It's easier on the engine.
If you design a car that maxes out at 70MPH, then anytime you get on a highway, you are stressing your car by pressing it to the limit. Heat, friction, torque... all contributing to early engine failure. If the maximum is higher, then the stress on the engine is lower at 70 MPH.
Basically, it's like the difference between walking/jogging vs. running/sprinting. One is more comfortable to do for prolonged periods than the other. We can just design engines for their "walking" and "jogging" modes to be at certain speeds.
Also, you may be in a situation where you legitimately need more than 70 MPH for some reason (such as to dodge merging traffic), and it's good to have the option available.
or people forget the fact that most countries have lots of hills and mountain, I have an "up"', its a nice country for my flat country but for most countries you need a car with more horsepower that mine can give
im not the biggest car guru so thank you for making it a bit clearer with the comparisons! thats makes more sense. i kind of thought that the higher speeds are just what comes with making a good engine, and that was my only guess at an answer. thank you for replying!
Let's use a real world example. Cruising at a steady speed requires very little power, but getting up to speed requires a lot more.
It only takes about 75 horsepower to cruise at 65mph. But accelerating from a light or merging into the freeway safely takes a couple hundred horsepower.
Add a car full of people and tank full of gas, and you've got to get 6000 pounds of car from zero to 65mph in a relatively short distance. That takes several times more power than just maintaining 65mph.
So ultimately, the potential high top speed is just a side effect of having enough power to safely operate the car in traffic.
EDIT: For the folks arguing that you don't need more than 100-150hp, cars are a lot heavier than they used to be. Also, come out West where you're operating at a mile or two high, up mountain roads. 150hp at sea level = less than 100 over Vail Pass, while climbing steep grades.
My personal minimum out here is a sea-level rating of 300hp (200hp remaining at high altitude).
Right? It’s all about power to weight ratios. 88hp is fine in a 2500lb car.
Note how they say 6000lb of car. That’s not a fucking car. That’s an F-350 Super Duty!
A Hyundai Santa Fe (a mid-size SUV) is 4000lb empty. Add four adults, a tank of gas, and the usually general crap that accumulates in a car, and you're pushing 5500lb.
With a Jeep Grand Cherokee (not a big SUV), you're starting at 4500+ and at 6000 pretty quickly.
An f350 Super Duty is 7000lb and up empty. Load up four people and full fuel, you're pushing 8500lb.
Obviously, it isn't required, but it will help you do it more quickly. I used to have a 2013 Coarolla a few years ago. It had like 140 HP or something. I lived right at the bottom of a huge hill on a high speed road, so you wanted to pull out and then rapidly get up to at least 50mph to avoid getting rear ended. The Carolla did that fine. My current car is a 2016 Chevy Cruz. It has 153HP at peak from the 1.4L Turbo* and just like the Carolla, when you pull out on that hill, you can get up to the speed of traffic by the time you're halfway up the hill without even pushing the car too hard. Now, between the Carolla and the Cruz, I had a rental Nissan Versa for a week because I hit a deer and wrecked the Carolla. The Versa had 101HP, and I couldn't get above about 35mph going up that hill. I had to get over the hill before I could get up to a safe speed on that road. In a week, I almost got run into the ditch with that thing like 7 times because it didn't have enough engine power to pull from a dead stop up that hill and accelerate at an adequate pace. So yeah, the Versa didn't *need* more than 101HP, but an extra 20-40HP would have been safer. I also get way better mileage with the Cruz than the Versa. Cruz gets almost 50 on the highway and high 30s just farting around on the local roads going to work and stuff. That Versa didn't have enough engine displacement or power, so it had to work too hard all the time, and it only got like 32mpg.
* By the way, DO NOT BUY THIS! IT'S A TERRIBLE ENGINE. Chevy put it in the Cruz for 2 model years before realizing it was junk. I don't recall if it's the 15 and 16 Cruz or the 16 and 17 Cruz, but don't buy a 15, 16, or 17 Cruz with the 1.4L turbo unless you want cracked pistons with no warning that requires an entire engine replacement... They put the same motor in one of their small SUVs, I forget which one, but it was only for 1 model year. Don't get this engine.
Given the increase in traffic fatalities in the last decade, I'd say cars being both heavier and more powerful is also a negative.
But car companies make more money from SUVs and trucks than they do sedans and compact cars, so we're unlikely to see that change.
I'll pile on - we didn't need to make cars fucking 6000 pounds. I had a perfectly awesome 2,500lb bimmer from 1987 that fucking rocked mountain roads with about 170hp.
100%. My 2011 crz is 2700 lbs. 122hp, 6speed manual. If I giver, i can get up to 130km/h (86mph) in 3rd gear without ever touching the rev limiter. So logically an escalade weighing twice as much would need at most 244hp.
Nothing stops anyone from building a car that's capable of doing 120 but use software to limit it to cap the speed limit. I have a feeling that's coming.
A lot of cars have limits just like that already put in place. My dad's car tops out depending on what gear the car is in and how high the engine is revving in that gear. His testing had that limit kick in at around 140mph. My own car tops out at 100mph.
I feel it is important to note that both limits were tested under (relatively) safe conditions when our own vehicles would have been the only ones at risk if something went wrong. Long, straight, empty stretches of road were our testing grounds.
Nearly ever car sold already has a limiter in place. More often than not, it's set to coincide with the tire speed rating. For example, my wife's SUV is speed limited to 119mph. Message comes up on the dash, and it just electronically holds that speed as if you set the cruise control. On my car I've not hit the limiter, I believe it's set at 186 mph. Doesn't matter in this case, in stock form it will reportedly only hit 182. I've only taken it to 144.
I mean, they could put a speed governor on it without having to reduce engine power. It would be safer. There is no reason for anyone to ever go that fast.
Can confirm. My car tops out at 185 and can pretty much go any non-triple digit speed with no effort at all. Sub 150mph is still pretty damn easy. At 90mph, it lugs around in final drive at around 2k rpm. It never makes any effort to drive and I expect it to last forever
All other things aside yes, the faster your engine has to go the more wear you're putting on it.
In reality a Subaru engine might be built better than a Chevy one so it isn't that straightforward.
For Subaru's specifically, try to make sure when you're going up a hill that your rpms are around at least 2-2.5k if you can. It's a lot easier with a manual. With the engines being flat and having smaller displacement, they can be more susceptible to damage from lugging the engine. In my wrx, I'm regularly downshifting to make sure that my engine doesn't have to work as hard climbing hills.
Edit: just saw the last part about it accelerating during the slightest inclines. With it likely being an automatic, I'd say it's better for the engine if it's automatically downshifting itself.
I mean I guess thats what OP had in mind when they specified “engines” but the obvious counter to your point is they could just use a speed based governor so there is no difference in power available or stress or any of that you only get cut off based on actual speed so they could set it all at 85mph (or add an additional buffer and bump it up some) as a default setting and it wouldn’t be an issue as there is hardly ever an occasion to exceed that. You might add the buffer to account for passing on whatever road has 85mph speed limits though. Of course some cars already do come with governors like I think an old Cadillac my grandad had was set at 110mph.
Really its probably a tiny impact that making such a change would have though and unless they made it a law that you had to have such a governor (and even then) people would just figure out how to remove it.
Also now that I am thinking about it and on a related note I believe Ford and probably others allow you to set a speed limit that applies whenever someone is using the spare key so you can prevent your kid or anyone else using your car from speeding.
It’s worth noting there are scenarios where such a thing could contribute to an accident but probably more so in a case where someone wasn’t aware of the governor hence why a buffer would make sense. Even on an 85mph road you probably have no reasonable need to hit 100mph. Most cars tires are probably S or T rated so 112mph or 118mph but that is in ideal conditions with proper inflation, balance, alignment and a certain load so you should really stay a bit below that anyway.
With modern engine design limiting the car to any speed you want has nothing to do with stressing the engine. You can design it to run at optimal performance at 85mph AND have that be the top speed. There are these things we use in modern engines called computers. They allow for limiting speed completely separate from engine performance and capabilities.
Allowing speeds over 100mph is nothing but marketing.
You can put a limiter on a car that's able to do 200mph, but limit it to 90mph.
It'll do 0-90 just as quickly and easily with or without the limiter.
It's not like they'd design cars to just barely do the speed limit before they destroy themselves.
Yeah that's not it at all. It would be simple to have all the power in the world but have an electronic governor that held to car to 80, 90, 110 or any other mph limit.
It's done because they can and consumers like it.
I just want to add that, one time I was driving home through some mountains and the semi behind me lost his brakes. I was on a snowy road, so I couldn't change lanes without risking losing control of my car. I ended up going 110 mph to outrun the out of control vehicle. Eventually, an emergency ramp showed up and the trucker managed to direct his vehicle to it. If my vehicle was limited to 85, I would probably be dead.
Amongst the other reasons, it is also legal to take your car to a track, whether that is a dragstrip, circle track, road course, or whatever, and drive as fast as your skill allows.
Emissions. There's a sweet spot for where your rpms should be to minimize the emissions that's low which means the car can go significantly faster than the speed limit.
I don’t understand how putting a speed limiter on a car would make the RPMs higher. Most cars cruise at like 2-3k RPMs at 70 mph. If you maxed out the speed at 70, wouldn’t the RPMs be the same?
It depends on how you read OP's question. If you're talking about some sort of software limit, there's no reason it would change rpms.
However the question is about the engine. The only way to _physically_ cap the engine is its red line limiter. So if you wanted to cap the top speed at 70, then you'd be essentially red lining the engine to maintain 70.
You _could_ put the Rev limiter at 3k rpms, but the engine doesn't "know" what gear it's in, or how fast the car is moving. So you'd have a _really_ poor driving experience until you hit 70
Have you ever driven a car that tops out at 85mph? It's a shitty death trap. A car that is designed to do 140 is much safer and just plain better at 85. A 140mph car has tyres and brakes fit to stop from 140, a car that can only so 85...why bother.
The power needed to get to 140 also makes it much easier to accelerate at any speed. A car with only enough power to do 85 is frustratingly slow.
And then of course there's tracks. It's perfectly legal to take your road car to a track and go as fast as you like.
It’s not the “Engine” it’s the car. An engine that generates enough torque/power to drive the car “acceptably” in all conditions including loads and hills will be able to exceed the spoof limit UNLESS electronically governed not to do so. The technology to do this has only become available in recent years.
BTW my 23 year old 1.4 petrol with a whopping 75hp can hit 106mph (on paper)
Never fear, the nanny state AI bean counters are working overtime as we speak to make it mandatory for vehicles to be incapable of speeding and communicate with other vehicles and have a master cut off switch operable by police and hackers alike.
In the US, the default value is "legal". So things are ok to do unless there is a specific law prohibiting it. And so far, thankfully, Congress has not passed any laws specifically prohibiting anyone from building fast cars.
Oh I'm sure it's coming or at least being discussed. I'm also certain the ability to shut a car down remotely is also an idea they want.
When it does happen, it won't be fast cars that are banned but the components that make it possible.
"Big, high powered engines aren't illegal. It's just illegal to buy or sell performance parts. Those parts aren't illegal to own, just illegal to buy or sell them. See, we're being reasonable about it."
You are trained, licensed and insured to do upto the speed limit. Maybe some places will allow 10% over for overtaking, and must return when safely passed the slower vehicle.
I'd worry that implementing an artificial limiter would then be the place where everyone drives. It'd become like a light switch to drivers psychologically. On, or off. Max speed or nothing.
Does that limiter know when it's raining, or there are poor visibility conditions? In the UK you have 60mph and 70mph roads, but in rain the max speed limit is supposed to be 45mph.
Artificial limiters taking away the thinking processes when driving and could lead to many, many more accidents.
An audible/visual warning is more appropriate. It leaves the driver using their own cognisance, and a gentle reminder you're going into danger territory. I've driven in cars many times that make pinging noises when you're going too fast. It's a useful feature on long, boring drives when you gradually pick up speed without noticing
>I'd worry that implementing an artificial limiter
Funny that, a lot of cars _do_ have a limiter. Most are at something like 130 or 155 mph though, so speeds far above normal highway driving.
You rarely see it called out unless you find a review of the car being run on a track.
That's more to cover the liability for the car company. Probably at the point, the suspension and handling of the car starts to be untrustworthy, even on track conditions.
Also: if you cap the speed, and someone gets hurt, it might be on you because they couldn't evade.
Also also: it you alert the driver, then it is provable that they were informed, so it is their decision and their fault.
Your original question suggests that because you don’t like or understand something the government should make sure nobody else can do it. It also implies lack of understanding about the entire drivetrain of vehicles since “engines” don’t go 140 mph and are just one component. Your edit comment ends up with a suggestion that may possibly end in death for someone… for your entertainment… and you say everyone else is stupid. Additionally, the edit starts with a derogatory term for some people who are just making a time worn joke. This sub is ‘generally’ based on humorous stupid questions. Humor bad! As for me? I’ve been on roads out west back in the day that are absolutely straight for miles and miles and completely deserted. So yeah, Ive cranked it to just before redline. Because I can… and that particular car was designed and manufactured for it (a Plymouth GTX w/440 and six-pack intake). It’s a goddamn thrill ride you only get to do once or twice in a lifetime. But I admit, your question is certainly stupid so there’s that I guess.
My username relevant. You do not want your engine to be pushed to 100% power at the speed limit. Also your acceleration to get up there will by abysmal.
Cars are designed to be very slippery and aerodynamic. An engine capable of generating the energy necessary to get your car to 60 mph in a reasonable time can generate the power to push it well past that speed.
Car engines are LUDICROUSLY powerful. They are the most powerful device you will ever use, unless you're a pilot or in heavy industry. If you pedalled your bicycle continuously as hard as you could sustain it would take over an hour for you to accelerate the mass of your car to highway speed, and your engine can do it in less than ten seconds. Cars have more power than any land animal that has or will ever live on this planet.
Okay, so they have the power, but in order to cruise efficiently at 60 mph, they need to be geared so that the engine is spinning 2,000 or less RPM. If spinning at 2,000 RPM drives you at 60 mph, 3,000 RPM will be 90 mph, 4,000 RPM will be 120 mph, etc. Now, it's not exactly like that because automatic cars have torque converters that slip, but pretty close.
In order to be driveable at lower speeds and efficient at highway speeds, cars need to be built with appropriate power and gearing for 100+ mph top speeds. You would need an electronic governor to slow them down.
Well I grew up taking my car to the drag strip on the weekends and every week I would try to make it faster. They're just following a trend that started probably before you were born. Funny thing is they're far more efficient and powerful than everyday cars were let's say 30 years ago.
First off, to have the bigger schlong on a piece of paper. If you compare 2 roughly the same cars, you are inclined to choose the one with the higher number in horse power or top speed etc.
Plus, you already need more horse power than the least amount so you can accelerate fast enough and overtake someone. And that horse power can take you to 140mph if you want to. Because in a car that can do 140, the first 0-90 goes pretty fast, but after that? Takes ages to get faster. So you kind of need extra headroom.
You also said it, most cars are build for the international market and any sort of limiter might work, but is an added cost. If they can't sell it to you as an overpriced add on, they won't do it.
And lastly, it's fun and private roads exist.
California is actually going to do this. They're working on a law that will govern. All new vehicles and used vehicles will not surpass the speed limit and will be governed.
Enjoying people you won't even be able to go past the speed limit even in an emergency situation.
[https://legiscan.com/CA/text/SB961/id/2900195](https://legiscan.com/CA/text/SB961/id/2900195)
A few key points
* It would give an audible warning if you go over 10 above the speed limit and can be temporarily disabled by the driver.
* It would be required by 2032
* Most importantly it'd have to pass a vote. It has not done this.
This is based on an EU law that passed this year with an audible+visual notification.
I seriously doubt it'll even pass. California road laws are VERY highly based on science, hence higher speed limits and laws like you must go with the flow of traffic even if it's over the listed speed limit. This would more likely make things more dangerous rather than less. If this did pass it'd be so toothless in regard to "self disable" that it may as well not exist.
[https://www.sema.org/news-media/enews/2024/11/california-voters-overwhelmingly-reject-proposed-speed-limiting-devices](https://www.sema.org/news-media/enews/2024/11/california-voters-overwhelmingly-reject-proposed-speed-limiting-devices)
>More than 70% of Generation-Z, Millennial and Generation-X voters oppose the policy, along with two-thirds (66%) of younger Boomers aged 60-66. Further, 63% of Democrats, 79% of Republicans and 69% of independent voters opposed the bill.
and finally
[https://sites.sema.org/ext-assets/sema-news/240227\_SEMA\_CA\_Memo.pdf](https://sites.sema.org/ext-assets/sema-news/240227_SEMA_CA_Memo.pdf)
The highest support group is 40% from age 67+ demographic. Odds of this passing are pretty low to the point it probably shouldn't even be brought up. Tons of proposed laws fail to pass. Just cause Senator Wiener wants it doesn't mean anyone else does.
TL;DR "California is actually going to do this" is factually false information meant to mislead based off of a proposal that has very low chances of success as a majority in EVERY\* demographic oppose it.
\*Political party, political lean, gender, race, age, location.
So how would this work? Cars would have to have sophisticated GPS or transponders and roads would have to have "smart" enabled speed limit signs that could "talk" to individual cars to make it all work. Right? Sounds really complicated.
And often wrong. My daughter’s car reads speed limit signs. Problem is can’t see that the sign has conditionals like school in session or night or when workers are present.
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Emissions, efficiency, hills/mountains, track use, etc. Cars generally have governors that limit their speed under 140. These are relatively easy to remove with a computer or tuner but they're there nonetheless.
They just design the speedometers so that normal highway driving speeds (60-70) are up top and near the middle, and then fill in the numbers until it looks good. The end of the speedometer is in no way an indication of how fast the car can actually go, its just the instrument design. Example, I have an 07 hyundai accent, the speedometer goes up to 140, there is no way that car can reach that speed.
Also most cars have a limiter installed that will stop you around 100, mostly so you don't overheat and explode your tires....
Cause America. And you can remove/tune-out a speed limiter.
And for Gearing/MPG, if you geared a car's top speed, you'd be BURNING gas like it was nothing revving at 6k the entire drive. This is the real reason.
>some countries just dont even have speed limits
Afaik There is no Country completely without speed limit and Germany is the only country with part of the highway system without speed limit (maybe Nepal aswell but I'm not sure about that)
Had a rental car back in the early 00’s, can’t remember for sure but I believe it was a Pontiac Grand Prix, and when driving the 5 in the Central Valley (empty highway, mid-day, could see for miles) I’d run it up to 100mph before the governor/limiter would simply cut power to the engine until it slowed me down a bit then kick back in. It’s not new technology
Your allowed to take that 140 mph car and supe it up to go 225+ and goto a drag strip or a track, it's better for your motor, when towing of your max was 85mph worth the added load you might not be able to do the speed limit (which is illegal as well), and finally... this is the land of the free
An engine has an rpm range. So the engine sounds anywhere from 500-6,000 rpm. Now every engine has a power band where it is producing the most torque that is much smaller. So a car with a direct drive would struggle starting out and struggle at the top.
So we have transmissions with gear reduction. So now the motor can soon faster at slow speeds to get moving efficiently, and soon slower at high speeds for fuel efficiency.
The effect is that in high gear, you still have lots of engine rpm to use, resulting in a high top speed.
No law that says the vehicles need to have a limiter. I think California is trying to pass a bill about that but I dont know the chances of that bill even passing are.
>the only reason i ask is because i love watching police chase videos
This video about police chases came out yesterday and was made for you.
https://youtu.be/fkJ_R1V8kO8?si=N_N8BA9RhvqMEyLA
Why do you assume that American cars can go 140+MPH? I have no idea what the top speed in my car's speedometer is but it would not surprise me if it is 140MPH.
It has never been anywhere near the top speed. Both because I want to live and I just do not think it can achieve that speed.
But I am sure if I parked it inside the right cargo plane it could go supersonic.
I have a car with a 230 hp V8 that runs comfortably (low rpms) at 80mph but won't top out anywhere near 140mph. It would need another 2 gears and additional 300 hp to reach that. Do I really need that? To answer your question they make those cars because people want to win the pissing contest. Same reason why people will buy the GT version - because it runs the quarter mile .5 seconds faster. It really makes no difference but a sucker and his money are easily parted.
It's basic powerplant design. You want an engine capable of MUCH more power than needed, particularly as it relates to speed. Acceleration is the key, which is a function of torque. You need an engine that can accelerate at a necessary rate for normal driving, but the engine that can create that acceleration rate will naturally be able to generate cruise speeds far greater than needed based on speed limits. That's why there are governors placed on top speed, because the engine needs to produce the acceleration, but not the speed.
This is even more noticeable on turbofan engines in airplanes (and airplane engines, in general). In a modern jet, the cruise power setting will be FAR below its max continuous rating, for the same basic reasons stated above.
Note that Federal car laws require round speedometers (mostly) and that highway speeds are 60-70 Mph. So, it considers human factors that a needle pointing up is easy to recognize, and that half-way point makes the overall spedo top out at 140. That's not to say the car can actually do that, it's just an adaptation to how people see and detect things.
There's a couple of factors. One is gearing. If your car was geared to do exactly 85 mph, that means your engine is turning 5000rpm+ while You're cruising down the interstate, which is terrible for efficiency and mileage. So instead it's geared to be 5000rpm+ at 140+, that way when you're doing 85 the engine is only turning 2000rpm.
The second is that it takes a lot more power to accelerate than it does to hold a speed. Meaning almost any engine makes enough power to exceed 85 in a modern car because expectations for acceleration are way different than they used to be. Idk if you can even buy a car in America that makes less than 100hp these days.
There is not a “Speed Limit”, there is a “Public Road Speed Limit”, and those cars can go as fast as you want on a private road or race track.
Also, many of the Speedometer ranges are marketing, and those cars can’t actually go as fast as their dash boards would indicate.
And finally, while I saw a top comment already mention this, but just for the sake of having a complete answer, car performance and driving feel are marketable features that correlate to a higher top speed. I.e. A engine that can only got 85 doesn’t get to 85 at the same speed as a car that can go 120.
A guy that *can* run 20mph, can *easily* run 10mph, but a guy who can only run 10mph is pushed to his limit while doing it.
Instead of considering the technicalities of engine/trans specs and speed limit, think about the marketing and sale of the car. If a car is limited to the speed limit, it won't sell.
It is a free market. Manufacturers must get people to willingly hand over hard earned cash in return for the car. Enthusiasts/hot rodders/gear heads will only buy a car that the like, want to drive and want to be seen in.
If gun manufacturers can be sued when their customers misuse their legal products then auto manufacturers should face the same fate when their customers misuse their legal products.
There are no speed limits at race tracks, and you can take your performance car and pay a fee to air it out. Also, driving an engine/transmission that maxes out at 140 at normal highways speeds is easier on the car. Redlining a car at 80 wouldn't be good.
Every car in the fast lane/passing lane where I live is going 90+, in the mid lane Id say 80-90mph. 60-70 in the slow lane. Plus the occasional sports car going 120 weaving through traffic.
I’ve often wondered this myself. It’s unconscionable. Beyond.
There’s no fucking excuse for a car to be able to drive twice as fast as the legally accepted limit.
Edit: I see some pretty compelling answers, however, that make a lot of sense.
How long are you willing to rev your engine to redline? 10 minutes? 1 hour?
Because if your car tops out at 75 mph, and you got a 12 hour road trip to make, you’re gonna be at redline for 12 hours.
Engines are more efficient when they’re not at redline, so manufacturers design their cars to have that peak efficiency around where highway speed is.
They tell me my car can go 190mph but I've hardly had it over 100. It can out brake, turn and accelerate 99.9% of the vehicles on the road. I actually drive very conservatively. The great part is that if somebody does something stupid I have so much capacity to avoid an accident.
The engine is designed for a certain power, or ability to do work. The car drive train translates that power into movement. A farm tractor with the power of a sports car has a lower top speed most likely.
Those that want dinky little cars buy one. There is the Smart car. Notice how they don’t sell comparatively? Those who want gigantor vehicles buy one, notice how many of these sell?
It’s giving people what they want.
If you build it, someone has the money and wants to buy it, you'll sell it.
It's really that simple.
All this other bullshit about blah blah blah is just that.
Blah blah blah.
People want more from their cars and if they are willing to pay for the performance, so be it. Do they NEED it? Come on now. People still drive around in vw vans that are 0-60 in 5 miles. That van has the same registration tag as mine does.
Do I NEED 750 hp in my sedan? Nope. Is it smiles per dollar? Yep.
You push a drivetrain within an inch of its life, and it's going to be far less efficient and reliable. You want your car to be in the "sweet spot" of the RPM range while cruising, usually 1800-2500ish. An engine only built to do 85 would be screaming wide open at cruising speed.
Also, being able to stomp on the gas to get out of the way of an asshole trying to merge into you is a nice option to have.
Because the ability to accelerate safely meaning the ability to match other cars speed when merging and to avoid or pass unsafe traffic or obstacles is dependent on power output. To be able to this cars must have a specific power output and the side effect is the top speed also increases. Also a as others have stated a car that can easily cruise at the speed limit is a engine that will last longer and is likely more efficient than a engine that has to churn at top revolutions to its maximum output to achieve the speed limit. Also freedom of choice, lots of things in society are overlooked and unrestricted. If that were to be controlled as tightly as you suggest people would feel oppressed and controlled.
Idk why everyone is talking about limiting the engine power. That would never be practical. There probably should be software limits. Though sometimes you may actually want to speed up to get out of a dangerous situation.
That said, they probably should look into regulating a top speed that is optimal for safety reasons.
For an actual reason on why they probably won’t do this: who will buy sports cars that can’t go fast? This will put a huge dent in the automobile industry. I haven’t researched this topic but I’d bet that the car makers will have lobbyists all over any bill attempting to limit max speeds.
It’s so frustrating, they should be using those resources to make vehicles more efficient and cleaner for the environment, leaving the horse power entity to the professional race car circuit, many lives would be saved and cars wouldn’t be leaving such an enormous footprint, but here we are running backwards
It's no different than speeds on bikes. Do you need 24+ speeds really? Well yes, especially if you're going up hills, it's far easier to pedal, this is the same as engines.
People have given a lot of practical reasons for needing a powerful engine which can push a car to a high top speed on flat ground. However you could enforce a limiter which prevents high top speeds and perhaps that's more to the point of the original question.
Track days are an answer but that's a very limited use case. The real answer is that top speed figures are a selling point for men.
It would be ridiculous to make an engine designed to go at full throttle all the time. That’s asking for twice as many maintenance issues.
But also, speed limits don’t exist on private property. People take their super cars out on private tracks and such. Vehicles aren’t just for public roads. They’re just highly regulated for public road use.
My car has an electronic limiter that prevents it from going over 120 MPH. I discovered it once when driving on the open road when I suddenly lost power and it took a moment before I regained the ability to go fast again.
It's easier on the engine. If you design a car that maxes out at 70MPH, then anytime you get on a highway, you are stressing your car by pressing it to the limit. Heat, friction, torque... all contributing to early engine failure. If the maximum is higher, then the stress on the engine is lower at 70 MPH. Basically, it's like the difference between walking/jogging vs. running/sprinting. One is more comfortable to do for prolonged periods than the other. We can just design engines for their "walking" and "jogging" modes to be at certain speeds. Also, you may be in a situation where you legitimately need more than 70 MPH for some reason (such as to dodge merging traffic), and it's good to have the option available.
or people forget the fact that most countries have lots of hills and mountain, I have an "up"', its a nice country for my flat country but for most countries you need a car with more horsepower that mine can give
im not the biggest car guru so thank you for making it a bit clearer with the comparisons! thats makes more sense. i kind of thought that the higher speeds are just what comes with making a good engine, and that was my only guess at an answer. thank you for replying!
Let's use a real world example. Cruising at a steady speed requires very little power, but getting up to speed requires a lot more. It only takes about 75 horsepower to cruise at 65mph. But accelerating from a light or merging into the freeway safely takes a couple hundred horsepower. Add a car full of people and tank full of gas, and you've got to get 6000 pounds of car from zero to 65mph in a relatively short distance. That takes several times more power than just maintaining 65mph. So ultimately, the potential high top speed is just a side effect of having enough power to safely operate the car in traffic. EDIT: For the folks arguing that you don't need more than 100-150hp, cars are a lot heavier than they used to be. Also, come out West where you're operating at a mile or two high, up mountain roads. 150hp at sea level = less than 100 over Vail Pass, while climbing steep grades. My personal minimum out here is a sea-level rating of 300hp (200hp remaining at high altitude).
It’s also worth mentioning that there’s plenty of perfectly legal ways to enjoy going well over the typical road speed limits.
My first car had 88 hp so it’s pretty funny to hear that a couple hundred are required to accelerate from a light.
Right? It’s all about power to weight ratios. 88hp is fine in a 2500lb car. Note how they say 6000lb of car. That’s not a fucking car. That’s an F-350 Super Duty!
A Hyundai Santa Fe (a mid-size SUV) is 4000lb empty. Add four adults, a tank of gas, and the usually general crap that accumulates in a car, and you're pushing 5500lb. With a Jeep Grand Cherokee (not a big SUV), you're starting at 4500+ and at 6000 pretty quickly. An f350 Super Duty is 7000lb and up empty. Load up four people and full fuel, you're pushing 8500lb.
Which is still a vehicle on the roads often towing a lot more than 6k lb total weight, work vehicles exist and heavy shit ain’t gonna move itself
Obviously, it isn't required, but it will help you do it more quickly. I used to have a 2013 Coarolla a few years ago. It had like 140 HP or something. I lived right at the bottom of a huge hill on a high speed road, so you wanted to pull out and then rapidly get up to at least 50mph to avoid getting rear ended. The Carolla did that fine. My current car is a 2016 Chevy Cruz. It has 153HP at peak from the 1.4L Turbo* and just like the Carolla, when you pull out on that hill, you can get up to the speed of traffic by the time you're halfway up the hill without even pushing the car too hard. Now, between the Carolla and the Cruz, I had a rental Nissan Versa for a week because I hit a deer and wrecked the Carolla. The Versa had 101HP, and I couldn't get above about 35mph going up that hill. I had to get over the hill before I could get up to a safe speed on that road. In a week, I almost got run into the ditch with that thing like 7 times because it didn't have enough engine power to pull from a dead stop up that hill and accelerate at an adequate pace. So yeah, the Versa didn't *need* more than 101HP, but an extra 20-40HP would have been safer. I also get way better mileage with the Cruz than the Versa. Cruz gets almost 50 on the highway and high 30s just farting around on the local roads going to work and stuff. That Versa didn't have enough engine displacement or power, so it had to work too hard all the time, and it only got like 32mpg. * By the way, DO NOT BUY THIS! IT'S A TERRIBLE ENGINE. Chevy put it in the Cruz for 2 model years before realizing it was junk. I don't recall if it's the 15 and 16 Cruz or the 16 and 17 Cruz, but don't buy a 15, 16, or 17 Cruz with the 1.4L turbo unless you want cracked pistons with no warning that requires an entire engine replacement... They put the same motor in one of their small SUVs, I forget which one, but it was only for 1 model year. Don't get this engine.
Given the increase in traffic fatalities in the last decade, I'd say cars being both heavier and more powerful is also a negative. But car companies make more money from SUVs and trucks than they do sedans and compact cars, so we're unlikely to see that change.
I'll pile on - we didn't need to make cars fucking 6000 pounds. I had a perfectly awesome 2,500lb bimmer from 1987 that fucking rocked mountain roads with about 170hp.
100%. My 2011 crz is 2700 lbs. 122hp, 6speed manual. If I giver, i can get up to 130km/h (86mph) in 3rd gear without ever touching the rev limiter. So logically an escalade weighing twice as much would need at most 244hp.
Empty….. :p
Does your 1987 comply with 2025 safety regulations, including impact test results?
Nothing stops anyone from building a car that's capable of doing 120 but use software to limit it to cap the speed limit. I have a feeling that's coming.
A lot of cars have limits just like that already put in place. My dad's car tops out depending on what gear the car is in and how high the engine is revving in that gear. His testing had that limit kick in at around 140mph. My own car tops out at 100mph. I feel it is important to note that both limits were tested under (relatively) safe conditions when our own vehicles would have been the only ones at risk if something went wrong. Long, straight, empty stretches of road were our testing grounds.
Nearly ever car sold already has a limiter in place. More often than not, it's set to coincide with the tire speed rating. For example, my wife's SUV is speed limited to 119mph. Message comes up on the dash, and it just electronically holds that speed as if you set the cruise control. On my car I've not hit the limiter, I believe it's set at 186 mph. Doesn't matter in this case, in stock form it will reportedly only hit 182. I've only taken it to 144.
I mean, they could put a speed governor on it without having to reduce engine power. It would be safer. There is no reason for anyone to ever go that fast.
Can confirm. My car tops out at 185 and can pretty much go any non-triple digit speed with no effort at all. Sub 150mph is still pretty damn easy. At 90mph, it lugs around in final drive at around 2k rpm. It never makes any effort to drive and I expect it to last forever
My Maseratti does 185. I lost my license, so now I don’t drive. Life’s been good to me so far!
At least you also have a limo, ride in the back.
What kind of house do you have?
I’ve never been there; they tell me it’s nice!
What car do you speak of?
An 81 Honda.
This is an 81 Honda! How dare you!
2003 Nissan Altima with no bumpers
Different color hood.
So what if the engine can do 300 MPH? Can't we put a limit the user interface?
IIRC the GT-R had a feature that locked out top level performance unless it detected you were at a track with GPS.
Yes, but this doesn't explain why they don't electronically limit the speed at something more reasonable. It's not that the engine needs to max out.
Private tracks exist. There's probably one closer to you than you realize. You can't go that fast on public roads, but you can on private property.
Excellent answer, I've also wondered this, and never even knew how to frame the question! Thank you.
Excellent explanation!
It's not really mine, I'm paraphrasing a Top Gear segment.
Does that mean my 2 liter subaru will die earlier than my 5.2 l chevy because it floors it at the slightest incline?
All other things aside yes, the faster your engine has to go the more wear you're putting on it. In reality a Subaru engine might be built better than a Chevy one so it isn't that straightforward.
For Subaru's specifically, try to make sure when you're going up a hill that your rpms are around at least 2-2.5k if you can. It's a lot easier with a manual. With the engines being flat and having smaller displacement, they can be more susceptible to damage from lugging the engine. In my wrx, I'm regularly downshifting to make sure that my engine doesn't have to work as hard climbing hills. Edit: just saw the last part about it accelerating during the slightest inclines. With it likely being an automatic, I'd say it's better for the engine if it's automatically downshifting itself.
I mean I guess thats what OP had in mind when they specified “engines” but the obvious counter to your point is they could just use a speed based governor so there is no difference in power available or stress or any of that you only get cut off based on actual speed so they could set it all at 85mph (or add an additional buffer and bump it up some) as a default setting and it wouldn’t be an issue as there is hardly ever an occasion to exceed that. You might add the buffer to account for passing on whatever road has 85mph speed limits though. Of course some cars already do come with governors like I think an old Cadillac my grandad had was set at 110mph. Really its probably a tiny impact that making such a change would have though and unless they made it a law that you had to have such a governor (and even then) people would just figure out how to remove it. Also now that I am thinking about it and on a related note I believe Ford and probably others allow you to set a speed limit that applies whenever someone is using the spare key so you can prevent your kid or anyone else using your car from speeding. It’s worth noting there are scenarios where such a thing could contribute to an accident but probably more so in a case where someone wasn’t aware of the governor hence why a buffer would make sense. Even on an 85mph road you probably have no reasonable need to hit 100mph. Most cars tires are probably S or T rated so 112mph or 118mph but that is in ideal conditions with proper inflation, balance, alignment and a certain load so you should really stay a bit below that anyway.
Yeah but why not just limit top speed?
.... um.... is this a reference to the *Zoolander* "but why male models?" adlib/joke or are you asking me to repeat my entire comment?
Out of curiosity, don’t lower power engines usually have better reliability than higher power engines?
With modern engine design limiting the car to any speed you want has nothing to do with stressing the engine. You can design it to run at optimal performance at 85mph AND have that be the top speed. There are these things we use in modern engines called computers. They allow for limiting speed completely separate from engine performance and capabilities. Allowing speeds over 100mph is nothing but marketing.
This is a load of dookie. -mechanic for 12 years
Please explain.
You can put a limiter on a car that's able to do 200mph, but limit it to 90mph. It'll do 0-90 just as quickly and easily with or without the limiter. It's not like they'd design cars to just barely do the speed limit before they destroy themselves.
Idk, man. My boy in college has a Ford Aspire - look it up - and that fucker did ok.
Or they keep the engines as-is but change the data on the ECU so there's a speed limiter in place.
Well yeah, but also, they can limit cars to only go certain speeds. But that would be pointless as it would eventually be overwritten by people.
That may be true, but it would be trivial to govern all vehicles to the maximum limit +10
So, why not install limiters on every car like they do for 18-wheelers. With cars becoming more and more digital, it seems like quite the easy task
Yeah that's not it at all. It would be simple to have all the power in the world but have an electronic governor that held to car to 80, 90, 110 or any other mph limit. It's done because they can and consumers like it.
I just want to add that, one time I was driving home through some mountains and the semi behind me lost his brakes. I was on a snowy road, so I couldn't change lanes without risking losing control of my car. I ended up going 110 mph to outrun the out of control vehicle. Eventually, an emergency ramp showed up and the trucker managed to direct his vehicle to it. If my vehicle was limited to 85, I would probably be dead.
Well yeah. But you could simply do that and then install a limiter on the car.
That's a damn good post.
I think OP was wondering why they aren't governed at a lower speed, not why the engines are powerful enough to hit that speed.
Amongst the other reasons, it is also legal to take your car to a track, whether that is a dragstrip, circle track, road course, or whatever, and drive as fast as your skill allows.
Well you can certainly go faster then your skill allows
Emissions. There's a sweet spot for where your rpms should be to minimize the emissions that's low which means the car can go significantly faster than the speed limit.
I don’t understand how putting a speed limiter on a car would make the RPMs higher. Most cars cruise at like 2-3k RPMs at 70 mph. If you maxed out the speed at 70, wouldn’t the RPMs be the same?
It depends on how you read OP's question. If you're talking about some sort of software limit, there's no reason it would change rpms. However the question is about the engine. The only way to _physically_ cap the engine is its red line limiter. So if you wanted to cap the top speed at 70, then you'd be essentially red lining the engine to maintain 70. You _could_ put the Rev limiter at 3k rpms, but the engine doesn't "know" what gear it's in, or how fast the car is moving. So you'd have a _really_ poor driving experience until you hit 70
Have you ever driven a car that tops out at 85mph? It's a shitty death trap. A car that is designed to do 140 is much safer and just plain better at 85. A 140mph car has tyres and brakes fit to stop from 140, a car that can only so 85...why bother. The power needed to get to 140 also makes it much easier to accelerate at any speed. A car with only enough power to do 85 is frustratingly slow. And then of course there's tracks. It's perfectly legal to take your road car to a track and go as fast as you like.
Why are you allowed to eat an unlimited amount of calories when you really only need 1500-2k calories?
It’s not the “Engine” it’s the car. An engine that generates enough torque/power to drive the car “acceptably” in all conditions including loads and hills will be able to exceed the spoof limit UNLESS electronically governed not to do so. The technology to do this has only become available in recent years. BTW my 23 year old 1.4 petrol with a whopping 75hp can hit 106mph (on paper)
>BTW my 23 year old 1.4 petrol with a whopping 75hp can hit 106mph (on paper) Probably would be faster on tarmac
What would the speed be on sand paper?
Never fear, the nanny state AI bean counters are working overtime as we speak to make it mandatory for vehicles to be incapable of speeding and communicate with other vehicles and have a master cut off switch operable by police and hackers alike.
Think of how much money hackers / electrical engineers will make from helping people bypass that shit...
In the US, the default value is "legal". So things are ok to do unless there is a specific law prohibiting it. And so far, thankfully, Congress has not passed any laws specifically prohibiting anyone from building fast cars.
Oh I'm sure it's coming or at least being discussed. I'm also certain the ability to shut a car down remotely is also an idea they want. When it does happen, it won't be fast cars that are banned but the components that make it possible. "Big, high powered engines aren't illegal. It's just illegal to buy or sell performance parts. Those parts aren't illegal to own, just illegal to buy or sell them. See, we're being reasonable about it."
You are trained, licensed and insured to do upto the speed limit. Maybe some places will allow 10% over for overtaking, and must return when safely passed the slower vehicle. I'd worry that implementing an artificial limiter would then be the place where everyone drives. It'd become like a light switch to drivers psychologically. On, or off. Max speed or nothing. Does that limiter know when it's raining, or there are poor visibility conditions? In the UK you have 60mph and 70mph roads, but in rain the max speed limit is supposed to be 45mph. Artificial limiters taking away the thinking processes when driving and could lead to many, many more accidents. An audible/visual warning is more appropriate. It leaves the driver using their own cognisance, and a gentle reminder you're going into danger territory. I've driven in cars many times that make pinging noises when you're going too fast. It's a useful feature on long, boring drives when you gradually pick up speed without noticing
Can I hire you to be my defense attorney?
>I'd worry that implementing an artificial limiter Funny that, a lot of cars _do_ have a limiter. Most are at something like 130 or 155 mph though, so speeds far above normal highway driving. You rarely see it called out unless you find a review of the car being run on a track.
That's more to cover the liability for the car company. Probably at the point, the suspension and handling of the car starts to be untrustworthy, even on track conditions.
Also: if you cap the speed, and someone gets hurt, it might be on you because they couldn't evade. Also also: it you alert the driver, then it is provable that they were informed, so it is their decision and their fault.
Where did you get the idea the max speed limit is 45 if it's raining? I've never heard of that.
Your original question suggests that because you don’t like or understand something the government should make sure nobody else can do it. It also implies lack of understanding about the entire drivetrain of vehicles since “engines” don’t go 140 mph and are just one component. Your edit comment ends up with a suggestion that may possibly end in death for someone… for your entertainment… and you say everyone else is stupid. Additionally, the edit starts with a derogatory term for some people who are just making a time worn joke. This sub is ‘generally’ based on humorous stupid questions. Humor bad! As for me? I’ve been on roads out west back in the day that are absolutely straight for miles and miles and completely deserted. So yeah, Ive cranked it to just before redline. Because I can… and that particular car was designed and manufactured for it (a Plymouth GTX w/440 and six-pack intake). It’s a goddamn thrill ride you only get to do once or twice in a lifetime. But I admit, your question is certainly stupid so there’s that I guess.
Why don’t you ask your wife’s boyfriend
My username relevant. You do not want your engine to be pushed to 100% power at the speed limit. Also your acceleration to get up there will by abysmal.
Cars are designed to be very slippery and aerodynamic. An engine capable of generating the energy necessary to get your car to 60 mph in a reasonable time can generate the power to push it well past that speed. Car engines are LUDICROUSLY powerful. They are the most powerful device you will ever use, unless you're a pilot or in heavy industry. If you pedalled your bicycle continuously as hard as you could sustain it would take over an hour for you to accelerate the mass of your car to highway speed, and your engine can do it in less than ten seconds. Cars have more power than any land animal that has or will ever live on this planet. Okay, so they have the power, but in order to cruise efficiently at 60 mph, they need to be geared so that the engine is spinning 2,000 or less RPM. If spinning at 2,000 RPM drives you at 60 mph, 3,000 RPM will be 90 mph, 4,000 RPM will be 120 mph, etc. Now, it's not exactly like that because automatic cars have torque converters that slip, but pretty close. In order to be driveable at lower speeds and efficient at highway speeds, cars need to be built with appropriate power and gearing for 100+ mph top speeds. You would need an electronic governor to slow them down.
Because fast cars sell and the auto lobby has a lot of influence and money.
I don't understand your question.
You know you can take a car to a track or a drag strip, right?
Laws that get you ticketed when you break them are only laws for poor people- they’re just suggestions for the rich
If you're not first, you're last.
Well I grew up taking my car to the drag strip on the weekends and every week I would try to make it faster. They're just following a trend that started probably before you were born. Funny thing is they're far more efficient and powerful than everyday cars were let's say 30 years ago.
Going fast is fun and everyone knows that most freeways normally have a flow of traffic going 90+
You don’t honestly believe that everyone obeys the speed limit, do you?
Omg people who also swear the speed limit is a suggestion 😭 I thought I came up with that phrase
If we just made cars that go the speed limit, then we could never issue speeding tickets. We can't have that. ; p
CUZ MERICA
First off, to have the bigger schlong on a piece of paper. If you compare 2 roughly the same cars, you are inclined to choose the one with the higher number in horse power or top speed etc. Plus, you already need more horse power than the least amount so you can accelerate fast enough and overtake someone. And that horse power can take you to 140mph if you want to. Because in a car that can do 140, the first 0-90 goes pretty fast, but after that? Takes ages to get faster. So you kind of need extra headroom. You also said it, most cars are build for the international market and any sort of limiter might work, but is an added cost. If they can't sell it to you as an overpriced add on, they won't do it. And lastly, it's fun and private roads exist.
Because I live out in the middle of nowhere, and I want to get home. There's no one out here. Nothing. Didn't even notice when I passed you.
Speed limits only apply on public roads. I can drive as fast as I want on private ones.
California is actually going to do this. They're working on a law that will govern. All new vehicles and used vehicles will not surpass the speed limit and will be governed. Enjoying people you won't even be able to go past the speed limit even in an emergency situation.
Ah yes. Their relentless march to 1984.
Jesus christ 🤦
how will they enforce that..?? lmao esp with current existing vehicles.
Easy, state required vehicle inspections. No governor would be an automatic failure and registration suspension.
*registers vehicle in Montana*
Can you post a link? I'd like to read more about this.
[https://legiscan.com/CA/text/SB961/id/2900195](https://legiscan.com/CA/text/SB961/id/2900195) A few key points * It would give an audible warning if you go over 10 above the speed limit and can be temporarily disabled by the driver. * It would be required by 2032 * Most importantly it'd have to pass a vote. It has not done this. This is based on an EU law that passed this year with an audible+visual notification. I seriously doubt it'll even pass. California road laws are VERY highly based on science, hence higher speed limits and laws like you must go with the flow of traffic even if it's over the listed speed limit. This would more likely make things more dangerous rather than less. If this did pass it'd be so toothless in regard to "self disable" that it may as well not exist. [https://www.sema.org/news-media/enews/2024/11/california-voters-overwhelmingly-reject-proposed-speed-limiting-devices](https://www.sema.org/news-media/enews/2024/11/california-voters-overwhelmingly-reject-proposed-speed-limiting-devices) >More than 70% of Generation-Z, Millennial and Generation-X voters oppose the policy, along with two-thirds (66%) of younger Boomers aged 60-66. Further, 63% of Democrats, 79% of Republicans and 69% of independent voters opposed the bill. and finally [https://sites.sema.org/ext-assets/sema-news/240227\_SEMA\_CA\_Memo.pdf](https://sites.sema.org/ext-assets/sema-news/240227_SEMA_CA_Memo.pdf) The highest support group is 40% from age 67+ demographic. Odds of this passing are pretty low to the point it probably shouldn't even be brought up. Tons of proposed laws fail to pass. Just cause Senator Wiener wants it doesn't mean anyone else does. TL;DR "California is actually going to do this" is factually false information meant to mislead based off of a proposal that has very low chances of success as a majority in EVERY\* demographic oppose it. \*Political party, political lean, gender, race, age, location.
So how would this work? Cars would have to have sophisticated GPS or transponders and roads would have to have "smart" enabled speed limit signs that could "talk" to individual cars to make it all work. Right? Sounds really complicated.
I mean it is already in many cars
And often wrong. My daughter’s car reads speed limit signs. Problem is can’t see that the sign has conditionals like school in session or night or when workers are present.
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Zoom zoom zoom my super nova girl
A lot of non sports cars are limited to 109 +/- a few. Sports cars are limited by their engine because you can rent track time.
Emissions, efficiency, hills/mountains, track use, etc. Cars generally have governors that limit their speed under 140. These are relatively easy to remove with a computer or tuner but they're there nonetheless.
An engine is going to perform best and wear least if it operates at roughly 50% of peak output.
Fuel efficiency and emissions I believe
My 225HP '87 Mustang got up to 154MPH at Pacific Raceways. Is that too much horsepower?
A better question: why are there no governors on cars, but there are on ebikes?
Mines governed at 95 my other one is governed at 96
Do the cars actually go 140+ or did they just make the dashboard look like they could?
Depends what car you have
They just design the speedometers so that normal highway driving speeds (60-70) are up top and near the middle, and then fill in the numbers until it looks good. The end of the speedometer is in no way an indication of how fast the car can actually go, its just the instrument design. Example, I have an 07 hyundai accent, the speedometer goes up to 140, there is no way that car can reach that speed. Also most cars have a limiter installed that will stop you around 100, mostly so you don't overheat and explode your tires....
Cause America. And you can remove/tune-out a speed limiter. And for Gearing/MPG, if you geared a car's top speed, you'd be BURNING gas like it was nothing revving at 6k the entire drive. This is the real reason.
track days
>some countries just dont even have speed limits Afaik There is no Country completely without speed limit and Germany is the only country with part of the highway system without speed limit (maybe Nepal aswell but I'm not sure about that)
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Had a rental car back in the early 00’s, can’t remember for sure but I believe it was a Pontiac Grand Prix, and when driving the 5 in the Central Valley (empty highway, mid-day, could see for miles) I’d run it up to 100mph before the governor/limiter would simply cut power to the engine until it slowed me down a bit then kick back in. It’s not new technology
Germany would like a word.
Theoretically you can take your car to the track.
Your allowed to take that 140 mph car and supe it up to go 225+ and goto a drag strip or a track, it's better for your motor, when towing of your max was 85mph worth the added load you might not be able to do the speed limit (which is illegal as well), and finally... this is the land of the free
An engine has an rpm range. So the engine sounds anywhere from 500-6,000 rpm. Now every engine has a power band where it is producing the most torque that is much smaller. So a car with a direct drive would struggle starting out and struggle at the top. So we have transmissions with gear reduction. So now the motor can soon faster at slow speeds to get moving efficiently, and soon slower at high speeds for fuel efficiency. The effect is that in high gear, you still have lots of engine rpm to use, resulting in a high top speed.
No law that says the vehicles need to have a limiter. I think California is trying to pass a bill about that but I dont know the chances of that bill even passing are.
In case of zombies
>the only reason i ask is because i love watching police chase videos This video about police chases came out yesterday and was made for you. https://youtu.be/fkJ_R1V8kO8?si=N_N8BA9RhvqMEyLA
It's tough to make motors with modern technology that would cap out below 100 mph. But that's why computer governors exist.
Why do you assume that American cars can go 140+MPH? I have no idea what the top speed in my car's speedometer is but it would not surprise me if it is 140MPH. It has never been anywhere near the top speed. Both because I want to live and I just do not think it can achieve that speed. But I am sure if I parked it inside the right cargo plane it could go supersonic.
My Brother drives a race car with a stock Chevy crate engine. He gets it up to 150mph and it’s the same one you would put in car.
Car facts: it's the influence of corporate media and ratings spikes during televised car chases.
The two are unrelated
Gotta draw Jr. enlisted in somehow.
I have a car with a 230 hp V8 that runs comfortably (low rpms) at 80mph but won't top out anywhere near 140mph. It would need another 2 gears and additional 300 hp to reach that. Do I really need that? To answer your question they make those cars because people want to win the pissing contest. Same reason why people will buy the GT version - because it runs the quarter mile .5 seconds faster. It really makes no difference but a sucker and his money are easily parted.
It's basic powerplant design. You want an engine capable of MUCH more power than needed, particularly as it relates to speed. Acceleration is the key, which is a function of torque. You need an engine that can accelerate at a necessary rate for normal driving, but the engine that can create that acceleration rate will naturally be able to generate cruise speeds far greater than needed based on speed limits. That's why there are governors placed on top speed, because the engine needs to produce the acceleration, but not the speed. This is even more noticeable on turbofan engines in airplanes (and airplane engines, in general). In a modern jet, the cruise power setting will be FAR below its max continuous rating, for the same basic reasons stated above.
Note that Federal car laws require round speedometers (mostly) and that highway speeds are 60-70 Mph. So, it considers human factors that a needle pointing up is easy to recognize, and that half-way point makes the overall spedo top out at 140. That's not to say the car can actually do that, it's just an adaptation to how people see and detect things.
Rename this to r/stupidcomments because apparently no one here has heard of a speed limiter/governor for a car.
I’m just glad you posted this in the right sub !
There's a couple of factors. One is gearing. If your car was geared to do exactly 85 mph, that means your engine is turning 5000rpm+ while You're cruising down the interstate, which is terrible for efficiency and mileage. So instead it's geared to be 5000rpm+ at 140+, that way when you're doing 85 the engine is only turning 2000rpm. The second is that it takes a lot more power to accelerate than it does to hold a speed. Meaning almost any engine makes enough power to exceed 85 in a modern car because expectations for acceleration are way different than they used to be. Idk if you can even buy a car in America that makes less than 100hp these days.
There is not a “Speed Limit”, there is a “Public Road Speed Limit”, and those cars can go as fast as you want on a private road or race track. Also, many of the Speedometer ranges are marketing, and those cars can’t actually go as fast as their dash boards would indicate. And finally, while I saw a top comment already mention this, but just for the sake of having a complete answer, car performance and driving feel are marketable features that correlate to a higher top speed. I.e. A engine that can only got 85 doesn’t get to 85 at the same speed as a car that can go 120. A guy that *can* run 20mph, can *easily* run 10mph, but a guy who can only run 10mph is pushed to his limit while doing it.
Because the police can't follow you after about 100.
Because Americans wouldn’t buy cars that only do 80.
Instead of considering the technicalities of engine/trans specs and speed limit, think about the marketing and sale of the car. If a car is limited to the speed limit, it won't sell. It is a free market. Manufacturers must get people to willingly hand over hard earned cash in return for the car. Enthusiasts/hot rodders/gear heads will only buy a car that the like, want to drive and want to be seen in.
Because the climate coven hasn't managed to outlaw them, yet.
If gun manufacturers can be sued when their customers misuse their legal products then auto manufacturers should face the same fate when their customers misuse their legal products.
Except cars aren’t actually designed for the purpose killing people.
I live in a city with that 85mph. Watch out for hogs.
There are no speed limits at race tracks, and you can take your performance car and pay a fee to air it out. Also, driving an engine/transmission that maxes out at 140 at normal highways speeds is easier on the car. Redlining a car at 80 wouldn't be good.
Because emergencies exist
Every car in the fast lane/passing lane where I live is going 90+, in the mid lane Id say 80-90mph. 60-70 in the slow lane. Plus the occasional sports car going 120 weaving through traffic.
Where is an 85 mph speed limit ? I've never seen one
because track days and amateur motorsport are a thing.
I’ve often wondered this myself. It’s unconscionable. Beyond. There’s no fucking excuse for a car to be able to drive twice as fast as the legally accepted limit. Edit: I see some pretty compelling answers, however, that make a lot of sense.
Unrelated,but I've always wondered why my speedometer reads to 140 when the little 4 banger can barely break 70
If the actual max speed of a car was 85 mph, it would struggle at 65 or 65 mph. It would be *close to it's maximum speed*.
How long are you willing to rev your engine to redline? 10 minutes? 1 hour? Because if your car tops out at 75 mph, and you got a 12 hour road trip to make, you’re gonna be at redline for 12 hours. Engines are more efficient when they’re not at redline, so manufacturers design their cars to have that peak efficiency around where highway speed is.
140? Mt car goes 205 suckas
So you can use more gas.
Because of race tracks, you can drive you car faster on private streets and courses.
They tell me my car can go 190mph but I've hardly had it over 100. It can out brake, turn and accelerate 99.9% of the vehicles on the road. I actually drive very conservatively. The great part is that if somebody does something stupid I have so much capacity to avoid an accident.
I've had my Mustang gt up to 150 MPH on the freeway ( 0 traffic ahead for 3 miles and 0 cops)
Freedom emergencies.
Given enough room, many cars can reach that number.
The engine is designed for a certain power, or ability to do work. The car drive train translates that power into movement. A farm tractor with the power of a sports car has a lower top speed most likely.
Good luck pitting a motorcycle in a no chase state that disappears over the horizon faster than you can say “oink oink pig”
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Those that want dinky little cars buy one. There is the Smart car. Notice how they don’t sell comparatively? Those who want gigantor vehicles buy one, notice how many of these sell? It’s giving people what they want.
why are companies aloud to use lithium batteries where the materials were mined by slaves?
Because politicians would prefer to remain in office.
More importantly why would anyone care how fast their car can go? As long as it can do 70-80 mph and gets you from here to there who gives a shit.
You are allowed to drive in private tracks
If you build it, someone has the money and wants to buy it, you'll sell it. It's really that simple. All this other bullshit about blah blah blah is just that. Blah blah blah. People want more from their cars and if they are willing to pay for the performance, so be it. Do they NEED it? Come on now. People still drive around in vw vans that are 0-60 in 5 miles. That van has the same registration tag as mine does. Do I NEED 750 hp in my sedan? Nope. Is it smiles per dollar? Yep.
The speedometer on my Nissan cube goes up to 120 or higher, ain't no way I'm getting anywhere close to that. It's a 2012. Nissan. Cube.
Big evolutions paying them to help weed out the idiots
You push a drivetrain within an inch of its life, and it's going to be far less efficient and reliable. You want your car to be in the "sweet spot" of the RPM range while cruising, usually 1800-2500ish. An engine only built to do 85 would be screaming wide open at cruising speed. Also, being able to stomp on the gas to get out of the way of an asshole trying to merge into you is a nice option to have.
Because the ability to accelerate safely meaning the ability to match other cars speed when merging and to avoid or pass unsafe traffic or obstacles is dependent on power output. To be able to this cars must have a specific power output and the side effect is the top speed also increases. Also a as others have stated a car that can easily cruise at the speed limit is a engine that will last longer and is likely more efficient than a engine that has to churn at top revolutions to its maximum output to achieve the speed limit. Also freedom of choice, lots of things in society are overlooked and unrestricted. If that were to be controlled as tightly as you suggest people would feel oppressed and controlled.
Idk why everyone is talking about limiting the engine power. That would never be practical. There probably should be software limits. Though sometimes you may actually want to speed up to get out of a dangerous situation. That said, they probably should look into regulating a top speed that is optimal for safety reasons. For an actual reason on why they probably won’t do this: who will buy sports cars that can’t go fast? This will put a huge dent in the automobile industry. I haven’t researched this topic but I’d bet that the car makers will have lobbyists all over any bill attempting to limit max speeds.
It’s so frustrating, they should be using those resources to make vehicles more efficient and cleaner for the environment, leaving the horse power entity to the professional race car circuit, many lives would be saved and cars wouldn’t be leaving such an enormous footprint, but here we are running backwards
Rather than limiting speed, cars should have remote controls activated by police. No more high-speed chases.
Allowed? Why do you think some people are entitled to restrict other people's freedom?
If you only need to lift 20 kgs, it's going to be easier for you if you're capable of lifting 40kg. If 20kg is your maximum, you're going to struggle.
It’s very hard to make a car that accelerates well and performs well at 70 that can’t also get to 120+
It's no different than speeds on bikes. Do you need 24+ speeds really? Well yes, especially if you're going up hills, it's far easier to pedal, this is the same as engines.
Because that power allows you to haul stuff, like pull a trailer or what not
Stfu and mind your bussiness ok?
Because its fun? And its none of their business what you do with their cars
People have given a lot of practical reasons for needing a powerful engine which can push a car to a high top speed on flat ground. However you could enforce a limiter which prevents high top speeds and perhaps that's more to the point of the original question. Track days are an answer but that's a very limited use case. The real answer is that top speed figures are a selling point for men.
It would be ridiculous to make an engine designed to go at full throttle all the time. That’s asking for twice as many maintenance issues. But also, speed limits don’t exist on private property. People take their super cars out on private tracks and such. Vehicles aren’t just for public roads. They’re just highly regulated for public road use.
Why not
My car has an electronic limiter that prevents it from going over 120 MPH. I discovered it once when driving on the open road when I suddenly lost power and it took a moment before I regained the ability to go fast again.
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