2004 Exige S2...

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andybond
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Fonzey wrote: Tue Sep 08, 2020 9:33 pm
andybond wrote: Tue Sep 08, 2020 9:24 pm
Fonzey wrote: Tue Sep 08, 2020 8:28 pm
What I'm not sure about through lack of experience is what proper knock would actually look like.
large peaks and troughs in very close succession that are significantly higher and lower than the norm.
Yeah that's about as much as I know, but "peaks and troughs" I guess can be ambiguous without context when it comes to scaling on a graph. My earlier logs before RRR and myself started finetuning the knock detection was FAR more spikey, looked very scary - we've smoothed that out purely by altering the knock sensor parameters a bit, nothing has changed with the engine itself - so my only remaining concern is that things have been smoothed out too much and a dodgy batch of fuel could be masked by a poorly calibrated sensor, but I need to rely on the expertise of others instead of second guessing them after a few nights on Google. :D
andybond wrote: Tue Sep 08, 2020 9:27 pm
Fonzey wrote: Tue Sep 08, 2020 7:03 pm t whether this was after the development of the Katana kits or not I really couldn't say.
There isnt really too much difference in the katana kit in raw terms. Its the same supercharger at lotus use, but with a greddy intake manifold and some shockingly bad injectors.

I am glad I went aftermarket ECU now and OEM lotus kit!
Yeah I meant more in terms of what ECU/mapping capabilities were used at that time. I believe most Katana upgrades came about along with T4 reflashes, so it's reasonable to expect they had similar limitations as BOE did back then with regards to knock detection. Perhaps rubber washers was their approach to tuning out the white noise.

One thing for sure, Katana conversions don't seem to have aged well - I think switching to an aftermarket ECU was absolutely the right move.
You will see anomolies in the peaks and troughs. Imagine a Windows CPU trace on perfmon at idle. Random spikes. Now 3 users RDP connect to it and all start doing some powershell. That kind of trace it what I would expect.

I am not sure that anyone actually did anything with the t4 ECU, I think it was BS TBH. I think they stuck in larger injectors and hoped ...
winthattt
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If it’s any use, when I used to produce controllers for production cars we used to start (from key on), with a conservative knock setting and then trim towards knock and back off when it arose. After that there was a very slow dithering into and away from knock to get the best performance with environmental changes (temp, pressure, humidity etc)I don’t think we saved settings over an ignition cycle. Refuelling could cause a big change. I think fuel level (or sudden increase) was used as well, at least we talked about doing so.

That was a long time ago and there may be better strategies
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andybond
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winthattt wrote: Tue Sep 08, 2020 10:45 pm If it’s any use, when I used to produce controllers for production cars we used to start (from key on), with a conservative knock setting and then trim towards knock and back off when it arose. After that there was a very slow dithering into and away from knock to get the best performance with environmental changes (temp, pressure, humidity etc)I don’t think we saved settings over an ignition cycle. Refuelling could cause a big change. I think fuel level (or sudden increase) was used as well, at least we talked about doing so.

That was a long time ago and there may be better strategies
Thats not too dissimilar to the way current cars are tuned from my understanding with the knock correction.
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Fonzey
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andybond wrote: Tue Sep 08, 2020 10:20 pm
You will see anomolies in the peaks and troughs. Imagine a Windows CPU trace on perfmon at idle. Random spikes. Now 3 users RDP connect to it and all start doing some powershell. That kind of trace it what I would expect.

I am not sure that anyone actually did anything with the t4 ECU, I think it was BS TBH. I think they stuck in larger injectors and hoped ...
But that's the whole problem here, using the CPU analogy you're not looking for RDP sessions on an idle server, you're trying to spot RDP sessions on a busy SQL server that's got an anti-virus on demand scan running rampant :lol: It's not just the fact the 2zz with a SC is noisy, it's the fact that the 'normal' noise is on a very similar frequency to the 'bad' noise - so picking it out on a graph is very difficult. Standalone ECU's like the SCS/EMU/etc allow you to smooth out that sound graph to remove the 'normal' peaks and troughs but who's to say that smoothing by the ECU isn't also smoothing out bad noise when it arrives? I can't get an answer on that which I'm happy with to be honest, and without obtaining a donor Corolla, connecting my ECU and intentionally blowing it up - I'm not sure what it would take to gain that confidence :roll:

All this is to say, I understand why the rubber isolation washers were present on the knock sensor, it's just a physical way to achieve what a modern standalone can do within software... I'm not saying it's the right thing to do, but there does seem to be a legitimate issue with successfully identifying knock on a SC'd 2zz. The Lotus approach is probably the most sensible one, which is to just pull timing and have done with it, even if it's a false alarm.

I'm definitely at the point of "too much information is dangerous" now, it's not like 2zz's are blowing up left right and centre in Exiges, so it's clearly not a widespread issue.
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Fonzey
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winthattt wrote: Tue Sep 08, 2020 10:45 pm If it’s any use, when I used to produce controllers for production cars we used to start (from key on), with a conservative knock setting and then trim towards knock and back off when it arose. After that there was a very slow dithering into and away from knock to get the best performance with environmental changes (temp, pressure, humidity etc)I don’t think we saved settings over an ignition cycle. Refuelling could cause a big change. I think fuel level (or sudden increase) was used as well, at least we talked about doing so.

That was a long time ago and there may be better strategies
The EMU has a similar approach, in many cases you would hopefully avoid knock ever coming up because the ECU already has ignition and fueling scales depending on IATs, pressure and coolant temp stuff like that, I guess if you added a flex fuel sensor you could be even more proactive about it. IF/when knock then occurs, it pulls timing and adds fuel based on the ratio of how much noise was being generated (over the preconfigured baseline) and then it slowly adds that timing/removes the fuel over the subsequent ignition cycles, which makes any 'pain' from a false detection relatively short term.

According to posts I found from Phil @ BOE from a few years back, the Lotus maps take much longer to scale back - even pulling the battery doesn't reset the trims, you needed a Lotus Scan tool to do it. Later versions of the BOE tunes apparently deal with this better as they've hacked their way into more and more of the EFI capability.
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The Hornet
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Fonzey wrote: Wed Sep 09, 2020 7:16 am
andybond wrote: Tue Sep 08, 2020 10:20 pm
You will see anomolies in the peaks and troughs. Imagine a Windows CPU trace on perfmon at idle. Random spikes. Now 3 users RDP connect to it and all start doing some powershell. That kind of trace it what I would expect.

I am not sure that anyone actually did anything with the t4 ECU, I think it was BS TBH. I think they stuck in larger injectors and hoped ...
But that's the whole problem here, using the CPU analogy you're not looking for RDP sessions on an idle server, you're trying to spot RDP sessions on a busy SQL server that's got an anti-virus on demand scan running rampant :lol: It's not just the fact the 2zz with a SC is noisy, it's the fact that the 'normal' noise is on a very similar frequency to the 'bad' noise - so picking it out on a graph is very difficult. Standalone ECU's like the SCS/EMU/etc allow you to smooth out that sound graph to remove the 'normal' peaks and troughs but who's to say that smoothing by the ECU isn't also smoothing out bad noise when it arrives? I can't get an answer on that which I'm happy with to be honest, and without obtaining a donor Corolla, connecting my ECU and intentionally blowing it up - I'm not sure what it would take to gain that confidence :roll:

All this is to say, I understand why the rubber isolation washers were present on the knock sensor, it's just a physical way to achieve what a modern standalone can do within software... I'm not saying it's the right thing to do, but there does seem to be a legitimate issue with successfully identifying knock on a SC'd 2zz. The Lotus approach is probably the most sensible one, which is to just pull timing and have done with it, even if it's a false alarm.

I'm definitely at the point of "too much information is dangerous" now, it's not like 2zz's are blowing up left right and centre in Exiges, so it's clearly not a widespread issue.
I agree with you that the person who fitted the washers knew the effect - but I think they were put there more as a MIL eliminator, and to fix an issue that actually has damaged the engine longer term... although not provable of course

Main thing is my car was up and running today, so we are on the path back :D
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thommo
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Phew! Fascinating. I need a lie down in a darkened room.
Exige S1 No: 139
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Fonzey
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The Hornet wrote: Wed Sep 09, 2020 9:23 pm Main thing is my car was up and running today, so we are on the path back :D
Awesome news, sorry for sidetracking the thread - it's just well timed that you uncovered this as I was balls-deep into reading about this sort of stuff.

I guess when all is said and done, disabling/mitigating/desensitising a knock sensor won't cause any harm on its own - and most owners might never come across a problem, but if this was done specifically to get around a mapping issue first time around then that's really worrying... Hopefully you're on the right path now, and hope it doesn't work out too expensive!
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The Hornet
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Fonzey wrote: Wed Sep 09, 2020 9:43 pm
The Hornet wrote: Wed Sep 09, 2020 9:23 pm Main thing is my car was up and running today, so we are on the path back :D
Awesome news, sorry for sidetracking the thread - it's just well timed that you uncovered this as I was balls-deep into reading about this sort of stuff.

I guess when all is said and done, disabling/mitigating/desensitising a knock sensor won't cause any harm on its own - and most owners might never come across a problem, but if this was done specifically to get around a mapping issue first time around then that's really worrying... Hopefully you're on the right path now, and hope it doesn't work out too expensive!
no issue on thread mate - its all very interesting stuff

I agree - I do think it was done to cover up an issue - but am going to move on now :)

It aint gonna be cheap - but at leat I prevented a major engine failure down the line....
pkw2704
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Wow,came to this late and in the process of deciding on a katana s/c kit(used) now you have me very worried.I am not after mega power 250ish would be fine ,but now I am wondering if its all worth it with the possibility of big bills that can occur.I have the emu on my n/a which may come in handy
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