does cover it but Rich is the man to ask
eta and you know where that will go
Edited by stigmundfreud on Thursday 12th November 15:59
wormus said:
Seems to be the topic of the moment so I was wondering what can be done to protect against it. Has anyone used something like this? http://www.motec.com.au/skm/skmoverview/
It would be interesting to find something that can reduce boost in FI applications when knock occurs.
Reducing boost would be a fatally slow method to try and prevent detonation.It would be interesting to find something that can reduce boost in FI applications when knock occurs.
Edited by wormus on Thursday 12th November 11:38
A better method would be to control ignition timing. Oddly, thats what nearly every modern car out there does including the LS's, although with certain limitations on control.
stigmundfreud said:
the engine map or rather the ECU on these cars should be able to reduce knock significantly already. It might be worth worums putting a scangauge on to monitor KR
Totally agree, but I was stating a boost controller can not be used to reduce the boost based upon the KR.If Wormus is that worried he can has a knock link installed. They are crude but when tuned work OK.
http://www.thor-racing.co.uk/Knock_Link-LNK_KNK_LN...
The problem with knock is that timing is retarded after its happened!
Of course if it is happening continually timing will remain pulled. But any knock is bad.
Under some throttle transitions you will get the odd tick which you cant do too much about, but at steady state if you get any knock then your tune sux.
Its managed in a fairly complex way and in fact each cylinder is tuned in later ECU's. I guess they have their own knock profile which you can adjust if you are keen enough.
Just depends on how anal you want to get.
You can also make timing retard more agressive if you want to err more on the side of caution, etc, etc.
FWIW mine runs 95 octane and always has done on the new engine. No need to waste even more money than necessary.
Of course if it is happening continually timing will remain pulled. But any knock is bad.
Under some throttle transitions you will get the odd tick which you cant do too much about, but at steady state if you get any knock then your tune sux.
Its managed in a fairly complex way and in fact each cylinder is tuned in later ECU's. I guess they have their own knock profile which you can adjust if you are keen enough.
Just depends on how anal you want to get.
You can also make timing retard more agressive if you want to err more on the side of caution, etc, etc.
FWIW mine runs 95 octane and always has done on the new engine. No need to waste even more money than necessary.
Yes, its in the pipeline, but more pressing maintenance is required
I ported the intake throttle already so hopefully am getting more air in.. next step was/is to retune on 98 octane and add a couple of degrees more timing Id like to hit 520rwhp eventually, Im sure its possible. Though to be honest with the ability to break traction at 100mph in the dry on 95 octane I dont really need any more power. It will be for Dyno Day purposes only
I ported the intake throttle already so hopefully am getting more air in.. next step was/is to retune on 98 octane and add a couple of degrees more timing Id like to hit 520rwhp eventually, Im sure its possible. Though to be honest with the ability to break traction at 100mph in the dry on 95 octane I dont really need any more power. It will be for Dyno Day purposes only
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