What is Detonation, and How Can It Kill Your Engine?
Vložit
- čas přidán 1. 08. 2024
- Some responded to this video stating that it was not hydrolock that broke my piston, but rather detonation.
• Hydrostatic Lock the S...
In this video I talk about the causes and effects of detonation. I also cover what I've done to help prevent it in my engine. I'll leave it for you to decide if it was hydrolock or detonation that broke my piston.
Check out my other channel for repair videos: czcams.com/users/EricTheC...
Thanks for watching!
The best place for answers to your automotive questions: www.ericthecarguy.com
Check out the ETCG Blog for the latest info: www.ericthecarguy.com/blog
My MSD Ignition Box: www.msdperformance.com/produc...
My Carburetor: www.jegs.com/i/Demon-Carburet...
Related Videos
The Fairmont Catches on Fire: • Oh Sh%*#!! The Fairmon...
How Did the Fairmont Catch on Fire?: • How Did the Fairmont C...
The Fairmont Fire, The Take Away: • The Fairmont Fire, The...
How To Properly Gap Rings: • How To Properly Gap Pi...
How To Assemble Pistons and Rings: • How To Assemble Piston...
Engine Assembly Crankshaft and Pistons: • Engine Assembly Cranks...
How To Balance an Engines Rotating Assembly: • How To Balance an Engi...
Knock Sensor Diagnosis: • P0325 Knock Sensor Dia...
Dissecting an Engine the Basic Parts and their Function: • Dissecting an Engine, ...
Ford 302 Complete Tear Down: • Ford 302 Complete Engi...
5 Things You Should Know When Building a Turbocharged Engine: • 5 Things You Should Kn...
What to do When Your Car is in a Flood: • What To Do When Your C...
**Answers to your Automotive Questions Here: www.ericthecarguy.com/faq
Social Network Links
Facebook: EricTheCarGu...
Twitter: / ericthecarguy
Google+: plus.google.com/1001951801966...
Instagram: / ericthecarguy
Want more content from ETCG? Information on Premium Membership: www.ericthecarguy.com/premium...
Stay Dirty
ETCG1 - Auta a dopravní prostředky
First off, Eric is an excellent speaker. He conveys his thoughts very concisely.
For myself, I would rather think of Detonation as being a result of a portion of the flame front that has been given a place to hide, so to speak, rather than: "detonation is a flame front that happens after the spark plug ignites". This causes an additional or secondary burn that sets up destructive shock waves.
That said, he gets the message across very well.
Causes of Detonation can be; poor cylinder combustion chamber design, high cylinder temperatures, excessive cylinder pressures, lean fuel/air mixture, etc.
He is dead on regarding the difference between "Detonation" and "Pre-Ignition", of which are often confused.
Keep up the good work, Eric!
And for those of you who are building SBCs, of which incorporate a wedge shaped combustion chamber, DO NOT use the GM Full Dished pistons.... unless you like the idea the detonation potential.
You need to add more fuel as you are in higher boost. not take fuel away. I ran 11.5-11.2 on 25 lbs as an example. running 14.7 at idle and smooth transitions into richer mixtures is key. I have never played with a boosted carbureted car before, but I can tell you that you need to richen your mixture when in heavy boost.
Little off-topic, but I really like that your toy car is not your daily. Not a hard lesson that I had to learn, but I've seen it too many times and it's really frustrating.
Very well said. I'm glad to see that you can go so far into depth on the failure of the motor. Sometimes those questions come and you gave everyone a perfectly clear answer. thanks Eric.
Some of the time I just enjoy the discussion, other times I learn new things but I am always entertained. Thanks for the videos
Thanks to you I was able to diagnose and fix the rattle on my 2004 Honda Element ( replaced rear sway bar bushings) $8 each on Amazon original equipment.
You learn new things every day. I shocked myself and I learned something new just buy watching this clip. Keep up the hard work Eric your a true legend. 🤠
Mission accomplished. Thanks very much for the feedback.
I Love your experimentation on all possibilities...please never stop. I know i'm behind and i'll try to catch up.
I agree with you, Eric, I think it was most likely when you tried to start it while it was flooded. This happens all the time on small construction equipment, like a Toro Dingo, when they get tipped over. They run a small diesel engine so the starter has enough potential force to bend rods. We've done a few rebuilds here because of this issue.
Finally, it's really my birthday. Thanks ETCG1
Happy Birthday!
Thomas Gant me too it was yesterday I spent it alone in my room with a steak and cheese pie only got 1 card which is still in the po box to collect. Another depressing Birthday. I'm celebrating today cause its over for another year.
Paul Williams happy birthday!!!
@@matowixunplugged7927 Hang in there brother
Good video. I need to ask my neighbor to watch this - he use to build engines for one or two NASCAR teams.
OMG! I'TS MY BIRTHDAY!. Thank you! I had told ETGC1 to make a video on my birthday and he did. And he made a very educational video! Wish does came true, thumbs up for this guy and subscribe!
Great analysis, not many people can do that without biased.
I've only rebuilt 5 engines in my life, so I'm no pro but one of them did have detonation symptoms and all the pistons had holing and pitting on them not just one. When my cousins tractor failed from a faulty pump that pushed too my diesel and hydro locked, that was one messed up cylinder and piston. I'm just using the examples I know of and to me it seems like hydro locking, but I could very well be wrong. Glad you're getting it sorted out though!
That's 6 more than me. I helped take one apart.
What's really ominous is that I've even seen demonstrations where it happened on rotary engine's where you don't really think of compression numbers in this category that I'm aware of anyway. In this case it actually dented the face of the rotor.
Well, you have more experience that Eric...
Lean detonation damages top of piston, or melts it down. Rich detonation damages ring lands, fuel ignites after it seeps down into them.
I’m not guessing as to what exactly happened in your case, just throwing some info out there.
Such a short and awesome description of detonation vs pre-ignition. With the information you have I think it's hard to know the exact cause, maybe a combination of both. I think I agree with your hunch that it was the hydro lock. What about putting on a knock sensor that puts a light on your dash, so if you get too much knock you can tone it done?
Gonna screenie this holy crap after 5 years finally on July 9 Eric Says happy birthday! :D He was a day late last year XD Thanks Eric!!!
Happy Birthday!
Thank you Eric!
Good information I always thought pre ignition was detonation I do know they are both bad learned something new.
great video eric
Thank you for the knowledge.
Today was my moms birthday. Thanks Eric :)
I had a scooter that burned a hole into the ringland cause I made the mistake of installing a big bore kit without up jetting the carburetor, didn’t realize it until it blew a crank seal. Learned that lesson and jetted the carb accordingly
Take a shot every time he says ‘detonation’
BustedWalletGarage
He said "detonation" enough to give the NSA evesdroppers all strokes. 😎
Refried Beans It is similar to a ....BOMB. and the best way to... TRUMP that is better fuel management so you don't...KILL the engine . Ok, NSA STFU you know I'm playin. I'm actually not triggered my Mr. Annoying Orange.
BustedWalletGarage ran out of alcohol halfway through. Lol
I've been driving my Toyota with detonation for over two years. Still ain't broke yet. It only pings while under-load when I hit 2,500 RPMS. Its much worse in the summer since its temperature based. Its just heavy carbon build up inside the combustion chamber. Snake oils don't fix the problem as they never work. Seafoarm is too risky nor its meant to be used in the intake. A great way to hydrolock your engine.
You rock pal
Great videos
I love the Fairmont. I grew up with a green 79 Fairmont station wagon.
Great video! I tend to believe that it was hydraulic lock. If I remember correctly you mentioned something about leaking extra fuel in.
My 2004 Corvette C5 (LS1) pinged really bad when under load, and it eventually got so bad it pinged just driving up small grades. I use 91 octane Shell (the highest in my state), and that means it should NOT be running like crap. I took my Corvette to a Chevy dealer and let them reflash the PCM to factory settings. That actually somewhat fixed the problem! The engine doesn't ping climbing hills, or ping when really hitting the throttle anymore. It only pings when the gasoline gets old in a course of weeks now. Kinda reminds me of how race cars get reflashed often to keep them running properly.
Another excellent video, Eric.
How can you possibly think it's an excellent video? He has no clue what he is talking about. 13:1 AFRs in boost is a sure fire recipe for broken ring lands, like the broken ring land he has. Guy is fuckin clueless about what he is doing
Mastodon maybe because he's a good video maker and knows way more about cars than I ever will?
Time for a Holley sniper EFI kit!!!!😍😍😍 that's the Direction I would go with the Fairmont!
cruising you can have a mixture up-to and around stoich, under load is where you want richer mixtures
The engine is actually giving you more power than you wanted. I don't know much about internal engine and transmission workings but from what you said the last minute of the video. The engine is for a little more power than you need and the only way to keep it going smoother is with it gulping gas. Though not easy on your pocket. Hopefully you'll get the money back in quarter mile races on the track. You need this idea as an ace in the whole.
Removing timing actually increases combustion temperatures. Too much timing can cause knock and so can too little timing. 13 AFR under boost is REALLY lean. You really want to be in the 11-12 area
@j bowers LOL
retarded timing makes the fuel continue burn after the exhaust valve opens and that is what increases the temperature at the exhaust ports. that can lead to overheating of headers, parts of the cylinder heads and valves and can even destroy them. timing being retarded if additional ignition spots occur they will have less impact
It's was probably hydro lock cause of the fuel overflow you had because it was only one piston, lean condition destroys everything. I don't see any issue with carburetor, but with boost, conditions change constantly. It's like flying a 1940s airplane where your constantly adjusting for the boost and altitude, a computer does it so much better and at all times, but w/e you do you Eric, love your content.
i thought detonation too eric. i just assumed you would have heard it. i think you should put a visual knock indicator on it. On a boosted application you should be around 11.5-11.9 wot.
I see tons of turbo/carbed cars, and they run just fine. I love the fact you kept it with a carb set up :)
I love my carburetor too.
The people that trash talk carburetors, do not seem to understand how they work or how to tune them. A good friend of mine has a beautiful, mostly original, 1975 Lincoln Mark IV 2 door with a 460, he yanked all of the emissions control garbage off, installed a better carb, dual exhaust with an x cross over, tuned the carb and the ignition..... it is a beast! And, he can get 24MPG out of it when he is just cruising around. A well set up carb is still a great thing. And I have seen in person a carb build up frost around it on a 95*F, high humidity day because of how well the vaporizing fuel cools the carb when its used hard... as in full throttle a 1/4 mile at a time. When you started building this car, I am not a Ford person, but I do find this pretty damned epic.
Wow it was my birthday on this video, and I love detonation in diesels! Awesome timing, eh?
Ur the perfect teacher I’d listen to🤣
Hey Eric! I have this Kia Sportage 2000, first gen. I've noticed lately after either heavy throttle or heavy braking, or fast turning. Basically driving it hard, i hear a squeaking when i turn afterwards, now its been getting worse, it does it when driving stright. I don't worry about it because i don't drive it hard but personally i think its a belt pully or serpentine belt maybe
Free internet, not that's a whole nother hot debate topic.
To stay on topic though, I always learn a little some thing when I come to watch one of your videos.
I have been watching since you had a shop with no hoist, the da Integra videos. You had put a boot on the passenger floor of the Integra to use as a cup holder. It’s the tips and tricks
@ETCG1 Can you do a vid on LPSI??? this would be a good sequel regarding the mini coop since its Direct Injection. also talk about the turbo in that aspect as well too? :D
I'm almost happy you had this problem (no, I don't want you to have additional expense or work) because I want to see you work through the planning and installation of fuel injection. I'm sure you will proceed with fuel injection with the same thoroughness as the rest of the project. I love ETCG1 and hate turbo's, just sayin'
I agree with you, Eric - if this was a detonation issue, there would've been other pistons damaged - especially so with a carburetor, since all 8 are fed whenever the valve opens. I think that piston there was the one that just happened to have the intake valve open when it took a big gulp of liquid fuel.
Disagree cylinder to cylinder distribution is not perfect. You will always have one cylinder that's closer to detonation. It's the first one to get damaged. They moly getting knocked out of the rings is consistent with detonation.
I love the birthday thing
Hey, I lost compression in a cylinder of my built and boosted engine the same time you did, and I thought I had a busted ringland. I tore it down, and found nothing wrong other than some carbon build up. I cleaned it and put it all back together and I'm back to normal compression.. Could it be that the ring gaps all lined up or maybe a ring got stuck?
Eric, I am not that well versed with power adders like turbos and superchargers. But I have seen almost the exact same damage from improper ring gap, with pistons that have rings closer to the top it usually takes the head land off, with lower ring sets it is usually the lower ring lands that breaks away. Just putting my 2 bits in.
Well. Explained
I'm always worried about carbon deposits making for preignition on performance engines. Your piston looked clean to me.
So I have a 2v 4.6 that just got 9:1 pistons would bad fuel injectors lead to a tick in the motor but would it still be ok if I was to fix the fuel with bigger injectors and race fuel pump
On gasoline, or E10, you should be targeting 11.2-11.7 AFR under boost. 13.0+ is very lean for positive manifold pressure. I'd start there, but ultimately carbs are great for NA applications, but it should be hitting the trash for a more modern setup unless you want constant issues. Most modern ECUs are flex fuel ready, loads of safeties, monitor fuel pressure, wide bands, etc. Would prevent engine damage like youre experiencing.
I'm interested in seeing a video about the cold intercooler side air temp
Very nice video. Why only one cylinder if detonation you would think more than one would be effected. Are you talking throttle body injection or direct ?
so I get being under 14ish for getting on it, but crusing, my car runs back and fourth between 15-18 on the A/F gauge. Never had problems but always wondered if it's normal...
hello Eric what part of Cincinnati are you in? I have a 03 chevy avalanche 2500 that I think has a ebcm but I don't have the diagnostic stuff to test it??
I sure hope we get a video in the distant future with all the comparisons between the Carbureted Fairmount and the Fuel Injected Fairmount.
Which means MORE dyno's, drag strips, gerage burnouts & another Fairmount road trip :).
I do not think we need anymore hydro locked and or Fairmount on fire video's this time around though.
Will it work for nos, how much is it?! Looking to run only a 50 shot wet system in a stock 2.7l v6 Hyundai Tiburon. Thanks etcg
My set up don't have a knock sensor either, after the car warmed up on the dyno and at 2,000 rpm started getting a pinging knock sound. After it got past 2,000 rpm it did great. Has me scratching my head any ideas
I read old Volvo research showing water methanol injection is especially good at preventing detonation. Can you out a water injection plate on a blow through carb?
So the torque from the starter on a hydro locked cylinder was enough to break a ring?
You should check out tavarish's Lamborghini Dyno video. Him and his tuner go all through the air/fuel mixture at various stages in throttle and program in all the amounts per rpm cycle. I never knew an aftermarket ECU could be so comprehensive. Its facinating to see how the tuner brought that engine right up to knocking and then just slightly dialed it back. Is there a basic aftermarket ECU that would actively help protect against pre-detination?
I'm sure there is, but it wouldn't matter, I'm not running fuel injection at this time.
So with fuel injection on this car is TBI a better setup or MPI?
Look into some EGT sensors for individual cylinders and monitor it.
Regarding Carb vs EFI I'm with the people suggesting an EFI swap, you won't look back.
What was your afr on boost? I heard you say it was in the 13s.. that’s way too lean
Thsnks Eric it was my Birthday yesterday, close enough. But the "place name here" on the cake cheapened the vibe 😃. I only got 1 birthday card and spent it alone just had a mince pie and 2 minute noodles very depressing. Thanks for the video 😀
As for the 'place name here', it was a joke. Sorry you didn't take it that way. As for the dinner and your birthday, I suggest changing your outlook. It really is the easiest thing to do. At least you're not in a hospital bed with tubes sticking out of you with the possibility that this will be your last birthday. Many people in the world live with that reality and some would stab their best friends eyes out to have mince pie and 2 minute noodles.
It's all about perspective my friend. This from someone who has spent more than one Christmas, and more than one birthday alone. Stay positive. Happy (belated) Birthday!
ETCG1 Eric I was just joking about the "place your name here thing" my apologies. Yeah ive had a few lonely Christmas days. Thanks for the reply. I'm going to the Adrift movie today to try make up for my lonely Birthday. Thanks for taking the time to reply and your thoughts putting it in perspective. You seem like a cool guy.
This video put me in inventer mode. Am I correct in saying where there are knocks there is NOX? If so I'm wondering if a portable (read on board) NOX sensor is something that could be developed, and although it would be slower to respond than a knock sensor in an OBD system it might serve a purpose in an old school system like this one. Thoughts/name calling etc?
The question is " what happened"? In my opinion it could have been anything I mean to really know what happened you would have had to been in that cylinder to know just saying. Never the less great video Eric and can't wait to see her back on the road. Until next time PEACE
We have a pretty good idea of what happened - in a previous video, we saw the amount of fuel it was shoving into the engine (it looked like a fire hose being turned on), and as there's no sign of detonation pitting on the other pistons...it's the logical culprit. No other problem he's experienced would cause this sort of damage. There's no need to be inside the cylinder to work out what had to have happened - all he needs is deductive reasoning. :-)
The logical culprit is detonation. it destroys ring lands..
I did a quick search for "engine detonation damage" tinyurl.com/ybhbcgoo Pretty much all the pistons have damage to the crown. All those that have land damage also have crown damage (starting directly above the land damage and extending into the lands) and the extreme cases have evidence of melting around the lands, rather than a clean break. Eric's piston shows no sign of damage over time, but a clean fracture. Occam's Razor applies, since there's no additional evidence of detonation, either on the broken piston's crown or any of the other pistons, and because we already know it has been subject to a hydrolock condition. So, while there's no way to be absolutely 100% definitive about the culprit at this point, it seems to me that the hydrolock would be the most likely explanation.
aussiebloke609 I believe there were issues from the onset. Watch the dyno testing video. But hydrolock would be my bet too.
Top Video
You going to have a video of the engine tear down and rebuild?
So I advanced my distributor all the way and floored my car! The video is new and on my page.
Subscribed
correct me if im wrong, my understanding of detonation is 2 flame fronts meeting under pressure which causes a supersonic effect at the point they meet or repel each other, this super sonic event causes temperatures much higher than the rest of the deflagration of the fuel, as we say find the hot spot
Hey Eric you ever come to Florida? Couple events going on during October, like half mile and Orlando vs Florida. Its prob quite a drive for you, but was wondering.
I'll consider it. I usually go to SEMA at the end of October.
Mr Etcg1 why don't you have a get and a oil temperature gauge? I know oil temp is very important, just curious.
What are some things that wear engines out or prevent an engine from reaching a million miles?
Next year, my birthday should finally fall on a day you wish people happy birthdays.
Don't forget spark plug heat range
The detonation problems that i have seen have always affected the top of the piston and top ring area. I wonder if that ring land wasn't cracked from the beginning. Has the engine builder seen the piston and if so what was his opinion?
The builder and his son agree that it was hydrolock. However, this seemed like a good opportunity to talk about detonation.
+wysetech2000 Gotta agree with you. Even allowing for variations in temp from front to rear, and variations in mixture from cylinder to cylinder (according to manifold shape, etc.) - for one piston to be that badly damaged by detonation, I would expect to see at least _some_ pitting on the other pistons, either on the piston tops, or the side of the crown where it goes down to the first ring. Not so likely for it to happen between the rings and not on the piston tops, without a major issue in that cylinder from the get-go.
Once you really understand how engines work the more it looks like magic...Its a lot of moving parts that have to do so in a very specific time frame thousands of times a minute...
but the movement mechanisms are cleverly designed to make that happen consistently
but the movement mechanisms are cleverly designed to make that happen consistently
You called it right the first time. Would not turn over. That's dead indication of hydrolock, and detonation or precombustion usually gets pistons or rods not so much rings.
Yes! Run the intercooler test. That should get you a ton of views anyway so why not. We want to know and you do too.
Accidental Ignition of random sections of the mixture that's waiting for the primary igniition wave.
A Double banger out of sync. (There must be a joke there) :)
Yes, there is, but this is a family show. 😉
ETCG1 you got that right. Lol. Families burp. They should have let you get away with that. Lol
Probably add a temp sensor to monitor your exhaust temps. Also it verry hell could be a defective part. There could have been a mirco crack in the ring land that spread over time. It was just a coincidence that you had the hydrolock problem.
Did you contact the guys that made your engine? What are their views?
Eric...you need to feed the monster...keep that engine happy or it will get upset. There was a time when to drive your race car from the pits to the start line you could not let it idle...with a carburetor you really need to decide what you are doing with it especially with a turbo...get yourself a Haltech Pro Knock Ears Knock Detection Kit....it helps to catch the hammer before it becomes terminal.
i have run blown bbc at 25 psi boost and my detonation has always looked much different. take a second look at the end gaps on both top rings and use at least 10x magnification that looks like ring gap closing up and breaking piston
I spent months trying to diagnose my detonation issues on my 09 Toyota. It all came down to carbon build up inside the combustion chamber as my pistons were very black with very heavy carbon build up. The carbon build up is what causes the combustion temperature to raise. I wasted all my money trying to use all those snake oils from Gum out to Techcron. The only real and safest way to remove heavy carbon build up is having a MotorVac or remove the cylinder head and clean the engine out. But what the heck, I still kept driving the thing as it pings around 2,500 RPM's under a load. Been driving it like that for over 2 years with light pinging.
I agree the hydro lock that occurred was most likely the issue with the piston. BUT at full boost while ripping on this thing I'd want to be seeing mid to high 11's a/f ratio with conservative boost of course. If it was still naturally aspirated then 12.5:1 WOT. Cruising normally on the highway 14 or 15 is fine.
I agree. I'll have to start over once the car is back together to get things right because of the new turbo and other parts, but that's what I'm shooting for.
Hey Eric do you think that damage may have started from when you
had that fuel lock in the engine when you had that wrong fuel spring
in your Fuel Regulator?? just a thought Thanks.
Yes, I believe I mentioned that in the video. Also, czcams.com/video/K0x5BUIuEPc/video.html
(pre)detonation can also come from high compression, low octane fuel, and excess heat (other factors as well can be an issue); in a piston engine, as the piston is compressing the air-fuel mixture the combination of conditions above will lead to the fuel detonating before the spark, before top dead center, creating the explosive force that normally drives the piston to rotate the crank; uses it against the piston coming up and all its forces from the rest of the pistons (plus the momentum of the system/parts). The forces can cause engine damage (such as rings/rods). This is a big concern for wankel rotaries; as all that pressure of a pre-detonation puts a ton of stress on the apex seals, but it can also dent the rotor face ... it is a ton of energy. This is the full force of the energy of the fuel mixture before all the mechanical losses that drive your car down the road.
Sorry for the messy paragraph, but someone else can probably put it more eloquently.
If you had the cash, airplanes have CHT and EGT sensors that is linked to a gauge that will give info on every cylinder. It's a pretty sweet setup to adjust your mixture to the best it could be.
Great idea but how am I going to control the fuel with a carburetor or throttle body FI system?
ETCG1 Its more difficult to get the perfect ratio for each cylinder in a carbed setup, usually when you lean the mixture in an aircraft, theres one cylinder that hits peak EGT before the others, so once that happens you enrichen slightly and leave it at that. All depends on altitude as well.
I'm not saying it's aliens, but ...
Eric, how, and how much has the Fairmont project help you in improving your skills at being a mechanic/ auto technician? I know we all learn something everyday, and aim to be better than what we were the day before,
More than anything else. With this build I've had to get intimate with every system on the vehicle. Diagnosing is one thing, but designing is on a whole new level. I love it.
And there is a third possibility, it could have just been a bad piston. I have had that before, had a piston end up exactly the same as this is it turned out there was a micro crack in the piston and over time it just came apart. Things happen. We may never know the real reason for this.
13:1 AFR under boost? Jesus christ no wonder it popped. Also watching your dyno "tuner" keep pushing into boost while going HARD lean probably didn't help. Hell Im surprised it didnt pop in the dyno cell...
He said in the 12's and 13's
That's QUITE rich air fuel ratio and you sound like you wish you knew what you're talking about, but know nothing
That build should have been in the 11.5 afr range to be safe. 125-13.1 is generally the WOT AFR range for naturally aspirated cars. 12 is not that rich for a turbo car.
dude, i pulled apart an Rb26 the other day, same thing as you dude. One piston had missing ring land. the rest were fine and showed no signs of detonation, no grey ring of death, plugs are fine. bearings and all that have normal wear. it beats me what happened.
Interesting.
You can run 14:1 or even a little leaner at cruising speeds. There is little to almost no load on the engine. Typically you want to be down around 11.0:1 at WOT and full boost. I believe the altitude change is what caused it to lean out. A fuel injection system can adjust for it. And the stock EEC IV system with a piggy back chip like a Quarter Horse from Moates.net is more than capable to control your engine. You don't need a $2000 stand alone. I'm running the same setup on my high compression, procharged 5.0. Stock block and bottom end.
your car looks particularly equipped to test the browns gas effect. enriching the air side of stoichiometry. I used to heavily test it on my car' then ca smog laws boned me for a persistent check engine light.
My tuner told me my N/A engine really liked 13.5:1 AF...experienced tuners are hard to come by, especially ones that have tuned from Miata's to half million dollar Lamborghini's
Octane and fuel quality, higer octane resist detonation as it can compres more before self ignition. That way a turbo car can gain 50 bhp with ethanol by increasing boost and fuel (my saab 9-5 biopower gain 30 bhp). So, in the future, when you go injection, make it ethanol compatibel. In sweden we got 95 octane gas at the pump, and ethanol E85 is rated 105 octane.
I’m not sure about that wave front theory. What is clear is that if ignition occurs in a secondary place within the cylinder, the result will be a lower burning time and that way the peak pressure will occur before it was supposed to happen. imagine what happens if the peak pressure is registered before TDC at WOT. it will definitely be a much higher peak. Regarding the timing (using knock sensors) will ensure the peak pressure stays within normal range
for the same reason an inappropriate spark advance can also destroy the engine.