Stock Knock Sensor Reliable?
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Stock Knock Sensor Reliable?
I am using a ktuner on my kraftwerks supercharged 2007 S2000, and I have been very slowly increasing timing. I am currently at about 15.5 degrees advanced at 15 psi at redline. I have yet to see any knock, the knock count does not increase throughout any of my wide open throttle runs. Can you rely on the stock knock sensor to detect legitimate knock? Or could I be knocking and the stock sensor is missing it?
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Yeah, and it is based off of the "Knock Counts" value. See Hondata's post (#3) in this thread.
https://www.s2ki.com/forums/s2000-en...l-work-745922/
https://www.s2ki.com/forums/s2000-en...l-work-745922/
Joined: Aug 2006
Posts: 5,589
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From: New England
I would NOT be doing any of what you're doing without knock audio detection. But I am a perfectionist and when I tune I choose to go above and beyond of what other tuners do. FYI: I run Link KnockBlock G4+ which uses Bosch donut style wideband knock sensors.
Our S2000 uses narrowband, resonant frequency style sensor. With a standalone ECU, even with our OEM narrowband sensor (which are so chatty that all you see is seesaw signal) you can set a ground floor where you KNOW you're not knocking and then if it goes above that floor it'll register as knock and pull timing.
With kTuner and Honda's knock strategy you are relying on these knock counts and that's about it. Honda's strategy is passive and slow. It allows for knock as Hondata mentions and does nothing unlike standalone ECUs which are active and attempt to save your engine immediately. Passive strategy might work with NA or low powered motors because they can deal with knock and survive for many years/miles... however now you've added a freaking supercharger and @ 16-18degrees past TDC (usually the point of highest pressure in the cylinder) your chance of a knock event doing damage is much higher.
Sorry about the long winded response. Just saying be careful.
Our S2000 uses narrowband, resonant frequency style sensor. With a standalone ECU, even with our OEM narrowband sensor (which are so chatty that all you see is seesaw signal) you can set a ground floor where you KNOW you're not knocking and then if it goes above that floor it'll register as knock and pull timing.
With kTuner and Honda's knock strategy you are relying on these knock counts and that's about it. Honda's strategy is passive and slow. It allows for knock as Hondata mentions and does nothing unlike standalone ECUs which are active and attempt to save your engine immediately. Passive strategy might work with NA or low powered motors because they can deal with knock and survive for many years/miles... however now you've added a freaking supercharger and @ 16-18degrees past TDC (usually the point of highest pressure in the cylinder) your chance of a knock event doing damage is much higher.
Sorry about the long winded response. Just saying be careful.
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Joined: Jul 2018
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I would NOT be doing any of what you're doing without knock audio detection. But I am a perfectionist and when I tune I choose to go above and beyond of what other tuners do. FYI: I run Link KnockBlock G4+ which uses Bosch donut style wideband knock sensors.
Our S2000 uses narrowband, resonant frequency style sensor. With a standalone ECU, even with our OEM narrowband sensor (which are so chatty that all you see is seesaw signal) you can set a ground floor where you KNOW you're not knocking and then if it goes above that floor it'll register as knock and pull timing.
With kTuner and Honda's knock strategy you are relying on these knock counts and that's about it. Honda's strategy is passive and slow. It allows for knock as Hondata mentions and does nothing unlike standalone ECUs which are active and attempt to save your engine immediately. Passive strategy might work with NA or low powered motors because they can deal with knock and survive for many years/miles... however now you've added a freaking supercharger and @ 16-18degrees past TDC (usually the point of highest pressure in the cylinder) your chance of a knock event doing damage is much higher.
Sorry about the long winded response. Just saying be careful.
Our S2000 uses narrowband, resonant frequency style sensor. With a standalone ECU, even with our OEM narrowband sensor (which are so chatty that all you see is seesaw signal) you can set a ground floor where you KNOW you're not knocking and then if it goes above that floor it'll register as knock and pull timing.
With kTuner and Honda's knock strategy you are relying on these knock counts and that's about it. Honda's strategy is passive and slow. It allows for knock as Hondata mentions and does nothing unlike standalone ECUs which are active and attempt to save your engine immediately. Passive strategy might work with NA or low powered motors because they can deal with knock and survive for many years/miles... however now you've added a freaking supercharger and @ 16-18degrees past TDC (usually the point of highest pressure in the cylinder) your chance of a knock event doing damage is much higher.
Sorry about the long winded response. Just saying be careful.
With the supercharger, I have actually been getting a lot of false knock in low load/around town driving, so I had to zero out all of the Knock Retard tables anyway; they were pulling all of the timing all of the time. I do find it amazing that Honda's strategy is so slow and is essentially a long-term adaptation. I am used to GM where it instantly pulls a bunch of timing and then tries to feed it back in. My dick gets hard for stuff like Haltech that can limit throttle and boost for anything including when Mercury goes into retrograde.
Since I don't have an aftermarket ECU with comprehensive engine protection options, I am trying to get it reasonably close with what I have; I don't need every last horsepower. My strategy was basically going to be to add a degree of timing with every iteration (and tweak the fueling to keep it dead-nuts on 11.8:1) until I see a knock count during a WOT run, then back out 2 degrees and call it good.
All of that being said, I still have not been able to get an answer to my core question; will the stock knock sensor reliably detect true knock? I know it will get all kinds of false knock. That is annoying, but I want to know if it is known for false negatives as well.
If I can assume that it will generally show a knock count when the motor is really knocking, I think my above tuning strategy is viable. If it is prone to missing true knock, I am truly blind to what is happening and I need to go pay $1.8 billion for a comprehensive dyno tune.
Thank you for the information so far, I really appreciate it.
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From: New England
Good road tuning strategy btw.
Also my response(s) to your core question is:
- Yes it can detect knock fine
- You'll never know true knock vs false without audio detection
- Audio detection is one of the *only true ways to confirm an onset of knock and catching it before it gets bad such as runaway knock
*Unless you're an F1 team or have infinite money and you're measuring each cylinder pressure and watch for seesaw spikes (knock)
- Pulling plugs immediately after WOT also works, you see Evans Tuning do that all the time... but at that point knock already occurred. Unsure why tuners do not use audio detection
I say, skip the $1.8B tuner and go str8 for the elite and self proclaimed $3.2B tuner... then watch him just dial in the knock frequency and blindly think that the knock sensor is sensing things
and you're back to square one and out of money.
Also, careful assuming that at lower RPM it's false knock. S2000 seem to be knock prone in 2-4K rpm med-high load.
Here is my approach to setting up knock detection with audio detection:
1. Dial in base frequency of knock sensor
2. Using audio detection listen to slightly de-tuned (lowered ign timing across the map) engine and get used to it
3. Pick a low RPM and medium-load range on the map, bump up the timing (thus making it knock prone there)
4. Go on throttle in that range, thus inducing "safe" knock temporarily. You've now heard the knock, you've dialed in your ear to it.
5. You've also further confirmed the correct frequency of ACTUAL knock, on your specific engine, with your specific (narrowband/wideband) knock sensor
6. You've set you knock floor and now not only can you tell what's real knock an what isn't but you'll catch it with audio and lift before it's really bad with primitive ECUs
Steps 2, 3, 4 can still be used with OEM ECU/Hondata that doesn't allow for strict knock control. Standalone tuning = steps 1-6
Also my response(s) to your core question is:
- Yes it can detect knock fine
- You'll never know true knock vs false without audio detection
- Audio detection is one of the *only true ways to confirm an onset of knock and catching it before it gets bad such as runaway knock
*Unless you're an F1 team or have infinite money and you're measuring each cylinder pressure and watch for seesaw spikes (knock)
- Pulling plugs immediately after WOT also works, you see Evans Tuning do that all the time... but at that point knock already occurred. Unsure why tuners do not use audio detection
I say, skip the $1.8B tuner and go str8 for the elite and self proclaimed $3.2B tuner... then watch him just dial in the knock frequency and blindly think that the knock sensor is sensing things
and you're back to square one and out of money.Also, careful assuming that at lower RPM it's false knock. S2000 seem to be knock prone in 2-4K rpm med-high load.
Here is my approach to setting up knock detection with audio detection:
1. Dial in base frequency of knock sensor
2. Using audio detection listen to slightly de-tuned (lowered ign timing across the map) engine and get used to it
3. Pick a low RPM and medium-load range on the map, bump up the timing (thus making it knock prone there)
4. Go on throttle in that range, thus inducing "safe" knock temporarily. You've now heard the knock, you've dialed in your ear to it.
5. You've also further confirmed the correct frequency of ACTUAL knock, on your specific engine, with your specific (narrowband/wideband) knock sensor
6. You've set you knock floor and now not only can you tell what's real knock an what isn't but you'll catch it with audio and lift before it's really bad with primitive ECUs
Steps 2, 3, 4 can still be used with OEM ECU/Hondata that doesn't allow for strict knock control. Standalone tuning = steps 1-6
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Good road tuning strategy btw.
Also my response(s) to your core question is:
- Yes it can detect knock fine
- You'll never know true knock vs false without audio detection
- Audio detection is one of the *only true ways to confirm an onset of knock and catching it before it gets bad such as runaway knock
*Unless you're an F1 team or have infinite money and you're measuring each cylinder pressure and watch for seesaw spikes (knock)
- Pulling plugs immediately after WOT also works, you see Evans Tuning do that all the time... but at that point knock already occurred. Unsure why tuners do not use audio detection
I say, skip the $1.8B tuner and go str8 for the elite and self proclaimed $3.2B tuner... then watch him just dial in the knock frequency and blindly think that the knock sensor is sensing things and you're back to square one and out of money.
Also, careful assuming that at lower RPM it's false knock. S2000 seem to be knock prone in 2-4K rpm med-high load.
Here is my approach to setting up knock detection with audio detection:
1. Using audio detection listen to slightly de-tuned (lowered ign timing across the map) engine and get used to it
2. Dial in sensor config
3. Pick a low RPM and medium-load range on the map, bump up the timing (thus making it knock prone there)
4. Go on throttle in that range, thus inducing "safe" knock temporarily. You've now heard the knock, you've dialed in your ear to it.
5. You've also further confirmed the correct frequency of ACTUAL knock, on your specific engine, with this specific knock sensor
6. You've set you knock floor and now not only can you tell what's real knock an what isn't but you'll catch it with audio and lift before it's really bad with primitive ECUs
Steps 1, 3, 4 can still be used with OEM ECU/Hondata that doesn't allow for strict knock control. Standalone tuning = steps 1-6
Also my response(s) to your core question is:
- Yes it can detect knock fine
- You'll never know true knock vs false without audio detection
- Audio detection is one of the *only true ways to confirm an onset of knock and catching it before it gets bad such as runaway knock
*Unless you're an F1 team or have infinite money and you're measuring each cylinder pressure and watch for seesaw spikes (knock)
- Pulling plugs immediately after WOT also works, you see Evans Tuning do that all the time... but at that point knock already occurred. Unsure why tuners do not use audio detection
I say, skip the $1.8B tuner and go str8 for the elite and self proclaimed $3.2B tuner... then watch him just dial in the knock frequency and blindly think that the knock sensor is sensing things
and you're back to square one and out of money.Also, careful assuming that at lower RPM it's false knock. S2000 seem to be knock prone in 2-4K rpm med-high load.
Here is my approach to setting up knock detection with audio detection:
1. Using audio detection listen to slightly de-tuned (lowered ign timing across the map) engine and get used to it
2. Dial in sensor config
3. Pick a low RPM and medium-load range on the map, bump up the timing (thus making it knock prone there)
4. Go on throttle in that range, thus inducing "safe" knock temporarily. You've now heard the knock, you've dialed in your ear to it.
5. You've also further confirmed the correct frequency of ACTUAL knock, on your specific engine, with this specific knock sensor
6. You've set you knock floor and now not only can you tell what's real knock an what isn't but you'll catch it with audio and lift before it's really bad with primitive ECUs
Steps 1, 3, 4 can still be used with OEM ECU/Hondata that doesn't allow for strict knock control. Standalone tuning = steps 1-6
I am concerned about the false knock, to be sure, but a lot of it shows up on startup and pulling away from a stop like an old lady. I believe it may be from the "twanging" of my cogged belt on the Kraftwerks kit. It is quite loud and sounds like exhaust hitting the frame. Basically, Kraftwerks used a static tensioner for a long belt on a huge aluminum plate holding the cogs, so if you make it tight enough not to twang when cold, it snaps the belt or rips off the supercharger pulley when hot. That is the price I pay for being too cheap to buy a TTS kit... Though, I am very conservative on the timing below VTEC (4600 RPM currently) because there isn't much power to be made there anyway. I am only making about 4 lbs of boost @ 4600.
That being said, last weekend I got a knock sensor circuit code and tried to unplug/replug the sensor. It fell apart in my hands. I did the starter 2 months ago and the clutch last month, so I guess I bumped it enough to break it at some point...not sure why it waited weeks to actually fall apart. I pulled 4 degrees out of the tune since that brought the tuning effort I mention above into question and ordered a new Honda sensor, which arrived 30 minutes ago. We'll see if that same "false knock" as before shows up, and if re-doing the last few iterations produces any true knock.
Joined: Aug 2006
Posts: 5,589
Likes: 69
From: New England
No problem!
Weird indeed. Completely OEM ECU would usually go into limp mode and heavily retard timing everywhere. When that happened to me the car was gutless with like 50HP until I replaced severed OEM knock sensor. (OEM ECU with Emanage)
Get that new knock sensor installed and run a few more logs to see what your knock counts are like. Then take the belt off and do the same? Rule out that it's the belt that way.
Also worth checking motor mounts. Both of mine were shot and were causing issues for sure. With S2000 you can't even really tell when they're bad unless you breaker bar the motor and watch it lift.
Edit: Heads up on the fueling when you remove the belt, with Comptech SC you're entering positive pressure aka 1PSI+ of boost at roughly 28-32% TPS... so keep an eye on fueling even though I think your closed loop should correct for most of it.
Weird indeed. Completely OEM ECU would usually go into limp mode and heavily retard timing everywhere. When that happened to me the car was gutless with like 50HP until I replaced severed OEM knock sensor. (OEM ECU with Emanage)
Get that new knock sensor installed and run a few more logs to see what your knock counts are like. Then take the belt off and do the same? Rule out that it's the belt that way.
Also worth checking motor mounts. Both of mine were shot and were causing issues for sure. With S2000 you can't even really tell when they're bad unless you breaker bar the motor and watch it lift.
Edit: Heads up on the fueling when you remove the belt, with Comptech SC you're entering positive pressure aka 1PSI+ of boost at roughly 28-32% TPS... so keep an eye on fueling even though I think your closed loop should correct for most of it.