Okay what's your preference: RPM, Boost, or Displacement?? If you enjoyed this, here are some additional videos you may like! McLaren Supercar Suspension - ua-cam.com/video/tkwL8lBo2e0/v-deo.html Driving a McLaren at 200 MPH - ua-cam.com/video/mGM4ASvcm6M/v-deo.html McLaren Doesn't Use Sway Bars - ua-cam.com/video/8AVBddY8ClM/v-deo.html Why McLaren Uses Open Diffs - ua-cam.com/video/gBHmWZcnWwM/v-deo.html
I like a compromise of displacement and RPM. Peak HP at 7000-8000rpm gives a sense of occasion and a reason to rev it out, but I also want enough torque to feel powerful at any RPM. And I don't want ANY throttle or turbo lag.
In a sense, but one has to consider hoe antiquated the Viper V10 is. Its still a Pushrod engine with all the limitations the pumping of air entails. Thats just the part where things get more complex when comparing engines and powerplants.
Today I was made aware of a 1.5 litre supercharged jetski making 310bhp. Can you imagine how much punishment that engine takes as the thing is smashed into the water every few seconds at 70mph. Naturally I want it more than anything. Naturally I can't afford it as I spend all my money on tires. PS Give me RPM all day.
The flaw in that logic is that between that massive wing acting as a spoiler and the stellar brakes, light weight and sticky tires, you are very likely to be rear-ended.
I have been watching you for what feels like a decade. If I want an in-depth engineering explanation of "how it works" when it comes to any component or overall build, you're my source! So freakin' good.
RPM and short gears all day, as a tactile experience. The linear power band and short gears give the driver finer control of the power, and is extra rewarding when dialing in grip at corner traction limits.
I used to have a 77 Coupe DeVille street rod with a 512cu custom crate Cadillac V8. 5200 rpm redline and an absolute tire roasting torque monster. Now I drive a Mustang with a 5.0L Gen 3 Coyote engine, 7600 rpm redline and 7 pounds of boost from an intercooled ProCharger P-1X supercharger. Doesn't have the tire roasting bottom end and the doesn't bark the tires when it shifts, but the perpetual acceleration is amazing
A Gen 3 Coyote fed 7psi doesn’t bark the tires when it shifts? Something sounds off there. That shiny should roast tires up through like 3rd or 4th gear changes.
@@ALMX5DP Definitely does not. Failed to mention it's a 10 speed auto. But at wide open throttle flat dry surface there's no slip after 1st or 2nd. 275/40R19 Michelin PS4S Last dyno I had done was 620rwhp at 7600
@@DanielReyes-hz1qk oh interesting, wonder if there is something in the shift logic which softens the actual shift or something. I’d think that 620 wheel would roast a general summer tire at low speeds when the throttle is matted.
@@ohheccwaddup3225 It was a beast. Custom mid length headers, dual 3 inch exhaust and Flow Master 50s (hot rod size). Had to drive it across a parking lot to an exhaust shop open headers....it was wild Edit: shout out to Cad Company in Albuquerque for that crate engine, which, in their terms, was a relative 'powder puff' 😂
Good video! As one of the racing engine masters, Keith Duckworth (look him up if you've never heard of him) says. 'The way you get power out of an engine is. The size of the bang, multiplied by the amount of bangs you can get into a minute!'
Interesting example for the differences between displacement, forced induction and fuel efficiency: when AMG changed from the 6.2L NA V8 to the 4L Biturbo, the smaller engine with the whole turbo, intercooler stuff was heavier than the 6.2. It had more power and torque, and due to cylinder deactivation and smaller displacement did use a little less fuel in low load scenarios. When the power was used, it didn't consume less fuel than the big V8. ti was right up there with it. Another funny comparisson: i remember reading car tests of a sporty car magazine years ago. (It wasn't a direct comparisson, but they tested each car the same way) They really used the power the cars offered on tracks and in testing. The Mitubishi Lancer Evo (don't remember which # though) with it's 2L Turbo engine had the same fuel consumption than an E63AMG with the 6.2L V8. So with a relly heavy right foot, both take the same amount of fuel even though one car was significantly smaller, lighter and had a smaller engine. But why was that? Because the Evo used additional fuel to cool down the air fuel mixture to prevent problems. (i think EE has a video on why some engine need that and what it preents-> needs more fuel, and makes for a dirtier combustion. (soot around the exhaust)
I've got a W205 C63S with the 4 litre biturbo. The fuel economy difference with the older W204 6.2 NA isn't insignificant. Cruising down a motorway/interstate at legal-ish speeds gets over 30mpg, (and hovering around 2,000rpm with a nice V8 rumble) which I reckon is pretty good for a +500bhp V8. The W204 is down to 25mpg, but at least it sounds good. The correct answer for what is best is a V8.
@@jamesweatherley9215 As i said, in low load scenarios it uses a little less fuel. That said, i drive my E63 over the whole year with a little over 19 mpg (had to convert it to us mpg as we use a different metric). Calculated via the fuel filled in and the distanced done with each tank of fuel, not by the instrument panel. And the lowest i did over a full tank were a bit over 22 mpg. (with 4 people in the car, in above 30°C temps and going 240kph in neighbouring germany for a short time. =above 86°F, 150mph) Oh, and yes i agree fully, V8 is best.
DIN 66036 defines one metric horsepower as the power to raise a mass of 75 kilograms against the Earth's gravitational force over a distance of one metre in one second: 75 kg × 9.80665 m/s2 × 1 m / 1 s = 75 kgf ⋅m/s = 1 PS. This is equivalent to 735.49875 W, or 98.6% of an imperial mechanical horsepower.
Huh. I thought it was calculated the same way, but you had use a metric horse (where its head length matched the length of Queen Victoria's arm, or something like that).
@@scottboettcher1344 For a metric unit it really is weirdly arbitrary as if 75kg (not a multiple of 10, 100 or 1000) was chosen to give a result very similar to HP. I wonder what the problem is with just using KW.
That's an abomination of a unit. For one, it's not truly metric. For another, it's just going to get mixed up with real horsepower, not only by the name but by how it's only 1.4% smaller so the numbers will sound reasonable but be slightly off. If you're going to go metric, kilowatts are the unit to use.
All I know is my 600whp 2.5 Forester is a ton of fun and will outrun about anything on the street. Turbo noises and spinning all four on dry pavement in a dad wagon with a kids seat in the back makes me smile all day long.😁
The grea thing about an engine that relies on size to make horsepower is that once it hits the sales room, the aftermarket can take care of the other two techniques for massive power 😁
Rpm and boost. I can't decide between the 2. Displacement is only good for a raw muscle sounds in my opinion. I love the sheer enjoyment when you rolled down the window! Totally awesome dude!
Great start! Now factor in compression ratio, the use of N2O, cam timing, valve spring weighting (pressure) and the use of lightweight sturdier components. When the engine is N/A, there are a number of things you (the builder) can do to make a large displacement engine still spin up to 8k rpm and produce large HP/Torque numbers.
When the Lexas LS first came out, it had a 4L V8 that made 250hp. Ford's CEO Alan Mulally said that was his finest car. Let's appreciate the fact that Honda produced a 4 banger 10 years later that's half the size, reved to 9k rpm, and made 4% less power than said Lexus Big displacement was required because they were hooked up to 3 speed auto that had wide gaps between ratios. Wide power band from a big engine was necessary. Nowadays, we have 9 speed transmissions that allow small engines with narrow power band to stay there when necessary and get out of it for efficient cruising. My preference would be high rev small engine with turbo compound as waste heat recovery
What I learned from this video is that the ability for an engine to make power and how immediately it can make power is dance between the rate it processes air, how much air is processed per cycle, and how compressed that cycle of air is when ignited. Based off the nature of how ICE engines are used in cars it makes sense that turbos have taken over in road cars, since the wide range of speeds they operate encourage a broad torque curve thats less easily achievable with high displacement engines. In a similar sense, that reveals why aviation engines are often so massive in displacement. The amount processes per cycle at a constant low rpm is whats king in making a propeller aircraft perform at modest altitudes (turbos find introduction the higher you go) And of course high rpm engines as key techniques make the most sense in motorsport and enthusiast cars because of the ease engine rpm can be transmitted into wheel rpm, and thus high speed performance, the same range of drivability not being needed in as wide an rpm range.
Aviation engines are similar to boat engines in that the reason you want large displacement is for reliability -- not necessarily for performance. Car engines can make really high peak power numbers, but absolutely not for seconds to minutes to hours at a time. Its why you'll see 20-30 liter engines making 2500hp; it sounds horrible, until you remember they can do that all day long. Larger bearings, larger pistons and rings, larger camshafts, larger oil capacities, larger areas to distribute heat, larger valves (and seats that wear slower) -- these all work together to make these engines exceptionally reliable at their highly limited peak power. What I wish he mentioned in the video is that low RPM is highly preferable for engine reliability, such is the benefit of turbos. All those super high revving race engines don't last long at all.
Another metric is the temperature of the air being processed, which is half (or so) the trick of nitrous. Chills the mix and adds oxygen, adds boom, and 😊
I get my fix for power and acceleration from superbikes at the track where lack of mass and RPM is king. I do sometimes ride them on the street, but having access to that much power and acceleration and not being able to use it without risking jail time or death is a constant sensation of being blue-balled, that does get old real fast. For a street car, my 981 Porsche Boxster GTS gives me all the thrills while still keeping it mostly legal. Its a great formula with a little bit of displacement, 3.4L with a little bit of rpms at 8k, combined with the increased sensation of speed from a convertible, and the super low CG from a naturally low sitting Boxer engine, and the best position to mount the engine rear-mid with RWD.
Boost, boost is the replacement for displacement. The car gods have spoken. Most engines are getting downsized and turbocharged to make similar power in a smaller, more *cough* fuel efficient package.
@@demetricklouis5710those new engines blow up a lot quicker though. A big ol’ 6+ liter V8 would be my ideal pick for an engine. Solid power, great sound, and can actually last for a while with few problems
I will say Jason that almost everything in life is optimised for a particular task, if you gain in one area you will often lose in another. I'd suggest that as fast as the Bugatti is at the 1/4 mile, it wasn't the focus of the designers, but he McLaren designers could pay more attention here because what they wanted to do was more attainable. Thumbs up though.
Hi Jason! Thank you for uploading today! I really like your videos and it continues to motivate me to pursue my mechanical engineering degree and career for the future. Thank you for always reminding me that one of my passions is learning about cars, and maybe driving more different cars in the future! Take Care!
2:44 I don't know about this specific analysis as a comparison for airflow. I think the efficiency of intake and exhaust flow vs rpm, vs boost, vs displacement seems much more relevant. Because The L/min is not adressed as function of L/per rotation. But it is obviously still relevant for the question of engine power being made at a given moment.
The l/rotation is the same as l/revolution and the time part of that is implied in the unit, literally 'per second', like it was expressed in rev/minute or you could state it rotations/second.
Yes certainly. I apologize, I did not phrase that well and imagined people were following along from the prior statement. I should have said something like: Because the L/min is not extrapolated from a more detailed scale. (Specifically, flow rate per rotation relative to the variables for each approach). It misses out on illustrating the differences across the 3 and suggests more parity than there is. (The line wasn't so much about the illustrated unit, but the process of having a smaller level of detail being examined then expanded.) *Though it ended up just being sort of a cursory discussion as a lead in to talking about the 750S anyway. As opposed to his more detailed whiteboard discussions. Thinking about it now, Driving 4 Answers may have made a video on the topic more like my initial thought, so one could argue there isn't need to cover it in the same way regardless.
I often wonder why power to weight ratio isn’t the most important number for any of these discussions. It doesn’t matter as much how you get to 700 hp if your vehicle is 6000 pounds. Edit: what I mean to say is, this video is about how power is generated, and that’s fine, but there aren’t very many discussions about power to wait, and to me, that would seem to be the most important consideration.
@@ALMX5DP oh, I’m not suggesting that that is a flaw in this video, I understand it’s only about power generation. I just find it interesting that manufacturers almost never talk power to weight when they sell their vehicles. Seeing a video that is all about how power is generated inspired me to ask the question, or make the comment. When I referenced “en these discussions”, what I mean to say is, people talk about power all the time, but only about 20% of the time is power to weight referenced.
@@EliotHochberg ah gotcha, yeah I definitely agree. I’m a fan of focusing on power to weight and especially the weight aspect as that helps improve braking, handling and benefits wear and tear of various components and aspects too.
@@Markbell73No, it's because it's engineered for the highest top speed. Power to weight is very important at lower speeds, but at higher speeds outright power and low drag coeffient is required for continued good acceleration.
I find in heavier cars forced induction is the way to go but in lightweight sports cars naturally aspirated engines give the best balance and fun 🤷🏻♂️ horses for courses.
750hp rwd in the rain doesn't mean you go sideways at the lightest touch of the pedal. It just means you tap the accelerator slowly with controlled steering inputs. I'm sure the car also has a rain mode setting for easier driving in the rain. Having said that it is also sad you can't safely make the vroom vroom sounds for the camera in a car that wants to sing!
I watch every video you post and I learn a lot from you. Thank you. I guess I'm old school. I prefer a big engine that has been designed for torque, from idle to mid-range. Not interested in high RPM's. Don't care for turbos. Give me a super charger with a water to air cooler on a big block, any day.
Lol, an old German saying goes "Hubraum ist durch nichts zu ersetzen ausser durch mehr Hubraum" = "displacement cannot be replaced by anything other than bigger displacement"
@@jonathansmith7306 bru haha, that was maybe th worst choice you could have taken especially because most german car manufacturers choose smaller engines nowadays (looking at the new c63 with a 2L I4)
You remind me of an old story. A famous motorcycle racer was talking to the tuner at the end of the season. "I barely held off the completion on the last couple of races. I must have more power next year, so how are you going to do that? Answer was Very simple Kenny-san, want more power - burn more gasoline!" Which is the reverse side of your description, and funny to boot.
The reality is, most Automakers building super cars opt for boost with turbos instead of higher displacement engines for tax reasons. If was the market to decide, not a surprise it would be all about displacement.
@@tristansimonin1376isn’t a GM 6.2 lighter than something like a 3.5 Ecoboost? Not sure saying larger displacement is heavy necessarily holds up every time in reality given many common engines on the road.
You've just proved American cars mostly turn gasoline into nothing. I never thought of being able to destroy energy until you mentioned that Viper engine LOL
Uh what? The viper is interesting, as it isn't your average muscle car. The Viper is more of an experiment that went very well for Dodge. But a few of MODERN American muscle use all three principles. Take Dodge Hellcat, GT500, and Camaro ZL1 as examples.
first things first - I love the video!!! Now, to answer your question. My least favorite is displacement - in my eyes, a thing from the past. Boost has replaced displacement, like a Cheetah has replace the dinosaur. However, RPM is my favorite. RPM are cool. RPM is technologically challenging, it sounds great and it provides horsepower. There you go. Simple :) Thanks for the video!!!
The viper’s numbers at 8:30 for volumetric airflow are really the ideal numbers if it had perfect volumetric efficiency, and the fact that it is so much more than the other engines despite making the same power as the t.50 shows that it should really be making more like 750-800 hp if the heads could flow better
You should have included adding electric power. And which one can compliment electric power best. If you go high RPM you can counter the lack of low-end power with motors.
As long as there are rules and regulations limiting the design and operation of engines (size, economy, emissions, etc. - even F1 has some pretty strict rules), the theory really doesn't matter. The rules will always determine which solution is best for power. Once you throw the rules out, then the current state of technology and the purpose of the engine decides. Naturally the best answer is yes to all 3.
Nobody talking about how he is saying all of this while driving. That leads me to believe he has all the information memorized or he is just that knowledgeable, which is actually commendable.
One of my silly engine swap ideas would be to put 250cc inline-4 18,000 RPM 45 hp engine, that sounds like F1, into any car. Imagine making F1 sounds while barely hitting 120 km/h top speed
I have always leaned toward displacement because of the three ways to make power it is the lowest stress and will most likely out last an similar output engine that either has to rev much higher or take a lot of boost to achieve. That said a big displacement motor can always be boosted for way more power and to a point reved a little higher so it has the most flexibility.
I'm all in for larger displacement, higher RPM & boost as well. You can get a 6.0 liter LS V8 to comfortably make 650 street-able HP with a good set of aftermarket heads, cam, water-to-water intercooler & about 15 PSI of boost. All at under 6000 RPM. And maybe some nitrous for good measure.
The advantage of smaller displacement turbo engines having better fuel economy is partially offset by the fact that most newer turbocharged engines are making quite a bit of boost at lower rpm. Peak torque on some of these engines is below 2000 rpm. So the engine isn't moving air like a 2.0 liter except perhaps at very low rpm. Personally, I enjoy higher strung, revvy engines. I have been lucky enough to drive some big block Mopars, though, and the torque is very impressive.
This is totally true. I have a 2L turbo that can produce max boost at under 1500rpm. Learning to drive while not engaging the turbo at lower rpms was something I had to learn how to do because of how quickly it spools up.
I always takes notes from this channel to do more research I’m always learning interesting things if I had the money to help people improve their vehicles That’s almost all O would do.
I really like the 2.0L L4 engine that's in my wife's 2016 Volvo XC90. Given the size the car (SUV) that that engine is trying to propel, I am amazed at how well that actually works given it has both a supercharger and a turbocharger. (235 kW @ 5700 rpm). Cruising at 110 km/h - I can get 7.5 L/100 km (~31.36 mpg), which again -- given the size of the vehicle -- that's pretty good without any kind of electrified assistance.
High RPM can be so fun, was the best thing about the CBR 600RR I had. Making that engine sing with a modest exhaust was fun. Crazy to think the Yamaha R1 can pump out 200HP in a 1L N.A. engine. The acceleration on those are absolutely brutal. Also wild to think with the advancement in technology and parts availability, how "easy" 1000HP is to make these days.
i dont remember anyone else having a faster drag and drive time. SMX 5 sec 1/4 mile and can go thru the drive thru. no one else on the planet has done this before. So who? @@S2KCYA
I don’t care about boost or RPM, there is nothing more satisfying than a big block V8 cross plane, the sound it makes is something you don’t get from the other alternatives, plus when you’re idling and step on the gas the hood actually shakes from all the low end torque. 👍
Great video! I'd love to see a video comparing the Audi/Mercedes 4.0 TT V8 against the BMW 4.4 TT V8... Maybe even throw the Porsche flat 6 4.0 in the mix if you're feeling crazy.
I think boost should be as low as possible, the power to torque ratio should be at 0.5 or above and torque at max rpm should be at 90% peak torque or above, which ranks rpm higher than displacement and displacement higher than boost. I tend to see peak power as a gimmick, as it only describes, up to which speed you can stay at peak wheel torque and how fast you can go. I would aim for usable power at low rpm (primary with displacement, only minimal amounts of boost) and peak power with a power to torque ratio of at least 0.5. So peak power would in the end be mainly achieved by using higher rpm but you don't have to rely on rpm alone. Let's say, you want to have about 70 kW at 2000 rpm. You need 335 Nm at 2000 rpm, which can be delivered with 3.0l displacement and about 0.1bar boost. Peak power should at least be at 167,5 kW or about 170 kW. If you are good at designing engines, you use the given limits and increase power with higher rpm, therefor flattening the torque curve. You should be able to reach at least ~240 kW at 7500 rpm. To put this in to scale: This translates into a range of displacements for normal road cars between 1,5l up to 3l (120 kW up to 240 kW), which one could claim to be reasonable.
Disappointed that you went with litres of air, when 'everybody' knows it's the _mass_ of air [ lbs or kg ] that makes the power. (The engine flows the same _volume_ of air on a winter day at sea level as on a hot day in Denver, but makes very different power).
I have been watching this channel for years and always wondered if Jason has a day job. He is definitely talented and smart. If I owned a car company I would hire him.
For a few years now, he left his engineering 'regular job' and only does these videos. He also does the editing and production work. There's a great interview of him on the Munro Live podcast a few months ago.
It'd be interesting to have you talk about Subaru with their 2.4 liter turbo engines, also using boost, cvt contributing to keeping in the best torque range, in a decent displacement.
So I do want to point out that the energy to spin the turbo isn’t free, the gasses are pushing back on the piston to get the force to do work on the turbine.
We love stuff like this, thank you Jason. Can you do a video on motorcycle single, twin, triple and four cylinders. Comparing their displacement, RPM and boost (like the Kawasaki H2 supercharged)
That's not really true... There is inherent energy left in the exhaust due to the fact that there isn't enough time during a power stroke to completely burn the A/F mixture. It still has explosive pressure as the exhaust valve opens and this is what you can hear, and also what drives the turbo. It's why turbos are quieter.
I had a 1976 trans am. 455 cu. The height of the malaise cars. Probably less than 200HP. But the torque was just fantastic. As long as you were moving you could just power out of 4th gear. No substitute for cubic inches! ;-)
Carwow did a drag race between the 750 and 720…both were said to be stock and the 720 beat the 750 in multiple standing starts as well as rolling starts. I think the only real difference that possibly gave the 720 an advantage in the dig races were the Michelin PS Cup 2’s over the PZERO’s on the 750, but that shouldn’t have made much difference in the roll races.
The best combination is a large displacement engine turning a lot of rpm with a lot of boost. There are plenty of 500+ ci engines running 70 psi of boost turning 9,000 rpm. It's just a matter of how much you want to spend.
I haven't watched the video, but I'm a newer mechanic(about 6 months experience, 3 as a lube and tire tech lmao). Anyways, my hypothesis is displacement. The others give you more power as well, but they are basically trying to force more displacement out of the constraints of the engine. Boost gives more, condensed air to allow more fuel to burn. Higher rpm displaces more frequently. I mean look at tanker/cargo ships. Their engines are like MAX displacement(multiple feet bore and stroke) and they output MAX horsepower(10's of thousands). If it was boost or rpm that gave the most horsepower, they wouldn't make them that big.
If we're talking about absolute maximum power, displacement is your first priority of the three for one reason - cooling capacity. Bigger engines have bigger coolant passages which makes cooling more efficient. Very important if you're trying to make a powerful yet aerodynamic car.
@@crackedemerald4930 You are correct. Surface area to volume ratio is higher for the same number of cylinders. I also don't think cooling is down to the capacity of the water passages so much as that of the external heat exchangers provided that the coolant can be moved efficiently.
What we need is excellent torque and power at low revs for tractability, a strong midrange to give you the thrust where you need it the most, and a screaming shockingly high revving top end to widen the powerband and give that feeling of endless power, and superb linear throttle response. In that case it is NA V12 all the way - Cosworth, Ferrari, Lambo, BMW S70/2, HWA - these have the best of all worlds. But somehow by some witchcraft the nerds at Koenigsegg and Ferrari managed to make even a Turbocharged engine respond like an NA one.
There are other trade offs between the 3 solutions that impact engine design such as size and shape, MPG (efficiency), emissions, and cost. BMW had great high RPM engines 15 years ago but they were trouble prone, poor low end torque and poor efficiency. Switching to twin turbo allowed reduced RPMs, greater torque and much greater efficiency.
Big displacement can lead to stresses as well - it can turn into large piston speeds if the engine layout is weird and you‘re asking for only reasonable RPM - eg. 3 L straight 4 in the Porsche 968 CS.
Displacement and RPM essentially work the same way runner length and cams do, you're just moving where peak power is achieved. Long runners and big blocks make better low-end, short runners and small blocks make better high-end, and of course cams are just modifying how much air you're moving and when that air is moving within a cylinder cycle. The trend is pretty much the same across the spectrum of engine design, you can only get so much power out of so much airflow, the design just dictates where the power figure will peak and how efficiently that target is reached. But the issue is, nothing is actually good low-end, unless you have a massive cylinder that kills any sense of fuel efficiency, all of the 'low-end' gains are more typical of mid-range when you consider idle to peak range. I think hybrids are the feasible way forward, electric motors are torque monsters as long as you can keep them fed, which in a hybrid isn't overly difficult to do compared to a battery-only EV. What most people don't talk about is power under the curve, most people only talk about peak numbers, but duration is important to discuss; if you're faster off the line and you're faster in the mid-range, you really don't need top-end numbers when your competition only matters towards their peak and when their peak is nearing their redline. And the thing about hybrids is you can easily have a system where the electric motor provides low-end while the gas motor provides high-end, with a mid-range hand-off once horsepower figures cross; though from an efficiency standpoint, ICE as range extension is better, though with the hand-off method you can likely get away with a smaller motor and a smaller battery pack. This is likely the sustainable way of chasing power figures until battery tech becomes more viable long-term. Just take drag racing for example, an EV will be off the line with zero idle, while your local hillbilly is idling at 2k+ just to keep enough boost on a big block to be off the line with non-lethargic performance, while they might make similar quarter-mile numbers consider the amount of energy used between the two, the optimal choice is simple enough for a child to make; now consider that with a performance hybrid system, the EV side makes up for lack of low-end, the ICE side trims out the EV weight and provides high end without pre-launch high idle as it can do the exact same job during the EV's phase before the hand-off.
What I really like is the thought that while Ive never gone past 200mph in a car, as a german I could just rent a supercar for a day and go on the Autobahn. I really like that thought. Might do so.
I remember my high school auto teacher said "an engine is just a giant vaccum. The more air you can suck in one end and blow out the other, the more power you'll make."
Okay what's your preference: RPM, Boost, or Displacement??
If you enjoyed this, here are some additional videos you may like!
McLaren Supercar Suspension - ua-cam.com/video/tkwL8lBo2e0/v-deo.html
Driving a McLaren at 200 MPH - ua-cam.com/video/mGM4ASvcm6M/v-deo.html
McLaren Doesn't Use Sway Bars - ua-cam.com/video/8AVBddY8ClM/v-deo.html
Why McLaren Uses Open Diffs - ua-cam.com/video/gBHmWZcnWwM/v-deo.html
Diesel with massive boost
I must say I never gave it much thought but displacement is my goat. im a Naturally aspirated kinda guy lol.
What about an engine allows it to rev higher?
Growing up with bikes, it's revs all the way. Keep it above 8000 all the time :)
I like a compromise of displacement and RPM.
Peak HP at 7000-8000rpm gives a sense of occasion and a reason to rev it out, but I also want enough torque to feel powerful at any RPM. And I don't want ANY throttle or turbo lag.
The way the Viper is 8.4L and the Koenigsegg TFG is 2L, and they both make about the same power is actually so insane.
In a sense, but one has to consider hoe antiquated the Viper V10 is. Its still a Pushrod engine with all the limitations the pumping of air entails. Thats just the part where things get more complex when comparing engines and powerplants.
Yes, but you only see Vipers winning races 😂 No one races Koenigseggs
No replacement for displacement. Complexity is generally an enemy of consistency and reliability.
Which one do you suppose has the longer TBO?
@@gwi8650 It depends on what the race is. If it's a drag then yeah the Viper will win but on a track maybe not so much.
Today I was made aware of a 1.5 litre supercharged jetski making 310bhp. Can you imagine how much punishment that engine takes as the thing is smashed into the water every few seconds at 70mph.
Naturally I want it more than anything. Naturally I can't afford it as I spend all my money on tires.
PS Give me RPM all day.
Wow - brutal!! And yesss, team RPM! (Though I do love a big engine)
Got to be a way to contrive tyres onto some kind of amphibious jet ski thing as an excuse...
@@EngineeringExplainedMeanwhile you have beasts like Valkyrie, 6.5L V12 at 11,100 RPM
Idk if you can actually utilise that power in the water on such a lightweight craft?
Good plan, I'll work on it @@ApothecaryTerry
"Can't really see what's behind you... Who cares! You're faster!" 😂😂😂😂
"All the new BMWs have hideous front grilles!"
"Not a problem if you keep everyone behind you."
The flaw in that logic is that between that massive wing acting as a spoiler and the stellar brakes, light weight and sticky tires, you are very likely to be rear-ended.
I'm also amused by that😂
There’s that saying “objects in mirror no longer matter”
Man you doing math calculations while driving a 720s on the rain must be some kind of achievement
750s*
The Plaid can do it all for you and faster ⚡️🇺🇸
@@larryc1616lol ok
This man is a professional he certainly has a script prepared
@@larryc1616And the plaid will do it whilst being completely soulless and bland
0:28 what a fantastic shot, capturing the lens flare popping through the wing. Top Gear quality shot, sir!
Thanks! 👌
It's b-roll provided by McLaren - all props to the film crew they hired!
James May thinks you drive very reasonably.
I'm glad we're all now standardizing our performance metrics on the Nissan Altima 🙌
😂😂😂
Altima drivers think they’re performance drivers with that janky CVT
@@Lancer_0010when it used to be a gtr zygote it could be considered a performance car but that was back in 05.
I have been watching you for what feels like a decade. If I want an in-depth engineering explanation of "how it works" when it comes to any component or overall build, you're my source! So freakin' good.
ROFLed at "Who cares, you're faster." Delightful. 🙂
RPM and short gears all day, as a tactile experience. The linear power band and short gears give the driver finer control of the power, and is extra rewarding when dialing in grip at corner traction limits.
"rpm and short gears" so...all noise, little movement 😂
@@viscountslappy5085you dont understand what you're talking about
I used to have a 77 Coupe DeVille street rod with a 512cu custom crate Cadillac V8. 5200 rpm redline and an absolute tire roasting torque monster.
Now I drive a Mustang with a 5.0L Gen 3 Coyote engine, 7600 rpm redline and 7 pounds of boost from an intercooled ProCharger P-1X supercharger. Doesn't have the tire roasting bottom end and the doesn't bark the tires when it shifts, but the perpetual acceleration is amazing
A Gen 3 Coyote fed 7psi doesn’t bark the tires when it shifts? Something sounds off there. That shiny should roast tires up through like 3rd or 4th gear changes.
@@ALMX5DP Definitely does not. Failed to mention it's a 10 speed auto. But at wide open throttle flat dry surface there's no slip after 1st or 2nd. 275/40R19 Michelin PS4S
Last dyno I had done was 620rwhp at 7600
@@DanielReyes-hz1qk oh interesting, wonder if there is something in the shift logic which softens the actual shift or something. I’d think that 620 wheel would roast a general summer tire at low speeds when the throttle is matted.
8.3L? Good LORD lol. That's awesome! Wish I could've seen and heard that!
@@ohheccwaddup3225 It was a beast. Custom mid length headers, dual 3 inch exhaust and Flow Master 50s (hot rod size). Had to drive it across a parking lot to an exhaust shop open headers....it was wild
Edit: shout out to Cad Company in Albuquerque for that crate engine, which, in their terms, was a relative 'powder puff' 😂
Good video! As one of the racing engine masters, Keith Duckworth (look him up if you've never heard of him) says. 'The way you get power out of an engine is. The size of the bang, multiplied by the amount of bangs you can get into a minute!'
One half of the geniuses from Cosworth who gave us years of title winning Formula 1 engines
Love these kinds of comparison videos Jason
Keep them up!
Happy to hear it, thanks for watching!
Interesting example for the differences between displacement, forced induction and fuel efficiency: when AMG changed from the 6.2L NA V8 to the 4L Biturbo, the smaller engine with the whole turbo, intercooler stuff was heavier than the 6.2.
It had more power and torque, and due to cylinder deactivation and smaller displacement did use a little less fuel in low load scenarios.
When the power was used, it didn't consume less fuel than the big V8. ti was right up there with it.
Another funny comparisson: i remember reading car tests of a sporty car magazine years ago. (It wasn't a direct comparisson, but they tested each car the same way) They really used the power the cars offered on tracks and in testing. The Mitubishi Lancer Evo (don't remember which # though) with it's 2L Turbo engine had the same fuel consumption than an E63AMG with the 6.2L V8.
So with a relly heavy right foot, both take the same amount of fuel even though one car was significantly smaller, lighter and had a smaller engine.
But why was that? Because the Evo used additional fuel to cool down the air fuel mixture to prevent problems. (i think EE has a video on why some engine need that and what it preents-> needs more fuel, and makes for a dirtier combustion. (soot around the exhaust)
I've got a W205 C63S with the 4 litre biturbo. The fuel economy difference with the older W204 6.2 NA isn't insignificant. Cruising down a motorway/interstate at legal-ish speeds gets over 30mpg, (and hovering around 2,000rpm with a nice V8 rumble) which I reckon is pretty good for a +500bhp V8. The W204 is down to 25mpg, but at least it sounds good. The correct answer for what is best is a V8.
@@jamesweatherley9215 As i said, in low load scenarios it uses a little less fuel.
That said, i drive my E63 over the whole year with a little over 19 mpg (had to convert it to us mpg as we use a different metric).
Calculated via the fuel filled in and the distanced done with each tank of fuel, not by the instrument panel.
And the lowest i did over a full tank were a bit over 22 mpg. (with 4 people in the car, in above 30°C temps and going 240kph in neighbouring germany for a short time. =above 86°F, 150mph)
Oh, and yes i agree fully, V8 is best.
I like this explanation very easy to understand, and i kinda prefer displacement rather than boost, gota love an NA V8.
DIN 66036 defines one metric horsepower as the power to raise a mass of 75 kilograms against the Earth's gravitational force over a distance of one metre in one second: 75 kg × 9.80665 m/s2 × 1 m / 1 s = 75 kgf ⋅m/s = 1 PS. This is equivalent to 735.49875 W, or 98.6% of an imperial mechanical horsepower.
Huh. I thought it was calculated the same way, but you had use a metric horse (where its head length matched the length of Queen Victoria's arm, or something like that).
@@scottboettcher1344 For a metric unit it really is weirdly arbitrary as if 75kg (not a multiple of 10, 100 or 1000) was chosen to give a result very similar to HP. I wonder what the problem is with just using KW.
@@reggiedixon2 1 KW is significantly lower number than 1horsepower and marketing is about bigger numbers always
kW is a better unit in my opinion, but at least we have a standardized definition against the SI units
That's an abomination of a unit. For one, it's not truly metric. For another, it's just going to get mixed up with real horsepower, not only by the name but by how it's only 1.4% smaller so the numbers will sound reasonable but be slightly off. If you're going to go metric, kilowatts are the unit to use.
All I know is my 600whp 2.5 Forester is a ton of fun and will outrun about anything on the street. Turbo noises and spinning all four on dry pavement in a dad wagon with a kids seat in the back makes me smile all day long.😁
The grea thing about an engine that relies on size to make horsepower is that once it hits the sales room, the aftermarket can take care of the other two techniques for massive power 😁
If you wanna spend 10-15k into an engine, making it less reliable, go ahead. I like well built factory engines that are already well optimized
Rpm and boost. I can't decide between the 2. Displacement is only good for a raw muscle sounds in my opinion.
I love the sheer enjoyment when you rolled down the window! Totally awesome dude!
Nissan altima casually having the same wheel design CANNOT be a coincidence
13:23 Blessings to you for your great mic setup 🙏
Great start! Now factor in compression ratio, the use of N2O, cam timing, valve spring weighting (pressure) and the use of lightweight sturdier components. When the engine is N/A, there are a number of things you (the builder) can do to make a large displacement engine still spin up to 8k rpm and produce large HP/Torque numbers.
You made me smile. Thanks for that. Genuine delight is contagious.
Had sound error before, sounds perfect now.
Excellent, happy to... hear it!
When the Lexas LS first came out, it had a 4L V8 that made 250hp. Ford's CEO Alan Mulally said that was his finest car.
Let's appreciate the fact that Honda produced a 4 banger 10 years later that's half the size, reved to 9k rpm, and made 4% less power than said Lexus
Big displacement was required because they were hooked up to 3 speed auto that had wide gaps between ratios. Wide power band from a big engine was necessary. Nowadays, we have 9 speed transmissions that allow small engines with narrow power band to stay there when necessary and get out of it for efficient cruising.
My preference would be high rev small engine with turbo compound as waste heat recovery
What I learned from this video is that the ability for an engine to make power and how immediately it can make power is dance between the rate it processes air, how much air is processed per cycle, and how compressed that cycle of air is when ignited.
Based off the nature of how ICE engines are used in cars it makes sense that turbos have taken over in road cars, since the wide range of speeds they operate encourage a broad torque curve thats less easily achievable with high displacement engines.
In a similar sense, that reveals why aviation engines are often so massive in displacement. The amount processes per cycle at a constant low rpm is whats king in making a propeller aircraft perform at modest altitudes (turbos find introduction the higher you go)
And of course high rpm engines as key techniques make the most sense in motorsport and enthusiast cars because of the ease engine rpm can be transmitted into wheel rpm, and thus high speed performance, the same range of drivability not being needed in as wide an rpm range.
Aviation engines are similar to boat engines in that the reason you want large displacement is for reliability -- not necessarily for performance. Car engines can make really high peak power numbers, but absolutely not for seconds to minutes to hours at a time. Its why you'll see 20-30 liter engines making 2500hp; it sounds horrible, until you remember they can do that all day long. Larger bearings, larger pistons and rings, larger camshafts, larger oil capacities, larger areas to distribute heat, larger valves (and seats that wear slower) -- these all work together to make these engines exceptionally reliable at their highly limited peak power.
What I wish he mentioned in the video is that low RPM is highly preferable for engine reliability, such is the benefit of turbos. All those super high revving race engines don't last long at all.
Another metric is the temperature of the air being processed, which is half (or so) the trick of nitrous. Chills the mix and adds oxygen, adds boom, and 😊
I get my fix for power and acceleration from superbikes at the track where lack of mass and RPM is king. I do sometimes ride them on the street, but having access to that much power and acceleration and not being able to use it without risking jail time or death is a constant sensation of being blue-balled, that does get old real fast.
For a street car, my 981 Porsche Boxster GTS gives me all the thrills while still keeping it mostly legal. Its a great formula with a little bit of displacement, 3.4L with a little bit of rpms at 8k, combined with the increased sensation of speed from a convertible, and the super low CG from a naturally low sitting Boxer engine, and the best position to mount the engine rear-mid with RWD.
No replacement for displacement! 😁 Great video. Something we argue about at work all the time.
electric engine
its true.
@@drummingbomb gay
Boost, boost is the replacement for displacement. The car gods have spoken. Most engines are getting downsized and turbocharged to make similar power in a smaller, more *cough* fuel efficient package.
@@demetricklouis5710those new engines blow up a lot quicker though. A big ol’ 6+ liter V8 would be my ideal pick for an engine. Solid power, great sound, and can actually last for a while with few problems
I will say Jason that almost everything in life is optimised for a particular task, if you gain in one area you will often lose in another. I'd suggest that as fast as the Bugatti is at the 1/4 mile, it wasn't the focus of the designers, but he McLaren designers could pay more attention here because what they wanted to do was more attainable.
Thumbs up though.
The oder I get, the more I learned to appreciate displacement. Much more fun to drive if you're not a track focused person.
Agreed - it's great!
Now you need to try 2 electric motors, one on each axle with instant torque. Charge it in your garage. Test drives are free.
And high revs is best for track focused fun! Turbo has to be the least enjoyable to drive from a pure enthusiast perspective
I'd say turbo is a good daily car, small light engine, lots of boost, turbo lag can be fun
@@tturi2it is not physically small or light.
Hi Jason! Thank you for uploading today! I really like your videos and it continues to motivate me to pursue my mechanical engineering degree and career for the future. Thank you for always reminding me that one of my passions is learning about cars, and maybe driving more different cars in the future! Take Care!
Loved the smile at the noise it makes.
2:44 I don't know about this specific analysis as a comparison for airflow. I think the efficiency of intake and exhaust flow vs rpm, vs boost, vs displacement seems much more relevant.
Because The L/min is not adressed as function of L/per rotation. But it is obviously still relevant for the question of engine power being made at a given moment.
The l/rotation is the same as l/revolution and the time part of that is implied in the unit, literally 'per second', like it was expressed in rev/minute or you could state it rotations/second.
Yes certainly. I apologize, I did not phrase that well and imagined people were following along from the prior statement.
I should have said something like: Because the L/min is not extrapolated from a more detailed scale. (Specifically, flow rate per rotation relative to the variables for each approach). It misses out on illustrating the differences across the 3 and suggests more parity than there is. (The line wasn't so much about the illustrated unit, but the process of having a smaller level of detail being examined then expanded.)
*Though it ended up just being sort of a cursory discussion as a lead in to talking about the 750S anyway. As opposed to his more detailed whiteboard discussions. Thinking about it now, Driving 4 Answers may have made a video on the topic more like my initial thought, so one could argue there isn't need to cover it in the same way regardless.
I often wonder why power to weight ratio isn’t the most important number for any of these discussions. It doesn’t matter as much how you get to 700 hp if your vehicle is 6000 pounds.
Edit: what I mean to say is, this video is about how power is generated, and that’s fine, but there aren’t very many discussions about power to wait, and to me, that would seem to be the most important consideration.
Weight wasn’t part of the discussion. How power is produced is the topic.
@@ALMX5DP oh, I’m not suggesting that that is a flaw in this video, I understand it’s only about power generation. I just find it interesting that manufacturers almost never talk power to weight when they sell their vehicles. Seeing a video that is all about how power is generated inspired me to ask the question, or make the comment. When I referenced “en these discussions”, what I mean to say is, people talk about power all the time, but only about 20% of the time is power to weight referenced.
@@EliotHochberg ah gotcha, yeah I definitely agree. I’m a fan of focusing on power to weight and especially the weight aspect as that helps improve braking, handling and benefits wear and tear of various components and aspects too.
That's why the Bugatti needed 1000 horsepower plus. Because its a 4500 pound porker.
@@Markbell73No, it's because it's engineered for the highest top speed. Power to weight is very important at lower speeds, but at higher speeds outright power and low drag coeffient is required for continued good acceleration.
Loved the video bro ! But you missed on that the 750s got a limited slip differential (LSD) which in theory should help with better 1\4 mile time
I find in heavier cars forced induction is the way to go but in lightweight sports cars naturally aspirated engines give the best balance and fun 🤷🏻♂️ horses for courses.
Why the hell would you want more weight in a heavier car?
You really helped me understand how engines are built and how they can be tuned , well done , it was all a mystery before for me
What any kook would do with a 750hp RWD car in the rain? Powerslides! Jason? A video…😂 BTW nice video, thanks for posting.
750hp rwd in the rain doesn't mean you go sideways at the lightest touch of the pedal.
It just means you tap the accelerator slowly with controlled steering inputs.
I'm sure the car also has a rain mode setting for easier driving in the rain.
Having said that it is also sad you can't safely make the vroom vroom sounds for the camera in a car that wants to sing!
I watch every video you post and I learn a lot from you. Thank you. I guess I'm old school. I prefer a big engine that has been designed for torque, from idle to mid-range. Not interested in high RPM's. Don't care for turbos. Give me a super charger with a water to air cooler on a big block, any day.
Lol, an old German saying goes "Hubraum ist durch nichts zu ersetzen ausser durch mehr Hubraum" = "displacement cannot be replaced by anything other than bigger displacement"
Thats already a thing in English: No replacement for displacement.
Leave it to the Germans to make it more technical and less funny.
@abdullahkilinc473
Last season in GT3, the BMW TT 3.0L was faster than the AMG NA 6.3L.
So Germany definitely does not practice that anymore
@@jonathansmith7306 I wonder what country makes AMG cars
@@jonathansmith7306 bru haha, that was maybe th worst choice you could have taken especially because most german car manufacturers choose smaller engines nowadays (looking at the new c63 with a 2L I4)
Nice thing about more rpm/less torque is better traction on takeoff. Big blocks are hard on tires when you drop the hammer at the stop light
Came for the maths stayed for the McLaren.
You remind me of an old story. A famous motorcycle racer was talking to the tuner at the end of the season. "I barely held off the completion on the last couple of races. I must have more power next year, so how are you going to do that? Answer was Very simple Kenny-san, want more power - burn more gasoline!" Which is the reverse side of your description, and funny to boot.
"Who cares, you're faster."
Someone got a new McLaren. Proud of you my friend. Thanks for the education as always.
What are you talking about...
The reality is, most Automakers building super cars opt for boost with turbos instead of higher displacement engines for tax reasons. If was the market to decide, not a surprise it would be all about displacement.
and turbos and revs
No, it would be about revs just like in the old days.
Displacement is for people who don't know how to make an engine it's heavy for the power output
@@tristansimonin1376tell that one to Bugatti
@@tristansimonin1376isn’t a GM 6.2 lighter than something like a 3.5 Ecoboost? Not sure saying larger displacement is heavy necessarily holds up every time in reality given many common engines on the road.
This helped me finally grasp how an engine works!! great video man!
You've just proved American cars mostly turn gasoline into nothing. I never thought of being able to destroy energy until you mentioned that Viper engine LOL
Not true at all, does the coyote not ring a bell?
Imagine being such a brand loyalty sheep you become a nation brand loyalty sheep. Yikes.
Uh what? The viper is interesting, as it isn't your average muscle car. The Viper is more of an experiment that went very well for Dodge. But a few of MODERN American muscle use all three principles. Take Dodge Hellcat, GT500, and Camaro ZL1 as examples.
I've learnt so much from you over the last 5+ years
This reminds me, I'd love your take on Porsche Active Ride. This was a great video, and that blue color on the car is GORGEOUS!
I liked my own comment.
And? Didn't you say that last time?
Okay? I always do. Everyone does. Do you want a trophy?
And I disliked this corny shite
I disliked your own comment
first things first - I love the video!!! Now, to answer your question. My least favorite is displacement - in my eyes, a thing from the past. Boost has replaced displacement, like a Cheetah has replace the dinosaur. However, RPM is my favorite. RPM are cool. RPM is technologically challenging, it sounds great and it provides horsepower. There you go. Simple :) Thanks for the video!!!
The viper’s numbers at 8:30 for volumetric airflow are really the ideal numbers if it had perfect volumetric efficiency, and the fact that it is so much more than the other engines despite making the same power as the t.50 shows that it should really be making more like 750-800 hp if the heads could flow better
You should have included adding electric power. And which one can compliment electric power best. If you go high RPM you can counter the lack of low-end power with motors.
I find it interesting that no one ever mentions that the GMA t50 is a hybrid. Not a huge power bump from the system, but it's there.
As long as there are rules and regulations limiting the design and operation of engines (size, economy, emissions, etc. - even F1 has some pretty strict rules), the theory really doesn't matter. The rules will always determine which solution is best for power. Once you throw the rules out, then the current state of technology and the purpose of the engine decides. Naturally the best answer is yes to all 3.
My preference is boost if I absolutely have to choose, but all three is the best!
Nobody talking about how he is saying all of this while driving. That leads me to believe he has all the information memorized or he is just that knowledgeable, which is actually commendable.
One of my silly engine swap ideas would be to put 250cc inline-4 18,000 RPM 45 hp engine, that sounds like F1, into any car. Imagine making F1 sounds while barely hitting 120 km/h top speed
I have always leaned toward displacement because of the three ways to make power it is the lowest stress and will most likely out last an similar output engine that either has to rev much higher or take a lot of boost to achieve. That said a big displacement motor can always be boosted for way more power and to a point reved a little higher so it has the most flexibility.
I'm all in for larger displacement, higher RPM & boost as well. You can get a 6.0 liter LS V8 to comfortably make 650 street-able HP with a good set of aftermarket heads, cam, water-to-water intercooler & about 15 PSI of boost. All at under 6000 RPM. And maybe some nitrous for good measure.
Fab video. Succinctly explained and a great tribute to the 750s.
9:12 if McLaren doesn't want to tell you the boost pressure, plug in an ODB Wireless adapter and monitor the peak boost during WOT.
Perfect timing.Was just in the market for a 750S.
The advantage of smaller displacement turbo engines having better fuel economy is partially offset by the fact that most newer turbocharged engines are making quite a bit of boost at lower rpm. Peak torque on some of these engines is below 2000 rpm. So the engine isn't moving air like a 2.0 liter except perhaps at very low rpm. Personally, I enjoy higher strung, revvy engines. I have been lucky enough to drive some big block Mopars, though, and the torque is very impressive.
This is totally true. I have a 2L turbo that can produce max boost at under 1500rpm. Learning to drive while not engaging the turbo at lower rpms was something I had to learn how to do because of how quickly it spools up.
I always takes notes from this channel to do more research I’m always learning interesting things if I had the money to help people improve their vehicles That’s almost all O would do.
I really like the 2.0L L4 engine that's in my wife's 2016 Volvo XC90.
Given the size the car (SUV) that that engine is trying to propel, I am amazed at how well that actually works given it has both a supercharger and a turbocharger. (235 kW @ 5700 rpm).
Cruising at 110 km/h - I can get 7.5 L/100 km (~31.36 mpg), which again -- given the size of the vehicle -- that's pretty good without any kind of electrified assistance.
High RPM can be so fun, was the best thing about the CBR 600RR I had. Making that engine sing with a modest exhaust was fun.
Crazy to think the Yamaha R1 can pump out 200HP in a 1L N.A. engine. The acceleration on those are absolutely brutal.
Also wild to think with the advancement in technology and parts availability, how "easy" 1000HP is to make these days.
Bro, MotoGP bikes are like 280hp from 1 liter motor.
@@vvevvevvvv True, I guess I was thinking more about pump gas power.
Good episode. This is classic Jason.
Steve Morris knows it is a combo of all 3
The goat
Funny most people run pro line... not steve morris and his crap
i dont remember anyone else having a faster drag and drive time. SMX 5 sec 1/4 mile and can go thru the drive thru. no one else on the planet has done this before. So who? @@S2KCYA
ugr runs 3500whp @ 10krpm, all proline engine
Top fuel fragsters dont use steve morris lol
I don’t care about boost or RPM, there is nothing more satisfying than a big block V8 cross plane, the sound it makes is something you don’t get from the other alternatives, plus when you’re idling and step on the gas the hood actually shakes from all the low end torque. 👍
Great video! I'd love to see a video comparing the Audi/Mercedes 4.0 TT V8 against the BMW 4.4 TT V8... Maybe even throw the Porsche flat 6 4.0 in the mix if you're feeling crazy.
I think boost should be as low as possible, the power to torque ratio should be at 0.5 or above and torque at max rpm should be at 90% peak torque or above, which ranks rpm higher than displacement and displacement higher than boost.
I tend to see peak power as a gimmick, as it only describes, up to which speed you can stay at peak wheel torque and how fast you can go.
I would aim for usable power at low rpm (primary with displacement, only minimal amounts of boost) and peak power with a power to torque ratio of at least 0.5. So peak power would in the end be mainly achieved by using higher rpm but you don't have to rely on rpm alone.
Let's say, you want to have about 70 kW at 2000 rpm. You need 335 Nm at 2000 rpm, which can be delivered with 3.0l displacement and about 0.1bar boost. Peak power should at least be at 167,5 kW or about 170 kW. If you are good at designing engines, you use the given limits and increase power with higher rpm, therefor flattening the torque curve. You should be able to reach at least ~240 kW at 7500 rpm.
To put this in to scale:
This translates into a range of displacements for normal road cars between 1,5l up to 3l (120 kW up to 240 kW), which one could claim to be reasonable.
Disappointed that you went with litres of air, when 'everybody' knows it's the _mass_ of air [ lbs or kg ] that makes the power.
(The engine flows the same _volume_ of air on a winter day at sea level as on a hot day in Denver, but makes very different power).
I have been watching this channel for years and always wondered if Jason has a day job. He is definitely talented and smart. If I owned a car company I would hire him.
For a few years now, he left his engineering 'regular job' and only does these videos. He also does the editing and production work. There's a great interview of him on the Munro Live podcast a few months ago.
12:14 "Nissan Altima, the Pinnacle of Performance, we all agree" 🤣 as a G35 driver, basically a nicer v6 Altima, this line absolutely cracked me up.
It'd be interesting to have you talk about Subaru with their 2.4 liter turbo engines, also using boost, cvt contributing to keeping in the best torque range, in a decent displacement.
So I do want to point out that the energy to spin the turbo isn’t free, the gasses are pushing back on the piston to get the force to do work on the turbine.
Really appreciate these very educational videos!
A good explanation on why nitrious/pure oxygen isnt a reliable option [or even the fuel alternatives].
Top fuel dragster:
500 CID (8.2L) V8
HEMI heads
65 PSI boost
9000+ rpm
13,000 HP
11,000 lb.ft
We love stuff like this, thank you Jason. Can you do a video on motorcycle single, twin, triple and four cylinders. Comparing their displacement, RPM and boost (like the Kawasaki H2 supercharged)
A turbo isn’t powered by heat from the exhaust. It is powered by the huge increase in back pressure.
That's not really true... There is inherent energy left in the exhaust due to the fact that there isn't enough time during a power stroke to completely burn the A/F mixture. It still has explosive pressure as the exhaust valve opens and this is what you can hear, and also what drives the turbo. It's why turbos are quieter.
Boosted Ford 5.0 on E85 has all three and it’s amazing. 1100+ HP
Love your work, Jason 👍
I was thinking to make a research about this topic the last night and now EE just read my mind ❤
Love this analysis, thanks Jason.
I had a 1976 trans am. 455 cu. The height of the malaise cars. Probably less than 200HP. But the torque was just fantastic. As long as you were moving you could just power out of 4th gear. No substitute for cubic inches! ;-)
Carwow did a drag race between the 750 and 720…both were said to be stock and the 720 beat the 750 in multiple standing starts as well as rolling starts. I think the only real difference that possibly gave the 720 an advantage in the dig races were the Michelin PS Cup 2’s over the PZERO’s on the 750, but that shouldn’t have made much difference in the roll races.
The best combination is a large displacement engine turning a lot of rpm with a lot of boost. There are plenty of 500+ ci engines running 70 psi of boost turning 9,000 rpm. It's just a matter of how much you want to spend.
I haven't watched the video, but I'm a newer mechanic(about 6 months experience, 3 as a lube and tire tech lmao). Anyways, my hypothesis is displacement. The others give you more power as well, but they are basically trying to force more displacement out of the constraints of the engine. Boost gives more, condensed air to allow more fuel to burn. Higher rpm displaces more frequently. I mean look at tanker/cargo ships. Their engines are like MAX displacement(multiple feet bore and stroke) and they output MAX horsepower(10's of thousands). If it was boost or rpm that gave the most horsepower, they wouldn't make them that big.
If we're talking about absolute maximum power, displacement is your first priority of the three for one reason - cooling capacity. Bigger engines have bigger coolant passages which makes cooling more efficient. Very important if you're trying to make a powerful yet aerodynamic car.
Less chance of overheat and WAY better TBO!
wouldn't they also have more trouble moving heat away from the combustion chamber since it gains volume quicker than surface area?
@@crackedemerald4930 You are correct. Surface area to volume ratio is higher for the same number of cylinders. I also don't think cooling is down to the capacity of the water passages so much as that of the external heat exchangers provided that the coolant can be moved efficiently.
What we need is excellent torque and power at low revs for tractability, a strong midrange to give you the thrust where you need it the most, and a screaming shockingly high revving top end to widen the powerband and give that feeling of endless power, and superb linear throttle response. In that case it is NA V12 all the way - Cosworth, Ferrari, Lambo, BMW S70/2, HWA - these have the best of all worlds.
But somehow by some witchcraft the nerds at Koenigsegg and Ferrari managed to make even a Turbocharged engine respond like an NA one.
Great video on breaking it all down !
EXELENT as usual 😊
There are other trade offs between the 3 solutions that impact engine design such as size and shape, MPG (efficiency), emissions, and cost. BMW had great high RPM engines 15 years ago but they were trouble prone, poor low end torque and poor efficiency. Switching to twin turbo allowed reduced RPMs, greater torque and much greater efficiency.
Big displacement can lead to stresses as well - it can turn into large piston speeds if the engine layout is weird and you‘re asking for only reasonable RPM - eg. 3 L straight 4 in the Porsche 968 CS.
Displacement and RPM essentially work the same way runner length and cams do, you're just moving where peak power is achieved. Long runners and big blocks make better low-end, short runners and small blocks make better high-end, and of course cams are just modifying how much air you're moving and when that air is moving within a cylinder cycle. The trend is pretty much the same across the spectrum of engine design, you can only get so much power out of so much airflow, the design just dictates where the power figure will peak and how efficiently that target is reached. But the issue is, nothing is actually good low-end, unless you have a massive cylinder that kills any sense of fuel efficiency, all of the 'low-end' gains are more typical of mid-range when you consider idle to peak range. I think hybrids are the feasible way forward, electric motors are torque monsters as long as you can keep them fed, which in a hybrid isn't overly difficult to do compared to a battery-only EV. What most people don't talk about is power under the curve, most people only talk about peak numbers, but duration is important to discuss; if you're faster off the line and you're faster in the mid-range, you really don't need top-end numbers when your competition only matters towards their peak and when their peak is nearing their redline. And the thing about hybrids is you can easily have a system where the electric motor provides low-end while the gas motor provides high-end, with a mid-range hand-off once horsepower figures cross; though from an efficiency standpoint, ICE as range extension is better, though with the hand-off method you can likely get away with a smaller motor and a smaller battery pack. This is likely the sustainable way of chasing power figures until battery tech becomes more viable long-term. Just take drag racing for example, an EV will be off the line with zero idle, while your local hillbilly is idling at 2k+ just to keep enough boost on a big block to be off the line with non-lethargic performance, while they might make similar quarter-mile numbers consider the amount of energy used between the two, the optimal choice is simple enough for a child to make; now consider that with a performance hybrid system, the EV side makes up for lack of low-end, the ICE side trims out the EV weight and provides high end without pre-launch high idle as it can do the exact same job during the EV's phase before the hand-off.
What I really like is the thought that while Ive never gone past 200mph in a car, as a german I could just rent a supercar for a day and go on the Autobahn. I really like that thought. Might do so.
I remember my high school auto teacher said "an engine is just a giant vaccum. The more air you can suck in one end and blow out the other, the more power you'll make."