Knock / Pinging / Detonation | What does it sound like? [FREE LESSON] 

I just had this video for an ad, I watched the whole thing and just wanted to say great job on the presentation of the information. I've been a mechanic for over 20 yrs and just want to say it takes a lot, especially in an ad, on a car video that I'm currently watching to get my attention.

@@rebeccabecky9814 so is it just like static high pitch rattling noise?

@@stevethea5250 rattling, yes sir

I have no idea why in 2020 RU-vidrs are still doing this. Just show us the sound. That's why we're here.

@@42elliott agree 👍🏾💯

@@42elliott have a Google search and see what HPA's business is founded on. They're an education provider - if they didn't explain what they were doing to trigger it, it'd be counter-intuitive to their business model. If you don't want detail, there are plenty of backyard hack videos for you to go listen to.

Hahahaha!!!!

🤣🤣🤣🤣🤣

I was just thinking he sounds like a pilot and saw this comment haha

I was thinking the same...

I read this comment before the video started 2 sec in the video i just couldnt say more how rightu arehavava

6400hz is the typical frequency of knock/ping

M

*o

Most Australian tuners don't want to tell you shit about what there doin. Just wanna make money 💸💰

I unpaused the video for 0.5 seconds and he blinked 20 times in that time.

Someone didn't get the joke

🤣

We get a bit of heat about the accent, but we always try to add captions so people have the option of muting and reading if it's too much of a struggle for them. Roles reversed, the world sounds weird as to us accent wise, so that is what we often do ourselves. Some people are a bit mean spirited about it weirdly (not you!) forgetting that there are millions of people out there that no doubt think they talk strangely too haha Hope the captions help if you just can't get an ear for Andres accent and other than that stoked to hear you are enjoying the content and have picked up on a few things Andre has trained himself to be better at for you guys over the years when it comes to this content. An Elite 1500 is also a solid investment! Did you listen to the podcast with Scott from Haltech? Gives a bit of insight into his career and a bit of Haltechs history too which I found interesting: www.hpacademy.com/blog/011-do-you-have-to-break-things-to-become-a-good-tuner-podcast/? - Taz.

Very smart knowledgeable man, but I know what your saying. It's the cadence of his speech, doesn't make him any more or less of a great dude.

steezyskids appreciate the recommendation... I'll be tuning on a Ford A9P with quarterhorse chip installed for a N.A 347 12:1 build just hoping my 40 lbs injectors will stay within duty limit... Only thing I haven't upgraded to another higher cc..

Man, I haven't had those for a few years! - Taz.

Last time I saw those a girl was... nevermind it was an interesting experience lol.

Hahahah... nostalgia

Man not sure that is a recommendation a tech/mechanic would give today haha How good! I'm sure you're happy to have that long in the past now though eh 😅 Things have come a long way for sure - Taz.

use low cut filter and high cut filter to remove anything lower than 5k hertz and higher than let say around 7.5k hertz. then find the exact knock frequency of your engine (depend on stroke and bore) and amplified it precisely like if its at 6574hz (6550-6600). I just hear ticking when it knock almost nothing else. for me hard part is to link it to my standalone...

Using filtering is a great way to really zero in on knock and remove unwanted background noise. Often though you'll find you get a better signal to noise ratio by focussing on the second harmonic frequency of knock (literally double the knock frequency) which may be around 12-14 kHz.

How do these knock readings compare to knock voltage that is seen on VAG vehicles? On my VW it is recommended to keep knock voltage below 10 to prevent tons of timing being pulled and damage over the long run. Even when tuned to go above 10 you don't hear it nearly as loudly like you do in other motors I have experienced knock in.

Yes, it will sound a little different depending on the engine but it will be similar to this. We have isolated it quite well here so note you might have some more background noise. We recommend using quality earbuds and then wearing ear defenders/ear muffs over the top of those. There will be other options that also work, that's just what we have found to be the most reliable with the least 'faff' for us over the years. Hope that helps - Taz.

Hope it helped 😎 - Taz

PANTYEATR1 Yes that's how I explain it to people. A marble in a coke can.... That's via in car only on the road and not wearing any knock detection headsets. Most people that do hear it for the first time mention there's something rattling in the exhaust and they aren't far off lol

Knock will sound a little different from one engine to the next but your description is pretty accurate. Using audio knock detection equipment this may sound slightly different though depending on what the digital signal processor does with the raw signal.

What causes that sound, and is it present only when car accelarate and going uphill? I have it, what can i do, is it dangerous for engine?

@@strahinjapantelic2869 Basically,t he sound, or "knocking," is when the flame-front caused by the spark plugs in the cylinder (the combustion) meets other flame-fronts that combust due to more compression and/or temperature than the fuel itself can handle before self-detonating. Instead of one clean flame-front per combustion per cylinder, you get multiple flame-fronts which can cause issues. It can happen at any time, really, depending on what is going on with your car. If you're going up-hill and it's occurring while you're accelerating up it, it could be that the combustion temperature is too hot (which could potentially be caused by a faulty EGR system, which is relative to your emissions), or your engine might be starved of fuel under that certain amount of load, RPM, and throttle levels. It's unlikely that your car's computer needs tuning. More likely is an issue preventing enough fuel from reaching your engine, such as a fuel regulator, fuel filter, or fuel pump that needs replacing. Of course, before going forward with any repairs, make certain of which issue it is before you spend money on new parts. Knocking is dangerous for your engine's health. Depending on the severity, it can be anywhere from potentially minorly damaging all the way to "this will destroy your engine within a week or less." I would absolutely avoid putting the vehicle in situations that cause the engine to knock, if at all possible, and get it looked at and/or repaired as soon as I could.

@UC88GZPTeS9Xml2YajWO-qxw thanks for such details and explanation...but, why my engine have that sound only when its hot weather, at night is ok, and at winter is fine, no sound, but in summer he makes that sound only at acceleration and under load due to day time...my mechanick told me everything is ok, maybe valve adjustment, and bad fuel but on this model that issue is not common...thanks again...

Ha! That's a throw back. Instead of audio 'sound off' competitions these days I think they do a rev thing? Knock is really more an issue with performance street cars that are not running 'race fuel' or in class racing where there are restrictions on what you can run. If you are running E85 or methanol etc etc, save for larger cooling issues, you're generally going to find MBT before you find knock which is why there is less of a spotlight on it in motorsports - Taz.

That's all an urban legend... Knock sensors are tuned to pick up frequencies in the 6400hz range. Well ABOVE any bass frequencies.

@@davelowets could be true as I’ve heard similar but from bad wiring causing stray emf and retarding timing

What are you listening to the video with? Use some headphones if your speakers are not up to the task. This is almost as clear as knock is ever going to be for you :) - Taz.

It's quite possible to have a particular engine where the knock sound is more prominent, however in my experience you're also more likely to find the knock signal to be worse than what we've presented above. If you're using a good quality head set and you listen to the explanation of what you're hearing, you should have little trouble detecting the knock.

they arnt actually listening to the motor. this video is really stupid. they essentially hooked a electrical signal up to a speaker.

thisisntme they are listening to the signal produced by the knock sensor which is essentially a microphone. oem cars use this method as well.

Thanks for your input there @Gary, I had missed this comment. @thisisntme, correct, and this is the best way to monitor knock. If you are just trying to listen with your 'naked' ears by the time you hear the knock it is too late. Watch this video to understand how this works regarding the sensor, which starts with a microphone so technically even though the signal is converted to a digital format, you are listening just in a way that is actually effective - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-N6lbBCqAGvc.html And read this to understand why your ears are not as good as you think they are if that is the only thing you're curretnly using - www.hpacademy.com/technical-articles/dont-waste-your-time-listening-for-knock/ If that doesn't clear things up come back with some questions and we'll help explain it further for you if we can :) - Taz.

Thanks! We do enjoy a good blink - Taz.

leave my baby alone or I will find you and take a dump threw your letterbox

I couldn’t hear it

Glad you enjoyed it Andrew! Cheers for the comment =) - Taz.

The sound of knock in a rotary is just one loud bang as your internal components convert themselves to external ones instead. They don't tolerate knock/detonation at all. We do go a bit deeper on this in a paid members video here though: www.hpacademy.com/previous-webinars/043-rotary-ignition-tuning-link-g4-vipec/ - Taz.

Yes it can be very difficult on some engines, but you are doing sweeps and do build up to full power runs so you can get a bit of a feel for things rather than just jumping in and going balls to the wall straight off the bat ;) - Taz.

Not silly at all, the dyno we use holds it there. You set what RPM you want (after initial setup of the dyno) and then you can move through the load cells, tune, and bump it up to the next target RPM and repeat. Once you start to get higher into the rev range, you start doing sweeping runs so you're not revving it out too hard and doing damage - Taz.

He gave his answer but thought I would add that since he mentioned the car was in 4th gear, and therefore the transmission engaged and wheels were spinning, you could simply just use the cruise control, am I right? That should maintain the rpm’s as well. You couldn’t do this in neutral though. If you did, I hope your rev limiter is working correctly, or you’d have a lot more than mild knocking to worry about

Hey mate, the rolling shell is sitting in the museum at Highlands Motorsport Park. The engine was sold and I believe it's now overseas. Not sure if it will race again. Time will tell :)

Its Pre ignition knock.

Definitely not that, piezo microphone all the way. From there Links Knock Block unit is very quick and easy to use, or the Plex unit which is aimed at commercial operations that see a lot of tuning and the features reflect that. Tuner Nerd have a product that is in the middle of the two that is good, but like the other two products has it's own compromises as well - Taz. PS: Here's a quick and dirty list: www.hpacademy.com/technical-articles/audio-knock-detection-systems/?

Hmm. How many V6's have you listen to through a piezo microphone? - Taz.

If the ECU does not come with knock detection/control, you will need an external knock monitor capable of outputting a 0-5V signal to an AVI input on your ECU. Check out the Plex knock monitor v2 or the Tuner Nerd knock detection system. Another good one is the Link Knock Block which has dual knock sensor inputs, but no 5v output to ecu. It is used with headphones for audible knock detection only. This is an old comment but I was also wondering the same thing for an elite 750 a few days ago. Maybe this will help someone in the future.

Have a watch of this: www.hpacademy.com/previous-webinars/203-ideal-knock-sensor-placement/? - Taz.

@@hpa101 Thanks much

Just a piezo microphone, they're pretty generic. You just need to try get one to match what bolt thread you have on the block, although you can drill them out in a pinch if you're stuck - www.msel.co.nz/Knock-Sensor-with-2-Way-Mini-Timer-Connector - Taz.

I think if you had knock headphones on when that valve let go you'd have lost an ear drum haha The 1UZ was running E30 so pretty much 0% chance of knock for it given that and being NA, however there's always more to go wrong with engines. At the time we were happy to take the risk knowing something wasn't 100% and just hoping to last for that last meeting - Taz.

No sorry, I'd ask around your local car and motorsport clubs personally :) - Taz.

Good luck. Not gonna happen without pulling excessive timing.

That's just the accent

the old school method is bolting stethoscope to the cylinder head, similar concept. but after tuning properly you shouldn't have to drive and listen to knock. in this video it seems as though he's routing the knock sensors signal through a computer and using it as audio, if not it's just a microphone right up against a head

There will be at least one knock sensor going to the plex knock detection device (audio) and at least one knock sensor (more likely two) going to the Link G4+ ECU (the graphs)

Frietpan Yes you could but it's heaps easier with a passenger doing the listening or at least helping with it! I've got a simple detonation detector that the Autospeed website put up years ago. The updated version I used is a simple sonic hearing unit (like what some old deaf cunts use). Just cut the mic, attach to a alligator clamp and extend the wire. Doubles as a locator for other noises like fucked wheel bearings, CVs etc....

For the knock audio we're using a standalone system from Plex called a Knock Monitor. This is used when we're tuning and then removed from the engine. Using this system the tuner can constantly listen for knock from the engine while tuning. The datalogging in the G4+ ECU on the other hand comes from the two factory knock sensors bolted to the block so the systems are actually independent.

Both =) It's from the EFI Tuning Fundamentals course which you can buy by itself, but it is also including in the package deal. It is 100% the course you want to start with, it covers all the basics to make sure you start on the right foot, even including a little bit of wiring knowledge - Taz.

What are you watching this video on? - Taz

You should still be able to hear knock over your exhaust. The knock sensor is attached to the block and then a knock monitor feeds the signal to your head phones. We recommend wearing ear defenders over your headphones :) - Ben

@@hpa101 Thanks for the reply but without headphones on the street is what I was referring to.

@@Starsquish you can't hear it without audible detection to any useful degree on the street, on the dyno or in the bathtub, it doesn't matter. Headphones are always the way to go - Taz.

I miss those days/diet! - Taz

Because he's giving a demonstration of how professionals would do this?

It depends on where it's occurring, and also on the engine. On low stressed NA engines, it's not ideal but also it's always going to be an issue even at high RPMs. On an engine that has forced induction or a highly stressed NA it can quickly cause catastrophic damage - Taz.

bcs its Honda :P thats why....

We've had mixed success with that and prefer to just use a higher octane fuel instead where knock limited. All depends on your application as to what is the best for you - Taz.

Just a baked bean can? That's very specific, I'd like to see your math on that vs a peach can 😂 As mentioned knock can and will sound different in different engines but in our experience of hearing knock hundreds of vehicles using audible knock detection the demonstration is accurate - Taz.

@@hpa101 The following video demonstrates the very audible pre-ignition sound that I'm on about: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-fTORN27-itM.html&ab_channel=Driver67

solved a problem?

This is just our local 98 octane pump gas. The engine really isn't knock limited on this fuel under normal circumstances.

@@hpa101 Does knock limited mean having a knock sensor? N/A engines haven't these usually, right?

Yes sir. This is something you have to set up to ensure it is accurate. We cover this in our course material and members only webinar lessons. If you have any questions feel free to email me via support@hpacademy.com There is a small Q&A video on it here but I'm not sure it will help you or not as it's just an answer to a question rather than a full lesson on it - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PzMN3zx5niI.html - Taz.

Thanks for the reply !

I have knock sensor problems .it happens when I'm driving down road it jurks momentary then stalls At stops?

Yes sometimes it's even harder to pick up than what you hear here depending on the engine. Of course in this case it also depends on what you're listening to the video through ;) - Taz.

Take a read of this article Don. It's going to help answer these questions for you and more :) - www.hpacademy.com/technical-articles/dont-waste-your-time-listening-for-knock/ - Taz.

Yes sir, for tuning you can use a standalone audible knock detection unit like the TunerNerd Knock Monitor, and then there is the mac daddy Plex Knock Monitor Pro as well. From there if you're running an aftermarket ECU it depends what features it has for what you can do regarding onboard knock control - Taz.

@@hpa101 thanks for the heads up, I appreciate the response. I wonder if it's possible to have a knock detection light, trying to keep the electronic engine control to a minimum.

Just keeping you on your toes there Thomas. Planning to throw some Cockney rhyming slang into the next one ;) - Taz.

artdamage0 when the cylinder heat increases dramatically the injected fuel particles will combust due to the heat before being compressed properly and ignited these random combustions do the most damage to the engine components HPA course will answer all your questions those guys are awesome :)

To add on to what silver said -it happens while the piston is traveling up on the compression stroke hence why it causes so much damage.It is also called preignition at times and as you can imagine the fuel igniting tying to push the piston down while its going up is not good ;-)

Not exactly, what happens in knock is that the fuel is self-ignited at more than one spot causing the flame fronts to crash to each other inducing a shock wave and a spike in pressure which "shakes" the cylinder walls causing the block to "ring". Pretty much what you would hear if you hit the engine with a hammer (from the knock sensor point of view)

There's a few replies here that offer a pretty good explanation which I'll add to. Essentially knock is the auto ignition of unburned fuel and air around the outside of the combustion chamber. This occurs after combustion has already been initiated by the spark plug. As combustion continues, the heat rises in the combustion chamber and these pockets of fuel and air spontaneously combust. When this occurs, the energy contained in the fuel is released very rapidly which causes a large spike in pressure in the cylinder. It's this spike in pressure that can be so destructive. Note that the audible sound associated with knock has nothing to do with colliding flame fronts (think about twin spark plug engines which by definition have two colliding flame fronts under normal operating conditions), but rather it's caused by the engine components resonating.

High Performance Academy so to induce knock in an engine like you are in the video are you simply leaning the AFR out?

CK_32 that is what knock sounds like through the knock sensors

gary quach oh I thought we were trying to listen to knock from a external mic like we would hear personally with out ears.

Just saw your reply there Cktime, if you can hear it audibly without a knock sensor, then it's too late, the damage is done. This is in regards to performance engines - Taz.

They're not, quite simply. This is something you need to be able to hear. Not our call. A deaf person would need someone else to so this side of things for them - Taz

@@hpa101 A deafie needs a normal hearie to hear things for them... Story of my life. So I'll never hear it Thanks for your reply. This confirms why I stopped training to be a mechanic as there were sounds I couldnt hear. Thanks for replying.

Yes, you have to pick your battles as you know, but still plenty you can do too No worries at all, we have a number of deaf students as we cover a range of topics and my in-laws are deaf. While I can never say I understand the struggle as I have not lived it, I do appreciate the challenges many face and work around where possible not always being the easiest by comparison to others - Taz

Actually it could, hotter spark means more heat more voltage means more spark, look at a plug chart for the brand plug you’re running and go one step colder

We're using a load-bearing dyno which allows us to increase engine load while holding the same RPM. This video dives into things - www.hpacademy.com/blog/steady-state-tuning-how-is-it-done-inertia-vs-load-bearing-dyno-tech-nugget/ - Taz.

Maybe low oil?

@@Blue__244 no man, oil is fresh, quality one, near max level...works fine...just that noise on acceleration and uphill killing my ears, i cannot hear it when windows is closed, just in summer when i open it, so its not loud, but, just like somebody hitting constantly with little hammer inside engine...i heard its detonation due low octan fuel but im afraid to destroy engine... 🤐