Why Petrol powered cars aren't obsessed with low drag coefficient like EVs?
Posted by Competitive_Art_9181@reddit | askcarguys | View on Reddit | 104 comments
What upper hand does gasoline still have that it allows some cars to afford drag increasing components like rear diffusers and wings?
MyCarIsAGeoMetro@reddit
Who says they are not? Most hybrids look like eggs.
thatoneblackguy17@reddit
I work for an OEM.
Compared to ICE, EVs have more drawbacks. They are heavier, and their range varies greatly depending on the weather, temperature, driving speed, etc. Even fast charging out on the road does not allow you to easily utilize the capacity ofnthe batter unless you have extra time needed to charge to 100%. To help with these factors, they have to rely on as many range extending features as possible to achieve the figures advertised from factory.
ICE vehicles are not as vulnerable to range draining factors like the extreme temperatures. Mainly comes down to driving habits and basic maintenance. Plus it takes way less time to full up than EV.
Ultimately this is the reason why, amongst other reasons, OEMs are going back to ICE PHEVs, and REEVs (Range Extended Electric Vehicles. For examples of REEVs, look at Scout Motors).
Whysoblunted@reddit
Some are, look into hypermilers.
Most aren’t because to achieve notable results you look like a space ship going down the road.
imightknowbutidk@reddit
I’m reminded of the prius with duct taped cardboard on the rear end
Rabbit_of_Caerbanog@reddit
Speedtail or boat tail effect?
HungryYeastStarter@reddit
Looking like a whole aircraft fuselage.
Background-House9795@reddit
Yep. When your mpg is in the low 20s, a 10% increase is still only 2 mpg. Big deal. In my 2000 Honda Insight a 10% increase is huge, and very noticeable. 76 average mpg will have you looking at everything effecting mileage. Just turning on the a/c costs me 8 mpg.
Now that I’m driving a 2020 Tesla Model Y and charging it up at home every night I just don’t care. It’s $3 to get me to work and back.
SkeletorsAlt@reddit
I think most people think about fuel mileage for about five minutes a week, while they’re actually standing at the pump, if that.
I could probably improve the average driver’s mileage by 10-15 percent, but most just don’t care, even when results unleaded is $5/gal.
No_Caregiver7273@reddit
Lithium Ion batteries are essentially what made modern EVs possible. While electric motors are around 90% efficient the power density of battery packs is a lot less than an equivalent amount of gasoline. Designing an EV is currently about doing everything you can to maximize range on a reasonable size battery pack. Lowering drag coefficient is one tool in the toolbox.
I_dont_know_you_pick@reddit
Gasoline is readily available and plentiful (for the moment), so gas vehicles don't have to stretch every mile as they can just fill up when empty.
nosajn@reddit
But... So is electricity?
L3mm3SmangItGurl@reddit
Yea but battery space is limited. So you have to eek out every mile you can to avoid annoyingly frequent charging
BouncingSphinx@reddit
Gas tank volume is limited. So you have to eek out every mile you can to avoid annoyingly frequent fill-ups.
That's not a real reason for EV, they're just trying to reach exceptional efficiency as a selling point compared to ICE vehicles.
ly5ergic@reddit
Way way more gas stations than chargers
WillieMakeit77@reddit
Not here. One has to search for a public charging station where I am.
No one is going to invest in a bunch of charging stations here because there’s no profit to be made. Only 2% out of 300 billion cars on the road are EV’s here.
loukaz@reddit
But the amount of electricity isn’t as plentiful when it’s in battery form. Batteries hold a lot of energy nowadays, but gasoline holds ways more per volume
JettandTheo@reddit
All the broken chargers say otherwise
Some_Level1682@reddit
Filling up takes longer and mostly done at home
I_dont_know_you_pick@reddit
Yes, but refilling a gas vehicle takes a fraction of the time of filling an EV.
umrdyldo@reddit
They are, just not the ones you can afford.
Competitive_Art_9181@reddit (OP)
Most supercars/hypercars, at least as far ive seen from their manufactures presentation all they talk about is downforce
FIMD_@reddit
Drah coefficient has been a huge focus for non supercars too. The 1989 Lexus LS and 1995 Mitsubishi eclipse had drag coefficients of 0.29-0.30.
Also, to be clear a rear diffuser or a wing or both are not strictly drag-increasing either. Fluid dynamics is a very unintuitive field.
Diffusers in particular are used specificallyto reduce drag by organizing the flow under the car, making a cleaner exit and letting it join more neatly with the air from the sides and top of the vehicle.
In many cases they are using the heat evacuated from the engine bay and sent down the firewall to accelerate the flow under the vehicle to reduce pressure, which can also significant downforce without a drag penalty and reducing energy required to maintain speed or under acceleration.
The wings can assist in this too. In many passive applications the wing or a lip can be used to create downforce via drag true, but some are shaped and angled to minimize the turbulence in the void behind the vehicle. If there's a diffuser they are designed to work together to varying degrees.
Many sports and supercars with active aero elements will use them depending on driver inputs and sensor feedback to accomplish low drag modes, varyimg downforce modes and in some models air braking to reduce braking distance and stabilize the tail of the car under hard decel above certain speeds.
Even the giant brick that is the G-Class today manages <0.5 CD.
Lastly, there's also the inherent compromises made to accommodate not only aesthetic, comfort and functional requirements and catering to the consumer they are targeting.
If your selling an SUV marketed with the suggestion you can take it off road while towing for example you're not going to have tight wheel wells, low ground clearance and a sharply sloped windshield and rear window, tiny mirrors that you can't see both your rear quarter or trailer with and sacrifice cargo space.
Gas/Diesel vehicles very much do and have been designed with drag in consideration. But they also have 44MJ/kg in energy density in a liquid fuel source that doesn't occupy much space and can permit weirdly shaped tanks they can tuck in and around the rest of the chassis and drivetrain. The "budget" for meeting a range target is much greater if they want to take liberties with aero for the benefit of other design goals.
BEVs have to be designed around a large and bulky battery with only 0.3MJ/Kg available. A ten gallon gas tank with a raw energy can offer the equivalent to upwards of an 100-120kWh battery, and a mass of about 60lbs.
A 120kwh integrated battery for an EV would occupy approx 80gallons worth of volume and 1500lbs in mass.
That's a battery almost as large as the recycling tote I wheel to the curb every week, and weighs about as much as a Polaris Ranger UTV. So the packaging constraints and efficiency demands are much more significant in an EV.
HoldingThunder@reddit
And downforce is generally inversely proportional to the drag coefficient.
You don't have a car that goes 200 mph without a really low drag coefficient. You don't go around a corner at 150 mph with a low drag coefficient.
Intelligent-Ad-6734@reddit
Best example of this is the McLaren F1 and it's F1 LM very limited sibling!
Can't find the article but was a great side by side of down force changes to allow high speed handling and the top speed drop off despite the increased HP/TQ of the LM.
For the modern every day vehicle.... They really start drinking fuel above 70... 16' GMC Sierra I had would do 73ish before it wouldn't flat cruise in 4 cylinder mode...below that it would happily bring back mid 20's mpg on a road trip. We've definitely gone backwards that a 16 Sierra 5.3L with a 6speed rates better fuel economy than 26' Sierra 5.3L with 10 speed. Smaller tank too!
That said the aveo I had seemingly couldn't get below 30mpg even if you were late for a date 😂... Tank of gas last a month!
HoldingThunder@reddit
The biggest thing is that the vast majority of people prioritize looks or capabilities over fuel economy. The majority of pick up truck owners do not need to drive one every day, and they certainly do not for the gas mileage...
jrileyy229@reddit
This is an entirely different discussion about truck owners... Myself included. Sure, only 20% of the time is my truck doing truck things like pulling a trailer in the summer or getting through snow in the winter. So when you see it at the grocery store, obviously I don't need a truck for that... But it's my only street vehicle.
To have a second depreciating asset like say a Honda Accord would not make up enough fuel economy savings to justify the purchase.
It has nothing to do with looks. Obviously there are outliers in every direction. You have some trucks that are lifted and never leave the pavement or tow anything.... That's a flex... But that's not the majority of truck owners
HoldingThunder@reddit
A studio from Axios indicates that only 28% of truck owners utilize their truck for personal hauling, and only 7% of truck owners use their truck for hauling frequently". Frequently is not defined, so I would assume this would imply monthly.
That means the vast majority of truck owners are not using their truck for truck things on a regular basis.
You are the minority, don't get so defensive with your little truck ego.
jrileyy229@reddit
I know the study.... Hauling frequently is 28%, hauling occasionally is 41%, and hauling rarely is 32%.
It's very vague, but considering there is a whole separate section around towing, so to me " hauling " basically means using the bed for some intended purpose... Mulch, tools, lumber, dirt bike, etc.
So by that rationale, 32% of truck owners don't need a truck. I'll buy that as believable.
It's a very small sample size with a bunch of undefined terms, hardly science. Also, those above numbers add up to 101%... Which means they need to use decimal places in their rounding and not to whole numbers... Which makes me ponder the competency of the guy who put the statistics together.
SeaPersonality445@reddit
The joys of cheap fuel...
BouncingSphinx@reddit
It all depends on the vehicle. Vehicles focused on speed will be all about lowering drag coefficient. Regular cars work to lower it, but they're more focused on passenger comfort and space than they are a lot of effort for reducing drag coefficient for a minuscule return.
Regarding your comments about downforce, that's how they're able to maintain traction and take corners at high speed. It's a trade-off depending on what the main focus is.
Anachronism--@reddit
Gasoline has more than ten times as much energy per pound as batteries. No need to try and save every bit of power possible like on an electric car.
vargemp@reddit
But electric motor is twice as efficient as ICE :)
CaliDude75@reddit
Typically 3x, actually.
MrRogersAE@reddit
Not to mention you can always just make the gas tank bigger.
EV batteries already take up the entire footprint of the car.
bangbangracer@reddit
Also, a gas tank can just be refilled.
MrRogersAE@reddit
True, but you still don’t want a gas tank that only gets you 200km, regardless of how quickly you can refuel
Kind-Pop-7205@reddit
Which is why nobody makes cars with 15 liter fuel tanks.
MrRogersAE@reddit
Which was my point of being able to add a bigger tank.
fuzzycuffs@reddit
They are, either for the sake of fuel efficiency or for performance. For your everyday cars it's more about fuel efficiency and I think for the most part it's a part of (but not the major source of) the total calculation, so there's not a ton of effort in getting every last drop, and modern designs generally are aerodynamic enough. For those extreme cases where you're either trying to get the absolutely most performance or greatest efficiency then yes, there is a ton of effort to lower drag coefficients.
Historical-Stuff-897@reddit
Wonder how much improvement in mpg that aerodynamic design would make to the overall efficiency. ICE engines are able to transform around 30% of the energy in gasoline into motion. A 10% improvement dur to design probably makes that 33%, while compromising the looks significantly.
When fuel efficiency is not the goal, like in super cars, they do take it into account
Leverkaas2516@reddit
There is a long history of fanatical obsession with aerodynamics and weight. My old Honda CRX-HF, for example, was touted as having a drag coefficient of 0.29, slightly better than a normal CRX's 0.31 because the HF had no right side mirror). The later Toyota Prius was more like 0.25. The Ioniq EV is 0.21, VW ID.4 is 0.28, Tesla Model 3 is 0.22.
A more normal car like a Subaru Outback or WRX might be more like 0.31-0.35. Terrible aerodynamics like a Jeep are above 0.50.
All that to say that even 40 years ago, cars were engineered with aerodynamics in mind. But the truth is most people don't care all that much. If it means you can only carry two people, or the vehicle looks weird, or whatever, the majority of drivers will buy a car with a less optimal shape. People USE cars, and they have many concerns.
lemmeEngineer@reddit
What upside? Energy density. A whole lot of it!
Gasoline/diesel is so energy dense that by burning 50kg of it in a modern ICE, you can literally discard 70% of it in the air (remember that modern engine are \~30% efficient), and with the rest 30% of energy, drive \~800-1000km nonstop.
Try to do the same with an EV. An efficient EV at highway speeds (120-140 km/h with AC on) will do \~20 kWh/100km. To do 800km you need \~160 kWh. Not to mention that most EVs don't even have so large batteries. Even the "long range" models are in the 80-90 kWh and the battery alone weights 400-500kg. A battery for 800-1000km non-stop will weigh almost 1000kg. Petrol/diesel can hold the same energy potential (even accounting for efficiency losses) in 40-50 kg...
ontheleftcoast@reddit
EVs pay more attention because high drag means more battery to get the range they want, and if they add battery, then they have to add weight which further lowers range. So they benefit more by having low drag.
TSLAog@reddit
Gas engines are only \~30% efficient, where EVs are \~90% efficient (relative to energy from input to output, nothing to do with aero)
So adding a bunch of aerodynamics tricks to a gasoline driven car yields pretty small overall mpg improvement because of the downright atrocious efficiency of the gas engine and transmission.
Where as improving aero on an EV yields a bigger delta of improvement, because the drivetrain is already super efficient. the next best thing to improve is high speed aero that will Improve overall vehicle efficiency.
jrileyy229@reddit
The only cars with wings are track cars like a zr1 or gt3rs... Nobody is worried about MPG there.
Most street cars have a spoiler... Doesn't hurt MPG.
A real diffuser would actually increase MPG a little bit, but almost no street car has one... They just have pretend ones that visually look the part.
sonofeevil@reddit
Nice to see some knowledge on the topic here!
A lot of "spoilers and diffusers add downforce and increase drag" comments.
Neither of which really tell the story when the truth is they usually reduce the size of the wakes and decreasing drag.
gokartninja@reddit
Yeah, a lot of people don't understand the difference between a spoiler and a wing
Rare-Bet-870@reddit
Drag grows at a squared rate with velocity. Gas is energy dense so it doesn’t matter the same to where a battery needs plenty of electric power to offset weight
nudistinclothes@reddit
It’s about range. Typical gas sedan can go over 400 miles on a full tank, even if it’s got a shitty drag coefficient. And in fact they just install a bigger tank if the mpg is shitty to keep the range around that 400 mile mark.
EV range is going up every generation, but they’re still range limited. Last time I looked, 300 miles was around the norm, but the cars can only get to that range by being as economical as they can with the electricity from the battery. So, regenerative braking, novel cooling solutions to reduce a/c load, low drag coefficients, lighter this that and the other.
Charging time is also important - if they could charge in 2 minutes people would probably be happier with the range. As it is, your stop to charge is around 30 minutes. Great if it coincides with lunch or a haircut, not so good if you’re driving a long-haul trip, and you can’t manage another lunch so soon
s_nz@reddit
The ability to install a cheap 40 to 80 liter fuel tank. This means basically every petrol car has a decently long range.
The 60 kWh battery in my model y is equliverlent to about 7 liters of fuel.
Even if we correct for ev's powertrains being about 3x as efficient, a petrol car equivalent would have a 21L tank.
If petrol cars had a 21L tank, range would be a selling point for them too.
ChainMiserable9618@reddit
If people who own gas powered vehicles are that obsessed with an extra 1% of mileage, they should probably be riding a bicycle.
srekkas@reddit
Because ICE is inefficient. No much difference if engine waste 65 or 70 percent.
1 liter of diesel if something like 10kwh, imagine driving with 5l fuel tank :)
Ev with 50kwh can drive 300km, ice 100km.
TellemTom@reddit
Are you kidding? Most cars look like jelly beans these days, including gas powered cars.
Vegetable-Ingenuity2@reddit
Turns out that's actually a pretty aerodynamic shape.
sohcgt96@reddit
Notice how all sedans have gone to super small rear deck lids that make the trunk opening almost unusable? Yeah, aero. Its not because it makes the car better it use, its better mileage.
Honestly a big driver of the homogenization of vehicle design is that regardless of a given brand's style and design language, they're all contending with the same physics problems, which means they'll arrive at similar answers.
Competitive_Art_9181@reddit (OP)
And they're selling to the same people and their parts are being supplied by the same companies
bradland@reddit
This is a bit of a false premise. Most cars have seen an improvement in Cd over time. For example, look at the BMW X3:
E83 (2003): 0.34 Cd
F25 (2011): 0.33 Cd
G01 (2018): 0.29 Cd
G45 (2024): 0.27 Cd
If you look at something more economical like a Toyota RAV4, you see a progression from 0.37 down to 0.31.
These might seem like small moves, but going from 0.37 to 0.31 is a 16% improvement. That's not insignificant.
The Tesla Model 3 has a Cd of 0.22, and the Prius is at 0.27. So the X3 has achieved Prius levels of Cd. The Model 3 is exceptional.
One of the main reasons EVs focus so much on Cd is because it impacts range to a significant degree. People care less about range on cars with an ICE because refueling takes only a few minutes. With an EV, you have to charge the battery, which takes many times longer.
As fuel economy standards have tightened, cars with ICE power have moved toward reducing Cd as a way to meet standards, so we're seeing a shift in that old trend.
AdEastern9303@reddit
Because you can refuel a petrol powered car in 5 minutes.
Heavy_Gap_5047@reddit
Energy Density.
kamikaziboarder@reddit
Not all EV’s. Mine is shaped like brick.
nonotburton@reddit
Early adopters of EVs influenced the culture surrounding them. The relatively short ranges of those early vehicles meant that drag was a meaningful measurement of efficiency. I'd argue that the higher prices of the early vehicles also means that a lot of early adopters were better educated, possibly in more technical fiends on average, compared to the average buyer in the market. Telling a farmer about his trucks drag coefficient isn't the selling point that it is to the engineer.
NeSToR_49@reddit
Because you need downforce to turn better in corners. Better handling in corners = more fun driving. Most people looking for fun cars like petrol engines. Also, most modern sportscars have active aero that tucks in the wings and front lips when going straight to minimise drag.
salvage814@reddit
The changing network still sucks is the problem. So you have to extend the range how ever you can.
TheKiddIncident@reddit
Car designs are driven by three things:
1) regulation
2) technology
3) market demand
For gas powered cars, market demand for efficiency has topped out. In the US market, you are not going to sell more cars because you get 5% better gas mileage. Thus, there is almost zero incentive to improve aero further. Most gas car efficiency gains have been driven by regulation in the USA, not by consumer demand. Features like auto stop/start are universally hated by consumers but they help the CAFE standard so they are very common. Just like automatic seatbelts twenty years ago.
For EVs, range is king. Most EV buyers state "range anxiety" as a major factor when deciding to buy or not buy an EV. For this reason, aero may be used to increase range. Even a relatively small range increase will improve an EV's market position. Another interesting side benefit is looks. Consumers expect EV's to look like spaceships. Blame the Prius, but if your EV looks like a big jellybean, the market will accept that. Until recently, EV sales were mostly driven by technology. Tesla did well because they had a better/bigger battery. They also had a better charging network. However, that advantage has vanished. Today, EVs are becoming more similar. This means that market demand and other factors will begin to drive the EV market more than just technology.
Pomador_0418@reddit
EV batteries are not as energy dense as a gasoline tank. For example, my EV has 73.5 kWh battery, the equivalent of 2.2 gallons of gas and it is a mid size suv. I can get 330 miles from that small “tank.”
A comparable Honda CRV has a 14 gallon tank or 472 kWh of energy and it only gets 42 mpg. I get 150 mpge.
The Honda CRV needs 472 kWh of energy to get 590 miles, while my SUV needs 2.2 gallons to get 330 miles.
Because batteries are not energy dense, to maximize the range EVs focus on aerodynamics more than gasoline cars. Once batteries become more dense and compact, then the obsession with low coefficient of drag will decline.
Gubbtratt1@reddit
An average EV battery contains the same energy as four liters of petrol. They have to be insanely efficient to get any sort of decent range. Electric motors are already 2-3x as efficient as petrol engines, but 8-12l of petrol is still very little.
SP3_Hybrid@reddit
Some of them are. Honda Insight, anything jellybean or Prius shaped.
Pickups and many SUVs and the like are more focused on looking mean, aggressive and intimidating these days, hence the brick-tier aero. And people only care during high gas prices anyway. Also electric cars get crucified for their race no matter what even though they’re not that much worse than some gas cars, since obviously you can just fill the gas car.
MagnusAlbusPater@reddit
Gas cars are usually designed to be aerodynamic as well.
Cars with wings and rear diffusers are typically either actual sports cars where the additional drag is worth it to produce more downforce for track use or cars designed to look sporty because people are willing to pay for it, in either case ultimate fuel economy isn’t their goal.
It’s similar to how popular off-road spec vehicles are these days despite the vast majority of their owners never going off of pavement.
People don’t actually use the capabilities of their Ford Raptors, Chevy ZR2s, Toyota TRD Pros, or Dodge TRXs but they’re willing to sacrifice fuel economy and ride comfort plus pay more to have the ‘tough’ look.
sonofeevil@reddit
Rear diffusers on most road cars actually reduce drag.
By cleaning up and smoothing the airflow as it leaves the bottom of the car it is able to "meet up" with the air going over the top of the car sooner and reduce the size of the low pressure wake behind.
This is one of the reasons that most modern cars have under trays now, it's not for cleanliness or aesthetics, it's to smooth airflow under the car and reduce drag.
Spoilers also reduce drag. Air is actually quite sticky and wants to follow the surface it's "attached" to. By creating a lip at the trailing edge you're essentially pushing the air off a cliff and giving it nothing to follow or stick to again, this also has the affect of reducing the size of the low pressure wake behind the car.
Note: spoilers and genuine wings are different animals.
Intelligent-Ad-6734@reddit
Raptor would be nice gliding over these horrid roads in the northeast lol
IceCreamforLunch@reddit
Buyers aren't as efficiency-conscious when they're shopping ICE cars. A five percent increase in efficiency might 31.5 mpg instead of 30 mpg in an ICE sedan and shoppers just don't seem to care about that as much as they do appearance. But a 315 mile range instead of a 300 mile range might make that headline spec higher than a competitor's and EV buyers definitely do look closely at that number.
But there has still been a huge push toward lower Cd designs, especially in smaller cars.
sohcgt96@reddit
Which is honestly reasonable. At that point, the net difference is so small, other factors become more important. I'm not going to buy a vehicle I like less than another vehicle just because its 5% more energy efficient.
But you're correct in that for EVs its trying to one up competition on a spreadsheet.
Living_Fig_6386@reddit
At the moment, the batteries used in EVs have a range of 250-400 miles, though in practice you don't want to run them down to 0 and many you don't want to consistently charge to 100%. So the practical range is 175-280 miles on a charge. There's a practical limit to how big you can make the battery (weight and volume), and large batteries aren't cheap batteries. EV drivetrains are about as mechanically efficient as possible, so there's not really much you can tweak there to eke out better efficiency; the only options you have are improved aerodynamics or more energy-dense batteries (in development).
A petrol car you typically make the gas tank large enough to carry fuel to go 300-400 miles. While deigning the car, you can easily tweak the size and shape to accommodate a gas tank that hits the target range to accommodate inefficient designs. You design the car as you like, adjust to get the target range, and then report the mileage. If the design is meant to be economical, maybe you sweat the drag coefficient, but if that's not the primary concern, you can ignore it.
There's the promise of batteries that have higher energy densities that allows more charge in a cheaper and smaller form factor, and ones that are more tolerant of going to the extremes of state of charge. It won't take too much of an improvement to more or less equalize the ranges of the vehicles, at which point they would have equivalent concern on efficiency.
Cold_Captain696@reddit
Range.
Economy is a financial issue in ICE vehicles, but with EVs it also has a practical impact that can have a fundamental effect on whether the car is considered usable or not.
OB1182@reddit
One of the selling points of saab was the low drag..
At 0,31 one for the estate.
Dexford211@reddit
CD of 2000 insight is 0.25
Ancient_Persimmon@reddit
There is a lot of focus on aero for ICE, but since combustion engines aren't very efficient to begin with, the benefit of better aero is that much smaller.
Wheel covers will bring 3-4% more range for an EV, but only about 1% for an ICE.
Boopped_Snoot@reddit
Most modern cars look like jelly beans because they actually are trying to be aerodynamic. Of course, emissions requirements mean even with modern aerodynamics, modern cars aren't really any more efficient than old ones.
I find it absolutely insane that my 02 trans Am gets better gas mileage than a lot of modern economy cars (regularly hits mid-thirties MPG) I've even had absolute land yachts like a Pontiac Bonneville which is a four-door sedan that could comfortably seat six or uncomfortably seat eight and with regularly hit MPG's in the low 40s with a. Supercharged 3.8L V6 that sounded amazing with glass packs and had enough power for effortless acceleration (mine also had a proper tow hitch and I used it to pull campers twice its size lol)
Gas cars also need a ton of air flow for cooling which means bigger grills and flatter fronts to direct air through the cooling system since they waste about 70% of the energy from gas as heat.
PurpleSausage77@reddit
I’ve had some slick gas cars, drag coefficient is one thing I use to pick cars lol. Means good design. My Toyota 86 has a 0.255, Model S 0.235, 2016 Mazda3 hatchback 0.26, etc.
No_Base4946@reddit
They used to be. The Citroen CX was called that because "Cx" is the term in French for drag coefficient ("Cd" in English), and there was one manufacturer - maybe Saab? - that had an advert in the 70s that said something like "One day people will ask 'What's its drag coefficient' instead of 'how fast does it go'", that I can't find on today's enshittified internet.
other_view12@reddit
It's about power. Air drag goes up exponentially (I think, it's certainly not linear) so the drag at 60 MPH is large and that take a lot of energy to keep that pace. It drains batteries fast. In gas powered cars, they have transmissions so the energy to push a car at 60 MPH is easier because of the gearing. Also, it's pretty easy to stop for gas and be back up to 60 MPH in no time.
OCsurfishin@reddit
It’s called a Prius.
Greenjeeper2001@reddit
Overcoming drag with ICE just requires more hp. Overcoming drag in an ev requires bigger batteries which kill overall performance.
iZMXi@reddit
1) Vehicle combustion engines in perfect scenarios hit around 45% efficiency. Realworld driving is often more like 20%. Electric cars are about 90% efficient regardless of how they're driven. 80% of the energy spent becoming heat vs 10%. So, combustion vehicles need a lot more open grill and radiator to catch air and shed heat. This is aerodynamically dirty, so it's simply not possible to achieve the same drag coefficient without major sacrifices to interior space, adding lots of expensively shaped bodywork to make the car bigger and trunk harder to get into, etc.
2) Combustion engines waste energy simply being on. Frictional losses from spinning, pumping losses from moving air, and thermal inefficiency from poor compression when the cylinders aren't full during cruising and part-throttle operation. The farther they are from \~80% load at moderate RPM, the greater percent of fuel they're spending simply being on. To a point, extra load comes cheaply. If an electric car has 5% more drag, it's using 5% more battery. If a gas car has 5% more drag, it might use 1% more fuel.
dr_reverend@reddit
Fuck me you are a funny one OP. There are many EVs with spoilers and wings. There are EV pickups! Where do you get off saying EVs are “obsessed” with low drag coefficients?
Terrh@reddit
The upper hand is the energy density of gasoline making the tradeoffs like wings and diffusers worth it.
neverspeakawordagain@reddit
The number one thing most people care about when thinking about buying an EV is the range, so manufacturers do everything they can to squeeze every bit of range out of the platform.
People don't care about that with gasoline cars because you can just fill up gas in 90 seconds anywhere at any time.
PckMan@reddit
Because people are not as concerned about the range of a petrol car.
mmspider@reddit
I personally think the design of low drag on EVs make them look weird and not as good.
Scooter477@reddit
They are, they just don't make a big deal about it.
toybuilder@reddit
When you have a power plant that wastes 70% of its power just to keep it running, wasting 5% of the remaining 30% starts to look like a rounding error.
On an EV, wasting 5% of power is nearly 3x more significant and has a greater impact on range.
TweeksTurbos@reddit
The body work added to the saab viggen helped over the standard 9-3.
Avery_Thorn@reddit
Because gas is relatively light and pumps relatively fast.
A lot of the drag coefficient is designed around increasing range and efficiency. With a BEV, you can't just add another 5 gallons on the gas tank, because the battery is heavier per unit of energy stored than gas + gas tank, plus the battery takes longer to recharge. The time difference between pumping 20 gallons and 25 gallons is minimal, and takes on order of 10 minutes to fully pump. And it adds about 40 pounds to the weight of the vehicle. An EV battery weighs about 5kg/kwh, and the 5 gallons is about 150 kwh, so that's an extra 750 kg or about 1,650 pounds - just for 5 more "gallons" of "gas".
So that's it. Having a very slippery, very efficient vehicle helps increase range without increasing battery size, and that makes it a lot more important.
Remember - a Model X battery weighs about 2600 pounds, compared to a Corvette which weighs about 4,000 pounds total.
nkrush@reddit
The simplish answer is: EVs are sold having a high range. If you want to increase the EVs range, you either need to increase the battery size, which is expensive, takes space and adds weight, so it's triple bad, or increasing efficiency like tweaking aero, which really pays off. The average ICE car buyer does not care about fuel efficiency that much, also because range anxiety is not an issue, because refuelling ist faster.
JCDU@reddit
Range is a massive factor in persuading people to buy EV's because charging is slow and chargers are not as easy to find, so every mile of range they can claim is a massive win.
With a gas car people don't care because filling up takes very little time and gas stations are everywhere.
NuclearHateLizard@reddit
The biggest difference is the extra airflow an ICE vehicle needs for cooling. EVs need airflow for cooling too, but they waste a lot less energy as heat. So a vehicle with an engine needs a larger grill opening, and the airflow that enters the grill usually ends up below the car, creating lift which is the opposite of what's ideal. It's simply easier to design an Ev to be more aerodynamic due to less limitations
generic2022@reddit
With a gasoline-powered engine, you can easily overcome drag by expanding the size of the engine and gas tank to give the car more power over a longer time period between fill ups.
With an electric vehicle, however, you can't easily overcome drag by expanding the engine and battery because batteries' charging lives are limiting factors. So, if you want to market the electric vehicle as having a long battery life (and this is a key marketing feature for electric vehicles), once you are already using the best battery available in the budget, you need to look elsewhere to maximize battery life. One easy target for maximizing battery life is reducing drag.
Stock-Swing-797@reddit
EVs need almost all of what they can get. A bit of increase in aero efficiency isn't going to move the needle on ICE cars.
yeeting_my_meat69@reddit
Gas takes <5 mins to put in your car and there’s gas stations everywhere. The EV obsession with drag has to do with the range the manufacturers can advertise.
snipsuper415@reddit
Do you live under a rock or are a bot? Literally almost all sports car do this.
Conspicuous_Ruse@reddit
They're sacrificing efficiency for sport with windgs and other down force creators.
They can easily and quickly add more fuel though so not using the supply they have efficiently isn't as big a deal.
lord_skidmar@reddit
definitely not in the engineering side of things, but my thought is EVs sacrifice range when they have additional drag, where that's much less of a concern with gasoline, and also they're kinda designed for different things, performance cars do want the "drag" for additional downforce & grip better on corners
Altruistic-Bat-9070@reddit
It can store more energy in a smaller space.
The issue with EVs is range and charge speed. Everything else is arguably superior. So the focus turns to these two metrics.
Charge speed increases through supporting increased voltage into the batteries whilst maintaining optimum battery temp. This is being resolved through improved heating and cooling features, circuitry that can handle increased voltage, improved high speed charger networks, improved battery tech that can take more power per unit time without blowing up.
Range improves by storing more energy or increasing effeciency. The main inefficiency in a car is ai resistance.
aringa@reddit
Because it's cheap to add range in a gasoline car. Fuel tanks are plastic and plastic is cheap. Engineering is expensive.
In electric cars, batteries are more expensive and so you can afford a little more engineering time and materials.