Turbo vs Naturally Aspirated Engine

[edyvw]

I owned in the last two decades only four naturally aspirated engines of some 20+ cars. None had turbo failure. Of those 4 NA engines, I own two now.
I made 485k km with BMW 525d E61 with M57 diesel engine. My brother and I own business in Europe and all our delivery vehicles were turbo, mostly 1.4 to 2.0ltr with exception of several VW’s and MB’s with 5 and 6cyl turbo engines. Only one had turbo failure, Skoda Octavia 1.9tdi but it was known issue on that batch of engines.
My brother now drives locally MB E220 cdi (2006) with some 400k km. Still can do 210km/h .

 

[edyvw]

It used to be that the turbo gave more power at higher RPMs so a bigger engine gave more torque at low RPMs, but that has obviously changed judging by the comments, unless you have a Volvo with a supercharger (low RPM torque) & a turbocharger (high RPMs power) I always though that Turbos had a shorter lifespan, but apparently that's no longer so due to improvements to the lubrication. Gee I'm too old and I ought to get out more!

80’s turbo had huge turbo lag.
Beginning in 90’s Europe already saw very reliable turbo engines capable of making several 100,000kms. North American market saw late entry of turbo engines mostly bcs. gas is cheap.

 

[CKN]

Hi Friends.
Google search already provides too many results about the comparison.
But i have more specific questions.
1. Given the both engines has same HP, which engine feels quicker ? For example , Hyundai has 2.0 L turbocharged engines with 275hp, and 3.5L Naturally aspirated engines with 290HP. While It may change from engine to engine, but is it likely that NA engine would feel quicker ? No Turbo lag, instant throttle response, more low RPM Torque ?
2. Which engine would be more reliable ? Are Turbo engines are less reliable than NA engines ? Because they are utilizing more advanced technology and have more parts and running hotter than NA engines?

PS: I know that every engines (both Turbo and NA) are different in design and made by different manufacturers. So we cant generalize that any NA engine is more reliable or feels quicker than its Turbo counterpart (Even if they actually are generally)

My wife's Hyundai has the 3.3 motor. 290ish horse power. I REALLY LIKE THIS MOTOR. Just before 100,000 miles-I plan on getting the Kia Sorento with the Turbo. Anything less will be a penalty box. It currently has 47,000 miles. No issues -just maintenance that included a transmission fluid change and last week a new battery.

 

[Dave9]

I owned in the last two decades only four naturally aspirated engines of some 20+ cars. None had turbo failure.

No! It's not at all isolated to whether the turbo itself failed, quite the opposite it is the increased stress on the entire, smaller engine and related cooling, transmission, etc.

It's about not just miles but cost to get there, offset by fuel cost. If someone drives a lot of highway miles, cruising where turbo assist isn't needed, it makes better sense than situations squeezing more power out of the smaller engine for more frequent acceleration situations.

However, unless this is a corporate fleet, stating it's "some 20+" cars suggests that you can't have put many miles on most of them, like you are suggesting it is a lot of experience when it seems more like you can't have enough experience (on average) with any of them to know if there's any difference. Even a very poor engine may last 3 years, so 20+ cars would be 60+ years of driving!

 

[edyvw]

No! It's not at all isolated to whether the turbo itself failed, quite the opposite it is the increased stress on the entire, smaller engine and related cooling, transmission, etc.

It's about not just miles but cost to get there, offset by fuel cost. If someone drives a lot of highway miles, cruising where turbo assist isn't needed, it makes better sense than situations squeezing more power out of the smaller engine for more frequent acceleration situations.

However, unless this is a corporate fleet, stating it's "some 20+" cars suggests that you can't have put many miles on most of them, like you are suggesting it is a lot of experience when it seems more like you can't have enough experience (on average) with any of them to know if there's any difference. Even a very poor engine may last 3 years, so 20+ cars would be 60+ years of driving!

1. I didn’t have any other failure.
2. I never bought new car except for my business fleet.
3. At one point I was making 80k miles a year on average before moving to the US.

Turbo engines are absolutely reliable.
And I stated in the end (which you didn’t quote) that I own business with fleet of delivery vehicles. We NEVER had naturally aspirated engines in the fleet. Yet we only had one turbo failure in 15 years and probably went through 100+ vehicles.

 

[vavavroom]

It's a different driving experience. Turbo engines are a lot of fun but there is something to be said for the smoothness of a powerful N/A engine. With less complexity the N/A engines have fewer failure points but are for the most part still pretty reliable.

 

[fisher83]

I would think that how well an engine is engineered overall is probably a much bigger factor in longevity than whether it is naturally aspirated or turbocharged. Surely there is some added potential for problems given the extra components but even naturally aspirated engines these days are pretty complex as it is.

 

[BMWTurboDzl]

I owned in the last two decades only four naturally aspirated engines of some 20+ cars. None had turbo failure. Of those 4 NA engines, I own two now.
I made 485k km with BMW 525d E61 with M57 diesel engine. My brother and I own business in Europe and all our delivery vehicles were turbo, mostly 1.4 to 2.0ltr with exception of several VW’s and MB’s with 5 and 6cyl turbo engines. Only one had turbo failure, Skoda Octavia 1.9tdi but it was known issue on that batch of engines.
My brother now drives locally MB E220 cdi (2006) with some 400k km. Still can do 210km/h .

I agree turbo failure is rather rare, but what turbo related maintenance has your feet experienced? Things like leaking oil feed lines and cracked charge pipes. For example BMW has revised the oil feed line for their turbo-V8's two or three times. I just had to replace a section of the charge pipe on my 435i. It's the first official failure I've had on the car.

 

[edyvw]

I agree turbo failure is rather rare, but what turbo related maintenance has your feet experienced? Things like leaking oil feed lines and cracked charge pipes. For example BMW has revised the oil feed line for their turbo-V8's two or three times. I just had to replace a section of the charge pipe on my 435i. It's the first official failure I've had on the car.

We operate different engines. You are talking performance engines, and especially in case of N63.
We had issues with oil coolers on MB V6 engines, but oil cooler is not a part specific to turbo engines only.
EGR valves that were common to fail on diesels due to short distances were never an issue as vehicles are constantly on the move. All delivery vehicles were manual, so bunch of clutches as several people would drive one vehicle. I mean there were maintenance items to do, but nothing unexpected or something that would make us say: ok get off this train. I mean there is always a vehicle being fixed.
We mostly moved to CNG lately, engines that operate gasoline and CNG. Small 4cyl turbos. Issues in diesels started to pop up with SCR system, not so much with DPF. DPF were becoming issue when we rack up kms. Generally these small gas engines are proving better maintenance wise.

 

[TiGeo]

The turbo-charged engine will have more ommph at lower RPM from all the torque so will feel faster in the RPM band most folks drive in daily. The lag is so minor on most modern turbos...

Reliability will surely be lower with a turbo over the long-haul.

 

[edyvw]

The turbo-charged engine will have more ommph at lower RPM from all the torque so will feel faster in the RPM band most folks drive in daily. The lag is so minor on most modern turbos...

Reliability will surely be lower with a turbo over the long-haul.

How many miles you have on your double the power 1.8T that you track? Yet, it didn’t disintegrated.
@BMWTurboDzl mentioned above N55 in BMW has charge pipe issue. But that is in reality really small issue.
Big issue on that engine that is directly related to turbo is water pump. More heat that turbo produces is making electric pump work harder. I changed water pump in my N52 naturally aspirated engine at 105k preventively. In N54/55 engines they are gone much earlier.
Big issue BMW had with N54 engine was cooling as a consequence of sequential turbos. They sent to US in 2007 335 but without any oil cooling. In Europe they had it. As usual, the US was getting downgraded package performance wise. Well, MotorTrend takes car to test against G37 and canot do hot lap at Willow Springs bcs. DME is activating limp mode as oil temperature is too high. So BMW after that Motor Trend debacle start putting fkuid/fluid heat exchangers trying to save some money during financial crisis and not go full radiator oil cooler, which eventually they had to.

 

[DwightFrye]

As others have mentioned, how well the transmission is mated to the HP and torque characteristics of the turbocharged engine is going to have a lot to do with the driveability and "feel" of the vehicle.

I have a turbocharged Mazda CX 5 with a 2.5L engine and 6 speed auto trans. The Mazda Skyactiv engines have a good reputation for reliability and their turbo system seems to be one of the better designs out there currently. The car makes a lot of torque at low RPM's and as most owners of that model will attest to, and you can read about on many threads on this site, the car drives very well under most conditions that you would use it for.

In fact my car spends most of its driving life under 2000 RPM's except when I need to put my foot into it to get around a slowpoke.
That alone should add to long term reliability as the engine is just loafing along and making plenty of HP and torque.

 

[TiGeo]

How many miles you have on your double the power 1.8T that you track? Yet, it didn’t disintegrated.
@BMWTurboDzl mentioned above N55 in BMW has charge pipe issue. But that is in reality really small issue.
Big issue on that engine that is directly related to turbo is water pump. More heat that turbo produces is making electric pump work harder. I changed water pump in my N52 naturally aspirated engine at 105k preventively. In N54/55 engines they are gone much earlier.
Big issue BMW had with N54 engine was cooling as a consequence of sequential turbos. They sent to US in 2007 335 but without any oil cooling. In Europe they had it. As usual, the US was getting downgraded package performance wise. Well, MotorTrend takes car to test against G37 and canot do hot lap at Willow Springs bcs. DME is activating limp mode as oil temperature is too high. So BMW after that Motor Trend debacle start putting fkuid/fluid heat exchangers trying to save some money during financial crisis and not go full radiator oil cooler, which eventually they had to.

Agreed - I've beaten on mine and no issues but failed turbo wastegate actuators on the VW IHI turbos are somewhat common and was the basis for my comment. Turbos are on so many cars now and you don't really hear about issues for people that drive "normally".

 

[edyvw]

Agreed - I've beaten on mine and no issues but failed turbo wastegate actuators on the VW IHI turbos are somewhat common and was the basis for my comment. Turbos are on so many cars now and you don't really hear about issues for people that drive "normally".

It is not even driving issues. “Problem” with turbos is that simple software code can bump power seriously. Most people bump power without addressing other components.

 

[Snagglefoot]

If you are leasing the car, for sure go for the turbo.

 

[FZ1]

Hi Friends.
Google search already provides too many results about the comparison.
But i have more specific questions.
1. Given the both engines has same HP, which engine feels quicker ? For example , Hyundai has 2.0 L turbocharged engines with 275hp, and 3.5L Naturally aspirated engines with 290HP. While It may change from engine to engine, but is it likely that NA engine would feel quicker ? No Turbo lag, instant throttle response, more low RPM Torque ?
2. Which engine would be more reliable ? Are Turbo engines are less reliable than NA engines ? Because they are utilizing more advanced technology and have more parts and running hotter than NA engines?

PS: I know that every engines (both Turbo and NA) are different in design and made by different manufacturers. So we cant generalize that any NA engine is more reliable or feels quicker than its Turbo counterpart (Even if they actually are generally)

Turbo is a non starter for me. Too complex, and it's already hot where I live.

 

[TiGeo]

Turbo chargers are mature technology at this point...this isn't something new.

 

[mightymousetech]

Turbo chargers are mature technology at this point...this isn't something new.

You are forgetting this is BITOG, where COP is still considered too new fangled.

 

[TiGeo]

You are forgetting this is BITOG, where COP is still considered too new fangled.

I know - luddite heaven around here.

 

[Cujet]

Note: I have experience with a major manufacturer's turbocharged engine development team (in a past life).

1) Turbocharged engines are not less reliable, they are often more reliable. Despite the conventional wisdom that says otherwise.
2) Turbocharged engines have lower rod bearing loads than high revving engines. The inertia of high RPM, TDC loads rod bearings far higher than 15 or 20 pounds boost.
3) Combustion in a properly tuned turbocharged engine can take longer, therefore peak connecting rod loads may not be significantly higher than when NA. A longer push on the piston, so to speak.
4) Turbocharged engines happily create adequate torque at lower RPM's than a comparable normally aspirated engine, and therefore, many components experience lower wear. Cams/followers/valves/bearings/chains etc.
5) Turbocharged engines always have more robust internals and better piston rings. As they must be capable of operation with higher pressures and temperatures (better heat transfer is required). The common ultra thin, "low tension" rings that fail so early are not used on turbo engines.