The Dunning Kruger Effect and the Automotive Enthusiast

I think people who suffer from this are more common nowadays because of their desire to look smart on social and other media.  Another thing is that this is a result of the self-esteem movement in education that has been all the rage over the last 20-plus years.  Everyone is a winner.  Every opinion is valuable. I sort of think this stuff has some validity but like anything there needs to be balance.  Not everyone should get a trophy!  This philosophy has led to a lot of people having an inflated sense of self-worth and a fragile ego.
I mean here is an example of someone trying to sound smart by quoting Ricardo’s book in a pretty pompous way when he obviously has never read any of it!  I will leave all the spelling and grammar stuff intact.

For a STREET engine, you MUST have some exhaust resistance or you will A: Burn exhaust valves B: Have NO low end horsepower (look at a dyno sheet!) C: Lose low-end torque D: Get HORRIBLE fuel economy. I’ve been building engines since before “Mike” was CONCEIVED and don’t believe me, read Sir Harry Riccardo’s book “High Speed Internal Combustion Engines”-Oxford Press 1911-annotated 1934 (OOP on Feebay for $200-up) THE “BIBLE” of engines. Riccardo designed engines for WWI areocraft and tanks and WWII aircraft and ships and up to 1960’s race cars (when he died!). Mr. Honda claimed he SLEPT with this book! And Sir Harry’s Formulae will PROVE no small block Chebby can make 400 horsepower with two valves per cylinder! It’s called “Volumetric Efficiency” and a Chebby can only make 61 HP per liter @ 12,000 RPM!!! Show me a skinny block that will TURN 12,000!!!

So my smart-ass reply…
Hahaha, Ricardo’s book lines up with exactly what I said. You must have skipped the chapters on PV diagrams also, you must have skipped Ricardo’s Wave.
So if you are really a good engine builder that needs to tell me to look at a dyno sheet and you have been doing it before I was born, you must know that good scavenging and back pressure are not mutually exclusive.  I mean, why don’t you know that when you “build” an engine to have better VE you are going to need to tune it so it doesn’t run dangerously leaner (the real reason behind the burned valves myth)?  I don’t know what a small block chebby is but it must suck as an engine.  From someone who has actually studied Ricardos Book (and actually owns two editions of it, it is super hard to find and expensive), there is no formula that proves a small-block Chevy can only make 61 hp per liter and needs to turn 12k rpm to do it.  I mean it’s super easy to make more than 400 hp from that and many other 2-valve per cylinder engines.  I mean do you know what Volumetric Efficiency is before you throw it out?
Or how about this one?  Some super condescending two-stroke “expert”.
@MotoIQ You are wrong, two strokes need backpressure to run.

It’s more like pulse timing than backpressure.

 @MotoIQ  No its pressure to feed the engine fuel. No backpressure no fuel , no power to run .
that is not how it works!

 @MotoIQ  enlighten me Einstein.

It’s kinda long but the first cone in the expansion chamber drops the exhaust pressure pulse created when the exhaust port opens fast, less than atmospheric pressure at the tail end of the pulse, this helps pull the exhaust out faster, then the pulse goes and hits the rear cone of the chamber, which creates a reflected wave, that goes back and pushes overscavanged fuel-air mixture back into the cylinder. With this, you can have transfer port timing for more top end and the reflected wave keeps your midrange from sucking. The tuning mostly depends on the length and diameter of the cones. The right expansion chamber can give a two-stroke 50% more power in some parts of the powerband over a straight pipe. So it’s not making more backpressure but using exhaust pulse tuning to extend the powerband.
Not at all! Two strokes sometimes use crankcase pulse pressure to operate pumper carbs (they have their own internal fuel pump) as Tillotsons or external diaphragm pulse fuel pumps like shifter karts use. Two-stroke dirt bikes are gravity fed. This is not exhaust backpressure. You do not use exhaust backpressure to pressurize the fuel tank! Is adding hot high-pressure exhaust gas into the fuel tank very smart? Likely to be an external combustion engine!  What I am “rambling” about is how exhaust tuning in two strokes works. Not 4-strokes. SO MUCH FOR YELLING AT ME IN ALL CAPS!


  1. 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!

  2. 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!

  3. 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

    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.

  4. 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.

  5. 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!

  6. 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.

    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.

      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.

  7. 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.

  8. 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”.

  9. 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.

  10. 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!

  11. 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!

  12. 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.

    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!

  13. 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….

    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.

  14. 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.

  15. 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.

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