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Comment by MBCook | Hacker News Reader

The number of ICE cars I get stuck behind from time to time that just REEK is amazing. I’m in a decently well off area too.

Some putting off soot clouds, white smoke, nothing visible but clearly not doing complete combustion. Sometimes I wonder if half the cylinders are even working.

I’ve heard one car like that is the equivalent of a surprisingly large number of modern ICE cars is in good shape.

I love EVs. I’ve had one for 5 years now, and I’m glad they help. But I think the “are new EVs worse than new ICE” discussions so often miss a fact.

The pollution from ICE isn’t just from very modern well tuned vehicles, things vary wildly. But all EVs use the same power supply (assuming local grid only), so no individual vehicles put off 10x the pollution per kWh.

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My city is covered by a low emissions zone so the odd van polluting sticks out. I was in Athens recently and the pollution from so many old rough cars was so noticeable (and quite unpleasant).

Reminds me of how I didn't really notice cigarettes until they were banned from public spaces and the base level of normal was recalibrated.

Many car enthusiasts remove the catalytic converter for a combination of additional power and/or better sound. It has a massive impact on emissions and what you might be smelling is hydrogen sulfide which is normally converted to sulfur dioxide which is orderless.

I should note the power increase may not have a major impact on newer cars where the cat has been optimized to reduce it's negative power impact.

Infact a popular tuner company, APR, that provides flashes tested the recent Volkswagen GTI and R generation with their most common tune and determined that with their tune removing the cat had a nominal impact.

*Basically they can bring the cars power as high as the OEM internals can handle reliably while keeping the cat. There are cars where it still has some impact and of course, different from power ,"straight piping" a car can offer a subjective sound change.

For every car enthusiast there are probably a hundred poorly maintained vehicles on the road. Black smoke is likely soot, and white smoke is almost certainly an oil leak.

Oil in the exhaust in quantities high enough to produce acrid white smoke is extremely common on a number of ICE engines, like blown head gaskets on E25s (found in most Subarus before their Toyota involvement in 2010) for example

Subarus with bad head gaskets leak combustion gas into the cooling system displacing the coolant. If you run a flat engine low on coolant it will score the upper cylinder walls and the you will have oil consumption. This is fundamental to all flat engines. Oil in the exhaust is blue smoke. Coolant is white.

I never got the "blue" and "white" thing. Both look "white" to me, but you're right about subarus also leaking coolant in the exhaust which is easily identified by a "sweet" smell. Blown gaskets on ICE engines like E25s leak both oil AND coolant, no? I might be mixing up blown heads with cracked manifolds which often go hand in hand since temp extremes in engines fissure cast parts like the manifold. Either way the end result is the same: noxious fumes in the exhaust.

You've never see an old vehicle blow a substantially "bluer than normal" cloud. That's what I'm talking about.

> Blown gaskets on ICE engines like E25s leak both oil AND coolant, no?

This is way, way too broad of a statement. The Subaru EJ25 tends to leak oil externally from the valve covers. When they have head gasket problems it tends to be combustion gas into coolant which blows the coolant out the expansion tank until equilibrium is reached. Typical head gasket failures cause some degree of that but coolant mixing with oil is more typical. Many V engines have intake gaskets that can leak coolant into the intake or oil or both.

Regardless, if you can taste coolant in the exhaust the car is basically at the point of "fix it now"

> I might be mixing up blown heads with cracked manifolds which often go hand in hand since temp extremes in engines fissure cast parts like the manifold.

A sizable minority of cars don't even use cast manifolds anymore. While it's possible for cast manifolds to crack in a way that makes them leak that's rare and it's more common for them to crack their mounting tabs off. Steel exhaust tubing can and does sometimes break after many years of vibration, say nothing of rust.

While cylinder heads can crack it usually takes the kind of overheating that requires major work to fix in order to make it happen so just about nobody is driving around with a cracked head.

So I was going to reply to mention that all VWs sold in the US at least for the last 10 years use an iron block. I wanted to know if the EA888 (VWs go to 4 cylinder engine) was cast so I asked chatgpt.

"No — the VW EA888 Gen 3 engine block is not cast iron in the latest versions. engines.... use an aluminum alloy block, not traditional cast iron."

So I know for sure it's iron so I said "Are you sure it's an aluminum block on the gen 3"

"No — the VW/Audi EA888 Gen 3 engine does not have an aluminum block"

My experience is limited to cars manufactured before 2008 (back to 1928). Maybe the new ones are all welded cold rolled steel tubes but I've only seen cast parts for intake and exhaust manifolds, nearly universally. Shit cracked all the time.

This isn't a new thing. Jeep used "factory headers" on the last years of the 4.0. Ford did welded manifolds on the 5.0 Explorers. Subaru went to welded steel for the EJ series engine in the 90s. GM had them on the LT5 in the early 90s. Just about every application that has the catalytic converter right up at the manifold used a welded one.

I recently worked on a 2008 ej25 and it was definitely a cast manifold. Possible we're mixing up terms? Maybe you meant the ejs are cast steel instead of cast iron? When I read "welded steel manifold" I think of perfectly cylindrical tubes welded to steel plate for the mounts. Likely we're saying the same thing and manifolds are just cast parts that are welded together

Note that the one I worked on was in a US Forester so definitely not stock parts (j is for Japan)

EDIT: link to example 2005 manifold listing on eBay

https://www.ebay.com/itm/157306917967

> Infact a popular tuner company, APR, that provides flashes tested the recent Volkswagen GTI and R generation with their most common tune and determined that with their tune removing the cat had a nominal impact.

Do you mean minimal impact?

Probably. I read it as “had an impact but kept the performance stayed nominal.”

Yes. I made a mistake in how I worded that. They are able to tune to other bottlenecks in the car while keeping the cat.

As someone into performance cars and motorcycles, removing a cat is pretty uncommon, and you're generally seen as a dick if you do it.

There are a lot of "street mechanics" who will remove your cat for free without even needing to ask.

I could see a single "bad" ICE car being the equivalent of 100 "good" ICE cars. Even the VW emissions scandal (where the cars were still functioning as designed, just not as well as they should) had instances where pollutants were 35x higher than they should be. So I could see an emissions deleted diesel (of which there are many, i.e. catalytic converter and DPF removed) could easily have more than 100x the usual emissions of noxious substances. Maybe even more! Especially if (as is often the case) the DPF was removed because something is faulty on the engine and was overwhelming the capacity of the DPF in the first place.

You can smell these cars from halfway up the road sometimes, when they're 100 metres ahead.

I don’t have hard numbers on this, but I once read a claims that the lawnmowers and weed-whackers in California with their two-stroke engines are responsible for more nitrate and particulate emissions than all the cars and trucks in the state put together, even though by fuel burned the latter outnumbers the former by orders of magnitude. I could totally see a malfunctioning four-stroke ICE with dirty burns being worse than 100 maintained ones.

That probably explains why California banned the sale of gas powered leaf blowers, law mowers, and weed whackers in 2024. You can still use them if you have an old one or by one out of state.

And at the right time too. At almost every point before that, a gas powered engine was justified for duration and power, but the significant advances in both batteries and electric motors in the past 10-20 years have finally made them good enough that ICE tools are totally unjustified.

> the lawnmowers and weed-whackers in California with their two-stroke engines

What's the intended precedence in that sentence?

I ask because I've never seen a lawnmower (in the US) with a two-stroke engine. There are probably some, but they're not common.

Even modern cars pollute a lot (especially in winter) because you need a certain temperature for the cats to start working. On short city trips it happens frequently that you never reach proper operating temperatures.

I used to work for the Air Resources Board of California, and while there is a warm-up period, modern ice cars are so profoundly cleaner than cars even from the early 2000s. It’s pretty stunning.

Regardless, there’s nothing cleaner than no combustion, and I can’t wait until EV‘s have replaced them all

Yes, any cyclist daring to drive in winter can easily confirm this. It is so disgusting (and unhealthy) having to stand behind a ICE car on a traffic light and being behind a electric car is such a relief, that thoughts of wishing to ban all ICE cars as soon as possible (at least in cities) come automatically.

Modern ICE cars have auto start/stop systems, so on a traffic light it has as much exhaust as an EV.

Also when the temperature is really low? Does not seem like it.

Also at some point they will start their engines again. Guess who will inhale that?

Ironically though, cyclists inhale less pollution than drivers (who inhale the most)!

Sources: https://usa.streetsblog.org/2019/10/08/report-drivers-arent-... which references the BBC

But not every car on the road is modern, and it smells like crap as a result

> auto start/stop systems

Most start stop systems will disable themselves when the heater of the car is turned ON and the car engine not hot enough yet.

As a cyclist (or motorbike owner), it is pretty usual in city to have >50% cars with engines ON at traffic light in cities when temperature are low.

The tire dust crossing the bridge that's next to four lines of heavy traffic isn't much better than the exhaust fumes IME.

Buses are my nemesis. Some of the dirtiest exhaust on the roads.

You could run them on propane, which doesn't need the catastrophic converters - they make no difference at all if there's no CO or HC in the exhaust stream.

You've got the added bonus that you don't need to strip-mine huge chunks of Africa for precious metals, too.

I try to keep my cat indoors, but he won't work anyway. Maybe I should get one of those newer electric cats.

Speaking of smells....

One good thing about driving an EV is that weird oil or hot coolant smells are from someone else's car (and not a problem with your car)

(although yes technically many EVs have coolant loops)

As the fleet of EV's age, I'm sure we'll see equivalents...

"The high voltage wires were just dragging on the street sparking, presumably with all the safety features disabled"

"They were driving with a 10 gallon coolant tank on the roof, presumably because the coolant loop had a big leak and needed continuous topping up".

Are those even user serviceable? So, it won't stop everyone but it will stop most of them.

It isn't until it is. Manuals will appear, guides will show up online, shadetree mechanics will get better at electronics(they used to be experts in carburetors after all), software will be cracked if necessary.

You're not allowed to drive cars like that in a functional society. When you go for your compulsory car checkup it wouldn't pass the required safety standards.

while I agree, there's many places where the compulsory car checkup is tied to your relationship with the mechanic. I don't think my parents ever had a "valid" car but the certificate always was. It never felt wrong (although I think it is) but more like mutual aid or service.

There’s also the fact that nearly 1/4 US states require no emissions or safety checks whatsoever [1]. So everything is valid by default and realistically the only thing stopping you from driving a literal rust bucket, with tailpipe dragging, poor combustion, or modified emissions filtering (like modifying your truck so you can roll coal down Main Street) is it a cop feels like pulling you over for it

[1]: https://goodcar.com/car-ownership/vehicle-inspections-by-sta...

What is allowed and what actually happens are two very different things, my friend.

In the neighbourhood I live, there's a guy who visits someone here several times per week. His headlights are broken, the tires are worn smooth, the exhaust is loud beyond all reason. Given the general state of the vehicle, I don't have high hopes for the brakes.

I reported it to the police. I'm really not the type of person to do that, but this is worse than anything I've seen. Of course nothing happened. I didn't even get a reply. They don't give a shit. Some day that guy is going to rear-end my car and break my neck because his brake lines finally gave out.

Also, the compulsory car inspections only work for honest people. People with illegal mods will put back the stock parts for the inspection, and switch them back after. I'm not gonna say the inspections are worthless, but it does make a lot of money for the state and the private actors who run the inspection centres.

EDIT to add: They made a law recently that the inspector has to take a photo of the car inside the inspection centre, because there was so much fraud happening with vehicles just being "inspected" on paper.

What I think is missing today is a way to challenge someone else's car. A few independent reports should force an early checkup, and if passed soon after the accusation, the accusers should get their own just to have something at stake.

It's missing because letting the minority of Karens harass everyone like that would cause the political will for the inspection programs to evaporate instantly.

Second, places with high touch governments already lose out on business due to registration arbitrage. Your proposal would dump gas on that fire.

A functioning bureaucracy can handle false reports. If someone has a habit of making false reports, they'd be ignored or even punished themselves.

I think the point they're making is that the ICE cars that OP is complaining about also aren't supposed to be driven in a functional society. The difference is that mostly wealthy people can afford EVs: https://ampo.org/electric-vehicles-are-out-of-reach-for-most... thus they stay maintained and have a polished image.

I think they are more accessible now than when that article was written. My wife and I bought a mid-trim Hyundai Kona Electric for under $35,000. Besides, lots of people buy used cars, and there are crazy deals on used EVs. I've seen Bolts go for under $15,000. 2 year old ID.4s are selling for under $20,000 in my area. You may not find a $5,000 beater, but EVs are penetrating further into the middle of the market now.

There are also lower ongoing costs for maintenance and fuel.

There is still the secondary wealth filter of having a place to park and charge, of course.

Most EVs have lockouts that will be very hard to bypass for things like this.

It’s more ‘I could have replaced a few cells in my battery pack, but the car bricked itself when I opened the pack! Assholes!’.

Notably many recent ICE cars aren’t much better.

Where I live there are yearly check ups that you need to do, or you simply cant legally drive your car

Unlikely. Many of these sensors are mostly CAN-based, rather than hardwired. It would be a time consuming enterprise to custom bake a solution for each vehicle model to fake out protection systems. For better or worse EVs are substantially more difficult to modify than typical ICE.

Only takes 1 person to make a "safety system faker: Makes car run even with faults" which is a $20 thing you can buy from aliexpress and can be clipped anywhere onto the canbus - just two wires to hook into.

It then runs code which auto detects the car model (fairly easy from the messages on the bus), and has a database of the messages to send/inhibit to change the behaviour in the desired way.

Because so many cars use electronics that are common across a whole manufacturer of cars - ie. all GM cars, or all cars with a Bosche ECU - there won't be awful lot of work making it compatible with hundreds of models of car.

Such devices already exist for faking data for engine tuning, and for faking 'zero faults, all monitors pass' to pass government tests.

You basically get internal faults and cable faults with HV stuff. A box reporting that the AC compressor motor winding isn't shorted isn't going to make the compressor work with a shorted winding. ECU probably wouldn't disengage the powertrain for that though.

And then things like battery temperature warnings will quickly turn into real failures.

And then the next generation or 2 of stuff is going to at least attempt to implement cybersecurity features that greatly complicate tampering at the message level.

If your high voltage line is conducting enough to the ground that it's sparking, your vehicle isn't going to work. Electricity follows the path of least resistance and a path to ground is a lot lower resistance than a motor coil.

EVs eliminate a lot of polluting failure states of ICE vehicles. There just simply aren't that many things to burn or leak and still have a functioning vehicle.

As an aside, I'd like to mention that like 9 times out of 10 if you are driving down the road in an ICE vehicle and smell weird oil or hot coolant smells you are smelling someone else's car. The wind blows away a lot of your own stink before it gets to you. I learned to ignore anything that didn't smell 1) when I was stopped, and 2) more than once in totally different locations. After trying to track down smells that I thought were mine and were invariably from someone else nearby.

I’ve driven an EV for 5 years now, and I still occasionally think it’s something wrong with my car, instinctively lol

I'd say that putting off sooth clouds is a way to sequester carbon (which obviously failed to burn). Such over-enriched fuel mixes must generate much more CO though, and I wonder if those who "tune" their cars like so take care about the catalytic converter :(

The health consequences of inhaling exhaust particulates are far more harmful than the equivalent CO2 contribution to greenhouse effect warming unfortunately.

All in all, a well tuned ICE is better for everyone than a poorly tuned one, if you had to pick between the two.

> The health consequences of inhaling exhaust particulates are far more harmful than the equivalent CO2 contribution to greenhouse effect warming unfortunately

Short term for the individual definitely, but long term for all individuals affected?

At least soot from ships is an issue in high latitudes, as it turns out that the soot reduces the albedo of the ice and it thus has an outsized global warming impact.

I know in some car tuning circles, or even just blue collar Joes in some places, will recommend removing the catalytic converter. Supposedly it makes the car use less fuel at the cost of worse emissions, and can make it sound better for those who care about that.

Depending on the type of catalytic converter, both of those things can be true.

> get stuck behind from time to time that just REEK is amazing

It’s crazy. How do we even allow selling cars without HEPA filters.

HEPA filters stop dust particles and not those tiny organic molecules that cause the smells. Filters for these exist as well, usually used in respirators, but those need to be exchanged pretty frequently and are not cheap.

Activated charcoal filters are a common option even out of the factory, and I’d be surprised if there were a car you can’t get them aftermarket. They don’t last that long but honestly I’d recommend swapping the cabin filter yearly anyway.

Someone recommended them to me years ago and I’m never going back.

One of the reasons I wrote the comment above is because my filter has worn out and needs replacing, so all of a sudden I can smell all this nonsense again.

1000% with the money.

I never smell anything in my Tesla. Only my own farts.

We love privatising the benefits and socialising the harms of everything.

If the exhaust had to go through the cabin so the driver got the worst of it, car exhaust would be the cleanest air on the planet within months and/or alternatives to cars would rocket.

But as long as it’s other peoples health affected, meh.

> If the exhaust had to go through the cabin so the driver got the worst of it, car exhaust would be the cleanest air on the planet within months and/or alternatives to cars would rocket.

This is why forklift trucks and Zambonis run on propane instead of petrol or diesel. If you burn gas, you get no carbon monoxide or unburnt fuel because it runs ever so slightly lean and all the fuel is burnt.

This means keeping the air clear is just a case of getting rid of carbon dioxide and water, so you can open some vents (warehouses have great big vents, big enough for trucks to drive in and out...) and let the place air out. You won't die if you breathe it, unlike the CO and unburnt fuel from petrol and diesel engines.

It's a simple and inexpensive conversion, too.

That's very interesting. I guess it could be a great option for when the % of ICE vehicles is low enough, it might be practical to ban more polluting fuels.

(Edited to add) Hmm actually people are already doing LPG conversions today as it's cheaper. Not sure if all LPGs are as pollution free, though.

It depends how you do it. The conversion on my elderly Range Rover is not as efficient, being an old-fashioned "single point" system - this has a thing a bit like a cooker ring attached to the throttle, a stepper motor controlled valve driven by a third lambda sensor, and a thing to disconnect the petrol injectors when it switches to gas.

You can get ones with a complete set of LPG injectors and an ECU that takes its timing from the petrol injectors, and these are incredibly efficient. They're a bit harder to install (you need to drill holes in the intake manifold, it's a faff) but the engine can be mapped for even more power than on petrol and a tiny amount of pollution.

There's still a lot of CO2 and water vapour, but as previously discussed you're burning all this shit anyway so you might as well extract useful work from it.

The time to have done this was 25 or 30 years ago, when it was ridiculously cheap to buy gas and there were a lot of old-fashioned carburettor-fed cars that were incredibly badly polluting.

I feel like ICE cars put out such a quantity of exhaust that any HEPA filter you put on it would reach its end of life within a few hours of driving.

We have mandatory inspection of road vehicles almost every year and we measure exhaust as part of it.

White smoke is water vapor. It's a normal byproduct of hydrocarbon combustion and tends to condense in the exhaust at low loads or immediately after exiting the exhaust, especially in colder temperatures, so you'll see a lot of it in stop and go traffic.

> White smoke is water vapor.

Could also be coolant or oil

Even the faintest bit of oil will turn the smoke blue.

Could be coolant, but "coolant into engine" failure modes are generally rare and are usually the kind of thing that needs to get fixed promptly.

Coolant will have the dead giveaway sweet smell.

If it "reeks" though it's not just water vapor. I see a lot of these cars too, and you can tell it's been going on for a long time when the back of the car is covered in a layer of black grime. I think that's what kind of car problem the post is referring to.

tragically, because of efficiency standards, modern engines are known to burn oil .

Otherwise you may be smelling cars who have had the cats stolen.

A lot of old cars also since new cars are so expensive.

I think expense is basically the problem.

Cost to replace the catalytic converter, cost for new exhaust pipes, cost to diagnose ignition timing problems. Whatever.

If the car drives and you don’t have the money I can completely understand why someone wouldn’t get the problem fixed. Even if it means they’re burning a 1/3 of their fuel, that’s still less in the short term than the $1500 it may cost to fix it.

It’s insanely rare I get the sense that the person is running really dirty on purpose.

I don’t know what a realistic fairway to fix it is. They’re probably isn’t one. I don’t think fines would work, it would probably just make things worse. Seems like the kind of thing where a little government group to find the worst 0.1% of cars on the road and just get them back to reasonable levels would be a huge help.

But that’s not how we do things.

Some states handle this by requiring cars over a certain age to be emission checked before you can renew its registration. Failing cars have to be fixed and rechecked before you can get your tags.

I think they stop checking cars after a certain year. Like, if you are driving a 1980 Buick, they won’t make you scrap it because it’s emission tech is way out of date.

I can only speak about Germany. Here the technical safety and exhaust check are mandatory every two years. The exhaust check is relative to what the manufacturer specified when they first started selling the car. No one is getting their car taken away because technology improved but you can‘t let your car degrade (or modify it) so it becomes more dirty.

Oldtimers are still excluded from all emissions checks.

I live in one of the US states with no emissions checks at all.

Well that’s not strictly true. If you move into the state you have to get one emissions check to get your car licensed.

After that, or if you buy the car in the state, no checks for you.

Yep. My newest car is over 20 years old. May be a bit more polluting (though it doesn't smell or smoke) but I've in theory saved the environmental impact of the manufacture of one or two new cars by keeping the old one.

I'm not spending $30-40k or more on a car. That just isn't going to happen.

2005-ish cars were more reliable and had better emissions profiles compared to cars today. Yes cars today are more advanced ,but less reliable, so their emissions overall are worse.

Stolen cars, exhaust leaks before the cat, incomplete combustion so bad the cat can’t cover it up. I assume it’s stuff like that.

It’s not whatever tiny bit of oil gets burned in a healthy engine.

Incomplete combustion will ruin a cat. That's not its purpose, it's there to reduce NOx emissions.

A lot of Americans take their cat off on purpose for louder noises.

Additionally, a lot of conservatives love to "Roll coal", and literally will shit up the environment on purpose just because they feel schadenfreude from pissing of an environmentalist.

I’ve run into a few of those. They’re generally pretty obvious. Usually a big truck, lots of MAGA & adjacent bumper stickers.

I haven’t noticed people removing the catalytic converters just for noise. The rare time I see a car that wants to be loud it usually just seems to be the exhaust end they changed, or maybe removed the muffler.

The kind of stuff I’m complaining about mostly seems to be older cars, or those in poor mechanical shape. Cases where the people probably just don’t have the money to fix it.

> A lot of Americans take their cat off on purpose for louder noises.

Some people remove catalytic converters when they install a performance exhaust. Nobody is doing it for louder noises because the muffler portion is what dampens the sound.

Also I wouldn’t say it’s “a lot of Americans”. We have emissions inspections in most major cities and your car won’t pass if you remove the catalytic converter. They can now detect modified ECUs, too. Someone would have to be so determined to do this that they’d swap the exhaust in and out every time they had to do emissions inspections.

I know a LOT of people personally who swap their exhaust in and out just for emissions inspections. That's the meta.

a lot of people have custom exhausts, particularly catback systems that don't affect emissions. A lot of people are definitely not rolling coal.

Yeah, it's definitely a small percent of people. But i do wonder how many there really has to be to have an outsized effect. One of those lifted kid killers blowing black smoke for the entire duration of the bicycle pack is definitely more than 3 of my tiny honda civics, i wonder how many it really is, and how much those modifications increase the "resting emissions rate"even when not blowing shit. Should be illegal, likely is.

I'd wager it's largely disruptive and dangerous in a highly localized way due to the small percentage of folks doing it. Doesn't make it an acceptable practice though. One person "rolling coal" can temporarily blind 3 or 4 cars back and several across depending on wind conditions, etc.

In terms of NOX it can be a factor of 100. If 1% drive without cats they produce half the NOX emissions. In reality it is probably less since there are other old cars as well that have higher emissions

I live in a progressive state and unfortunately encounter "coal rolling" regularly. I also assume that's the point. Someone has to "own all the libs" as it were

However, I do agree that there aren't enough folks "rolling coal" in aggregate to really move any needles on planet-scale environmental impacts though. Just VERY unpleasant to be caught behind.

Conservatives seem to be largely unaware that most libs already have an owner and don't need any further owning.

The internet classic “I know a lot of people” does not substitute for your original “A lot of Americans” claim

You’re describing your small friend group, not Americans in general.

You got ratioed. I’m way up in upvotes from Americans who know that I’m right and you’re wrong! Na na na na na na!

Sometimes the plural of anecdote really is data.

> Nobody is doing it for louder noises because the muffler portion is what dampens the sound.

Cats also act as mufflers, they significantly reduce the sound coming out the exhaust.

I had downvotes on this post until you (and the other car enthusiasts) pointed this out / saw this.

HNs lack of knowledge around cars is sort of frightening.

Don't worry, it's just cars. You can trust the rest.

If I had to guess, the downvotes were from the “A lot of Americans” claim

> HNs lack of knowledge around cars is sort of frightening.

I actually have a lot of knowledge and experience in the automotive space, including with exhaust systems!

Catalytic converter removal alone doesn’t have a big change exhaust tone. I have seen it first hand, and also with 100-cell and 200-cell race cats as an intermediary step.

Your posts are full of condescending assumptions about Americans and HN’s comments about cars, but you’re ignoring the actual facts others are trying to share.

They muffle slightly, but removing the cat alone isn’t going to make a big difference with modern high efficiency single cat exhausts.

I’ve seen (heard) the effects first hand. Trust me, people aren’t removing the cat just to make their car annoyingly loud. If they are, they’re going to be disappointed.

Besides the crap they pump into the air, they also excrete gunk onto the road. It’s so primitive.

The exhaust from a well functioning modern ICE is likely enough to have less pollutants than the air. Of course it still has carbon dioxide, but less other pollutants.

you still have tyre rubber, which is a major source of microplastics

And not a distinguishing factor of ICE vehicles

EV have far more tire wear because they are heavier and also probably from regenerative braking

Why would regenerative braking emit more particulates? It’s no harder on tires than braking mechanically but doesn’t abrade the pads or rotors.

>> EV have far more tire wear because they are heavier

Is this true?

If an EV were 30% heavier than an ICE, would it produce 30% more tyre wear emissions? Or would it produce more or less than 30%? Is the primary factor in tyre wear weight and is the relationship linear?

The types of tyres appear to be quite different, the EVs seem to have smaller contact patches (narrower wheels) and they're made of different "less grippy" compounds that drag less. Does this change the equation at all?

yeah I just wanted to contest the very idea that a car could be clean.

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