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On 12/26/2024 at 12:13 AM, Murray_Calavera said:

I have questions - 

* what are you using to detect knock? 

* do you have knock ears or any other way to listen to knock? 

* your driving a R33 yeah? what are the knock sensors your running, factory is the old school style yeah? Do you have modern bosch knock sensors? 

* have you deliberately induced knock to see what it looks like on your ECU/knock monitor and listened to it to hear what it sounds like? 

1. Factory knock sensors for now, honestly the RB26 OEM knock sensors seem ok as they're flat response instead of resonant type but they appear to be internally grounded to the block. If I do replace the sensor it would just be to get ones that are not internally grounded so a differential input can be used to reject common mode noise. Definitely plan on fixing this as a part of the tuning process.

2. Never deliberately induced knock, though I guess I could try that experiment if I really wanted to.

3. All of this is basically on a stock engine + ECU, only modification is HKS GTIII-SS turbos and a Nismo plenum. Currently I run it with the wastegate solenoid unplugged so it won't try to raise boost past wastegate pressure.

Edited by joshuaho96
1 hour ago, joshuaho96 said:

1. Factory knock sensors for now, honestly the RB26 OEM knock sensors seem ok as they're flat response instead of resonant type but they appear to be internally grounded to the block. If I do replace the sensor it would just be to get ones that are not internally grounded so a differential input can be used to reject common mode noise. Definitely plan on fixing this as a part of the tuning process.

2. Never deliberately induced knock, though I guess I could try that experiment if I really wanted to.

3. All of this is basically on a stock engine + ECU, only modification is HKS GTIII-SS turbos and a Nismo plenum. Currently I run it with the wastegate solenoid unplugged so it won't try to raise boost past wastegate pressure.

Ah yep. The main message I want to pass on is, try not to get scared of ghosts when thinking about knock/knock detection. 

What I mean is, healthy engines make noise. Knock is also noise. Your knock sensor and ECU combo are trying to determine bad noise from good noise based on how loud the noise is. The factory knock sensors and ECU are not good at doing this. 

Modern ECU's are pretty decent at it, however I'd still say that you would want to verify that if your ECU says it's knock, that you actually listen to it and confirm that it is correct. 

Are you familiar with the plex knock monitor?  https://www.plex-tuning.com/products/plex-knock-monitor-v3/

I expect you're the type of person that would be very keen to play with something like this. It is great knock detection and you can pop some headphones on and listen to what's going on. 

Knock that you've deliberately induced in low load low RPM areas is not really putting anything at risk and is a great tuning/learning/verification tool. 

I just thought this was worth mentioning based on the way you were talking about setting up a base map and the Haltech base map settings. There are better ways to spend your time then chasing ghosts and worrying about detonation in scenarios that it is crazy unlikely to encounter it. 

I was also wondering, what ECU are you planning to get? Will it be long til you pick it up?

  • Like 1
9 hours ago, Murray_Calavera said:

Ah yep. The main message I want to pass on is, try not to get scared of ghosts when thinking about knock/knock detection. 

What I mean is, healthy engines make noise. Knock is also noise. Your knock sensor and ECU combo are trying to determine bad noise from good noise based on how loud the noise is. The factory knock sensors and ECU are not good at doing this. 

Modern ECU's are pretty decent at it, however I'd still say that you would want to verify that if your ECU says it's knock, that you actually listen to it and confirm that it is correct. 

Are you familiar with the plex knock monitor?  https://www.plex-tuning.com/products/plex-knock-monitor-v3/

I expect you're the type of person that would be very keen to play with something like this. It is great knock detection and you can pop some headphones on and listen to what's going on. 

Knock that you've deliberately induced in low load low RPM areas is not really putting anything at risk and is a great tuning/learning/verification tool. 

I just thought this was worth mentioning based on the way you were talking about setting up a base map and the Haltech base map settings. There are better ways to spend your time then chasing ghosts and worrying about detonation in scenarios that it is crazy unlikely to encounter it. 

I was also wondering, what ECU are you planning to get? Will it be long til you pick it up?

I have an Elite 2500, honestly most of this has been a lot of smaller tasks chasing little details and a whole lot of life getting in the way of bigger projects. I don't mind too much looking at a spectrograph vs having audio knock ears. 

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