A DETAILED overview of KNOCK and PRE-IGNITION - BOOST SCHOOL #7

[@d4a]

Become a Tuning Pro: hpcdmy.co/dr4a Support the channel by shopping through this link: amzn.to/3RIqU0u Patreon: www.patreon.com/d4a AEM ECU: bit.ly/D4Ainfinity5​ AEM water-meth: bit.ly/2zrOkSp?D4A...​ AEM boost controllers: bit.ly/D4AtruboostX​ AEM wideband AFR gauge: bit.ly/D4Axserieswb​

[@alienpoker]

Have you looked at LiquidPiston development rotary engines. In essence an inversion of the Wankel engine. It could be used in a hybrid go charge batteries and extend range, among other uses.

[@valentinuiliqnow6198]

you can use and cool EGR like mazda sky-actyve engine

[@athalfridhu]

Talk about SAAB ION SENSING PLEASE.

[@samsungultra6094]

15:30 kHz or MHz? U said kilo and wrote megs

[@lestergillis8171]

Did you say "deflagration" ? Or... "defecation" ?💩

[@BOB24502]

One of the most underrated KZbin channels… the presentations are so well done, and so clear! Thank you for the free knowledge!

[@Pablo-Esco509]

5

[@electric7487]

Preignition, basically a situation where your piston is trying to compress an explosion.

[@sillysad3198]

he is trying to become a diesel! it is TRANS diesel motor. you need to let him be.

[@frontspring1]

@@sillysad3198 I think your cylinders are suffering from abnormal combustion. Clean them

[@Alex-di8ti]

You have an F=ma from the piston and con-rod and a F=pa coming from the pre-ignition. Something in the middle has to give, the piston and/or the con-rod.

[@bakters]

@@Alex-di8ti "F=ma" When approaching TDC the piston slows down, so the acceleration is negative. The forces you mentioned do not oppose each other.

[@Alex-di8ti]

@@bakters My question is, how can pre ignition cause such damage as bent/snapped con rods. There must be substantial forces to achieve this. If pre ignition can occur anytime in compression stroke, I am thinking is it more the pressure from the shockwave that does the damage. If piston is decellerating it still has an F=ma but yes negative, If the force is far greater from the pre ignition, than your suddenly applying greater loads to the components. My thinking is probably wrong in my previous comment, it would be easier to understand with some force recordings.

[@MultiMightyQuinn]

As a non-gear head (term used with love, I have many friends who are) I have to say I love your videos. You obviously have a very good understanding of the science and mechanics and you are able to translate that well a larger audience without dumbing things down too much. Great content, thank you for sharing with us!

[@lilmike2710]

It's safe to consider him an Automotive Engineer. I'm not sure if I'd consider him a "gear head". Engine nerd maybe (term lovingly used). 💜 ⚙️ 🚗

[@lilmike2710]

I have definitely learned things I didn't really know or fully understand before. He certainly explains things in a way that people like myself (dummies) can understand.

[@dappxx]

😅😅

[@Herpitor]

This guy's videos are uniformly well-researched, well-presented, accurate and extremely useful. Kudos.

[@bryanleal9836]

it's okay yeah sure he's a novice in performance world but he's still learning

[@ahnafzahid9450]

i thought boost school was dead!...how ever, today's topic IS CRUTIAL...Thanks again brother, for bringing out another informative episode

[@generaldart6567]

Yes thats right 👌

[@LMBLNCR]

Pardon me for saying so a year on but it's CRUCIAL And yes I agree this guy is good

[@terjejohnsen3651]

I have allways wanted to know what knock is and now I know thanks to my teacher at D4A .i recomend this sunday school it makes the day perfect.

[@davidgrisez]

Another way of controlling engine knock many years ago in the days of carburetors was for the driver of the car to back off the gas pedal when the driver heard engine pinging and knocking. Less air and fuel would stop the pinging and knocking. Also engine pinging and knocking tended to occur with a wide open throttle and low engine rpm. In those cases shifting to a lower gear to increase engine rpm reduced pinging and knocking.

[@user-si5fm8ql3c]

Less fuel/air means a pressure drop across the throttle body, lowering intake air temps. Higher RPM means the fuel/air mix is not as long in contact with the hot cylinder walls, making it cooler when the spark fires. Its even more interesting on even older glow chamber/tube engines, early 20th century, big, slow running, single cyclinder engines. I remember my old neighbour showing of his skills with a 1930s tractor, got the glow bulb way hot (this advances timing) after hauling firewood up a mountain, then, to reverse he slowed down the engine, got it to stop mid compression stroke, pre-ignition occured from the overheated bulb and reversed the engines rotation. I got to drive one once, its a odd experience, you need to keep the bulb in the right temp range using a small burner below the bulb at low load and idle and water injection on the intake while its doing heavy work.

[@gregfaris6959]

Good presentation - excellent visuals! What he says at 6:00 is crucial to understand; Most light knocking does not cause engine damage. Engine developers have run test engines for hundreds of hours under light to moderate knocking conditions, and disassembly inspection usually shows no significant damage. What knock ALWAYS causes, and the main reason we wish to avoid it is that it destroys power. As soon as the engine enters a knocking condition, power dissipates rapidly, and if the operator increases inlet mean effective pressure by pressing the accelerator, it only makes the knocking worse. A further point that I feel needed to be made; Without wishing to criticize an excellent introductory video, before introducing exotic solutions like water/methanol injection, it should be noted that knocking tendency is directly correlated to engine speed, or RPM. The ratio of indicated mean effective pressure to knock-limited indicated pressure (IMEP/KLIMEP) increases with increased RPM. This effect is even more pronounced with some bio/gasoline grades. Therefore, the driver’s first line of defense against knocking is to choose the fuel grade that works best for your vehicle (without overspending on unnecessary knock grades) and, if you are fortunate enough to be driving a manual transmission, to select gear ratios that deliver higher RPM, especially when you need to add power.

[@foxman105]

*Knock knock* "I'm not playing this game." *piston has left the engine.*

[@moisesezequielgutierrez]

Piston Ring: *"Adios"*

[@WhiteTrashMotorsports]

Uncle rodney noooo!

[@bigcazza5260]

@@WhiteTrashMotorsports cant believe they left the factory rods in the 4g"k24" miVTEC swap

[@bluebird8004]

I think your confusing it with big end bearing knock, which is more what pre ignition can cause.

[@valentinuiliqnow6198]

you can use and cool EGR like mazda sky-actyve engine

[@TheFakeFatLegitimate]

I’d like to say, you’re explaining things that I’m interested in super well. I would personally rank you above Engineering Explained. You’ve answered a few of my own theories in this video! 😀

[@justayoutuber1906]

I was thinking the same thing!

[@carsonho9338]

I gradually got into it myself in 1 year, and you explained it in 16 mins.

[@jakebatty530]

As a training mechanic, this video is invaluable, absolutely fantastic explanation really appreciate it

[@teshane8784]

This video deserves an award. Incredible explanation, well though out, well put together. Everything is just perfect. Bless up from Jamaica 🇯🇲 💯

[@MrWilliam.Stewart]

Knock knock, "Who's there?" Not Rodney, he was here, but couldn't handle the pressure. "So Who's there?" Toe "Toe who?" Toe truck.

[@SoulTouchMusic93]

Good one!

[@ilham7345]

lmao that's the best one

[@AlphaFarouk]

😂😂😂😂😂👌

[@valentinuiliqnow6198]

you can use and cool EGR like mazda sky-actyve engine

[@mmerc1349]

Dafuq hahahhaa love it

[@JerZeyFiveOh]

Thank you for this video! I am an engine head never really understood timing, knock, and preignition. I’m going to watch this video over again. I have V8 and turbo I-4 cars.

[@barry-cq4xg]

Great stuff. It is not easy to describe such a complex subject to non-engineers; but you do a really good job.

[@amirfmaster2515]

I don't know how many university courses i should've taken just to understand this subject as good as you explained. well done, you are a legend.

[@bradhuffjr777]

The best way to avoid knock that I know of is DON'T take your car to Vengeance Racing!! If you want to avoid CANCER, don't use MTBE ( Methyl Tetra Buytl Ether ) and that's what Vengeance Racing uses to exaggerate dyno numbers along with a space heater in their dyno weather station!! John Brown RIP and Matt Isbell Swinging Richard's Dancer are other good examples to avoid Vengeance Racing and related destructive problems!!

[@jozsefizsak]

Very informative. I knew the basics but the details are fascinating.

[@tinymotogarage]

Absolutely excellent from start to finish. I am more into motorcycles (older ones at that) but for someone self-learning about engines in general, this was a masterclass. Thanks!

[@peterjohn3180]

You'll be used to pistons with lumps missing then!

[@DiscoFang]

Great video that describes the difference of knock from pre-ignition at the start BUT then you only talked about KNOCK and how to reduce or control it. Not once was PRE-IGNITION referred to in the ways KNOCK is controlled or managed. Questions left unaddressed: Does a Knock-Sensor manage PRE-IGNITION? Does fuel octane affect PRE-IGNITION?

[@rv6ejguy]

Hey, that's my piston at 7:05. Stuck wastegate caused the boost to go through the roof and I attempted to modulate boost with the throttle. I was leading the race at the time (road racing). Clearly it didn't work out for me. Great vid.

[@anastasisparastatidis5479]

The fact that he always answers my question just before I make it is almost frightening😂😂😂

[@idontstunt2613]

Thank god ive been trying to explain knock to my brother for like the past 2 weeks

[@jamesyoung5610]

Hello McFly

[@negativeindustrial]

@@jamesyoung5610 “Make like a rod, and get out of here”

[@almostbutnotentirelyunreas166]

One of your BEST, most accurate videos to date!. Excellent contrast between knock and pre-ignition.

[@BYENZER]

DAGNABIT! STOP! No, no, NO! It's NOT called KNOCK. YOU are describing PINGING as KNOCK. KNOCK is from worn out con-rod piston pin bushings. GeezusHKrist! Foreigners. Why can't they keep WORDS STRAIGHT. What is wrong with you people? IT IS CALLED PINGING PINGING PINGING PING PING PING PING PING! NOT KNOCK!

[@petertimowreef9085]

Really nice how AEM decided to spend a part of their marketing budget on this content instead of traditional commercials and advertisements. WIn-win-win situation. We get to enjoy excellent content. Driving 4 answers gets to do what they love. And AEM gets to advertise amongst exactly the sort of customers they're looking for, probably for a fraction of the cost of traditional advertising too.

[@timothybracken1728]

most underrated car channel on youtube hands down, best explanations keep up the great work!!

[@justayoutuber1906]

Great info! I never knew there was a difference knock and pre-ignition. Also the way you promote AEM is perfect as it is directly relevant to what you are talking about - well done. Promotions like this are not seen as ads, but helpful suggestions!

[@jeremywhittler8591]

All this is true , well done video. Higher lift Cams and big single turbos and direct injection are today's keys to keeping engines alive and why we are achieving so much hp today. Cams act differently linear than thier static numbers suggest reducing compression at higher rpm . Coming in with boost after 3500 just like nitrous is the key to keeping everything from breaking, that's why we ditch twins. Staying in compressor map efficiency areas that are making more airflow and less heat to begin with. Then with the computers and meth or timing e85 strategies last. Gearing and the weight of the car are also players as a strategic white paper end game plan. Preventing any detonation from happening in the first place. Big single set ups are faster and live longer. Come in later and tune for boost the way you would nitrous. Move the area under the curve higher in the rpm range , especially in an open deck block . Rods especially hate big torque low , probably too often misinterpreted as a detonation side effect. This is how thier running streetbikes with such high compression ratios. The aggressive Cams and linear not static specs of the camshaft.

[@Francisco-sx7th]

Thanks for this very clear explanation. I had an idea about knock but now I understand it much better thanks to your course. You really have talent to simply explain complex things.

[@shawnodell4382]

Nice video. In the future you might mention that knock breaks down the thermal boundary layer and melts/reduces the strength of the piston. Another sign of knock is spark plug ground strap erosion. Also for comments about the oil you want to use SP oil with turbocharged engine or whatever level the manual calls out. Oil is a source of pre ignition and the newer oils have a higher auto ignition temp helping to prevent PI.

[@luftstolle]

I love your videos. I have seen several other videos of people trying to explain what knock is, why it's bad, and how the ECU manages it, but never quite understood them. This explanation is really, really good and finally made me understand! Thank you so much!

[@galetyler7770]

Great explanation. Best I've heard yet. The only detail that wasn't explained was that compressing of the end gases creates radicals that are not regular old gasoline anymore when knock occurs. It's not a normal air fuel mixture that autoignites. It has been changed by heat and pressure into something that detonates at the local speed of sound.

[@RakeshGuptak]

Wow, this video is operating at the TDC of the information and knowledge on engine combustion and at the edge of the knock not to create information overload! Amazing!

[@questfor10s]

Thanks for the good overview of knock for beginners. Looking forward to the next video where you discuss the details.

[@djisydneyaustralia]

You're the best on KZbin, giving thorough, factual explanations of engine dynamics.

[@25kmgb]

This was excellent. I appreciate how you manage to explain complex technical information in a way I can understand and retain. By the way, we just had a horrible 3 month battle with AEM trying to get their ECU working on a 4AG race motor. Tech and product support was terrible and our shop is only a hour from the main office. Finally gave up an had a Haltech installed and operated on the dyno in 5 days. Hope you're able to cash their check!

[@Jimmysidecarr]

Positively brilliant simplification and explanation of knock and preignition! SUBSCRIBED! Knock and preignition are absolutely the number one killer of modified boosted engines, that are running more than stock boost. Stop blaming your engine oil and start checking the center electrode insulator porcelain for any tiny flecks of aluminum, those are the first evidence that knock has occurred or is occurring. Then either run higher octane, less timing advance or less boost. Localized over heating in cylinders is also a thing but those are the BIG things. This video is SOLID GOLD!

[@AMGTOM]

Very important and I bet lot of mechanic don't know exactly what's knock including me. Thanks a lot bro 😊

[@MrFordy90]

ECU can also cut boost or reduce boost to manage knock. Hopefully you can cover the logic regarding that safe guard in a future video :D Great work as always!

[@gort8203]

What a great video. This channel really shines in comparison to all the slipshod drivel on KZbin. Subscribed!

[@tahoon2009]

Knock beautifully explained like no other video here , all the best

[@luistrejo7249]

I'm really amazed about the explanation in this video. Great work. Good balance between causes of knock, how to avoid it and how the knock sensor works. Greetings from Venezuela, thanks for this valuable information.

[@gbudning]

This is one of your best videos. I will be showing it to my grade 8 Power Technology class. Thank you!

[@JablesMullet]

Learned a lot. Excellent video. Main take away is the word knock has two syllables.

[@melwillseptember752]

That was an amazing video, always wanted to know what nock and pre ignition was. The video about ignition timing and knock, plus the visuals of internal combustion is amazing.

[@massimopusceddu6008]

Great video as always: clear, focused..Spot on!!!

[@valentinuiliqnow6198]

you can use and cool EGR like mazda sky-actyve engine

[@alvesthegreat]

Man oh man this man is smart..... I know my thing but this man breaks it wayyyyy down.... Thank you... Do a video about knock in old diesel engines.... You earned a sub.... Very first video ice watched for you... That has never happened to me before

[@VinnyXL420]

Yep, i had a nice introduction to the destructive powers of knock after it blew apart one of my pistons, im currently in the proccess of rebuilding it with forged internals

[@mickwolf1077]

I love watching your videos, you explain things so clearly then further explain incase people don't get it. I've learned so much and sometimes your videos have reinforced what I know, also you have a great accent. 👍

[@jamest.5001]

Knock is more damaging than a hammer, it's like holding a torch on the position and hitting it with a. Hammer, it melts and shocks the piston, rings, rods, crank, transmission, everything connected, even the head and gasket, knock can lift the head, and push out the head gasket! Then the burning gasses can cut away the head and deck surface! If not shut off, it can destroy the block and head! Amazing explanation, thanks for the effort,

[@ronskopitz2360]

Holy crap - this channel is AMAZING! Your explanations are not only accurate and thorough, but SO we’ll thought out and plotted. THANK YOU!!!!

[@johnlovett8341]

Watching D4A ... plus a beer or two ... awesome way to spend an evening.

[@tonywilkey4369]

Well spoken and with diagrams very easy to understand , well done Tony

[@d4a]

Thank you Tony 😊

[@alexandru_donca]

Hi, You mentioned in the video that knock is not really an issue in diesel engines, but from what I can gather from reading about it on the internet, it actually is, although it's cause is different from knock in petrol engines; it seems to always be a too long ignition delay, which in turn can be caused by other aspects.

[@tdm_nicky5603]

As someone who plays automation my strategy to avoid engine knocking is to increase the size of your exhaust setup and potentially go naturally aspirated along with reducing compression increasing fuel mixture and stop running on nitro methane with cast iron everything

[@johnkufeldt3564]

I fracking love your channel, you have made this Canadian gearhead happy as I always learn something from you. Ell researched, well presented, and your love of subject is contagious as COVID. KEEP IT UP, i MAY SOMEDAY AFFORD TO SPNSOR. Cheers ffrom Calgary, Alberta.

[@gabrielmacedo6121]

Ethanol in Brazil uses this technology since 80's. Is a 92% of cane sugar alcohol and 8% of water mixture, so you can use it in your 1000hp race car directly from the fuel pump. Is not clear in the video, but it has 4 extremely helpful benefits for the engine: reduces intake temperature, reduce temperature inside the combustion chamber, increase the compression ratio (since water expands when comes in gas state) and is more resistant to detonation (the temperature ignition is the highest above the fuels [~392°C], only losing to diesel [~430°C])

[@nevilledredge910]

Thanks for all your subjects that can be very educational for those that are still learning. I say this after 58 years in the trade. Thanks again

Best explanation Ever! Don’t know how you could explain it any better! Great info!

[@giraoshaw]

Never tell a knock knock joke to someone with a boosted car

[@Frenchiemecanick]

Specially a subaru owner

[@billybuchanan385]

@@Frenchiemecanick in my supercharged saturn i never get to hear knock knock jokes. Hsrd when the STI is so far behind and blowing a head gasket

[@RianoTjo]

Knock knock

[@jasonkeech7513]

Absolutely the best video and most informative I've ever seen on KZbin

[@adibz959]

Definitely a video Im looking for! So, to prevent knock and pre-ignition, you need to reduce the compression ratio. Can you make a video on how to reduce compression ratio of an engine? I would like to know about the subject. Thanks 😊

[@robmidgley]

I have to disagree with the definitions. Detonation is runaway exothermic reactions in the fuel without an ignition source. Generally close to sonic speed shock waves and is a pressure and thermal event. Pre-ignition is a hot spot in the combustion space (hot exhaust valve, overheating spark plug, carbon deposit) which acts as an alternative ignition source to the spark plug. Flame fronts are normal speed, but if this happens ahead of the spark plug ignition then it leads to high heat transfer rates that can easily overcome the ability for the surrounding material to dissipate that heat. Pre-ignition can occur after the spark plug fires, but then is not normally an thermal issue for an engine, but can lead to running on after the ignition is turned off. The fundamental chemical difference is that detonation is a runaway exothermic reaction of radicals formed during compression and is a feature of the fuel (and its consequences are pressure and temperature related), whereas pre-ignition is an ignition event, is independent of fuel composition and is a purely thermal event.

[@galetyler7770]

Bravo! Radicals yes!

[@fidztshuma1986]

how is it "pre-" ignition is it happens after?.. 🤔 Wouldn't it be called "post-" ignition.. 🤔

[@robmidgley]

@@fidztshuma1986 Hi Fidz Tahuma. That is a good observation. In normal combustion cycles, secondary flame fronts occurring after ignition aren’t an issue, aren’t noticeable and so don’t really attract a name. However all I was trying to say that such events (where secondary combustion events occur after normal ignition timing) can still be noticeable after the engine ignition is turned off, where it can result in the engine continuing to run on. Again this is not dangerous to the engine when the timing is late in the cycle, but some readers might have noticed this type of behaviour in some engines. It is a feature with similar causes to pre-ignition. The main point of my post is that knocking / detonation isn’t the same as pre-ignition in either root cause or combustion effect and certainly the difference isn’t determined solely by the timing of the event. I also disagree with the video comments that pre-ignition is more damaging than detonation - both can be catastrophic and it is important to understand which mechanism is at play if the engine designer is to be successful in eradicating it.

[@ArneChristianRosenfeldt]

@@fidztshuma1986 ignition pre the flame front reaches this spot, maybe? Some engines even have multiple spark plugs. Exhaust valves are prone to knock due to their temperature anyway, so pre-igntion there ( and retarded ignition due the the ECU at the spark-plug ) could even save the engine.

[@muhammadhaq7773]

Simply fantastic....I'm learning so much...thanks a lot brother...respect from Bangladesh

[@flyingpeter]

good to see boost school again! now that we are talking about aem again, how can i make my own custom made fuel system? i have a daihatsu terios, the fuel sending unit went bad and is nearly impossible to find parts for that, could you guide on how to aproach the problem?

[@sharifazmi1907]

You can try searching for oem unit but I'll stick to original part

[@swagempire6803]

You can get orginal parts from Caribbean islands

[@scotthodges5214]

I've been wanting to know this type of info for years. Thanks for the simplified and educational presentation. Super helpful series.

[@ACommenterOnYouTube]

Its quite amazing how someone can take a topic that only needs like 1 or 2 minutes to explain, even for dummies, and stretch it out for well over 10 minutes ...

[@d4a]

What's more amazing is that there's people who think oversimplifying things can help others understand them better. Fortunately the relevance of such people is often negligible.

[@ACommenterOnYouTube]

@@d4a If you are over simplifying a topic, you should not be a teacher.

[@Dan_Divebomb]

Very minor addition to this video: I've seen pre-ignition also occur after the ignition or at the same time as the ignition. There is a delay between the ignition event and the actual start of the flame propagation. Knock is best charachterised by the meeting of two flame fronts (hence the ripple in the pressure signal - from the meeting shockwaves that add and subtract), while a pre-ignition is just one flame front that combusts all the fuel and therefore doesn't have the ripples in the pressure signal, but can have very high pressure amplitudes (hence the nice holes in the piston shown in this video).

[@valiktoma2542]

Very informative, high quality background material, and very clear explanation. Good work.

[@jojopojo9516]

Long time watcher. First time commentor. I love your channel. Keep up the good work.

[@driftorcircuit]

Amazing video. I thought I knew most of this but still managed to learn a thing or three. Thank you.

[@invisiblekid7374]

I don’t know when the term knock took over for preignition or detonation, but we used to call that pinging. knock was always used to describe the sound of a spun rod bearing, or bent connecting rod, literally metal to metal contact making knocking sound, called rod knock. that’s automatically what I think of when someone says knock. As a matter of fact a lot of pinging was solved by using a higher octane gasoline!

[@cellphonelightsaber]

"I am teaching you something. Now, here is a product from my sponsor that does the thing I just lectured you on. Not only am I still on topic, I am giving you a real-life example of the thing that does the thing." Based senpai.

[@89StarquestTSi]

Now that you have covered knock and pre ignition you should explain how the combustion chamber quench size and shape will affect flame propagation and why location of peak pressure is of utmost importance in ignition timing and why the combustion chamber size will affect ignition timing

[@gibronjamaludin3683]

I just enjoy watching your videos it's easy for me to understand what Is going on in a combustion chamber . So if I'm right editing a aem injection kit will help keep the cylinder temperature down but will Interfere with the AFR su you will need to tune your ECU to edit more feul .I'm no export just watching and learning .thanks in advance

[@fridaycaliforniaa236]

Pre-ignition is actually the reason oil catch cans are a good thing if you plan to drastically increase your boost pressure in the engine. All the oil/burnt particles are hot spots than can generate pre-ignition.

[@G1itzik]

one of the best explanations on KZbin good-work!!!!

[@nordic5490]

All 2021 OEM TURBO cars, are 11:1 compression ratio. The knock is controlled through ignition timing, VVT, and electronic throttle bodies, all of which can respond to the knock sensor detecting knock. 11:1 gives the best part throttle fuel economy, and response.

[@joshuadoliveiro]

superb video. glad to know there's loads of steps to mitigate knock.

[@tentotwo8290]

If you watch the latest Hydraulic Press Channel upload he shows the difference between a flame front burn and a knock explosion! It really brought home to me the difference in the two. Thanks for sharing 👍

[@St1ngerGuy]

I just installed WMI in my KIA Stinger and the results are impressive. At 85°F ambient I have seen my intake temperatures go as low as 49°F. I have to floor it though to get them to drop that low and being not slow I can't do it for very long.

[@JimmyMakingitwork]

Excellent video, i’ll send my customers here when they ask why the car they drive requires 91+ octane fuel and complain that it’s more expensive. Seems I can talk my brains out, but a video, that’ll work. Engines are far more expensive.

[@johnlocatelli9633]

Congratulations on producing and presenting this topic. Excellent technical knowledge and brilliant communication skills. Thank you.

[@drtweak87]

Dude love your videos. So easy to understand and you really put it out in detail and visually

[@stevesloan6775]

Getting your conventional (non-vacuum advance) counterweighted distributor curved to your cam is worth every cent!!

[@TurboS-gh5wc]

Subscribed. Most informative channel on KZbin. Thank you!

[@billshiff2060]

It's worth noting that higher octane fuels do NOT burn slower. They simply resist exploding a bit longer than regular fuel. That is called the delay period , which is what differs between them.

[@joshbrennan8545]

Best explanation of knock I've seen to date..

[@darylreed7771]

I just want to say, I fuckin love your channel! This is seriously the most thorough and best explained engine internals I’ve ever heard. I’ve always wondered about knock when it came to old BMW boxer engines and this totally makes sense to me now. Way to go my dude. You really nailed it and the visuals are perfect. You the man!

[@mohammad7500]

your explanation is very simple and beneficial, thank you!

[@LeZturbo]

I’m so in a hurry to see the next episode ! Greatest explanation !

[@onlyeyeno]

Thanks for another 1:st rate video, informative and clear, and as always even when I believe I "know the subject" I learn something new from Your video. Best regards.

[@yawarriaz4127]

awesome explanation. gem of a youtube channel related to automobiles. i respect "Engineering Explained" but he is too fast and confusing usually.

[@thisisyourcaptainspeaking2259]

Knock is the result of the fuel air mixture combustion ending prematurely. This includes spontaneous combustion but isn't a result of two flame fronts colliding. Optimum location of peak pressure (LPP) is 14 degrees ATDT for all internal combustion engines. The center frequency of a knock event is around 6400 Hz.

[@TheTmshuman]

I run 100% pure meth injection, but my Vette’s grill fell out and it won’t turn off for days on end. It also sold all my tools for another drum of meth.

[@oinka720]

I suggest you check the part number on the heads. Could be meth-heads. Rehabbing those is a pain. Better to just swap them out.

[@billf4429]

I'm glad you can explain all this. I've seen some other videos and all is a run around. No offense to the other videos, but some reps have a heavy accent so that makes the video hard to understand.

[@KingdomAuto]

Fantastic explanation, animations and content. Thanks for taking the time to make such informative videos :)

[@JazzbLu]

Thank you for explaining the difference between knock and pre ignition. I have a truck that is gutless and drinks gasoline like it is going out of style! I have a question about running it on fuel vapor. Does gasoline vapor have potential for knock and pre ignition?

[@iansmith6728]

Gaseous fuels develop less power than liquid fuelled engines, which is a retrograde step. Your truck is gutless for many reasons. Usually the biggest reasons are that it is a heavy blob with the aerodynamics of a house brick and the engine doesn't flow air properly. That can be coupled with deficiencies in the fuelling system (muxture), spark timing and quality, compression ratio, head port flow, swirl and tumble, combustion chamber design, valve shrouding, cam profile, valve size and cut, bore and stroke, bearing sizes, flywheel mass, exhaust manifold design and exhaust pipe size/layout. I'm sure I missed a couple more.