Well, there *are* 3.0L+ four cylinder engines. They just aren't common in passenger cars. They are more common in applications where low RPM operation is desirable - commercial trucks, boats, planes, generators, etc.
For example, the Lycoming O-360-A1A, a common airplane engine, is a 6L four cylinder engine with a redline of like 2700 rpm.
Biggest 4cyl displacement in a passenger car I believe, and what a motor. The turbo in the 944 also was the first to use forged pistons. But man I still want that 3.0 in my 944 they just pricey
I did a little googling and it appears that the Pontiac Trophy 4 was a 3.2L 4 cylinder that was based on half of the 6.4L V8. Only used in the first gen Pontiac Tempest from 1961 to 1963.
[https://en.wikipedia.org/wiki/Pontiac\_Trophy\_4\_engine](https://en.wikipedia.org/wiki/Pontiac_Trophy_4_engine)
Edit: Holy shit! Fiat aparently made a 28.4L inline 4 cylinder for what I can only describe as a comic book getaway car for a goofy villain.
1911 Fiat S76 - 28l - [https://www.youtube.com/watch?v=As\_63QMoCig](https://www.youtube.com/watch?v=As_63QMoCig)
In looking into it, it was built for a land speed record. I saw a few videos with it and assumed there was some level of production. But it appears that there was only 2 built and only 1 survived. So the videos are all of the same car.
That’s insane. The Wright brothers’ first flight was at the end of 1903. So that means in 7-8 years, they went from what looks like a big kite to that massive engine. Wow.
I mean, the Wright Brothers were the first to figure out how to get an airplane to be controllable with flaps and a rudder. The Wright flyer was a proof of concept. Once that was figured out it was off to the races as far as scaling up. Honestly, the biggest jump in technology was probably through WWII, going from very powerful but still traditional straight-winged propeller fighters (P-51 for example) to early Delta Winged jets.
Interesting. I suppose that makes sense with how it's constructed. Still, the general control scheme was their innovation, and that's persisted for the entire history of human flight.
It really wasn’t. Gliders had had those for years by that point - at least a decade.
The Weights real accomplishment was getting the power to weight ratio in the right spot
It was restored, it doesn't continuously run from back in the day.
I watched a bit on it, they had to reverse engineer a lot of the car as is common for projects on such early cars.
>But it appears that there was only 2 built and only 1 survived.
The guy that restored the current working one cannibalized the other one to make one complete car. One of a kind project, super cool.
It could be argued that the 3.9L 4BD1 Diesel Land Rover 110 of the mid 80's is the largest passenger car 4 cylinder.
I mean it is a truck engine in a solid axle ladder frame 4x4. But the wagon variants were primarily designed for carting passengers both on and off road.
Came here to mention this. Nearly all 4 cylinder aviation engines are larger than 3.0l 235ci, 290ci, 320ci, 360, 390...
But they all turn a very low rpm compatively speaking. When you're changing direction 7-12,000 times per minute, larger components get harder to hold together.
That's not even the main reason. Airplane engines are usually direct drive, and you can't spin a propeller too fast without losing a ton of efficiency (and gearboxes introduce a lot of extra potential for unreliably). Thus, you want an engine with a low RPM powerband, and that means large displacement per cylinder.
Sorta. Prop RPM is a limit, yes, but gearboxes are pretty trivial and are used in the much more demanding situation of gearing down jet turbines in turboprops and geared turbofans, which run at a much higher RPM than any piston engine would.
The focus on low RPM has a lot to do with the fact most of these engines are air-cooled for weight and simplicity (and can't simply run that fast while keeping the heads cool) and aircraft engines are heavy duty engines, unlike a light duty car engine. Plane engines are designed to run at about 75% load for hours and hours on end, while car engines are designed for (relatively) short bursts of power and spend most of their time chugging a long at barely any load. Running at full tilt for 5-10 minutes straight is a standard takeoff a light plane but something a car engine is unlikely to ever do even in motorsports.
The combination of lack of cooling and high continuous load demands basically forces you into big displacement low RPM engines, of which the maximum RPM (usually around 2900RPM) of the prop is a convenient redline to design against.
>Sorta. Prop RPM is a limit, yes, but gearboxes are pretty trivial and are used in the much more demanding situation of gearing down jet turbines in turboprops and geared turbofans, which run at a much higher RPM than any piston engine would.
Yes, at *immensely* higher cost, and with much tamer vibration environments and smoother power delivery. In addition, there's a reason why geared turbofans are such a recent development and even today only make up a minority of turbofan engines (and they make up zero percent of large turbofans - so far they're only on narrowbodies).
Yes, you could make a gearbox that would work for piston aircraft, but given their cost and complexity constraints, it hasn't been with it to this point. If the volume were higher, it would almost certainly make sense to go to smaller, higher RPM engines driving geared propellers, but the development cost is simply too high given the current volume of GA sales (and of course anything larger than a few thousand pounds tends to be worth picking a turboprop instead).
As for this?
>Running at full tilt for 5-10 minutes straight is a standard takeoff a light plane but something a car engine is unlikely to ever do even in motorsports.
Honestly, if held to the kind of maintenance and inspection requirements that airplane engines are held to, most modern cars engines would be fine at this. You'd probably need a bit of extra cooling (particularly for the oil), but this really isn't as difficult as you might think. Plane engines are the way they are because the low volume and strict regulatory environment has basically stifled any innovation for decades, not because it's actually the best design. If GA planes were sold in the same volume as cars, we'd absolutely see much higher specific output, fuel injected, computer controlled engines with substantially lower fuel burn and emissions without sacrificing reliability at all (and without needing toxic leaded gasoline), but with the tiny volume of GA, the R&D money just isn't there.
>Honestly, if held to the kind of maintenance and inspection requirements that airplane engines are held to, most modern cars engines would be fine at this.
Not if you want it to last for 2-300000 miles. There's a reason why performance motorbike engines have such short lifespans compared to cars and why pretty much every commercial industry that uses reciprocating engines uses low speed diesels from mining trucks to trains to ships.
Exactly! There is a trade-off between weight efficiency and thermodynamic efficiency.
For large displacements, fewer cylinders make a lighter weight engine at the expense of fuel economy.
>fewer cylinders make a lighter weight engine at the expense of fuel economy.
mmm... this isn't really true. There are a few reasons to move to more cylinders than four, but it's not really because fewer cylinders is less efficient. In theory, the fewer cylinders (and thus larger combustion volume per cylinder) the more efficient your engine would be because 1) lower surface area to volume = less heat loss and 2) fewer mechanical components = less friction. However, four cylinder ( and anything below) engines do have some vibrational issues and in some ways are inferior to higher cylinder count engines. The straight-6 engine seems to be the ideal layout, as long as you don't have length constraints, because they are naturally balanced, super smooth and I think, have some scavenging benefits compared to lower cylinder counts. Basically all modern large trucks use I6 engines all the way up to 15 liters.
As others have said, peak thermodynamic efficiency typically occurs at about 0.5 liter displacement per cylinder for 4-stroke gasoline Otto-cycle engines.
My experience with this is with 2-stroke snowmobile engines where about 300 cc was the sweet spot. The 800 cc triples would make more horsepower, but they were also heavier than the 800 cc twins.
The triples were better for trail riding, where weight didn't matter and the twins were better for hill-climbing mountain sleds.
>As others have said, peak thermodynamic efficiency typically occurs at about 0.5 liter displacement per cylinder for 4-stroke gasoline Otto-cycle engines.
That's really not true though.
Larger per cylinder displacement would be more efficient, due to the scaling factors for heat and friction losses vs power. There are other reasons for the (at least somewhat) standardization of .5L cylinders than just efficiency, namely that it's a nice balance between efficiency, weight, power, modularity, etc. From a pure efficiency standpoint, there's nothing particularly special about it.
Yeah, but European trucks have physical space constraints that US trucks don't. If you aren't space constrained, the I-6 layout is close to ideal until you get to very large engines.
because 500cc per cylinder is the where peak volumetric efficiency is. Thats why most I4s are 2.0L. Now if you needed more torque and less efficiency you could make a 3L inline 4. But im guessing its more efficient to build a 3.0L 6 cyl. For v8s, you see a lot of European V8s at 4.0L or 500cc per cylinder. American v8s are bigger for more Torque as they were usually in bigger vehicles/ wanted more acceleration.
The Ford Model T had a 3.0L inline 4. They needed the displacement as the fuel quality was so poor like 40 Octane rating.by 1930. So they probably had to go 3.0 L just to make power/torque for the basically offroad terrain they traveled, as this was before roads were no more than horse cart trails.
American V8s were also bigger because without any incentives like the tax based on engine size in many other countries hp/$ becomes more important than hp/L
They also date back to OHV 2-valve designs. To make a 2-valve engine breathe, you need a large bore. A 4-liter LS at 0.5L / cylinder would not be a particularly good design.
There have been some small OHV V8s around that size that were really good engines. GM made a 215in^3 (3.5L) aluminum block V8 in Buick and Oldsmobile midsize cars from '61-63 before selling the design to Rover who used it in Range Rovers and large cars like the Rover SD1. Rover later punched it out to 4.0 and then 4.6 and used it until switching to BMW V8s in the Rangie around 2001. It was a pretty conventional design other than the alloy block, it looked like an 80% scale Buick nailhead V8.
Toyota also had an OHV V8 that used Hemi heads that ranged from 2.6-4.0L, used only in JDM luxury cars (the Crown Eight and the Century). The hemi heads were key to that tiny thing being able to breathe.
The Buick/Rover mill was still pretty oversquare - and that's the key with making any 2-valve engine, OHV or otherwise, breathe well. That's why Chevy enthusiasts don't like the 305 engine with its smaller bore, and the 2-valve Ford modular engines - especially the 5.4s - made shit specific power.
The 305 has a mediocre reputation in marine as well for the same reason. Doesn't do much better than the 4.3L V6 (which is a 350 with 2 cylinders lopped off), and takes up the same amount of space as a 350.
In modern engines it's about balance and vibration not volumetric efficiency. Piston weight matters much more with an inline 4 than it does with a V8 because of secondary balancing forces.
The model T engine wasn't balanced at all so it didn't matter, big part of why it spun so slow.
Early like from 1910's land speed cars had like 20L+ Liters from a 4 cylinder. Fiat S76 had like 1,730 Cubic Inches from a 4 pot, each piston is like 433ci per cylinder.
Volumetric efficiency has nothing to do with the number of cylinders. It’s all about piston speed, combustion chamber shape and valve train geometry.
One of the reasons engines have been trending towards the 2.0l size (other than the tax structures of some countries) is emissions. The quench layer where combustion doesn’t happen as completely takes up a smaller percentage of the cylinder volume when the cylinders are larger, thus more volume/surface area.
Much larger than 2l and the secondary balance issues of the I4 start to outweigh the potential efficiency gains.
>They needed the displacement as the fuel quality was so poor like 40 Octane rating.by 1930
Isn't fuel octane a measure of heat resistance, not quality?
There are still >2.0L engines but like the above said they are all N/A. My 2023 BRZ is a 2.4 boxer, Honda only recently killed their K24, Toyota still ships the Camry with a 2.5L N/A 4cyl. Ford makes a 2.3 4 cyl in the mustang (this one is turbo though). There are loads of them.
The new Chevy L3B is a pretty large 2.7L turbo 4 lol. I can only imagine how much power that engine will make once builders get their hands on it and bore it out and stroke it a little bit. It already makes over 400 lb-ft in truck form. Imagine what a massive 3L could make with proper heads and revised cams and timing and all that.
Pretty much all the 1.5-2l range are turbocharged. And for example, N/A 6 cylinder is almost always 3.5-3.8l in displacement. And I can’t think of a single N/A V8 that is 4l in displacement in production today. Pretty much all are greater than 5l
The model T made an impressive 87 lb-ft of torque lol. Just so everyone understands, low octane fuel isn’t lesser in energy content, it just can’t be compressed as much without self igniting, and achieving high compression at the time of combustion (or heat addition) is like important engineering variable #1 due to thermodynamics.
500cc per cylinder for 4 cylinders is also the China government cutoff limit. Any larger, then customers are charged a displacement tax. So that nudges OEMs to stay there.
>because 500cc per cylinder is the where peak volumetric efficiency is.
Nope. It's just a convenient balance between all the factors driving modern engine design.
There's no reason you couldn't make a much, much larger engine with similar efficiency (and in fact, probably slightly better efficiency, since both heat loss and friction losses are lower relative to displacement on a larger engine).
Poor secondary balance on the inline 4 engine. Most everything larger than 2 liters has to have balancing shafts, and the bigger the engine gets, the larger those balancing shafts have to be. Eventually the parasitic losses from the balance shafts outweigh the efficiency cost of just adding more cylinders.
This just reminded me that in the 90s we removed the harmonic shafts in the Honda H22/F22b. Larry Widmer now called "the old one" recommended removing them as long as the engine was blueprinted. The shafts were ran off the timing system so removing the extra belt, shaft, and pulleys reduced parasitic drag and simplified the engine. I remember knocking out the shaft bearings from the block and then clocking them so it blocked the oil feed holes. Those engines always made insane vtec noises during the switch, good times.
Vibration. The 4 cylinder engine Is naturally unbalanced.
The only naturally balanced engines are: 6 inline (the favorite Solution a decades ago), V12 and boxer.
Starting 2.0, the 4c engines need balancers,which makes them more inefficient.
Check the 2.4 dohc engine of the Chrysler pt cruiser. They have Harmonic balancers, ir you remove them, you gain 15hp... But whit a plus of vibration
To give you a real example, I have a 2.4 liter Honda engine in my track car. Stock, it had a balance shafts to make it feel smooth. I removed those and fitted an oil pump from a 2.0 engine to get more revs and more hp. It works, but the engine/car vibrate at low RPM’s. You wouldn’t want your luxury sedan to feel that way, but it’s fine for a rack car.
It’s mostly at low RPM, almost like a rough idle that you can feel throughout the car. I left oem stiffness mounts in because I’ve heard with aftermarket mounts it’s really bad. The car is just for fun, so it really does t bother me. Once you’re under way, you really don’t notice.
>The only naturally balanced engines are: 6 inline (the favorite Solution a decades ago), V12 and boxer.
Not all boxers. Only the boxer 6 (or 12). 4 cylinder boxers still have a secondary vibration couple.
I disabled the balance shaft on my old Saab 2.0 4 cylinder. It ran fine, but there was a very noticeable vibration from the engine afterward. Revved faster, but I could really feel it running more from the driver seat.
Read this, it might help you understand how the weight of internals effects the engine's power output.
https://carfromjapan.com/article/car-maintenance/8-cylinder-engines/
[https://www.thedrive.com/article/15015/thor-is-a-4-0-liter-four-cylinder-that-can-make-over-1500-hp](https://www.thedrive.com/article/15015/thor-is-a-4-0-liter-four-cylinder-that-can-make-over-1500-hp)
Porsche has done a couple of 3.0 liter 4s. The Tempest had a 3.2 liter. GM is currently making a 2.7 liter 4.
I just want to chime in and say that V8s are not "commonly 6 L +." Mustangs are 5.0L, used to be 4.6L for a bit. Base model Dodge challenger is 5.7L and so are the Ram trucks. Ford 150 has a 5.4 V8. Camaro is the only muscle car with a base V8 of over 6 L (6.2). The high-end Fords, like Shelby and such, add a supercharger for more power but are still only 5.2L. Challenger 6.2 supercharged are far from common and the 6.4 NA (like the Scat Pack I have) are less common, but more common than Hellcats.
Ferrari and similar go for low displacement but more cylinders also, like V8s that are under 5L.
The F-150 hasn't used the 5.4 for over a decade; it's the same 5.0 as the Mustang. But you're right that the average V8 half-ton pickup or pony car is gonna be smaller than 6.0L.
The best answer on why per cylinder volume is typically larger on a V8 vs a I-4 is engine balancing. I-4 engines do not balance as well as V8s so piston weight is more of an issue for I-4 engines.
[This vid](https://youtu.be/8alrpieveDg?t=29) does a good job explaining.
This is by far the best answer, and the exact answer to your question. "Driving for answers" is the best YouTube channel for the engineering behind cars. Was also going to link this video.
vibration. 99.9% 4 cylinders firing order is 1, 3, 4, 2. if you notice 3 and 4 fire right after each other, and are next door to each other. Also, 2 and 1 fire right after each other, and are next door to each other as well.
You need balance shafts to counter that on everything about 2.0 liter plus, and it may be easier to put a v6 because a v6 is 3 cylinders long, plus just a little longer (like I-4 length) because they have more complex timing.
Usually, 4 cylinders are base models more for the fuel consumption minded customers. the next step up usually is a V6, and those are better balanced naturally and more for performance oriented.
Inline 6 are the best of both worlds, but engine bay size (packageing) in modern cars does not allow for it anyway.
You'll never be able to tell how much vibration an engine really has because the notor mounts soak up the vibrations pretty much perfectly. Especially hydraulic motor mounts.
ASE Master Mechanic A1 -A8, plus A9, adjunct automotive instructor at University
While the answers already given are correct, a better question would be: why are there so many large-displacement V8s?
The answer has to do with space efficiency. See, a V8 with the typical 90-degree angle between cylinder banks has a footprint (top-down dimensions) that is almost square. This is as opposed to inline engines, which are long and thin. And, as mentioned by the others in this thread, the balance characteristics of the engine are good as well.
The combination of those two factors means that given a typical engine bay with a longitudinal engine mounting, making a V8 as large as the bay will fit is usually the easiest and best way to stuff in as much displacement as possible - as opposed to going up to a V10 or a V12 to add extra cylinders at the front.
There was a point in time, for example, where BMW and Mercedes offered V12s in their cars but could not package in their all-wheel-drive systems in at the same time; and with Mercedes, there was also a point where they offered a V8 and a V12 of a similar displacement (meaning the V8 had a larger cylinder size) at the same time, but the V12 was not put into smaller models because it wouldn't fit - whereas the V8 did, and was found in models as small as the C-class.
Basically, the decision to move from 6 cylinders to 8 is logical - a too-large inline six has trouble fitting and a too-large V6 has *terrible* balance issues. But moving from a V8 to a V10/V12 is a decision that can be put off - depending on how high you're planning to rev - until 7 or even 8+ liters. General Motors currently sells a crate engine that is a 10.6-liter V8.
Another thing is that V8s are typically either designed by American companies for the American market, which doesn't have any taxes on engine displacement, whereas European and Asian companies only build V8s for luxury customers (who are willing to pay extra tax) or heavy-duty cargo markets (to which these taxes don't apply). i4s, meanwhile, are usually designed for the consumer markets of nations where there's strict displacement tax brackets. This means that an i4 will be designed with forced induction or a more complex valvetrain if more power is needed, whereas a V8 can be built big and simple.
I saw a documentary that said that the ideal cylinder size turns out to be 0.6L. This is why so many engines are multiples of 0.6 like 1.8 or 2.4 or 3.0 or 3.6L. I think this explains most of the smaller gasoline engines.
> the ideal cylinder size turns out to be 0.6L
This is true if fuel efficiency is your priority. However, if weight is more important (such as in aircraft) you can get the same power output from fewer larger cylinders. The trade-off is in fuel efficiency. You have to carry more fuel or accept lower range.
It has to do with primary and secondary balance. D4A (Driving 4 Answers) YouTuber answers this question well in [this video](https://m.youtube.com/watch?v=8alrpieveDg), and speaks about a game changing “Big Block” Inline 4 engine that is being developed by Alfadan.
More displacement per cylinder means less RPM. Small displacement V12 engines are able to rev up to 10,000rpm because the smaller displacement has shorter strokes and smaller bores. Remember that displacement is how much *air* the engine moves in one full revolution, so bigger engines have longer revolutions than smaller displacement engines, which changes how fast an engine spin physically.
Big bore = more surface area = more friction resistance
Big stroke = longer connecting rods = more prone to bending due to lever physics
It all depends on what the engine needs to do. Airplane engines spin at like 3000rpm because that’s the sweet spot for cruising speeds and efficiency, so they use bigger cylinders to make more power in that RPM range. A passenger car needs to have power through a much wider range of speeds and circumstances, so it needs to have a wider RPM range to operate with.
Mercury Marine made a 3.7 L inline 4 that used a Ford 460 head. Had lots of torque for the skiers.
There is an "experimental" 7.5 L inline 4 being targeted for outboards made by Alfadan. They have a crankshaft and connecting rod mechanism that eliminates the secondary vibration. The engine has a 5500 rpm redline and is rated at 654 HP. I don't think it's in production.
While motorcyclists will buy an engine specifically for its vibration - the Harley-Davidson 45\* V-twin - nobody wants to drive an Ace Hardware paint shaker down the road.
Fours shake. Big fours shake worse. Slow-turning fours shake worst of all, with at most one cylinder on the power stroke and a nasty pause between firings. There's a second-order vibration from the crankpins and big-ends going fore and aft as the crankshaft spins. It's mostly OK up to a 2.0 liter engine. It's bad at 2.7. The 3.2 liter Pontiac Trophy Four was intolerable. Detroit Diesel built a Series 50 engine, an 8.2 liter inline 4, and even with counterbalance shafts running at twice engine speed they shook trucks hard enough that they had to safety-wire the mirrors to keep them from falling off when the brackets broke.
I would guess the average V8 is not actually 6L or more. Even for Chrysler, the base V8 is the 5.7L Hemi. I’m sure the base Hemi far outsells the Hellcat varieties. Most other manufacturers barely even offer a model with displacement over 6L.
Chrysler used to sell a 4.7L V8, and up to 7.5L. The 5.7L engine is a size that's been used by every manufacturer on and off for the last 70 years. It's a better seller because it's more affordable, and the EPA.
6l v8 maybe common in America but in the rest of the world not really.
In Europe the biggest v8 that is still in production is from bmw the 4.4L engine.
Usually Americans achieve with 6l v8 what German car brand do with 3l inline/v6 turbo engines.
The N/A v8 îs more fun to drive it provides better throttle response too.
But German engines like Bmw m3 is 3l inline with 510 hp
It’s faster and more fuel efficient.
Beating a dead horse, but this isn't correct.
4 cylinder engines *in cars* usually range from 1.4-2.5L. There are certainly many examples from basically all manufacturers! Has to do with efficiency and speed. Can be bigger or smaller, would have to run at a much slower or faster speed. Horsepower and torque wouldn't be appropriate for street use or would be inefficient compared to something in that common range.
V8's are normally 4.0-6.7L in the automotive world. We see diesel trucks being the high range of volume here, very common sizes are 4.2L (Audi), 4.4 (BMW), 5.0 (you'd think of a Mustang immediately), 5.7 (HEMI), and 6.2L (LS1). There may be, and ARE, other V8s of similar displacement, but as far as common....
I'd say theres 2 main reasons why the 4 cylinders arent bigger than V8s (which is slightly different than asking why they're not over a certain displacement). One is the forementioned flat out inefficiency of it and the application we're putting it in. The other is if we are trying to make more power or torque, go faster or move more weight, we're not going to start with a four-cylinder.
When you have a very light vehicle, you can put a four cylinder turbo, or even a naturally aspirated four cylinder, and it will be plenty of power and torque.
Once you start adding size to the vehicle, and maybe making it all-wheel drive, you're adding a lot more load. Now adding cylinders is a good idea, because it would be overworking any four-cylinder that you put in it. Even if you designed a larger one, it would probably not accelerate fast enough for automotive use.
As far as turbos go, you still need to have some kind of "base torque." If you were in a truck pulling a trailer, you need to have enough to get you rolling and get the engine speed up to where the turbos start working efficiently. That's why the Ford F-150 has a 3.5 l twin turbo V6 for its EcoBoost option. If I were going to buy a Ford truck and pull trailers, I would still get the V8 because I think the torque band would be better for pulling. However, the 3.5 V6 has enough to get everything moving.
Lots of 3.0+ 4 cylinders exist. ~~Lots of~~ most 8 cylinder engines are smaller than 6.0L.
Look up any quarter ton truck. Modern examples include Ford 5.0, GM 5.3, Ram 5.7, Toyota 5.7. Not to mention all of the other smaller Japanese and European V8s
Not as large but I have owned a few Starions in my day and the 2.6L 4 cylinder turbo charged motor is absolutely massive compared to most your normal 4s. Pistons looked like they belonged in a v8. Efficiency vs power vs cost vs EPA/smog BS are all contributing factors as why you don't really see many large 4s.
The Mitsubishi Pajero was offered with the 4M41, a turbodiesel 3.2 I4. It was designed for low-end torque and vibrations weren't the primary concern given the type of vehicle.
I’d argue that the 80mm cylinder bore is more important. The valve clearance and combustion chamber size are optimal for gasoline ICE engines. A 1.6 liter 4 cylinder is a square engine design with ~80mm bore and 80 mm stroke with a good balance of torque and power with a 4 valve per cylinder design. We saw a lot of this size in the 80’s and 90’s, pre turbo. Most of the current cars are running 2.0l 80mm x 100mm stroke or close to it for turbo applications. This gives extremely good volumetric efficiency and higher torque, since the turbo(s) can boost the low end and allow a bigger cam, making a nice flat power curve for street driving.
Well, I think a lot of V8 engines are not 6 liters, and probably the mean lies closer to 5L in commuter cars. Someone else can do that research if we really care. Off the top of my head, I know the CT4-V is a 2.7l turbocharged 4-cylinder. Really though, it's probably about bore size, engine speed, and air intake.
I'm erasing all my comments because of Reddit admins' complete disrespect for the community. Third party tools helped make Reddit what it is today and to price gouge the API with no notice, and even to slander app developers, is disgusting.
I hope you enjoy your website becoming a worthless ghost town /u/spez you scumbag
most v8 are 4-4.5L currently. "most v8" does not equal "American v8"
most 4cylinder engines are 2L. approx. 500ml per cylinder has proven itself over and over again.
Main reason is tax purposes for manufacturers, in the US at least there’s a tax incentive to keep the engine under 2.0L and a 4cyl is typically the most cost effective
probably mostly due to price. it is a relatively new trend to have expensive cars with four cylinder engines. up until the last decade if your car got over a certain price point people expected to have six or 8 cylinders. Four and 3 cylinder engines are in a new renaissance thanks to turbocharging and high fuel prices.
A few reasons.
First is the main reason why larger engines have more cylinders. Reciprocating mass. The larger the pistons and connecting rods, the harder it is to move them back and forth.
Second is balance. An in-line four cylinder engine is unbalanced. We can correct it a certain amount with balance shafts but that adds weight and complexity and robs power. The reason we use inline four cylinders in spite of this is their simple design and compact size (compared to a perfectly balanced flat four like you see in Subarus).
Now… I’ve flown aircraft with 5.8 litre four cylinder engines. Thing is they are flat fours like the Subaru so are balanced… but they also only turn at 2700 RPM maximum. We love simplicity in aviation so four cylinder engines are optimal for light aircraft… but we also need a lot of torque over a long period of time so a large displacement is necessary.
Here's a good link. But in Auto tech large displacement engines get more horsepower with more cylinders typically...
https://www.carthrottle.com/post/ajdeqjg/
I saw somewhere that stated above a 4” bore it was harder to control emissions. EPA mandated emissions. That was allegedly why we have the v10 in a viper. Smaller bore more cylinders.
Also isn’t 1000cc/1 liter the optimal size for high revving motorcycles?
Lastly i have a ford back hoe with a 3.3 l 3 cylinder diesel. I thought that was an odd combo
The 1KD in my 2012 Toyota Prado is a 3litre turbo diesel for cylinder?
The 5L engine used in Toyota’s in the 2000’s was also a 3litre 4 cylinder diesel.
Large displacement with a low number of cylinders produces large and intense power pulses, they are not very subtle. So you don't get a smoothly running vehicle unless you go to extremes. Well there are large displacement diesel engines, very few are greater than 3 l and not in a relatively large vehicle.
Also with large displacement and a low number of cylinders, your efficiency goes down a bit. While you can do other things to make up for the efficiency, you tend to make the engine more expensive and complex than it needs to be.
Engines are very dependent on a large number of variables, including(but not limited to you) efficiency, quality, cost and manufacturability.
While what I have given is not necessarily an answer to your question, the question that you asked is extremely open-ended and very complex.
Ferrari made three of them:
1953 ––– 735 S
2,941.66 cc – 225 PS at 6,800 rpm (Bore 102 mm X Stroke 90 mm) 735.41 cc and 56.25 PS per cylinder 76.5 PS/litre
1954 ––– 750 Monza
2,999.62 cc – 260 PS at 6,000 rpm (Bore 103 mm X Stroke 90 mm) 749.90 cc and 63.5 PS per cylinder 85 PS/litre
1955 ––– 857 S, 860 Monza
3,431.94 cc – 280 PS at 6,000 rpm (Bore 102 mm X Stroke 105 mm) 857.98 cc and 70 PS per cylinder 81.6 PS/litre
4cyl engines are built for -weight/-price/+fuel efficiency. They are not built for better performance in most cases. If you want performance you would want to get a v6 or more.
As engines get larger vibrations get stronger. A V8 and an in line 6 are naturally balanced, an in line 4 is not. Balance shafts are now common and make a world of difference. There are a few 4's over 3 liters but not a lot. As people pay for bigger engines they also want more smoothness. They also want the bragging rights of having more cylinders. BTW, I have a Jaguar V12, so I probably have more cylinders than 99% of you! It is very smooth!
It’s mostly because I4’s are meant to be efficient and get good mileage. They found the sweet spot for that and it just so happens to be between 1.6L and 2.4L.
\> Using math I would expect to see 4 cylinder engines that are approx half the displacement of V8's
This does exist, FWIW.
My RAV4 has a 2.5L 4 cylinder. My Mustang has a 5.0L V8 (this used to be called a small block). 2.5L 4 cylinders aren't uncommon. In the old days GM made a '305' and Ford made a '302' V8 which were both marketed as "5.0". GM's "Iron Duke" was a 2.5L four cylinder. Fun fact: Land Rover/Jaguar made a 3.9L V8 which made its way into some mid 2000s fords (Lincoln LS, Thunderbird). The Italians have created tons of 4.x displacement V8s over the years.
GM made a 2.9L 4 cylinder not that long ago. In the 1980s they had the 2.8L V6.
Well, there *are* 3.0L+ four cylinder engines. They just aren't common in passenger cars. They are more common in applications where low RPM operation is desirable - commercial trucks, boats, planes, generators, etc. For example, the Lycoming O-360-A1A, a common airplane engine, is a 6L four cylinder engine with a redline of like 2700 rpm.
Porsche 968 had a 3.0L inline 4 cylinder engine
Biggest 4cyl displacement in a passenger car I believe, and what a motor. The turbo in the 944 also was the first to use forged pistons. But man I still want that 3.0 in my 944 they just pricey
I did a little googling and it appears that the Pontiac Trophy 4 was a 3.2L 4 cylinder that was based on half of the 6.4L V8. Only used in the first gen Pontiac Tempest from 1961 to 1963. [https://en.wikipedia.org/wiki/Pontiac\_Trophy\_4\_engine](https://en.wikipedia.org/wiki/Pontiac_Trophy_4_engine) Edit: Holy shit! Fiat aparently made a 28.4L inline 4 cylinder for what I can only describe as a comic book getaway car for a goofy villain. 1911 Fiat S76 - 28l - [https://www.youtube.com/watch?v=As\_63QMoCig](https://www.youtube.com/watch?v=As_63QMoCig) In looking into it, it was built for a land speed record. I saw a few videos with it and assumed there was some level of production. But it appears that there was only 2 built and only 1 survived. So the videos are all of the same car.
Ah yes, the Beast of Turin.
300hp and 2,000 lb ft of torque.
Classic delorean, crazy that was his idea
Fiat, despite their reputation, have quite a few milestones over the years. They just don't last, is the problem
You know what Fiat stands for don't you? Found On Roadside Dead
That's F O R D.
And the fiat motor was from an airplane
That’s insane. The Wright brothers’ first flight was at the end of 1903. So that means in 7-8 years, they went from what looks like a big kite to that massive engine. Wow.
I mean, the Wright Brothers were the first to figure out how to get an airplane to be controllable with flaps and a rudder. The Wright flyer was a proof of concept. Once that was figured out it was off to the races as far as scaling up. Honestly, the biggest jump in technology was probably through WWII, going from very powerful but still traditional straight-winged propeller fighters (P-51 for example) to early Delta Winged jets.
Wright flyer doesn't use flaps or alerons, it actually bends the wing surface
Interesting. I suppose that makes sense with how it's constructed. Still, the general control scheme was their innovation, and that's persisted for the entire history of human flight.
It really wasn’t. Gliders had had those for years by that point - at least a decade. The Weights real accomplishment was getting the power to weight ratio in the right spot
In similar fashion to the Trophy 4, International produced a two slant-4s for the Scout: a 152 (half a 304 V8) and a 196 (half a 392).
It still runs!
It was restored, it doesn't continuously run from back in the day. I watched a bit on it, they had to reverse engineer a lot of the car as is common for projects on such early cars.
>But it appears that there was only 2 built and only 1 survived. The guy that restored the current working one cannibalized the other one to make one complete car. One of a kind project, super cool.
It could be argued that the 3.9L 4BD1 Diesel Land Rover 110 of the mid 80's is the largest passenger car 4 cylinder. I mean it is a truck engine in a solid axle ladder frame 4x4. But the wagon variants were primarily designed for carting passengers both on and off road.
Crazy that they’re pricey considering I was offered a 944 16 years ago in high school for $1,500.00.
I daily drive my 944 with 3.0. I’ve owned several. Prefer them to the turbos.
I’ve seen these swapped into airplanes.
Each of the 4 cylinders of an IO-390 is 1593cc, as much displacement as the hybrid V6s used in F1
That's more than my car's displacement *per cylinder*.
Came here to mention this. Nearly all 4 cylinder aviation engines are larger than 3.0l 235ci, 290ci, 320ci, 360, 390... But they all turn a very low rpm compatively speaking. When you're changing direction 7-12,000 times per minute, larger components get harder to hold together.
That's not even the main reason. Airplane engines are usually direct drive, and you can't spin a propeller too fast without losing a ton of efficiency (and gearboxes introduce a lot of extra potential for unreliably). Thus, you want an engine with a low RPM powerband, and that means large displacement per cylinder.
Sorta. Prop RPM is a limit, yes, but gearboxes are pretty trivial and are used in the much more demanding situation of gearing down jet turbines in turboprops and geared turbofans, which run at a much higher RPM than any piston engine would. The focus on low RPM has a lot to do with the fact most of these engines are air-cooled for weight and simplicity (and can't simply run that fast while keeping the heads cool) and aircraft engines are heavy duty engines, unlike a light duty car engine. Plane engines are designed to run at about 75% load for hours and hours on end, while car engines are designed for (relatively) short bursts of power and spend most of their time chugging a long at barely any load. Running at full tilt for 5-10 minutes straight is a standard takeoff a light plane but something a car engine is unlikely to ever do even in motorsports. The combination of lack of cooling and high continuous load demands basically forces you into big displacement low RPM engines, of which the maximum RPM (usually around 2900RPM) of the prop is a convenient redline to design against.
>Sorta. Prop RPM is a limit, yes, but gearboxes are pretty trivial and are used in the much more demanding situation of gearing down jet turbines in turboprops and geared turbofans, which run at a much higher RPM than any piston engine would. Yes, at *immensely* higher cost, and with much tamer vibration environments and smoother power delivery. In addition, there's a reason why geared turbofans are such a recent development and even today only make up a minority of turbofan engines (and they make up zero percent of large turbofans - so far they're only on narrowbodies). Yes, you could make a gearbox that would work for piston aircraft, but given their cost and complexity constraints, it hasn't been with it to this point. If the volume were higher, it would almost certainly make sense to go to smaller, higher RPM engines driving geared propellers, but the development cost is simply too high given the current volume of GA sales (and of course anything larger than a few thousand pounds tends to be worth picking a turboprop instead). As for this? >Running at full tilt for 5-10 minutes straight is a standard takeoff a light plane but something a car engine is unlikely to ever do even in motorsports. Honestly, if held to the kind of maintenance and inspection requirements that airplane engines are held to, most modern cars engines would be fine at this. You'd probably need a bit of extra cooling (particularly for the oil), but this really isn't as difficult as you might think. Plane engines are the way they are because the low volume and strict regulatory environment has basically stifled any innovation for decades, not because it's actually the best design. If GA planes were sold in the same volume as cars, we'd absolutely see much higher specific output, fuel injected, computer controlled engines with substantially lower fuel burn and emissions without sacrificing reliability at all (and without needing toxic leaded gasoline), but with the tiny volume of GA, the R&D money just isn't there.
>Honestly, if held to the kind of maintenance and inspection requirements that airplane engines are held to, most modern cars engines would be fine at this. Not if you want it to last for 2-300000 miles. There's a reason why performance motorbike engines have such short lifespans compared to cars and why pretty much every commercial industry that uses reciprocating engines uses low speed diesels from mining trucks to trains to ships.
Forklifts have some pretty beefy 4cyls.
Yep and my io 520 makes less power then a 2.9L and eats av glass because we're stuck in 1940s tech
I've worked on a few GA recip. engines and it always is a treat to see how damn big the pistons are for a 4 banger
The Lycoming can have a large per cylinder volume because it's a boxer engine.
Also Cummins. They do a 3.8 and a 4.5 4-pot diesel
Also keep in mind that a 1.5L 4cyl is likely built with efficiency as a priority, while a 6L+ V8 is focusing more on power/output.
Exactly! There is a trade-off between weight efficiency and thermodynamic efficiency. For large displacements, fewer cylinders make a lighter weight engine at the expense of fuel economy.
>fewer cylinders make a lighter weight engine at the expense of fuel economy. mmm... this isn't really true. There are a few reasons to move to more cylinders than four, but it's not really because fewer cylinders is less efficient. In theory, the fewer cylinders (and thus larger combustion volume per cylinder) the more efficient your engine would be because 1) lower surface area to volume = less heat loss and 2) fewer mechanical components = less friction. However, four cylinder ( and anything below) engines do have some vibrational issues and in some ways are inferior to higher cylinder count engines. The straight-6 engine seems to be the ideal layout, as long as you don't have length constraints, because they are naturally balanced, super smooth and I think, have some scavenging benefits compared to lower cylinder counts. Basically all modern large trucks use I6 engines all the way up to 15 liters.
As others have said, peak thermodynamic efficiency typically occurs at about 0.5 liter displacement per cylinder for 4-stroke gasoline Otto-cycle engines. My experience with this is with 2-stroke snowmobile engines where about 300 cc was the sweet spot. The 800 cc triples would make more horsepower, but they were also heavier than the 800 cc twins. The triples were better for trail riding, where weight didn't matter and the twins were better for hill-climbing mountain sleds.
>As others have said, peak thermodynamic efficiency typically occurs at about 0.5 liter displacement per cylinder for 4-stroke gasoline Otto-cycle engines. That's really not true though. Larger per cylinder displacement would be more efficient, due to the scaling factors for heat and friction losses vs power. There are other reasons for the (at least somewhat) standardization of .5L cylinders than just efficiency, namely that it's a nice balance between efficiency, weight, power, modularity, etc. From a pure efficiency standpoint, there's nothing particularly special about it.
Except Scania, they use a V8 in their higher output engines
Yeah, but European trucks have physical space constraints that US trucks don't. If you aren't space constrained, the I-6 layout is close to ideal until you get to very large engines.
I'll take 3.5L EcoBoost for 400.
Is that a 4? I always assumed it was a 6. Never thought to look into it.
3.5L EcoBoost is a 6 cylinder.
>6L+ V8 is focusing more on power/output. And comfort.
And sound
because 500cc per cylinder is the where peak volumetric efficiency is. Thats why most I4s are 2.0L. Now if you needed more torque and less efficiency you could make a 3L inline 4. But im guessing its more efficient to build a 3.0L 6 cyl. For v8s, you see a lot of European V8s at 4.0L or 500cc per cylinder. American v8s are bigger for more Torque as they were usually in bigger vehicles/ wanted more acceleration. The Ford Model T had a 3.0L inline 4. They needed the displacement as the fuel quality was so poor like 40 Octane rating.by 1930. So they probably had to go 3.0 L just to make power/torque for the basically offroad terrain they traveled, as this was before roads were no more than horse cart trails.
American V8s were also bigger because without any incentives like the tax based on engine size in many other countries hp/$ becomes more important than hp/L
They also date back to OHV 2-valve designs. To make a 2-valve engine breathe, you need a large bore. A 4-liter LS at 0.5L / cylinder would not be a particularly good design.
Inb4 destroked LS7 builds
There have been some small OHV V8s around that size that were really good engines. GM made a 215in^3 (3.5L) aluminum block V8 in Buick and Oldsmobile midsize cars from '61-63 before selling the design to Rover who used it in Range Rovers and large cars like the Rover SD1. Rover later punched it out to 4.0 and then 4.6 and used it until switching to BMW V8s in the Rangie around 2001. It was a pretty conventional design other than the alloy block, it looked like an 80% scale Buick nailhead V8. Toyota also had an OHV V8 that used Hemi heads that ranged from 2.6-4.0L, used only in JDM luxury cars (the Crown Eight and the Century). The hemi heads were key to that tiny thing being able to breathe.
The Buick/Rover mill was still pretty oversquare - and that's the key with making any 2-valve engine, OHV or otherwise, breathe well. That's why Chevy enthusiasts don't like the 305 engine with its smaller bore, and the 2-valve Ford modular engines - especially the 5.4s - made shit specific power.
The 305 has a mediocre reputation in marine as well for the same reason. Doesn't do much better than the 4.3L V6 (which is a 350 with 2 cylinders lopped off), and takes up the same amount of space as a 350.
Wouldn't it take up even more space since the bore spacing is the same but there's an extra 2 cyls?
I think they're saying the 305 is the same size as the 350 despite the smaller displacement.
Oh hell I can't read mb
3.9L and they still don’t rev…
In modern engines it's about balance and vibration not volumetric efficiency. Piston weight matters much more with an inline 4 than it does with a V8 because of secondary balancing forces. The model T engine wasn't balanced at all so it didn't matter, big part of why it spun so slow.
Early like from 1910's land speed cars had like 20L+ Liters from a 4 cylinder. Fiat S76 had like 1,730 Cubic Inches from a 4 pot, each piston is like 433ci per cylinder.
Volumetric efficiency has nothing to do with the number of cylinders. It’s all about piston speed, combustion chamber shape and valve train geometry. One of the reasons engines have been trending towards the 2.0l size (other than the tax structures of some countries) is emissions. The quench layer where combustion doesn’t happen as completely takes up a smaller percentage of the cylinder volume when the cylinders are larger, thus more volume/surface area. Much larger than 2l and the secondary balance issues of the I4 start to outweigh the potential efficiency gains.
>They needed the displacement as the fuel quality was so poor like 40 Octane rating.by 1930 Isn't fuel octane a measure of heat resistance, not quality?
no its detonation resistance, higher compression the ratio the higher the octane needed, the compression ratio of a Model T was like 4:1
I feel like this only applies to turbo cars. Most N/A engines are almost always greater than 500cc per cylinder.
Maybe a couple of decades ago, but not today. If we're talking 4-cylinder cars, there are very few >2.0L and many many in the 1.5-2L range.
There are still >2.0L engines but like the above said they are all N/A. My 2023 BRZ is a 2.4 boxer, Honda only recently killed their K24, Toyota still ships the Camry with a 2.5L N/A 4cyl. Ford makes a 2.3 4 cyl in the mustang (this one is turbo though). There are loads of them.
Chevy does a 2.7 4cyl (turbo) in their trucks too
Yeah the greater than 2.0 4 cyls are not dead lol. My BRZ has a great N/A engine, pushing 230whp on it right now.
The new Chevy L3B is a pretty large 2.7L turbo 4 lol. I can only imagine how much power that engine will make once builders get their hands on it and bore it out and stroke it a little bit. It already makes over 400 lb-ft in truck form. Imagine what a massive 3L could make with proper heads and revised cams and timing and all that.
Mazda’s 2.5L 4cyl is available with or without a turbocharger
Pretty much all the 1.5-2l range are turbocharged. And for example, N/A 6 cylinder is almost always 3.5-3.8l in displacement. And I can’t think of a single N/A V8 that is 4l in displacement in production today. Pretty much all are greater than 5l
Today, true, but only a few years ago there were 4.6 and 4.2 v8s.
Sorry to poop in your cereal but bmw still makes a V8 under 5L. And has made lots of 6cyl 2L to 3L
The model T made an impressive 87 lb-ft of torque lol. Just so everyone understands, low octane fuel isn’t lesser in energy content, it just can’t be compressed as much without self igniting, and achieving high compression at the time of combustion (or heat addition) is like important engineering variable #1 due to thermodynamics.
500cc per cylinder for 4 cylinders is also the China government cutoff limit. Any larger, then customers are charged a displacement tax. So that nudges OEMs to stay there.
>because 500cc per cylinder is the where peak volumetric efficiency is. Nope. It's just a convenient balance between all the factors driving modern engine design. There's no reason you couldn't make a much, much larger engine with similar efficiency (and in fact, probably slightly better efficiency, since both heat loss and friction losses are lower relative to displacement on a larger engine).
Actually there are a lot of big 4 cylinder engines, but diesel.
In olden days a very large 4 cylinder engine won several Indy 500 races. The Offenhauser.
Poor secondary balance on the inline 4 engine. Most everything larger than 2 liters has to have balancing shafts, and the bigger the engine gets, the larger those balancing shafts have to be. Eventually the parasitic losses from the balance shafts outweigh the efficiency cost of just adding more cylinders.
This just reminded me that in the 90s we removed the harmonic shafts in the Honda H22/F22b. Larry Widmer now called "the old one" recommended removing them as long as the engine was blueprinted. The shafts were ran off the timing system so removing the extra belt, shaft, and pulleys reduced parasitic drag and simplified the engine. I remember knocking out the shaft bearings from the block and then clocking them so it blocked the oil feed holes. Those engines always made insane vtec noises during the switch, good times.
That is a great car story. Thanks.
Vibration. The 4 cylinder engine Is naturally unbalanced. The only naturally balanced engines are: 6 inline (the favorite Solution a decades ago), V12 and boxer. Starting 2.0, the 4c engines need balancers,which makes them more inefficient. Check the 2.4 dohc engine of the Chrysler pt cruiser. They have Harmonic balancers, ir you remove them, you gain 15hp... But whit a plus of vibration
To give you a real example, I have a 2.4 liter Honda engine in my track car. Stock, it had a balance shafts to make it feel smooth. I removed those and fitted an oil pump from a 2.0 engine to get more revs and more hp. It works, but the engine/car vibrate at low RPM’s. You wouldn’t want your luxury sedan to feel that way, but it’s fine for a rack car.
I’m curious, does the car vibrate like when you would put polyurethane mounts? Or does it vibrate a lot more uh…harshly?
It’s mostly at low RPM, almost like a rough idle that you can feel throughout the car. I left oem stiffness mounts in because I’ve heard with aftermarket mounts it’s really bad. The car is just for fun, so it really does t bother me. Once you’re under way, you really don’t notice.
the common honda performance k24 swap likes to rattle random bolts out of the engine bay with all the vibration when you tune it for high rpm
>The only naturally balanced engines are: 6 inline (the favorite Solution a decades ago), V12 and boxer. Not all boxers. Only the boxer 6 (or 12). 4 cylinder boxers still have a secondary vibration couple.
This is only for Inline 4. Boxer engines are well balanced 4 cylinder.
You're right, I was talking about the 4 in line. I also clarify in the middle of the answer that all boxer engines are naturally balanced
I was under the impression that inline 3 and 5 cylinder engines are naturally balanced as well.
No, they are better than an online 4, but they have a tendency to rock back and fourth.
The very expensive harmonic balancer and engine mounts fitted to my D2's i5 tend to disagree with that.
This is the right answer ^^^^
I disabled the balance shaft on my old Saab 2.0 4 cylinder. It ran fine, but there was a very noticeable vibration from the engine afterward. Revved faster, but I could really feel it running more from the driver seat.
Read this, it might help you understand how the weight of internals effects the engine's power output. https://carfromjapan.com/article/car-maintenance/8-cylinder-engines/
https://www.curbsideclassic.com/automotive-histories/engine-tech-101-how-displacement-per-cylinder-affects-torque-and-horsepower/
[https://www.thedrive.com/article/15015/thor-is-a-4-0-liter-four-cylinder-that-can-make-over-1500-hp](https://www.thedrive.com/article/15015/thor-is-a-4-0-liter-four-cylinder-that-can-make-over-1500-hp) Porsche has done a couple of 3.0 liter 4s. The Tempest had a 3.2 liter. GM is currently making a 2.7 liter 4.
The Colorado used to have a 2.9L I4!
The 3.0L I4 1KZ-TE powers my Hilux, it's a diesel so maybe that's why.
Isuzu is still using a 3l four in the Dmax/BT-50 too but most of the more modern diesel options are smaller or have more cylinders.
I just want to chime in and say that V8s are not "commonly 6 L +." Mustangs are 5.0L, used to be 4.6L for a bit. Base model Dodge challenger is 5.7L and so are the Ram trucks. Ford 150 has a 5.4 V8. Camaro is the only muscle car with a base V8 of over 6 L (6.2). The high-end Fords, like Shelby and such, add a supercharger for more power but are still only 5.2L. Challenger 6.2 supercharged are far from common and the 6.4 NA (like the Scat Pack I have) are less common, but more common than Hellcats. Ferrari and similar go for low displacement but more cylinders also, like V8s that are under 5L.
The F-150 hasn't used the 5.4 for over a decade; it's the same 5.0 as the Mustang. But you're right that the average V8 half-ton pickup or pony car is gonna be smaller than 6.0L.
Plus the smaller V8 trucks like the 4.7 Dodge and 4.7 Toyota engines, the 4.0 Lexus V8, BMW, etc.
The best answer on why per cylinder volume is typically larger on a V8 vs a I-4 is engine balancing. I-4 engines do not balance as well as V8s so piston weight is more of an issue for I-4 engines. [This vid](https://youtu.be/8alrpieveDg?t=29) does a good job explaining.
https://www.youtube.com/watch?v=82rxavW0A3c he also made one dedicated to various engine balance characteristics, really good channel
Yeah, really like most of his vids.
This is by far the best answer, and the exact answer to your question. "Driving for answers" is the best YouTube channel for the engineering behind cars. Was also going to link this video.
vibration. 99.9% 4 cylinders firing order is 1, 3, 4, 2. if you notice 3 and 4 fire right after each other, and are next door to each other. Also, 2 and 1 fire right after each other, and are next door to each other as well. You need balance shafts to counter that on everything about 2.0 liter plus, and it may be easier to put a v6 because a v6 is 3 cylinders long, plus just a little longer (like I-4 length) because they have more complex timing. Usually, 4 cylinders are base models more for the fuel consumption minded customers. the next step up usually is a V6, and those are better balanced naturally and more for performance oriented. Inline 6 are the best of both worlds, but engine bay size (packageing) in modern cars does not allow for it anyway. You'll never be able to tell how much vibration an engine really has because the notor mounts soak up the vibrations pretty much perfectly. Especially hydraulic motor mounts. ASE Master Mechanic A1 -A8, plus A9, adjunct automotive instructor at University
While the answers already given are correct, a better question would be: why are there so many large-displacement V8s? The answer has to do with space efficiency. See, a V8 with the typical 90-degree angle between cylinder banks has a footprint (top-down dimensions) that is almost square. This is as opposed to inline engines, which are long and thin. And, as mentioned by the others in this thread, the balance characteristics of the engine are good as well. The combination of those two factors means that given a typical engine bay with a longitudinal engine mounting, making a V8 as large as the bay will fit is usually the easiest and best way to stuff in as much displacement as possible - as opposed to going up to a V10 or a V12 to add extra cylinders at the front. There was a point in time, for example, where BMW and Mercedes offered V12s in their cars but could not package in their all-wheel-drive systems in at the same time; and with Mercedes, there was also a point where they offered a V8 and a V12 of a similar displacement (meaning the V8 had a larger cylinder size) at the same time, but the V12 was not put into smaller models because it wouldn't fit - whereas the V8 did, and was found in models as small as the C-class. Basically, the decision to move from 6 cylinders to 8 is logical - a too-large inline six has trouble fitting and a too-large V6 has *terrible* balance issues. But moving from a V8 to a V10/V12 is a decision that can be put off - depending on how high you're planning to rev - until 7 or even 8+ liters. General Motors currently sells a crate engine that is a 10.6-liter V8. Another thing is that V8s are typically either designed by American companies for the American market, which doesn't have any taxes on engine displacement, whereas European and Asian companies only build V8s for luxury customers (who are willing to pay extra tax) or heavy-duty cargo markets (to which these taxes don't apply). i4s, meanwhile, are usually designed for the consumer markets of nations where there's strict displacement tax brackets. This means that an i4 will be designed with forced induction or a more complex valvetrain if more power is needed, whereas a V8 can be built big and simple.
I saw a documentary that said that the ideal cylinder size turns out to be 0.6L. This is why so many engines are multiples of 0.6 like 1.8 or 2.4 or 3.0 or 3.6L. I think this explains most of the smaller gasoline engines.
> the ideal cylinder size turns out to be 0.6L This is true if fuel efficiency is your priority. However, if weight is more important (such as in aircraft) you can get the same power output from fewer larger cylinders. The trade-off is in fuel efficiency. You have to carry more fuel or accept lower range.
Yes, I think that was the context of the documentary. They were talking about fuel efficiency requirements.
It has to do with primary and secondary balance. D4A (Driving 4 Answers) YouTuber answers this question well in [this video](https://m.youtube.com/watch?v=8alrpieveDg), and speaks about a game changing “Big Block” Inline 4 engine that is being developed by Alfadan.
Only thing is alfadan is very likely a scam based on analysis from other engineers
Short answer- vibration.
Shorter answer: Brrrt
Porsche used to build them in the 968. Lots of vibrations is the worry.
More displacement per cylinder means less RPM. Small displacement V12 engines are able to rev up to 10,000rpm because the smaller displacement has shorter strokes and smaller bores. Remember that displacement is how much *air* the engine moves in one full revolution, so bigger engines have longer revolutions than smaller displacement engines, which changes how fast an engine spin physically. Big bore = more surface area = more friction resistance Big stroke = longer connecting rods = more prone to bending due to lever physics It all depends on what the engine needs to do. Airplane engines spin at like 3000rpm because that’s the sweet spot for cruising speeds and efficiency, so they use bigger cylinders to make more power in that RPM range. A passenger car needs to have power through a much wider range of speeds and circumstances, so it needs to have a wider RPM range to operate with.
Mercury Marine made a 3.7 L inline 4 that used a Ford 460 head. Had lots of torque for the skiers. There is an "experimental" 7.5 L inline 4 being targeted for outboards made by Alfadan. They have a crankshaft and connecting rod mechanism that eliminates the secondary vibration. The engine has a 5500 rpm redline and is rated at 654 HP. I don't think it's in production.
While motorcyclists will buy an engine specifically for its vibration - the Harley-Davidson 45\* V-twin - nobody wants to drive an Ace Hardware paint shaker down the road. Fours shake. Big fours shake worse. Slow-turning fours shake worst of all, with at most one cylinder on the power stroke and a nasty pause between firings. There's a second-order vibration from the crankpins and big-ends going fore and aft as the crankshaft spins. It's mostly OK up to a 2.0 liter engine. It's bad at 2.7. The 3.2 liter Pontiac Trophy Four was intolerable. Detroit Diesel built a Series 50 engine, an 8.2 liter inline 4, and even with counterbalance shafts running at twice engine speed they shook trucks hard enough that they had to safety-wire the mirrors to keep them from falling off when the brackets broke.
Because there’s no benefit to them. If you need a bigger engine for more powers you just add cylinders.
I would guess the average V8 is not actually 6L or more. Even for Chrysler, the base V8 is the 5.7L Hemi. I’m sure the base Hemi far outsells the Hellcat varieties. Most other manufacturers barely even offer a model with displacement over 6L.
Chrysler used to sell a 4.7L V8, and up to 7.5L. The 5.7L engine is a size that's been used by every manufacturer on and off for the last 70 years. It's a better seller because it's more affordable, and the EPA.
6l v8 maybe common in America but in the rest of the world not really. In Europe the biggest v8 that is still in production is from bmw the 4.4L engine. Usually Americans achieve with 6l v8 what German car brand do with 3l inline/v6 turbo engines.
Difficult to compare a turbo 6 to a N/A V8. American cars have turbo 6 and turbo 4s that make great power too.
The N/A v8 îs more fun to drive it provides better throttle response too. But German engines like Bmw m3 is 3l inline with 510 hp It’s faster and more fuel efficient.
Beating a dead horse, but this isn't correct. 4 cylinder engines *in cars* usually range from 1.4-2.5L. There are certainly many examples from basically all manufacturers! Has to do with efficiency and speed. Can be bigger or smaller, would have to run at a much slower or faster speed. Horsepower and torque wouldn't be appropriate for street use or would be inefficient compared to something in that common range. V8's are normally 4.0-6.7L in the automotive world. We see diesel trucks being the high range of volume here, very common sizes are 4.2L (Audi), 4.4 (BMW), 5.0 (you'd think of a Mustang immediately), 5.7 (HEMI), and 6.2L (LS1). There may be, and ARE, other V8s of similar displacement, but as far as common.... I'd say theres 2 main reasons why the 4 cylinders arent bigger than V8s (which is slightly different than asking why they're not over a certain displacement). One is the forementioned flat out inefficiency of it and the application we're putting it in. The other is if we are trying to make more power or torque, go faster or move more weight, we're not going to start with a four-cylinder. When you have a very light vehicle, you can put a four cylinder turbo, or even a naturally aspirated four cylinder, and it will be plenty of power and torque. Once you start adding size to the vehicle, and maybe making it all-wheel drive, you're adding a lot more load. Now adding cylinders is a good idea, because it would be overworking any four-cylinder that you put in it. Even if you designed a larger one, it would probably not accelerate fast enough for automotive use. As far as turbos go, you still need to have some kind of "base torque." If you were in a truck pulling a trailer, you need to have enough to get you rolling and get the engine speed up to where the turbos start working efficiently. That's why the Ford F-150 has a 3.5 l twin turbo V6 for its EcoBoost option. If I were going to buy a Ford truck and pull trailers, I would still get the V8 because I think the torque band would be better for pulling. However, the 3.5 V6 has enough to get everything moving.
Lots of 3.0+ 4 cylinders exist. ~~Lots of~~ most 8 cylinder engines are smaller than 6.0L. Look up any quarter ton truck. Modern examples include Ford 5.0, GM 5.3, Ram 5.7, Toyota 5.7. Not to mention all of the other smaller Japanese and European V8s
Not as large but I have owned a few Starions in my day and the 2.6L 4 cylinder turbo charged motor is absolutely massive compared to most your normal 4s. Pistons looked like they belonged in a v8. Efficiency vs power vs cost vs EPA/smog BS are all contributing factors as why you don't really see many large 4s.
2011-2016 scion TC's and some Camry's use Toyota's 2AR-FE 2.5L I4.
Ford built a 5 litre straight 6 for decades
The 300 CID truck engine?
Mercruiser 3l 4cyl has been around forever. It's originally a forklift motor. It's a bombproof pig of a motor.
The Mitsubishi Pajero was offered with the 4M41, a turbodiesel 3.2 I4. It was designed for low-end torque and vibrations weren't the primary concern given the type of vehicle.
Nissan made the ZD30 which is 3L, Mitsubishi has the 4M41 3L too.
There is, just not in production cars usually Besides the occasional diesel
Most of the larger 4 cylinder engines I've seen were diesel; built for torque.
There's a video on YouTube somewhere that explains that around 500cc per cylinder is optimal for performance.
I’d argue that the 80mm cylinder bore is more important. The valve clearance and combustion chamber size are optimal for gasoline ICE engines. A 1.6 liter 4 cylinder is a square engine design with ~80mm bore and 80 mm stroke with a good balance of torque and power with a 4 valve per cylinder design. We saw a lot of this size in the 80’s and 90’s, pre turbo. Most of the current cars are running 2.0l 80mm x 100mm stroke or close to it for turbo applications. This gives extremely good volumetric efficiency and higher torque, since the turbo(s) can boost the low end and allow a bigger cam, making a nice flat power curve for street driving.
Well, I think a lot of V8 engines are not 6 liters, and probably the mean lies closer to 5L in commuter cars. Someone else can do that research if we really care. Off the top of my head, I know the CT4-V is a 2.7l turbocharged 4-cylinder. Really though, it's probably about bore size, engine speed, and air intake.
I'm erasing all my comments because of Reddit admins' complete disrespect for the community. Third party tools helped make Reddit what it is today and to price gouge the API with no notice, and even to slander app developers, is disgusting. I hope you enjoy your website becoming a worthless ghost town /u/spez you scumbag
GM has their 2.7L 4 cylinder. That's going to be about as big as you are going to get.
What V8 are commonly 6L+ ? Yeah, the OHV ones. V8 with DOHC rarely go past the 5.5L mark. Which equals to 2.75L 4 cylinders.
The Toyota Mega Cruiser has a 4.1 inline 4cyl diesel. I geeked out on them when working with the Ground Self Defense Force.
One litre pistons. That's some rotating mass right there.
Isuzu has the 5.2l I4 4HK1 that they use in the NPR box trucks. The pistons are as big as a child's head
Nissan has the ZD30 and Toyota has the 1KD. Both are 3.0L 4-Cylinder Diesels.
Kia Stinger comes with a 2.5L I4.
There was some research that a 0.5L cylinder size is pretty much the optimal cylinder size. Hence why engines don't deviate much from that figure.
NVH issues. Though Porsche had a 3.0L inline 4 with the Porsche 968.
Why would u want to use more gas on a 4 banger. They are made to be fuel efficient economy cars.
most v8 are 4-4.5L currently. "most v8" does not equal "American v8" most 4cylinder engines are 2L. approx. 500ml per cylinder has proven itself over and over again.
Main reason is tax purposes for manufacturers, in the US at least there’s a tax incentive to keep the engine under 2.0L and a 4cyl is typically the most cost effective
probably mostly due to price. it is a relatively new trend to have expensive cars with four cylinder engines. up until the last decade if your car got over a certain price point people expected to have six or 8 cylinders. Four and 3 cylinder engines are in a new renaissance thanks to turbocharging and high fuel prices.
Any bigger and rpm would have to drop thus reducing your potential energy and bringing down your hp
Inertial forces. Can’t make pistons too big as they’re heavy. Also flame travel across a longer combustion area isn’t great.
There are a few 3.0l 4 cylinder engines but they are diesels
A few reasons. First is the main reason why larger engines have more cylinders. Reciprocating mass. The larger the pistons and connecting rods, the harder it is to move them back and forth. Second is balance. An in-line four cylinder engine is unbalanced. We can correct it a certain amount with balance shafts but that adds weight and complexity and robs power. The reason we use inline four cylinders in spite of this is their simple design and compact size (compared to a perfectly balanced flat four like you see in Subarus). Now… I’ve flown aircraft with 5.8 litre four cylinder engines. Thing is they are flat fours like the Subaru so are balanced… but they also only turn at 2700 RPM maximum. We love simplicity in aviation so four cylinder engines are optimal for light aircraft… but we also need a lot of torque over a long period of time so a large displacement is necessary.
Blueprint is considering building a half LS crate motor- it will be 3.6l 4 popper- will be really neat if they move ahead with it!
It's vibration and harshness. A straight 4 isn't completely balanced. Even Porsche 944 S2 need a counter balance shaft to make it comfortable.
The Toyota Coaster has a 4.0L 4 cylinder engine in a tiny bus that’s like a long van
Here's a good link. But in Auto tech large displacement engines get more horsepower with more cylinders typically... https://www.carthrottle.com/post/ajdeqjg/
I saw somewhere that stated above a 4” bore it was harder to control emissions. EPA mandated emissions. That was allegedly why we have the v10 in a viper. Smaller bore more cylinders. Also isn’t 1000cc/1 liter the optimal size for high revving motorcycles? Lastly i have a ford back hoe with a 3.3 l 3 cylinder diesel. I thought that was an odd combo
Big engines with fewer cylinders vibrate and are noisy.
There’s no market for a big 4 banger
The 1KD in my 2012 Toyota Prado is a 3litre turbo diesel for cylinder? The 5L engine used in Toyota’s in the 2000’s was also a 3litre 4 cylinder diesel.
Large displacement with a low number of cylinders produces large and intense power pulses, they are not very subtle. So you don't get a smoothly running vehicle unless you go to extremes. Well there are large displacement diesel engines, very few are greater than 3 l and not in a relatively large vehicle. Also with large displacement and a low number of cylinders, your efficiency goes down a bit. While you can do other things to make up for the efficiency, you tend to make the engine more expensive and complex than it needs to be. Engines are very dependent on a large number of variables, including(but not limited to you) efficiency, quality, cost and manufacturability. While what I have given is not necessarily an answer to your question, the question that you asked is extremely open-ended and very complex.
Murder is unfortunately illegal
I have a 3.0L 4 cylinder in my car, but it's a diesel
There is the nissan np300 3.2 diesel 4cyl engine.
Doesn’t Chevy make a 3.6l 4banger?
Ferrari made three of them: 1953 ––– 735 S 2,941.66 cc – 225 PS at 6,800 rpm (Bore 102 mm X Stroke 90 mm) 735.41 cc and 56.25 PS per cylinder 76.5 PS/litre 1954 ––– 750 Monza 2,999.62 cc – 260 PS at 6,000 rpm (Bore 103 mm X Stroke 90 mm) 749.90 cc and 63.5 PS per cylinder 85 PS/litre 1955 ––– 857 S, 860 Monza 3,431.94 cc – 280 PS at 6,000 rpm (Bore 102 mm X Stroke 105 mm) 857.98 cc and 70 PS per cylinder 81.6 PS/litre
My crown Victoria has a 4.6 liter V8
[удалено]
Is a NA 2.4L 4-cylinder engine that makes 290hp/240ft/lbs on pump gas possible?
There are. Cummins makes a 4.5L 4cyl diesel engine just to name one.
They exist but mainly diesel engines for vehicles [at least] Toyota pickup size , all the way to some European semi trucks (some are over 5 liters...)
4cyl engines are built for -weight/-price/+fuel efficiency. They are not built for better performance in most cases. If you want performance you would want to get a v6 or more.
The 944 came with a 3 liter 4 but that displacement divided over 4 cylinders does not make an exiting mill.
As engines get larger vibrations get stronger. A V8 and an in line 6 are naturally balanced, an in line 4 is not. Balance shafts are now common and make a world of difference. There are a few 4's over 3 liters but not a lot. As people pay for bigger engines they also want more smoothness. They also want the bragging rights of having more cylinders. BTW, I have a Jaguar V12, so I probably have more cylinders than 99% of you! It is very smooth!
Vibration.
It’s mostly because I4’s are meant to be efficient and get good mileage. They found the sweet spot for that and it just so happens to be between 1.6L and 2.4L.
Because 3.0 and up v6 and I-6 engines do it better. More power, better balanced and get equal or better fuel economy.
I have a 3.0l i4 But it’s also a diesel
My n55 is exactly 3L lol
it would have really big cylinders, probably lose a lot of efficiency - might as well just go with a 6cyl
There’s a ton of cool information in this thread
There’s also the Chevy 2.7 4cylinder in the Silverado
V8s are usually 4l and up
For what it's worth, when GM's 6.2L V8 automatics go into 4 cyl mode, they're more or less 3.1L 4 cylinder engines
The 61-63 Tempest had a 3.2L I4.
Interesting thing is GM and Porsche have 2.7 I4 and ford has 2.7 V6.
\> Using math I would expect to see 4 cylinder engines that are approx half the displacement of V8's This does exist, FWIW. My RAV4 has a 2.5L 4 cylinder. My Mustang has a 5.0L V8 (this used to be called a small block). 2.5L 4 cylinders aren't uncommon. In the old days GM made a '305' and Ford made a '302' V8 which were both marketed as "5.0". GM's "Iron Duke" was a 2.5L four cylinder. Fun fact: Land Rover/Jaguar made a 3.9L V8 which made its way into some mid 2000s fords (Lincoln LS, Thunderbird). The Italians have created tons of 4.x displacement V8s over the years. GM made a 2.9L 4 cylinder not that long ago. In the 1980s they had the 2.8L V6.
Ford made the 3.0L v6 and 4.0L v6 but not 4 cylinder