The Dunning Kruger Effect and the Automotive Enthusiast

The Dunning Kruger Effect and the Automotive Enthusiast

I want to apologize for this one AS IT’S LONG AND PAINFUL but I put some of this up for your amusement.  I don’t know why I continued for so long but I was amazed at how some people think and process information.  That they think their own weird theories that they made up are more valid than scientific facts.  This guy insists that you need backpressure to cushion the engine at high RPM to keep them from blowing up and backpressure smooths out combustion. I had previously provided this guy with links scholarly to stuff proving he was wrong… I continued for my own amusement because it’s amazing how some people think.

TO SUM THIS ALL UP AND PUT A END TO THIS MISINFORMATION GOING AROUND TODAY THAT A ENGINE DOESN’T NEED BACK PRESSURE. THE PROOF IS RIGHT BEFORE EVERYBODY’S EYES AND EVERYONE IS OVERLOOKING IT. THE HEAD IS DESIGNED TO PRODUCE BACK PRESSURE AND FOR THIS REASON THE ENGINEERS DESIGNED THE EXHAUST VALVE TO BE SMALLER. THE PROOF IS IN THE PUDDING HERE AND NAILS THE COFFIN SHUT ON THIS MISINFORMATION. A ENGINE REQUIRES BACK PRESSURE TO FUNCTION PROPERLY.

The reason why the exhaust valve is smaller is it doesn’t need to be as large as the intake valve because of the big pressure differential between the cylinder and the exhaust port on blowdown. When the exhaust valve opens, there is a lot of pressure still in the cylinder and most of the exhaust comes out in a big poof in just a few degrees of crankshaft rotation. The intake gets sucked in and the pressure differential is way less so it needs more help with a larger valve. You can see this happening in the pressure-volume charts of the otto cycle in the references I gave you. If you refuse to look at facts, I gave you plenty of reference information so you can see how 4-stroke engines work but you deliberately choose to be ignorant. It’s not theory but proven facts, derived over 100 years ago. Learn, don’t be ignorant.
 @MotoIQ  THE EXHAUST VALVE IS SMALLER TO CREATE NEEDED BACKPRESSURE. IF THAT WASN’T THE CASE AND BACK PRESSURE WAS SO DETRIMENTAL. THEN WHY DIDN’T ALL THE AUTOMOBLE MANUFACTUERS ALL OVER THE WORLD MAKE THE EXHAUST VALVES THE SAME SIZE OR EVEN BIGGER (WHICH REDUCES BACK PRESSURE) THAN THE INTAKE VALVES.
Jeeze I just explained why the exhaust valve is smaller! It’s like saying the earth is flat.
 @MotoIQ  IF IT COMES OUT IN A BIG POOF WITH MORE PRESSURE. THEN WHY USE A SMALLER EXHAUST VALVE, RESTRICTING THE FLOW SO IT HAS TO FIGHT ITS WAY OUT OF THE CYLINDER?
Read what I wrote!!!! It’s only for a few degrees of crankshaft rotation so you don’t need a bigger valve. Don’t be lazy, instead of arguing, educate yourself. You can probably search in Google or something about the Otto Cycle, PV diagrams for the Otto Cycle, and the Thermodynamics of the Otto Cycle. Search these actual things, not something stupid like why is the exhaust valve smaller where you get unqualified people presenting opinions as facts.
Here is a video of a clear engine. You can see how long it takes the intake mixture to get into the engine and how fast the exhaust poofs out. https://www.youtube.com/watch?v=nvMcFQqhbpM, it doesn’t need a bigger valve in proportion to the intake.
 @MotoIQ  HERE IS A VIDEO MADE BY CHRYSLER OF A CAMERA IN A HEMI ENGINE MADE YEARS AGO I HAD BOOKMARKED. https://www.youtube.com/watch?v=q0Rsa-zWGEo ALL IT DOES IS SHOW THE 4 STROKE CYCLE. WHAT YOU ARE DOING IS GRASPING FOR STRAW HERE AND YOU HAVE BEEN DOING IT SINCE THE BEGINNING OF THIS DISCUSSION (NOT AGRUEMENT) INTO ANOTHER DIRECTION TO AVIOD ANSWERING QUESTIONS DIRECTLY. YOU NOW CLAIM THE EXHAUST VALVE WAS NOT MADE SMALLER TO CREATE BACK PRESSURE, THAT ITS SIZE BEING SMALLER DOESN’T MATTER. IF BACK PRESSURE IS SO DETRIMENTAL AS YOU CLAIM AND. THEN WHY DIDN’T THEY MAKE THE EXHAUST VALVE THE SAME SIZE AND BIGGER TO GET RID OF THAT BACK PRESSURE WHICH IS BAD. SO HERE IS THE QUESTION AND A YES OR NO ANSWER IS ALL I WANT FROM YOU. IF YOU USE A SMALLER EXHAUST VALVE. WILL IT RESTRICT/HOLD BACK THE EXITING OF THE EXHAUST FROM THE CYLINDER AS OPPOSED TO USING A LARGER EXHAUST VALVE? YES OR NO?
That’s a cool video! But even this video show that the intake event takes longer due to lower pressure differentials driving the process. Here is the pressure, volume, and heat diagram of the Otto cycle. https://www.quora.com/What-is-otto-cycle , you can see the pressure differentials here, and the higher exhaust pressure which is why you don’t need as big of an exhaust valve, you can also see how residual pressure affects the work (power) you can extract from the combustion. I made it really easy for you. This isn’t theory, it’s fact proven through repeatable experimentation over 100 years ago.

 @MotoIQ YOU’RE STILL REACHING FOR STRAWS. I TOLD YOU THAT IN MY LAST POST.. SO WE DON’T KEEP GOING AROUND IN CIRCLES. I ASK YOU TO ANSWER A SIMPLE QUESTION. BUT INSTEAD ANSWERING THE QUESTION YOU HAVE INSISTED TO TAKE THIS CONVERSATION INTO A DIFFERENT DIRECTION.

Not really, I am very objectively explaining to you that you are wrong and why. Very solidly, very mic drop solid. You are either not bothering to look at or cross-check the reference material I am giving you or you don’t understand it. I am very solidly answering your question undoubtedly with the absolute truth. Don’t be lazy, look at and cross reference what I am giving you so you can see that this is common knowledge, and if you don’t understand what you see, ask objective questions.
 @MotoIQ  SINCE YOU CLAIM THE EXHAUST VALVE WAS NOT MADE SMALLER TO CREATE BACK PRESSURE, THAT ITS SIZE BEING SMALLER DOESN’T MATTER. IF BACK PRESSURE IS SO DETRIMENTAL AS YOU CLAIM. THEN WHY DIDN’T THEY MAKE THE EXHAUST VALVE THE SAME SIZE AND BIGGER TO GET RID OF THAT BACK PRESSURE WHICH IS BAD. SO HERE IS THE QUESTION AND A YES OR NO ANSWER IS ALL I WANT FROM YOU. IF YOU USE A SMALLER EXHAUST VALVE. WILL IT RESTRICT/HOLD BACK THE EXITING OF THE EXHAUST FROM THE CYLINDER AS OPPOSED TO USING A LARGER EXHAUST VALVE? YES OR NO?
Like smaller than a stock valve? Yes. You don’t want back pressure retained in the cylinder. If you look at the Otto cycle PV diagram I sent you, you will see very clearly that if you retain pressure in the cylinder at the bottom of the cycle, it reduces the amount of work or power that is recovered from combustion. Extending the exhaust cycle to recover more energy by making the pressure lower is the principle behind the Aitcheson cycle and Miller cycle super-efficient engines used in the Prius and some Mazdas. I mean if you don’t believe me after all this, you never will believe anyone. It’s like those flat-earth people.
 @MotoIQ  YOU HAVE AN AUDIENCE HERE READING YOUR POSTS. SHOULDN’T YOU MAINTAIN YOUR DIGNITY WITH THAT LAST POST. YOUR SHOWING THEM INCOMPETENCE BY SAYING “SMALLER THAN STOCK VALVE”. INSTEAD OF SAYING YES! THE EXHAUST VALVE IS SMALLER TO PRODUCE BACK PRESSURE. SECONDLY, AGAIN YOU ARE REACHING FOR STRAWS. POSTING THINGS TO TAKE THE CONVERSATION INTO ANOTHER DIRECTION. THE EXHAUST VALVE IS DESIGNED SMALLER TO CREATE BACKPRESSURE TO CUSHION THE FORCE, SHOCK LOAD OF THE ROTATING ASSEMBLY AFTER THE COMBUSTION STROKE. TOP FUEL DRAGSTER MAKING 1000’S OF HORSEPOWER HAVE SMALLER EXHAUST VALVES FOR THIS REASON. IT ALSO STABILIZES THE ASSEMBLY TO SLIGHTY SLOW IT DOWN TO ALLOW THE VACUUM ADVANCE TO PERFECTLY ALIGN ITSELF AT THE SET IGNITION POINT FOR THE NEXT COMBUSTION CYCLE. WHERE THE ROTATIONAL INERTIA DOESN’T JERK FORTH THE ROTATING ASSEMBLY FASTER MISALIGNING THE TIMING EVENT. (IT ALSO APPLIES TO COMPUTER CONTROLLED TIMING, I wrote this so you don’t us this to come back to argue your point). AS THE ROTATING MASS INCREASES IN SPEED. YOUR DESIRED IGNITION POINT AFTER TOP DEAD CENTER STARTS RUNNING AWAY FROM YOU. THIS IS WHY CARS HAVE A ADVANCE EITHER VACUUM, MECHANICAL, ETC.

I will make this completely clear. You are absolutely wrong. You don’t know the differences between opinion and fact. I am not even arguing with you, I am trying to explain the truth but you won’t hear it because, to you, your opinion is the same as facts. I give up, go believe whatever you want. You don’t even build engines so what you think doesn’t matter.

 @MotoIQ  I’M WRONG AND YOU ARE RIGHT. I’M HAVING TROUBLE ABSORBING THIS, AFTER I CLEARLY PROVED TO YOU, WHAT YOU DIDN’T SEE COMING. THAT BACK PRESSURE IS BUILT INTO EVERY COMBUSTIBLE ENGINE AND WHY THE EXHAUST VALVE IS ALWAYS SMALLER TO CREATE BACK PRESSURE TO ALLOW THE ENGINE TO FUNCTION PROPERLY AND HAS BEEN THIS WHY FOR OVER 100 YEARS. THIS IS WHEN YOU ONCE AGAIN REACHED FOR STRAW AND CAME BACK WITH A SIMPLE ANSWER SAYING A BIGGER VALVE IS NOT NEEDED. IF THE OBJECT OF THIS DISCUSSION IS TO ELIMINATE BACK PRESSURE AND THAT IT IS NOT NEEDED AND A MYTH. WHAT WILL HAPPEN IF YOU MAKE THE EXHAUST VALVE THE SAME OR BIGGER THAN THE INTAKE VALVE?
And the earth is flat. You didn’t prove a single thing, you expressed your opinion. There is a big difference between opinion and fact. The sooner you learn this, the more you can grow intellectually. It’s good to question things, but it’s better to learn the answers than to spout your opinion loudly. Look up what the Dunning-Kruger curve is. This is you. I attempted to teach you like any teacher in a thermodynamics class in college. I sent links to the math and the visual pressure-volume curves in case you didn’t get the math. I even sent you links to the historical stuff on how this stuff was discovered and researched 100 years ago. I presented facts, I even explained why the exhaust valve is smaller. What you are presenting is a fallacy of logic. To me, this is engine stuff simplistic and straightforward. I am a mechanical engineer and a motorsports engineer, I live this stuff, it’s been my profession for 35 years. For you, you need to crack a book or listen and learn. You have not presented one bit of information to prove you are right other than your opinion. Do your own research to prove your opinions and present proof with data for peer review and then you can have your own cycle named after you and go down in history. Things don’t work a certain way because you said so. I am telling you that you are wrong, not because I said so but because the work of more than a century of research by many smart people says so.
 @MotoIQ  ONCE AGAIN YOU ARE REACHING FOR STRAWS WITH A HALF PAGE OF MISMASH. YOU HAVE A AUDIENCE HERE AND YOU ARE DIMINISHING YOUR CREDABILITY. ( I ASKED YOU) IF YOU USE A SMALLER EXHAUST VALVE. WILL IT RESTRICT/HOLD BACK THE EXITING OF THE EXHAUST FROM THE CYLINDER AS OPPOSED TO USING A LARGER EXHAUST VALVE? YES OR NO? (YOU CAME BACK AND SAID) Like smaller than a stock valve? Yes. AND THEN SAID: You don’t want back pressure retained in the cylinder. <— I THINK YOU SHOT YOURSELF IN THE FOOT WITH THIS ONE. IF THIS IS THE CASE AND THE WORDS CAME RIGHT FROM YOUR MOUTH. THEN WHY ISN’T THE EXHAUST VALVE MADE BIGGER?
Not really, the exhaust valve size is calculated and verified by testing, and the proper size is used. If you put something smaller than what has been designed and validated in there, then yes you can have more pressure in the cylinder than you are supposed to have. So YOU ARE MESSING UP THE EFFICIENCY OF THE ENGINE! Surely you can understand that. You are so absolutely wrong. I carefully explained why the exhaust valve is smaller a few replies up but you either didn’t read it or dismissed it with no thought. If anyone else is reading this they are laughing at you, I passed this around to some of my colleagues and they are dying laughing.
@MotoIQ  YOU NEVER DIRECTLY ANSWERED THE QUESTION FROM MY LAST POST. I WILL GO DIRECTLY TO THAT QUESTION. I WILL CUT AND PASTE IT. (You don’t want back pressure retained in the cylinder. <— I THINK YOU SHOT YOURSELF IN THE FOOT WITH THIS ONE. IF THIS IS THE CASE AND THE WORDS CAME RIGHT FROM YOUR MOUTH. ——————————this is what I want you to answer and give me a straight answer no grabbing for straws—————————- > THEN WHY ISN’T THE EXHAUST VALVE MADE BIGGER?) If anyone else is reading this they are laughing at you, I passed this around to some of my colleagues and they are dying laughing. <—-IT IS YOU THEY ARE QUESTIONING AND LAUGHING AT BEING THOSE WHO HAVE SUBSCRIBED TO YOU WHO HAVE BEEN READING THESE COMMENTS. I WILL ASSURE YOU IT DIMINISHED YOUR CREDABILITY IN THEIR EYES. AS FOR YOUR COLLEAGUES CHOOSE THE ONE YOU CONSIDER THE BRIGHTEST TO TAKE OVER THIS DEBATE. THESE ARE THE CONDITIONS THEY MUST POSSESS. 1. THEY MUST HAVE AN ESTABLISHED YOU TUBE CHANNEL WITH A REPUTATION TO EITHER DEFEND OR LOSE. NOT A CHANNEL WITH A MADE UP NAME THEY CREATED OVER NIGHT AS MANY HAVE DONE OVER THE MANY YEARS, SO THEY CAN HIDE BEHIND A CURTAIN IF THEY ARE CALLED ON SOMETHING TO REMAIN ANONYMOUS.

These are just a small sample of the face-palming comments we get. Amazing how the mind works and how people think, I find it pretty fascinating because I guess it’s the opposite of how I think.  I mean I like to think I present facts and facts and opinions as my opinion and to me opinions are always up for debate unless they are based on factual evidence.  Apparently, to a lot of the world, this doesn’t hold true.

Maybe some of you reading this will have some interesting comments. If you want some entertainment come on over to our YouTube channel and look at some of the comments and maybe you too will be amused.

 

 

 

 

 

 

27 comments

  2. Unfortunately many, many people never reach the point of realizing “the more you know, the more you know you don’t know.” One can pretty quickly spot these types from miles away (correction: MILES AWAY), both in person and in message boards/comment sections. They make it a point of pride to bring you down to their level and “outwit” you with inarguable logic.

    Time permitting, even more laughs are possible once you appear to inquisitively agree and test to see how deep the rabbit hole goes. “Yeah maybe you are onto something. I’ve thought maybe the exhaust valves can be made even smaller for more cushioning effect with high horsepower engines. Do you think if I just used a bigger crankshaft damper, engines could have even more combustion cushioning effect?”

    On second thought, you have an well deserved professional reputation (aka CREDABILITY) to uphold. As entertaining as engaging with armchair experts is, I’d rather MotoIQ continue creating interesting and fact (FACT!) based quality content rather than wasting time addressing trolls. In summary, there’s no helping those who don’t want to be helped, so keep on making awesome content instead!

    Reply

  3. What an asshat!

    In my experience it’s really hard to explain science to anyone over a message board without knowing exactly what there level of understanding is. When I was in school 10 odd years ago I had to take a class called engineering communication to learn how to communicate with non engineering majors in industry. On its face seemed its seemed horrendously boring but as I’ve gotten older I’ve realize it has helped me tremendously. Most people don’t think like engineers and therefore can’t connect the dots between multiple facets of an engineering problem or do some from a completely different direction.

    I think it would have helped to make your point if you reiterated that when designing a cylinder head automakers have a fixed amount of space to work with to fit valves. This bit of context is obvious to you, but not likely a consideration of the asshat in his brain dead rant. When coupled with your info on the Otto cycle curve it provides a better picture of why you want a larger intake valve. Ie having the valves be the same size in the same head would make the intake valve smaller and exhaust valve larger than it needs to be.

    You can’t fix stupid with smart.

    Been a motoIQ reader for 10+ years and personally love that your content dives so deep. As always keep up the amazing work!

    Reply

  4. Hey Mike and team,

    I’ve been an avid reader of your site for many years now

    Sorry that you’ve got a bad apple giving you shit; we love your content and let us know how we can continue to support you

    Reply

    1. It’s just amazing how some people are since I don’t understand what you are saying, it’s not true. It is the fault of our education system and the self-esteem movement.

      Reply

  5. Ahh yes, the “Thats just engineering and math, not real proof” argument.

    Hard part is these people also scream loudest spreading their misunderstandings of fundamental principles.

    Reply

  6. Mike, that was absolutely entertaining. thank you for sharing. I learned many years ago from you, Jim, Clark, and Mike S. that I learned only enough to be dangerous. And the more I learned and understood, The more I realized what I do NOT know. I feel I am somewhere still climbing that slope on enlightenment with steadiness and balance for cars and life in general! thank you for MotoIQ!

    Reply

  7. I’m not sure about the contribution from what you’re calling the self esteem movement – simply because I see this same sort of magical thinking from boomers and Xers just as much as folks my age and younger. But definitely people get too much ego wrapped up in being “right” vs trying to actually figure out what makes sense.

    Reply

    1. My wife is a teacher and they were told to improve students’ self-esteem, it’s been a thing in education, everyone’s opinion is important, everyone gets a trophy, and we are all winners, it’s a thing. My wife says it’s a problem in American education, that’s her opinion.

      Reply

      1. I wasn’t trying to say anything about that education trend existing or not; I’m an engineer, not a teacher, and while my wife teaches, she hasn’t really been in long enough to have the same perspective on changes over the years. I was only trying to say, I see a lot of the same failure to think things through from folks who weren’t in school at any time in the last few decades… and for that matter, some pretty sharp younger-20s folks.

        Reply

  8. Reminds me of the time a guy tried to argue that my NACA duct for my S2000 wasn’t used correctly, that NACA ducts only worked to extract air.

    Reply

  9. Man Mike, you hit the nail on the head.
    I’ve seen this for decades in different field, so it isn’t just an automotive thing.
    LoL, the bible addresses this in Proverbs 9:8, and again in Proverbs 23.9.
    “Don’t try to teach an idiot, they will hate you for it”.

    Reply

  10. Never argue with a dumbass. They’ll just drag you down to their level and beat you at being stupid! You really found the Mt Everest of stupid with that one. Back pressure is a fight I pick every time. I’ll keep this article in mind next time that comes around.

    Reply

  11. Just wow… I’ve always said the difference between your average parts swapper and a technician is being able to actually diagnose a problem. You do this by using various tools and in my case a multimeter (commercial kitchen equipment repair). An engineer can actually use math and physics to explain why. I work as a technician and have never claimed to actually understand how the science works. Some people just want to think because they read an article on it once that they know how the world works. Ignorance combined with arrogance are my least favorite kind of people. Keep up the good work Mike!

    Reply

  12. It has been said opinions are like assholes. Everyone has one!

    But opinions are not facts or they would be called facts!

    Facts are established truths.

    Conversationally, it’s the difference between saying “I know for a fact” or I have an opinion or a belief something may be true!

    One is factual because it is scientifically proved. The other is unproved!

    In short, facts and evidence are really the only reasons for anyone to believe anything is true!

    Thank you, Mike!

    Reply

  14. Some people you just can’t argue with. When it reaches a certain point I just agree and walk away. I’m usually in the mindset that I know less than a good amount of people in a room so usually go into a conversation very open minded. Not one of this guy’s arguments made any sense whatsoever.

    It’s funny, I just learned about the Dunning Kruger Effect last week talking about certain places selling horribly designed parts and people buying them in large numbers.

    Reply

    1. It’s pretty interesting. I was wondering if just car and gun guys were like this, then I discovered this study and was ah ha!

      Reply

  15. Hey Mike,

    Long time no speak. This isn’t really a generational thing, as is it as much of thing of intelligence: It runs out with most people and they get convinced they’re right.

    I I remember correctly we talked about netscape (getting old) and that in beginning of the internet only educated people where on there. Nowadays with smartphones everybody on there whether you like it on not.

    As a tip that you honestly need in your life: Try watching “Idiocracy”. It’s a 2006 movie made by Mike Judge of Beavis & Butthead fame. It will explain a lot.

    And fear not: It’s the same everywhere: It’s over here in Europe as well. Gone are the days of netscape and forums….

    Reply

    1. Most of these types of personalities never make it past the peak of mt stupid. Then they develop a cult of personality and get followers and start conspiracy theories about why they are being held back for not towing to convention.

      Reply

  16. You have the patience of a saint. The fact that you could even go back and forth for that long without punching a wall, while giving detailed responses is astonishing.

    Reply

  17. Not an engine engineer here, but I guess you could have
    tried another reason to explain why the valves are not bigger is because of diminishing return and added weight for bigger valves. At some point the increase in volumetric efficiency by having a bigger valve would be overweighted by the added mass of the bigger valves increasing valvetrain power consumption. And probably many other factors, including cost of manufacturing bigger valves which is a big factor for manufacturers.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

*
*