For daily driving over 200k miles, do naturally aspirated engines still hold a reliability edge over turbocharged ones?
Posted by EvelynClede@reddit | askcarguys | View on Reddit | 147 comments
TemporaryKooky9835@reddit
Stresses are definitely higher. Consider somethinf like a 1.5-2.0 liter turbo four vs a 3.0-3.5 naturally aspirated V6. For the same power, each cylinder of the turbo four must produce 1.5 times the power of each cylinder in the NA V6. This increases stresses all around. Sure, you can make stronger components. But (1) it’s harder to make these things stronger when they also have to be smaller (think small pistons, rods, and crank trying to make V6 power), and (2) cost constraints get in the way of optimal designs using the best possible materials.
CrazyJoe29@reddit
In general: as conplexity increases, reliability decreases.
I’m not aware of any engines that become more reliable once a turbo is bolted on to them.
william_f_murray@reddit
7.3 IDI would like a word, but that's generally true of all diesels.
NathanDeger@reddit
Does anyone even sell a naturally aspirated diesel anymore?
Bagomostlywater@reddit
A diesel is a great engine to turbo but it’s not the same for gasoline. Diesels like to burn lean, gas does not.
SkiyeBlueFox@reddit
Honestly turbos seem tailor made for diesels. Thing wants to breathe and we're shoving more air through? Works a treat
biggunzcdb1@reddit
Boost was invented for diesels. The 1st hot rodded gasoline cars used old diesel super chargers. Way before turbos showed.
TunerJoe@reddit
Superchargers existed years before the first diesel engine was made
SkiyeBlueFox@reddit
Oh it seems tailor made bc it was lmao
crazykingfear@reddit
They sell tons of them, just not in road-going vehicles. Small diesels in lawn mowers and small tractors are commonly naturally aspirated.
Individual_Step2242@reddit
Yep my Kubota 17 hp lawn tractor is a NA 3-cyl diesel.
series-hybrid@reddit
Yanmar boat engines.
maybach320@reddit
Hard to know they still haven’t made it to a phone given how slow the acceleration is.
william_f_murray@reddit
Not to my knowledge, no.
Individual_Step2242@reddit
Until emissions diesels had a lower exhaust gas temperature than gas engines so their turbos weren’t stressed. Now with diesel particulate filters that periodically burn off soot, EGT on diesels can go very high. Diesels, at least for light vehicles, are no longer all that cost effective due to complex emission control systems.
Last year I sold my VW Sportwagen, gas, turbo. The turbo failed 1000 km before the warranty expired. I replaced it with a RAV4. No turbo!
ajaxp0wder@reddit
What mode did your turbo fail? Lots of times the waste gate gets stuck and can be fixed with some PB blaster and manual function
240 ExxonMobil mileage factory turbo sport wagon.
Individual_Step2242@reddit
It was indeed the wastegate actuator. However the car was still under warranty so the dealer replaced the turbo. Got lucky, it was 1000 km before the end of the warranty.
ajaxp0wder@reddit
It blows my mind that VW replaces the turbo when this happens.
OrganizationNo42069@reddit
Ford 2.7L is rock solid for having two turbos.
Ok-Office1370@reddit
This is 1900s thinking, and it's all relative. For example, lots of diesels are blown and run forever. Lots of ultra reliable cars now have variable valve timing.
Today's cars are much more complex than older cars. Today's cars last forever compared to old cars. You're just used to survivorship bias. Heaps of Ford Model T's didn't last. You see a restomod in a museum and go wow cars back then lasted forever.
7ar5un@reddit
This ^
the one caveat being; as long as the engine was designed with forced induction in mind. It should last just as long.
There are other factors at play though. Epa regulations, di injection, low tension piston rings, thinner walled and lighter engines.
Forced induction engines can absolutely be reliable. But manufacturers are forever cutting costs, cutting corners, and trying to maximize profits as much as possible.
sunvisor69@reddit
BS. Profit margins for cars is way lower now than it was 40 years ago.
Brilliant_Account_31@reddit
Sure forced induction can be reliable. But it is inherently less reliable compared to one without.
Calm-Frog84@reddit
What about a non turbo car of today compared with a turbo car of today?
I own a 2015 turbo diesel honda civic, and had to replace the turbo at only 190 000km.
I also own a 2019 naturally aspirated suzuki Baleno, and I will never have to pay a new turbo for it.
Why are you comparing old naturally aspirated car to new car with turbo? This is not the question that has been asked.
AlaskaGreenTDI@reddit
Does having to replace the turbo once make it unreliable though? Or is that just an added expected maintenance item?
Calm-Frog84@reddit
Yes, the fact that a component may fail affects the reliability of a car.
(And my car was serviced by Honda dealership as per maintenance plan for its whole life.)
https://en.wikipedia.org/wiki/Reliability_engineering
So: - from a theoritical point of view, the simple existence of a component makes a reliabilitity hinderence, execept if it improves the reliability of other components beyond its own failure occurence probability (think about cooling system for instance);
-a turbo has a significant probability to fail between 100 and 300 000km, and 300 000km is a pretty common usual service life for a car.
AlaskaGreenTDI@reddit
So if it needs a timing belt at 100k miles, is that a failed to you or maintenance?
Brilliant_Account_31@reddit
If you could build the same engine without a timing belt, then yes, that would make it less reliable.
Calm-Frog84@reddit
Please refer to what I wrote 2 comments above:
"from a theoritical point of view, the simple existence of a component makes a reliabilitity hinderence, execept if it improves the reliability of other components beyond its own failure occurence probability (think about cooling system for instance)"
Calm-Frog84@reddit
From the article I have sourced:
". Reliability is defined as the probability that a product, system, or service will perform its intended function adequately for a specified period of time; "
So if maintenance plan that service belt has a service life of 100k and you change it at 100k, it is planned maintenance; and if service life is defined as 200k and it fails at 100k, it is a reliability issue.
If one over xxx timing belt fails before end of it service life while one over yyy timing chain fails before end of it service life and xxx<yyy then a belt is less reliable than a chain.
So back to the turbo discussion: a turbo that has a significant probability of failure before end of the car service life and no indication for change in car maintenance plan is a significant reliability issue. It does not mean it is bad to have a turbo in a car (since it has other benefits like better performance), but it impacts on car reliability shall be considered if reliability is an important factor.
7ar5un@reddit
By that logic, a ford model T is one of the most reliable cars ever made...
Calm-Frog84@reddit
No it looks you misundertood, unless you consider a Model T would never fail and only planned maintenance would be performed.
Push__Webistics@reddit
I would say it depends on how many miles are on the turbo and how many long it is expected to last. The manufacturing quality of the turbo is also something to consider. Turbos are a wear item with enough miles at the end of the day.
coastalneer@reddit
Yes but compare a modern turbo diesel truck for example to a modern naturally aspirated v8 truck of the same model.
Across the board and the NA trucks are more reliable, less maintenance, and cheaper than the turbo diesel equivalent.
bickdiggles@reddit
You’ve managed to miss the point entirely
Jubsz91@reddit
I would trust an older truck (Toyota or Ford) with an iron block v8 over the new twin turbo v6 models by a long shot. Mine is nearly 20 years old and has 215k on it. No real concerns. The TT v6 drives really nice but that’s a lot of complexity compared to my dinosaur.
elementarydeardata@reddit
Especially when you consider most modern turbocharged engines (the good ones anyway) are designed with this in mind; they aren't an NA engine that someone added a turbo to. I would guess that this is why turbodiesels aren't perceived as unreliable. They've been designed for a turbo for several generations at this point.
quizzicalbear@reddit
We're not comparing 1900s naturally aspirated engines to modern turbo engines. If we are comparing like for like, the above poster's statement stands. Why wouldn't a more complex machine be, in general, less reliable and more expensive to maintain than a simpler one?
Jakomako@reddit
Turbo can be a decrease in complexity over the alternatives. For example, 2 liter turbos compete with V6s. V6s tend to have two cylinder heads. I’d consider a turbo to be less added complexity than an entire additional cylinder head.
Own-Inflation8771@reddit
Yeah. Interestingly it is a decrease in complexity due to less moving parts but not necessarily an increase in reliability. With the V6 you still dont have something spinning at 100k rpm with forced induction trying to blow off both heads constantly and carefully calibrated software/sensors preventing that from happening. Also the 4 cylinder with a turbo is often doing the job of a V6 or V8 and is under a lot more stress throughout it's life compared to a big lazy v8 that just has to go a to tick over idle before the car is at go to jail speeds.
ABobby077@reddit
Any turbo 4 I have owned was running at a higher RMP in highway driving speeds vs V6. I just wonder if longer term if running at a higher RPM continuously would put more stress and wear on a 4 cylinder vs a 6 or 8 (??)
Own-Inflation8771@reddit
Yes ofc.
Brilliant_Account_31@reddit
Yes
Sad-Offer8857@reddit
I guess in the end it just ends as a bunch of trade offs. 4 cylinder with turbo will be worked harder as compared to a v8 if they are making the same amount of hp/torque. But your v8 will be consuming much more gas as compared to your 4 cylinder turbo.
gotcha640@reddit
Are you asking for no replacement parts? I’d be skeptical of picking out any individual engine and saying “Weld that hood closed and drill a couple holes, all we’re doing is oil changes and wiper fluid”.
Every one of the 22 cars I’ve owned have needed some kind of replacement - water pumps are common in the 80-120k range, alternators and starters maybe a little longer, timing belt has a replacement schedule.
Is a turbo different because it’s more expensive? A timing chain is the same or more.
mar78217@reddit
How do you drive 200k miles in a day?
RaylanGivensOtherHat@reddit
You set the cruise control to 8,500 MPH
ConsistentMove357@reddit
More moving parts
Ok-Highlight-3402@reddit
I don't know. I'm at 197.900.
Still on the factory turbo.
Other than the factory PCV system and some parts of the cooling system being silly geese the engine has been quite reliable.
ScaryfatkidGT@reddit
I would say yes, other than diesels
They COULD use expensive ball bearing turbos and not have all the extra oil lines and issues but they always go the cheap rout
AvesPKS@reddit
Not sure of the veracity of this, but Pat Goss referred to it as only being able to get so much power out of an engine over its lifetime. So his idea was that as you upgrade specific output, lifetime output decreases.
jondes99@reddit
In a row?
No_South_9912@reddit
I'd be more concerned with transmissions and electronics in modern cars vs the turbos.
AdInternational6902@reddit
Depends on how its designed
A natural aspirated ls3 or pre gen 3 coyote will run forever
A Kia/huyndai thretta 2 motor will be lucky to make it 60k miles without shitting the bed
A ford fiesta st 1.6 will go 300k+ with just maintenance
Where a honda 1.5t will blow its headgasket before 100k
Now if you take a generally reliable natural aspirated motor and than turbo it without any other design mods, sure you'll end up with a less reliable engine, however today thats not really how engines are made. An example would be mazdas 2.5 na skyactive engine and their turbo, sure they are the same engine, but the turbo has significantly beefed up internals, oiling and cooling which theoretically should mean it will last aslong as the na version.
AtomKreates@reddit
TLDR: if I can’t get 200k plus with two modded turbo VW’s and nearly a 3rd, so can anyone.
200k+ miles on two 1.8t Volkswagens that both had stage 1 ecu tunes. One was a 2004 GLI with the AWP variant and the other was a 2014 Jetta 1.8tsi ea888. The two most bullet proof cars I’ve owned. Anecdotal sure but if you take care of your cars they will, for the most part, be good to you in my experience. Honorable mention: I also had a mk3 vr6 gti I turbocharged at 90k miles and sold it at 150k. It made 315whp 290wtq on 93 at 10psi. Original head gasket to boot.
VarmintTheCritter@reddit
GM won't even make a small block V8 that doesn't spin its bearings any more. In my experience, anything made in the last five years or so is a toss-up regardless of aspiration.
basscycles@reddit
A low pressure turbo reduces stresses on the crank, conrod and piston on the inlet stroke. In an NA engine the piston pulls fuel mix into the combustion chamber putting stress on those parts, with a turbo the piston, conrod and crank do less work on the inlet stroke. Once you turn up the boost the stress reverses and the piston, conrod and crank get more force on the combustion stroke. A turbo engine generally produces more power at lower RPM so the motor doesn't have to spin as hard meaning less wear and tear on bearing surfaces and rings.
So the answer would be in low pressure situations the internals of the engine are less stressed, though you have the extra complexity and parts. In performance situations you are creating a more efficient hand grenade.
Banishedandbackagain@reddit
Brand matters more than turbo vs NA for reliability.
I'd say turbo reliability has improved so much that it'd be close, but you would probably need to replace the turbo, 200k miles is a long way.
bruh_the_person@reddit
Brand doesn’t matter at all, “good” brands can shit out bad cars and “bad” brands can make good cars
newtonreddits@reddit
What's an example of a bad brand with a good car?
Fancy_Chip_5620@reddit
Ford fusion 2.5 naturally aspirated with a normal automatic transmission
newtonreddits@reddit
Lol is that a good brand bad car example?
Fancy_Chip_5620@reddit
Bad brand good car
newtonreddits@reddit
Can't tell if joking. Ford's bad brand good car is the GT.
Fancy_Chip_5620@reddit
Im a ford tech, those fusions in particular are good "white rice" cars
newtonreddits@reddit
Gotcha good to know. Any other Fords that seem rock solid?
Optimal-Giraffe-7168@reddit
Had to circle back to name the Durango. That's a product that is too good for dodge and it's now sold at a good price. You'll just also be paying through the nose at the pump
bruh_the_person@reddit
I don’t consider brands good or bad, that’s why I put it in quotations. But for most brands that you might personally consider bad I could probably name at least one good car from them
newtonreddits@reddit
Stellantis from the past decade
Optimal-Giraffe-7168@reddit
The only stellantis product anyone should be cutting right now should come with a Cummins... and only if the buyer can afford it
bruh_the_person@reddit
Alfa Romeo Guilia Quadrifoglio and Dodge Charger and Challenger (the outgoing generation with the hellcat, not the new one) are two that come to mind. I don’t even think the new one is a particularly bad car it just doesn’t have a place in the market for the price
newtonreddits@reddit
I suppose those are "good" for stellantis
Optimal-Giraffe-7168@reddit
Chevy is a historically good brand that's recently gone quite bad. They can't even produce reliable cars from reliable formulas anymore.
doc_55lk@reddit
Nissan and sports cars
newtonreddits@reddit
The only good Nissan sports cars come from the era of when Nissan was good in general
doc_55lk@reddit
The Z isn't bad it's just not good either.
RAMBIGHORNY@reddit
Cummins Ram
wuhanbatcave@reddit
Yeah but Chrysler exists
Unironically even the most dogshit Honda engines are likely to last longer than a Chrysler NA engine
bruh_the_person@reddit
Chrysler 300 is a decent car
wuhanbatcave@reddit
Decent for scrapping. The only thing a 300 is good for is being scrapped so it can be remanufactured into a Honda, Mazda, or perhaps even a Ford
bruh_the_person@reddit
you’re being disingenuous
wuhanbatcave@reddit
You're right. That's because the Chrysler 300 shouldn't have been manufactured in the first place.
It's a good looking car, don't get me wrong, but it also makes the Ford EcoBoost 1.0 look reliable
kinga_forrester@reddit
“Old people cars” are their own category, and shouldn’t be compared to mainstream cars.
BeerandGuns@reddit
Previously good vehicles from good brands can also go bad, e.g. Tundra
CarbonInTheWind@reddit
How well the owner maintains the vehicle matters much more than brand or turbo vs NA.
But if your high mileage vehicle starts burning oil and you don't catch it quickly you're much more likely to blow a turbo than to have a major issue with a NA engine.
Anistappi@reddit
I’ve had 90’s Turbo Saabs last for 600k kilometers. I’ve also had much newer cars, both NA and turbo, Saab and others, break down way before that.
Brand, history, ease and cost of repair. Those are the keys to longevity.
Fwd_fanatic@reddit
You’ll wanna do oil changes in the turbo more frequently since most of them are oil cooled and get quite warm using exhaust gasses to spin them up. The oil gets pretty warm and this can degrade it faster than non turbo applications.
But if you keep up on maintenance, I’d imagine the boosted ones are just fine.
Katyw1008@reddit
What company still uses oil cooled turbos? Yes oil gets hotter from the turbo but I can't think of any current vehicles that rely on oil as the cooling for a turbo.
Unique_Watch4072@reddit
Uh, most companies do. I can't remember when I saw a water cooled turbo the last time...
Affectionate-Ant8@reddit
My car, M2, has a water cooled turbo
7ar5un@reddit
Honda/acura is water cooled in their k20c engines...
Unique_Watch4072@reddit
I'm sure there are plenty of them out there, and given the comments apparently more than I realised. I know it's better but for some reason I've rarely encountered one (except in BMW I think)
Katyw1008@reddit
Really all are at this point.
jasovanooo@reddit
Brother nobody is using solely oil cooled turbos...
Last one i even remember was some of the old cosworths 35 years ago
Hot_Lava_Dry_Rips@reddit
I think a small company called bmw has water cooled their turbos for at least the past 20 years.
thegreatmattsby24@reddit
VW as well. They also use auxiliary coolant pumps that run when you shut off the ignition or when the auto stop shuts the engine down to help prevent/minimize heat soak.
Neat_Telephone_2525@reddit
Lol every modern diesel turbo is water cooled.
Katyw1008@reddit
Even something as low as a Chevy Cruze has water lines for the turbo The hurricane six is for Chrysler. Honda has water line so does Mazda so does BMW so does Mercedes. So it is forward with all the EcoBoost. I'm not sure you know what you're looking at to be honest. I haven't seen a strictly oil cool turbo on a OEM car since the early '90s
series-hybrid@reddit
Yes. One of the most amazing devices in an engine is the piston ring. In a sense, they are like a spring that flexes outwards on the power stroke, and thon pull back on the other three strokes. The pressure of the combustion process doesn't just push the piston and its ring downwards, it also gets in behind the ring and pushes it outwards.
If it didn't do that, much more of the combustion gasses would slide past the ring into the crankcase. Its a delicate balance, because if it doesn't push out enough, lots of blowby, and if it pushes out too much it can scrape away too much of the oil film.
A surprisingly small amount of the piston wears away from the aluminum piston cycling in the cylinder. Most of the wear is taken up by the top steel compression ring, and the cast-iron cylinder.
In a turbocharged engine, not only does the top ring run hotter, but the additional cylinder pressure pushes the ring outwards harder.
I drove an 18-wheeler with a turbo-diesel that logged many hundreds of thousands of miles, but...the oil was always changed on schedule, the turbo pressure was capped, and I rarely went over 2,000 RPM's, due to the governor limiting it.
croppedcross3@reddit
I did the math once and assuming you hit 200,000 miles a piston goes up and down around 500 million times. It's honestly insane engine components last as long as they do
Novel-Current139@reddit
With modern cars, when you look at what kills them, it's not turbo failures but some other high cost part failing at a point when the vehicles value is below or near the cost of the repair. Realistically, if you drive an average amount, it will take you almost 20 years to drive a car to 200k, in that time there are a thousand other problems that are likely to occur that could make you get rid of the car, not to mention you'll probably just get bored with it. Water pumps, head gaskets, transmission failures, timing components, aging rubber in coolant system, all are more likely to kill whatever car you buy early than the turbo.
SaucySon@reddit
Yup N/A will generally be more reliable than any forced induction system as there are less points of failure. They are generally more forgiving to lack of maintenance as well which helps in this scenario.
OutlandishnessOk5549@reddit
Features you don't have cost you nothing, weigh nothing, and don't break down.
allisayisbeautiful@reddit
You have something extra on the car that can fail. It's inherently will always be more unreliable than a na.
7ar5un@reddit
So an old ford model T is the most reliable thing out there? Since it doesnt have fuel injectors to go bad or a fuel pump or an ecu or a tcm or anything really that a modern car has...?
allisayisbeautiful@reddit
I see your point, but im comparing modern cars. You are comparing a modern car to an ancient relic. Not really apples to apples.
Fancy_Chip_5620@reddit
The point flew over your head
7ar5un@reddit
The argument is that the fewer the parts that can break, the more reliable the car.
So in that case, a car with very few parts will be more reliable than one with more parts.
Saying that an engine with more parts to break will be less reliable is flawed.
HKEnthusiast@reddit
Let's be realistic. Nobody is out here dailying a Model T.
GlassCannon81@reddit
In general, yes. Modern turbo engines are generally pretty reliable, but an NA engine is more reliable as a baseline. There are going to be some exceptions, of course. A good turbo engine is going to be better than a bad NA engine is.
Hot_Lava_Dry_Rips@reddit
Probably, but at this point im not sure that edge is really that material. Turbo engines are pretty reliable at this point. They probably dont fare as well as na of they arent maintained, but na will have a short life too if not maintained well. The variable valve trains on most cars these days make even na cars sensitive to oil change frequency so any unreliabiliy added by the turbo doesnt seem to be that substantial.
Also, turbochargers, wastegates, etc are way more reliable now that theyve been mass produced in modern vehicles for decades at this point. Even in the past 20 years theyve gotten way better.
VegasBjorne1@reddit
I live in a desert where summertime heat will be in excess of 110 degrees, and the street temps are even hotter. Am I wrong to assume a daily driver with a turbo stuck in traffic to be a poor vehicle choice?
Hot_Lava_Dry_Rips@reddit
I dont think it would matter. Youre not really using the turbo that much in traffic. You only really use it during heavy acceleration. Maybe dont do a full throttle pull up to highway speeds after youve been essentially stopped for the past 30 min, but normal traffic driving and using the recommended fuel octane it should be just like any other car.
AntiSonOfBitchamajig@reddit
As long as the oil is clean, and the air filter works, turbos will often last a very long time.
The whole mpg dynamic comes down to the volumetric efficiency % and if you're running the engine in that efficient range.
If you look at efficiency maps for BSFC or Turbo maps, there are NA engine designs that do extremely well in a normal driving range (often at a lower horsepower) and there are numerous turbo attached engines where 3 to 5 psi at a certain RPM will produce amazing efficiency results as well, and sometimes even better than a NA under certain conditions. Finding a turbo / turbo internals to match horsepower requirements and bolting them on is often easier when spec'ing an engine than completely designing the entire intake / exhaust on a NA engine to achieve similar efficiency or horsepower goals. Plus there are other methods / turbocharger tech out there that can make the engine more efficient over a wider RPM range.
honkyslonky@reddit
Basic science. Cylinder pressures increase, oil degrades faster, and there are more points of failure. The boomer saying “there’s no replacement for displacement” still holds true. It’s basic physics.
7ar5un@reddit
Which is why the 5.7L v8 corvette from the 80s made less hp than a modern 2.0 accord...?
And why the 1,000+ hp corvette we have today is an 8L...?
Or why the dodge viper holds the record for the highest hp engine...?
None of this is true. Theres no replacement for displacement is a thing of the past.
honkyslonky@reddit
Nice try dingus. I was clearly referring to reliability. Power =/= reliability
7ar5un@reddit
My bad. Usually people are referring to power when they say there is no replacement for displacement. Thought that was the whole point.
So youre saying bigger engines will always outlast smaller engines?
honkyslonky@reddit
Are you physically incapable of nuance or reading comprehension? Are you purposefully misinterpreting my statements?
7ar5un@reddit
You said "theres no replacement for displacement" and that it was true.
Normally that refers to power when people quote that.
You then said it was in reference to reliability as the OPs original question. And that power does not equal reliability.
What are you getting at when you say "there is no replacement for displacement"?
Leech-64@reddit
While the recycling of exhaust pressure and heat are excellent for and increase in fuel efficiency, the pairing with a smaller engine for large vehicles puts and unnecessary strain on those engines.
qlwkerjqewlkr@reddit
who drives 200K daily?!
No_Topic5591@reddit
A turbocharger is one more thing that can go wrong, but ultimately, it depends. A big turbo-diesel will be lightly stressed and extremely reliable. Some tiny little 3-cylinder petrol with a turbocharger, will be highly stressed and wildly unreliable (even more so if it has a wet timing belt, as many do) - most won't last anywhere near 200k miles (whereas the big diesel engine will outlive the rest of the car).
PlayingWithFIRE123@reddit
Over 200k miles the gas savings from the lower displacement turbo engine will more than make up for any higher repair costs.
Fernweh5717@reddit
Good point.
Warmonger362527339@reddit
N/A engines will always be more reliable than turbocharged ones. Really old non turbo diesel with mechanical fuel pumps will easily reach 600.000+ miles while modern turbo diesels barely scrape past 250.000 miles
No-Percentage6474@reddit
I got 320k out of GM3800 with supercharger.
doc_55lk@reddit
This is VERY brand and model dependent, but yes, generally speaking, NA cars still hold an edge over turbo cars for reliability.
shredlikebutter@reddit
Yes, naturally aspirated lasts longer than forced induction in nearly all cases in gasoline engines
techno_cats@reddit
I'm probably in the rare majority but I have a 2007 Audi A3 (2.0T FSI engine) with 220k miles. Never had a major mechanical failure.
Everything is still original including the clutch, turbo, and radiator. Heck, the original pcv was still fine but I recently replaced it anyway.
It's direct injected and I still haven't "needed' a valve cleaning.
I'm religious with maintenance. Oil changes every 5k, timing belt job every 100k, brake fluid 2yrs, trans fluid every 60k.
The Achilles heel of this engine is the cam follower for high pressure fuel pump. Easy enough to change every 40k.
Only major issue was with was bad coils. There are many revisions but the current ones seem to be holding up.
Oh, and it's had an APR stage 1 tune since new.
PckMan@reddit
Yes and no. Turbocharged engines tend to be less reliable than naturally aspirated ones but it's actually rarely the turbo that's the failure point. After all, diesel engines are more reliable than gasoline engines and all diesel engines have turbochargers.
The reason for this is that diesel engines are made to be much more robust than gasoline engines due to the much higher compression and energy of diesel fuel. They can easily take the stress of a turbocharger with no issue. Gasoline engines on the other hand are not quite as sturdy.
The main issues stem from the increased stress on the engine and the higher temps. Increased cylinder pressure stresses the piston rings and rods more, as well as the headgasket. Higher temps are also bad for the headgasket and also for the oil and cooling system. Also, while the turbo itself is rarely the failure point, it's part of a whole system that just introduces a bunch of extra failure points. If the wastegate actuator fails, it takes the turbo with it, same for boost control solenoids. Boost pipes may leak. The intercooler may crack. All those things are not present in a NA engine.
The turbo itself is actually quite robust and only has one failure point, its shaft. The bearings and oil seals on that shaft are the main things you have to worry about. The best way to keep a turbo happy is to stay on top of oil changes, keep your air filter clean, and ideally, if you want to be extra safe, idle for 30-60 seconds after parking before shutting off the engine, so that oil still circulates and cools down a bit before you shut the oil flow off. Scalding hot oil on the turbo can cook the seals and bearings. A few more minutes if you were driving hard.
Of course saying it like that makes it sound like turbos are a really bad idea. They're not, and obviously engines designed for turbos are degined to take those loads, but they're closed to design limits compared to diesels. The main reason is because usually when a manufacturer decides to put a turbo on an engine, they also downsize it. So when they might have once used a 2-3L for 200 NA horsies, now they have a 1600cc turbo engine for the same power output instead.
And if you're wondering why manufacturers don't just make gasoline engines more robust like diesels the answer is cost. They used to, now they don't. It's the reason why engines like the 2JZ are so popular. That's an engine that's reinforced from the factory and the stock power output does not even come close to stressing it, which is why it's so popular for performance upgrades. At the time Toyota wanted to put out a sportscar without jeopardizing their reputation of reliability and the solution was to overengineer the engine to make sure it could take it. Nowadays with modern modelling software available and an emphasis on cutting down production costs manufacturers are cutting it closer to design limits.
ManOrangutan@reddit
Yes absolutely do not believe otherwise. If an OEM cannot manufacture a reliable NA engine you should not even consider a product for them, as this is the bare minimum nowadays.
kooldudeV2@reddit
Definitely better for reliability but a Turbo engine will do it. Mine is!
jasovanooo@reddit
Drove an old saab 9-5 aero to 250k a few years ago still on its original turbo and tuned for a solid 100k of it
configbias@reddit
The 2.4L earthdreams era of NA Accord engines (and CRVs) are bulletproof, aside from some oil consumption and on some models VTC actuators.
As soon as the new 1.5T and 2.0T engines came out, fit with turbos, you can't step a foot without someone mentioning their issues.
ClickKlockTickTock@reddit
Depends on the engine, but in general, if you own a higher mileage car, anything extra that can go wrong, will go wrong. 200k is where id expect nearly everything to start going bad.
But shit a ford ecoboost? Couldn't catch me pokin those things with a 10 foot pole. But the turbos themselves isn't the biggest issue on those engines it's usually some other bs.
deltalew@reddit
I’ve got three trucks well over 250k miles, once you fix one thing another goes wrong. But still cheaper than the BS in newer vehicles
GraphicWombat@reddit
Simply: less features/parts less to break.
My 08 matrix still runs like new at 228k miles. Super basic. No t/c, no abs. Outside maintenance I’ve only replaced 2 minor parts in the last 6 years i’ve owned it. Surprisingly it still has the factory 6 disc HU and moonroof both working flawlessly.
My wife’s 2014 chevy cruze (1.4T) is at 160k miles and needs constant repairs. Replaced the whole turbo in dec 2024. And yes, it is water cooled. Just replaced a hub to fix abs and t/c. Thermostat housing, intake manifolds, valve covers, coil packs, etc…. Too much to list in the last 10 years. Plastic engine components do bot hold up.
I know these are two extreme examples of each. But from personal experience I never want a boosted engine as a daily.
Pinkys_Revenge@reddit
Yes, unless it’s a diesel.
CompetitiveLab2056@reddit
Yes: Lower compression less moving parts.
On today’s cars especially: manufactures like stuffing tiny engines in big cars and slapping turbos on them to keep the epa happy….. surely putting a turbo on a small engine to increase cylinder pressure so it makes enough power to be able to push a heavy turd around won’t end in failure…..
ZSG13@reddit
Yeah. The turbo will almost definitely fail at least once before 200k.
ChidiOk@reddit
Certain Turbo Diesel engines can definitely outlast Naturally aspirated Petrol engines however the turbo may have to be replaced. But when it comes to Turbo petrol and NA petrol engines then the NA engines is typically going to be more reliable, it’s just less complex and less stress and pressure overall in the engine.
Cinderpath@reddit
Gasoline or diesel?
VW 2.0 TDI diesel motors are legendary for their reliability and have a turbo.
brokensharts@reddit
Yes, one less piece to break and tubros work by raising compression i the cylinders
user_9780@reddit
Edge of n/a: 0k - 197k miles and from 241k - 244k Edge of turbo: 197k - 241k.
Keep in mind thar rotex rype superchager peaks at one value at 201k.
So you need to be precise with your driving.
Keep in mind this is for daily driving
Successful_Piano8118@reddit
Nearly equivalent I'd say. The real difference will be time, since turbos have inherently more things to go wrong, it'll be edged out by the NA but turbos have gotten so far they stopped being something you really need to worry about and can expect 200k miles with most modern turbo cars
Zarfa@reddit
That's an unanswerable question. It's like asking if Red cars are faster than Blue cars... it completely depends on the car.
A car designed for a turbocharger and a car designed for natural aspiration will be largely indistinguishable in terms of reliability on a purely aspiration standpoint. Turbocharged cars, specifically sports models that are subject to tuning, may experience increased wear due to user abuse (ie. increasing the boost beyond the OEM limitations).
Turbos themselves are a replaceable item. Not necessarily a wear item, as it's largely designed to live as long as the engine itself, but may need replacing (primarily due to failing seals). But that's one part of many.