*Warning!* A little derivation will be involved, but it will be worth it! BMEP is fascinating! If you watch through to the end, I'm 99% sure your mind will be as blown as mine was researching for this video! Really cool stuff, like how Ford shows up Ferrari with the Mustang, how Rolls-Royce builds a head-scratcher of an engine, and if naturally aspirated engine mods are actually worth doing. Hope you enjoy!

Jason lowkey flexing that his brand new miata is as cool as the LFA

Jason is a BMEP. Big Math Equation Person

Fun fact: The Cosworth DFV has a BMEP of 13.9. Quite impressive for an engine made back in 1967.

"...they'll walk away from you." - You said that with conviction. You must have experience!

Me: "is this going to be a normal video?" Video starts with Jason in front of a wall of math Me: "ahh, just like I remember."

"...IT BREAKS THE SCALE (that I made up)..."

At 120% of natural air pressure you’re looking at nearly 3 lbs of boost with an intake, this is very impressive!

If I was back in high school with him as my teacher making these equations relevant to my interests then I would of been an A+ student

The Rolls-Royce engine is most likely optimized for smooth power delivery (flat torque curve) and quiet operation.

"it breaks the scale -- that i made up" sums up my life

I found a formula sometime ago that used the maximum torque the engine made in lb/ft, multiplied by 2473 then divided by the cubic capacity. e.g. 425(lbs/ft) x 2473 / 5665(c.c.) = 185psi [~200psi being about the upper limit for N/A engines]

Someone: hey my Ferrari V8 is amazing Jason: (takes out a whiteboard)

"only compare similar vehicles!" > compares the mitsubishi mirage with the ferrari 458 haha very cool video

This is one of your best physics lessons in my view. I’m an earth science teacher who enjoys watching other great teachers teach. I’ve also enjoyed working on, maintaining and analyzing engines, airplanes, cars and motorcycles since I was a child, the offspring of an engineering wizard. So I like the topics you discuss. You have a great teaching style. I hope you keep this kind of thing up for years to come. We need more teachers like you who can inspire as well as enlighten!

I would really be interested in a video about BMEP calculations for rotary engines. I know they dont have many "similar engines" to compare with, but it interests me nontheless. Great video as always :)

15:30 "Let's say this is a 2.0L engine we're modifying". Gee, I wonder why? ;)

I'm going to be so cool at parties. Too bad we're in quarantine and my dogs don't understand anything other than if they sit long enough they get peanut butter.

The joy of learning how it all works. I love "Engineering" when it is "Explained". Thanks Jason for a great video as usual.

Ha, I haven’t seen BMEP calculations since my ICE course in Mech Engineering 🤓🤓. Wünderbar

To be fair to Rolls, they want that engine to be as quiet as possible, and to last at least 10 years without needing an overhaul, while the Ferrari is likely to not make the distance, and in general will not be a daily use car like the Rolls. Thus run the engine in a lower stress region, but have the turbo small to maker it accelerate fast off the mark, giving the impression desired of "effortless power", the exact opposite of the Ferrari, which is meant to be heard.

Jason basically speaking gibberish the entire time: Me: Yes, I completely understand

Engineering Explained... is really the perfect name for this channel. I've learned so MUCH cool stuff on here! Thanks Jason for continuing to come up with fantastic video content, and making it INTERESTING. Stay safe amigo!

I have to say first how much I enjoy your videos. Your ability to use equations to describe your point is impressive. I was fascinated as well when I learned that engineers were able to get over 100% efficiency out of a naturally aspirated engine. One thing I noticed you neglected to mention in that is how important valve timing, overlap, and size play a roll in both air velocity and pressure. They use the exhaust valves scavenging effect to draw fresh air in like a vacuum during the overlap to maintain air speed. Also why the ratio of the intake valve to exhaust valve size can be so critical. Again hats off to you for super fun content. Thank you.

"Spreadsheets Heck Yeah!" take my thumbs up EE :p

Can you make an online university just for car stuff like this. Right now with isolation and everything. I would be the first student. Great vid as always ! Up the Mazda with the 12.6 !!

I’m glad there’s another smart person out there thinking in engineering terms. Years ago, when I talked like this in my engine building class I got that “deer in the headlight” look from the instructor. Thanks for a great video. Now onto compression ratio, quench area and L/D intake valve calculations. Yes!

Love the way you break it all down in you videos, informative to say the least. Keep it going! 👍🏻

Basically: BMEP (bars) * 8 = Torque from 1 liter displacemant [4 stroke engine] BMEP (bars) * 16 = Torque from 1 liter displacemant [2 stroke engine] for US: BMEP (psi) * 0.544 / 61 = Torque from 1 cu inch displacemant [4 stroke engine] POWER: Torque (NM) * RPM * 0.104 / 735 = Power (PS) Torque (lb-ft) * RPM * 0.142 / 745 = Power (HP)

If my math teacher in highschool used cars as a way to teach equations, I would have passed every class with an A+.

It is nice to watch a KZfaq video that does not bore me with incompetence. Thank you for all the work you put into developing your videos.

yours videos are always great, but man this is just amazing!!

"But think of how much more interesting people will find you at parties when you say words like 'Brake Mean Effective Pressure' instead of 'torque'... they'll walk away from you" You mean "Keep their social distance". Also... how are you having parties?

I think these videos are very useful, especially for us mech engineering and automotive students, but you make it easy to understand even for other people. Keep doing this good work

This was seriously one the most fascinating videos you’ve done to date. Freakin’ awesome.

8:58 "... extraordinarily expensive and super fast." LOL I love how you are working the geeky sense of humor into the videos. Thanks for another great video.

He's literally the only person on KZfaq who is capable of proving an MX-5 is just as good as an LFA.

Perfect timing ! Just today I was looking for this info because found out bmep are always there on every engine spec sheet. Now I know, thank you !

This might be my favorite EE video! Great work!

Thanks for your videos. A great balance of information and interest.

Love cars, hate math - Jason is like my paradox emulsifier

Thanks for taking me back 20 years to my IC Engines class!

Best...by far... content on the show! To who can understand...altough it was laid down in a very comprehensive layout Praise the excellent good work.

That was really interesting, thanks for the video! The beginning reminded me of a physics class with the rearranging of the equations, it was great! Your videos are very informative and thorough, also I like the occasional editing and humor sprinkled in!

Send out the spreadsheet so we can calc our BMEP!! Great video!

Oooooh, more tools for my social distancing toolbox

Thanks for making videos. 👍Nobody else gets into the nitty gritty of gear head stuff like you do!!! Excellent work too, btw.

Amazing, as usual. One of your best explanations.

Hi, Jason. You forgot to mention your BMEP of your previous sport(ier) car. The F20c from the HONDA S2000 has a BMEP=13.1. And that's on a 20+ year old design! Take that, Miata!

Love the videos, Jason. The math is way above me, but I like to pretend I understand everything you’re saying 😂. It makes me feel smarter

Brilliant video. Never has physics/mechanics/mathematics been so much fun and easy to understand! :)

I usually watch your videos when they are available. I just saw this video on my list. Great video, very informative. I have a modified push rod 5 litre fox Mustang that makes the same amount of tq as the new Gt. It's nice to know I have roughly the same efficiency as the new engine. Keep up the great content.

Great video! Two things come to mind: 1. The power stroke does not end at bottom dead center, it ends when the exhaust valve opens. This typically happens at 120-125 degrees after the piston reaches top dead center, so for the 55-60 degrees remaining after the valve opens, the cylinder pressure is effectively zero. I guess that BMEP means the average pressure over the 180 degrees from top to bottom, despite there being no pressure for those 55-60 degrees? 2. Two engines with the same BMEP, the same displacement, and the same RPM can have quite different mid range torque and thus power. If one of them has a very long connecting rod and the other a short connecting rod, the long rod engine's piston will "dwell" for a longer period near the top of the cylinder while combustion is taking place, thus developing far more pressure than the short rod engine, and it will have way more power in the middle of the RPM band. Why? Draw this out on a piece of paper and you will see why. Draw a crankshaft throw and a connecting rod/piston that is long and another one that has the same stroke but a rod half as long. Imaginarily move the long rod's crankshaft 15 degrees or so and see how far down the piston moves. Now, do the same thing with the short rod drawing- You will see with the short rod the piston moves FAR MORE than with the long rod. Since the exhaust valve opens typically while the mixture is still burning, the dwell period of the long rod design allows more of the charge to be burned before this happens which produces the same BMEP but with more actual torque and power for the long rod design. Jason, you ought to do a video about this effect. Volkswagen used very long rods in the VR6 engine just for this reason.

LOL this just boils down to you trying to cost justify putting a supercharger on the new Miata :p

I'm student in internal combustion engine your videos are great to learn my class in another languages TY

wow that chart is actually very cool for seeing what upgrades might do - awesome video

This was a really good video chocked full of interesting information and presented very understandably. Just one question, though: For distance you used the stroke, or the distance the piston travels in one half a revolution during the power stroke. For the time, you used the revolutions per second divided by 2 since the power comes only every other revolution. But, that’s the entire revolution, and the power stroke is only half a revolution, so shouldn’t you divide by 2 again, or rev/sec/4, to get the actual time the piston takes to travel the power stroke? (And for a 2-stroke engine, you would divide by 2. ) That would make MEP = 8 * Torque * RPS / Vd, or twice what was presented.

Can I get the spreadsheet you used to calculate every car's BMEP? Asking for a friend.

Awesome video dude! Looking forward for more videos like this in the future!

Wow dude, everything single video you release is an eye opener.

I think some people refuse to believe that for a daily driven car, top end power isn't as important as how the power builds up and how the car handles. Too many people think that they drive at redline 100% of the time and forget about things like torque and power to weight ratio.

Well done! I learned a lot! Now please explain diesel engine NVH apart from high pressure inside the combustion chamber. How some diesel engines are quieter than others.... AND high BHEP on low displacment engine does it have reliablity issues in the long run with that too much stress?

Consistent PHD level content! Keep up the great work!

So I saw the notification for this video while procrastinating on my Physics homework. Somehow you explained my physics homework better than my teacher could, and made it enjoyable too. Your videos are awesome, keep up the great content!!

Tuning your car up to double the horsepower it can make naturally That's why he named the spreadsheet Heck Yeah!!! 👍👍👍👍👍☺

please include motorcycle engines in your videos, they have impressive power for their displacement (200 HP per Liter is not uncommon for street legal bikes). For example the 2019 Suzuki GSX-R1000R has a BMEP of 14.83

Very informative video, thank you!

I love these videos, helps me massively with my degree!

I was playing this video in full screen and my siblings thought this was an algebra lecture........

"Spreadsheets Heck Yeah!" Made me laugh 😂

Thanks for the metric units regarding torque!

Just love this videos!! Thank you!!

RPS of the wheels is RPS of the engine divided by final drive ratio. Is that cancelled out by engine torque increasing by the same ratio at the wheels?

There was me about to go “Woooahh my little Skoda is about 15 on that scale”... before I remembered it’s both Turbocharged and Supercharged 🤣

Awesome, very clearly explained.

So refreshing to see sums without any calculus. makes it so much easier to understand.

Wow, my 2003 V6 Mustang came out with 10.1. Although who knows maybe that isn't too bad for the time. Also Go Wolfpack!

It would be interesting to see the value of some motorbike engine. Just for comparison.

Respect to you Jason, you take the craziest concepts and explain them really well. I think maybe it’s a gift. I had a philosophy professor in college who had the same gift. Others could talk The Who semester and it made no sense. Not here. This video was SO interesting. I hope you consider applying to other types of engines. Cool.

Brilliant explanation. Thank you

Wondering where an S2000 would land, but I don’t wanna convert units lmao.

10:55 So you're saying some naturally aspirated engine make boost?

Well done Gerson. Looks like you can impact knowledge in simple terms

Great vid!!!! Excellent detail on bmep.

As a mechanical engineer, this is Porn🤤

Ah haha... "more interesting at parties " ... like my future wife's reaction when I said "g-force." 😆

Thank you, very informative, as always!

Love it - this is great content! Thanks

Yeah, I've been noticing for years now that when it comes to motorcycles, despite wild variations of HP/litre between different models; there isn't that much variation in terms of torque/litre, with most of them being somewhere around 9-11 kgf.m/litre (keep in mind that virtually all bikes are naturally aspirated, AFAIK the only factory non-naturally aspirated motorcycle nowadays is the supercharged Kawasaki H2/H2R). Jason, have you ever thought of comparing engines in the form of some integration of the power curve? Of course this would require some consideration; for instance if it were integrated in terms of rpm, you would probably have to choose an arbitrary range of rpm (say the top 3000rpm with greatest power), and this would not be ideal if you were to compare between engines with significant variations of the rev limit... So I guess it could be in terms of a certain proportion of the rev range, for instance the top 50% of the rev limit (for a 6000rpm redline, this would mean the range of 3000 rpm with greatest power). I believe something like this would give you a more significant value to compare the ability to accelerate than simply peak power.

Somehow feel like this needs a mentioning of a Honda K20 somewhere ;)

This was fantastic, thank you!

As an mechanical engineering student these videos are fantastic. Keep up the good work!

P.S.: RR "low" BMEP for a turbo-powered engine means it is built to last (quite the opposite regardng the Ferrari engine). Also, increasing BMEP while maintaining the same engine original components (pistons, rods, cranckshafts) will ALWAYS result in shorter engine life simply because the original materials were not designed/manufactured to stand the additional stress.

Did the test for my 2014 Aprilia Tuono and it scores... 13.97! Higher than a Ferrari!

Very cool and very well explained you make a good teacher!

Thanks Man. I learned something today.

It breaks the scale . ...That I made up 😂

My mom thought this was on zoom in a math class

Your explanations are excellent and the whiteboard illustrations are easy to follow. I'd love to see you explain the Chrysler Turbo Encabulator. LOL!

I needed you as an algebra teacher. Engines are way easier to understand than random problems