# Why is BMW turbo charging all of their new models?



## gosee (May 27, 2009)

Is it just me that noticing that BMW is putting a turbo in almost all of of their new models? I remember when the 335i first came out, and that was like the only car that was turbo charged in their line up, and now almost every car has a turbo. Also the current M3 will be the last M with a naturally aspirated engine. 

I think BMW doesn't know how to make a good turbo charged car, given all of the problems the N54 has. 

I could be wrong, and all comments are welcomed.


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## Campfamily (Sep 20, 2010)

Fuel mileage vs horsepower. BMW isn't the only one, look at the most recent V6 that Ford is putting in their pickups, has equal hp and more torque than their V8, with far better fuel mileage.


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## SD ///M4 (Jan 24, 2011)

Turbocharging an engine allows it to put out more horsepower more efficiently allowing for smaller (lighter weight) engines. All of this is done to meet increasing stringent mileage and emission standards. All manufacturers are looking for any way they can for their cars to get better mileage and reduce emissions.

The HPFP is only one component of the turbocharger system on a BMW and just because it failed doesn't mean that BMW doesn't know how to make a turbocharged engine.


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## Kamdog (Apr 15, 2007)

And, the HPFP is not even part of the turbocharging system. It is part of the direct injection system.

As to why, well, I can do 0-60 in the mid 5s, and get almost 30 mpg on the highway.


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## SD ///M4 (Jan 24, 2011)

Kamdog said:


> And, the HPFP is not even part of the turbocharging system. It is part of the direct injection system.


Yes, but I mentioned it in this context because the turbo charged engines are using the HPFP and the NA engines aren't.


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## cwinter (Feb 3, 2009)

Had the Internet existed, the same threads would have popped up about going from carbureted engines to fuel injected ones. Somehow everyone made it through to the other side alright, as far as I can tell...I expect the same to happen with wide-spread use of turbos.


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## Kamdog (Apr 15, 2007)

SD 335is said:


> Yes, but I mentioned it in this context because the turbo charged engines are using the HPFP and the NA engines aren't.


I understand that, I was only pointing out that it was not a turbo issue, and other, non-turbo cars with an HPFP are out there (and Porsche has its fair share of problems with it too).


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## tagheuer (Jun 10, 2004)

cwinter said:


> Had the Internet existed, the same threads would have popped up about going from carbureted engines to fuel injected ones. Somehow everyone made it through to the other side alright, as far as I can tell...I expect the same to happen with wide-spread use of turbos.


but this is different...not necessary evolution and better from a pure performance perspective...

the switch to turbos is a compromise/sacrifice...not simply because they are "better"...

BMW is doing this for fuel economy reasons, not performance.

one of almost everyone's reasons for not buying an A4 over a 3 series was "I shouldn't be paying $40k for a luxury car with a 4 cylinder"...

And when driven hard, turbos often get the same or worse mileage...than a comparable 6 cylinder...

But BMW is becoming more like Toyota every day, the new 3 series is coming in packages, i.e. option groups, instead of pure a la carte options...its obviously a cost saving move...yet another reason BMW is changing its corporate identity for the worse.


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## hotrod2448 (Jun 2, 2007)

I think it's combination of consumers wanting better fuel economy without giving up power and increasingly high fuel mileage standards brands are required to meet like CAFE.
http://en.wikipedia.org/wiki/Corporate_Average_Fuel_Economy


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## sno_duc (Sep 3, 2008)

SD 335is said:


> The HPFP is only one component of the turbocharger system on a BMW and just because it failed doesn't mean that BMW doesn't know how to make a turbocharged engine.


The wife and I both drive BMWs with the direct injected engine (N54/55), neither of us have had any trouble with the HPFP. Of coarse Alaska does not have E-10.
IMHO the problem is ethanol in the fuel, mixed with high humidity. Any alcohol has an affinity for water, the ethanol sucks moisture out of the air, and the ethanol water mix is what kills the HPFP.


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## gosee (May 27, 2009)

tagheuer said:


> *But BMW is becoming more like Toyota every day*, the new 3 series is coming in packages, i.e. option groups, instead of pure a la carte options...its obviously a cost saving move...yet another reason BMW is changing its corporate identity for the worse.


I agree! BMW doesn't feel as special as they used to be


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## ProRail (May 31, 2006)

gosee said:


> I agree! BMW doesn't feel as special as they used to be


Well, maybe to some.


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## ProRail (May 31, 2006)

tagheuer said:


> but this is different...not necessary evolution and better from a pure performance perspective...
> 
> the switch to turbos is a compromise/sacrifice...not simply because they are "better"...
> 
> ...



This is a BMWNA decision. In Europe they still have "a la carte" selections.


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## SD ///M4 (Jan 24, 2011)

Kamdog said:


> I understand that, I was only pointing out that it was not a turbo issue, and other, non-turbo cars with an HPFP are out there (and Porsche has its fair share of problems with it too).


I understand your point, but I thought I was safe in assuming that we were talking about BMWs, and specifically turbocharged BMWs.


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## Zeichen311 (Mar 31, 2011)

tagheuer said:


> the switch to turbos is a compromise/sacrifice...not simply because they are "better"...
> 
> BMW is doing this for fuel economy reasons, not performance.


No, they're doing it because _both_ are important to defining a BMW. Like it or not, they must comply with ever-more-stringent emissions regulations, while delivering the performance customers expect. Forced induction is, at the moment, their best option for resolving that dilemma. If it was only about economy they'd just cut emissions (and power) and be done with it. Instead, they gave us efficient turbocharged engines that outperform all their normally-aspirated, non-M predecessors. My kind of compromise. :thumbup:



ProRail said:


> tagheuer said:
> 
> 
> > But BMW is becoming more like Toyota every day, the new 3 series is coming in packages, i.e. option groups, instead of pure a la carte options...its obviously a cost saving move...yet another reason BMW is changing its corporate identity for the worse.
> ...


+1, because we Americans collectively are impatient car buyers with an annoying, stubborn resistance to custom-ordering a car and waiting for it to be built and delivered. It's hard to fault NA for reducing the variety dealers must stock when we keep behaving that way. The _a la carte_ choice is still there, for the fortunate, polite and patient: You can special-order a car with off-the-(US-)menu options as long as (a) the options are DOT-legal in the US and (b) the order is approved by the dealership GM and BMW NA. (Oh, and you have to pay for the car before it's built. :angel

On the other hand, trim lines may help BMW be more competitive on price without changing content, by creating the _appearance_ of a bargain. Remember the breadth of that option list: You can strip a 3er sedan down to $35,475 or load it up to $61,350 (and that's excluding the M3). With fewer choices, some buyers will be less prone to feel they're being nickel-and-dimed to death.


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## tagheuer (Jun 10, 2004)

I'm just not that impressed with the new 4 cylinder turbocharged 4 cylinder that makes 260bhp.

You can get a direct injection, turbo 4 cylinder in a $24k Kia/Hyundai that makes 274bhp and 269lb ft torque...and also has great FE....

But when BMW does it, and offers it in a car costing $10-15k more, its a "technological marvel" :rofl:

Where did you hear that you'll still be able to order BMWs with full a la carte options from US Dealers?

I thought they were only coming in certain trim levels...

Please provide a link or source, because I'd really like to know for my next car purchase.

Thanks.


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## Saintor (Dec 14, 2002)

Just another foolish Euro fashion.

Given the level of technology, 4-cyl. don't take less fuel for the same power of NA 6-cyl. It is a myth.


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## dalekressin (Sep 3, 2008)

Campfamily said:


> Fuel mileage vs horsepower. BMW isn't the only one, look at the most recent V6 that Ford is putting in their pickups, has equal hp and more torque than their V8, with far better fuel mileage.


 yep absolutely true

Porsche has the natuarlly aspirated 911 GT3 and the 911 Turbo S PDK.
You will also see change ups with the wheel base to recategorize the cars for fuel consumption


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## 3ismagic# (Mar 17, 2011)

I hope they continue to view diesel as part of that strategy. 

Also there is only so much power you can squeez out of a NA engine. Given the never-ending HP arms race turbo engines just make sense.

Everything I've read about the new turbo 4 has been very positive.


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## Saintor (Dec 14, 2002)

dalekressin said:


> yep absolutely true


Actually that's *false*.

http://news.consumerreports.org/car...0---to-ecoboost-or-not-ecoboost-v6-vs-v8.html

Both V8 5.0 and V6 Ecoboost got the same fuel economy under and without load.

At best, EPA gives only 1mpg advantage to the Ecoboost. If the V8 had direct injection (as the Ecoboost), it would probably have a better fuel economy than the Ecoboost!!!


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## Jashley73 (Mar 28, 2011)

The efficiency gains with a turbo-4 are seen at light-throttle cruising, where you're not having to feed and move two extra cylinders. The power gains are seen at heavy-throttle, at the low to mid rpm range, where the turbo can fill in. With small turbo-4's you can have your cake and eat it too (gains in efficiency and power) but not at the same time. During heavy-throttle situations, (where you see the power gains) there might be an actual loss in effiency trying to keep the engine fueled and cool. But on the whole, for everyday cruising, the small turbo-4's should be more fuel efficient.


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## Saintor (Dec 14, 2002)

> With small turbo-4's you can have your cake and eat it too (gains in efficiency and power) but not at the same time.


FYI, the *272HP 6-speed* N53 direct injected Euro 330i Xdrive gets the same combined fuel economy as the *240HP 8--speed* N20 X1.


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## beeemerdude (Apr 4, 2011)

read on other web forums, that the t/chargers are a ticking time bomb for huge $$ maintenance/replacement precisely at the moment the warranty is up....not sure if true...just read it s-where else, so posting as that stuck in my mind about them...


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## hotrod2448 (Jun 2, 2007)

beeemerdude said:


> read on other web forums, that the t/chargers are a ticking time bomb for huge $$ maintenance/replacement precisely at the moment the warranty is up....not sure if true...just read it s-where else, so posting as that stuck in my mind about them...


If you ever want to be talked out of buying a car, go read a forum for that car. You'll read about problems you never knew cars had and it will sound like every one of those cars is either a death trap or a mechanically unreliable thief just waiting for the right time to strike and leave you stranded somewhere penniless and crying.

With proper maintenance their is no reason turbochargers shouldn't live a long and happy service life. Look at tractor trailers they rack up hundreds of thousands of miles on turbos.


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## tagheuer (Jun 10, 2004)

yeah, I don't think reliability is a huge concern....turbos have been around for a while, and can be implemented reliably...maybe except for BMW...which thinks it needs to use two, or even three, to avoid turbo lag...:rofl:

But again, why is everyone kissing BMW's a$$....Hyundai/Kia already have a turbocharged, direct injection engine that makes more HP and torque.

and for all the added complexity and heat (i.e. stress) that turbos add, the fuel economy benefit is very marginal, and that is only when they are driven gently...

who wants to drive a 3 series sedan with four adults using a 4 cylinder turbo....gently?

You might as well buy a true economy car at that point.

But if you drive the turbo moderately hard, whoops, there goes all your perceived FE benefit.


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## Jashley73 (Mar 28, 2011)

tagheuer said:


> and for all the added complexity and heat (i.e. stress) that turbos add, the fuel economy benefit is very marginal, and that is only when they are driven gently... But if you drive the turbo moderately hard, whoops, there goes all your perceived FE benefit.


I couldn't agree more. I guess I should have stated that I'm not a particular fan of smaller turbo engines. And this is part of the reason why...



Saintor said:


> FYI, the *272HP 6-speed* N53 direct injected Euro 330i Xdrive gets the same combined fuel economy as the *240HP 8--speed* N20 X1.


 And this is the direction I'd like to have seen them gone. I don't know much about the N53 engine, but that's an example that there is still room for improvement for the I-6 engines (for the US market) in both power and fuel economy gains. Not to mention that the I-6 engine will be smoother and probably more pleasurable to drive. And when driven hard, it will be much more throttle-responsive and powerful near the top-end.


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## jatbeni (May 28, 2010)

I think the two distinct considerations are the standardized EPA tests vs. the real world fuel economy. 

BMW needs to do better on those standardized EPA tests, without going to diesel or hybrid (as much as I would like to see the 2 liter diesel, I don't think diesels in BMW's sell very well at the moment - though, I would buy one in a heartbeat)...

And there may be the possibility of further improvements down the line. I believe (from what I read) that BMW was getting frustrated with how much power it could get out of the inline 6, without expanding it beyond 3 liters.


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## Saintor (Dec 14, 2002)

Jashley73 said:


> And this is the direction I'd like to have seen them gone. I don't know much about the N53 engine, but that's an example that there is still room for improvement for the I-6 engines (for the US market) in both power and fuel economy gains. Not to mention that the I-6 engine will be smoother and probably more pleasurable to drive. And when driven hard, it will be much more throttle-responsive and powerful near the top-end.


Direct injection is important, but it doesn't explain everything.

See current Car&Driver magazine with their comparo;

Accord V6 5-sp. no direct injection; 27mpg
Passat V6 DSG, direct injection; 27mpg
Sonata 4-cyl. turbo, direct injection; 26mpg

So the 4-cyl. gets the worse real-life mileage.


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## johndp (Aug 31, 2011)

Well when I went to the Motion Auto Show in Long Beach, CA two weeks or so ago I noticed several cars from MFEST installed supercharges in their cars instead of turbochargers. Even the Bimmer M3's that came stock with turbos installed had been converted into superchargers! Hell i figure if this many people are willing to remove their turbo for a super, BMW might as well start making M3's and M5's with the supercharger as a stock option. Or maybe they have already done so idk, let me know.


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## ventsyv (Jul 12, 2008)

What happened with engines that run on a different number of cylinders depending on conditions? When you are cruising on the highway, or driving in the city, 2 cylinders turn off, when you punch the gas, you start running all 6.
How about making cars lighter. Dragging 3000 lbs of crap around can't be good for fuel economy.


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## MrZip (Oct 8, 2006)

My wife bought a Mazda Speed 3 - 4 cy turbo - she loves the car and the cost was like 25 grand


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## Turbosmart (Sep 2, 2011)

Turbocharging definitely looks like its becoming the way to the future for BMW.

Its a lot more efficient, not to mention the greater HP that can be achieved much easier.
You don't need many mods on a turbo setup to really increase the HP, which costs a whole lot less than modifying a naturally aspirated setup.


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## Munich77 (Jul 16, 2008)

Turbosmart said:


> Turbocharging definitely looks like its becoming the way to the future for BMW.
> 
> Its a lot more efficient, not to mention the greater HP that can be achieved much easier.
> You don't need many mods on a turbo setup to really increase the HP, which costs a whole lot less than modifying a naturally aspirated setup.


The downside is that BMW has not yet perfected the combination of turbo charging and direct injection.


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## JimD1 (Jun 5, 2009)

Turbochargers use energy that is otherwise wasted to raise the pressure of the air/fuel mixture coming in to raise hp. Their effiency advantage is due to the use of the energy in the exhaust. Superchargers use engine power to raise the air pressure so the do not increase theoretical effiency. To reduce turbo lag for every day driving requires a relatively small turbo charger that will not provide the same over-pressure at high rpm. Twin scroll helps resolve this conflict but does not eliminate it. It is a good tradeoff to get everyday low end torque in exchange for high rpm power you use only occasionally but that sort of tradeoff is inherent in turbo motors. 

Big trucks go millions of miles on turbo-diesel engines. Not turbo-gas engines.

Turbos also raise the temperature of the incoming air and thus the engine. That is good for power but not longevity. I would shorten the oil change interval to help. Even with that, I would expect more issues with gaskets and other non-metallic components. 

Gas mileage is driven by a lot more than just engine effiency. Gearing our bimmers to turn lower rpm on the highway would help but then we would have to downshift to pass. I would take the trade but I think BMW worries about it. Smaller tires at higher pressure would help but then we wouldn't be able to corner as well.

I worry about longevity and harshness of turbo 4s. I think they are more appropriate for a hot hatchback than for a sporty luxury car.

Jim


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## Michael Schott (Dec 7, 2007)

Saintor said:


> Direct injection is important, but it doesn't explain everything.
> 
> See current Car&Driver magazine with their comparo;
> 
> ...


It's not a good idea to use a car magazine's test mileage to make your point. These figures are always way lower than you and I would get due to the nature of the testing procedure and the tester's heavy foot. Turbo's do poorly in these tests as well as the test driver's are in to the throttle more than even hard driving owners like you and I. Under normal cruising the turbo 4 should easily beat its V6 competition.


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## JimD1 (Jun 5, 2009)

I don't remember anybody mentioning this but adding a turbo is less expensive than adding two additional cylinders. Turbo motors are cheaper, in other words. That has to be part of BMW's logic.

You can't prove anything based upon a test with a lot of uncontrolled variables and a 1 mpg difference. Maybe there was more traffic so longer stops at lights in the Sonata test. Maybe they "enjoyed" the turbo power more. Maybe the cars are geared differently or there is a weight or aerodynamic difference. Lots of things can cause a 1mpg difference in economy. On the other hand, the similarity of the result shows there is more than one way to get good mileage. Perhaps that was the point.

I think the points about turbo's not getting the best mileage if you are really using them is probably correct but the reason may not be obvious. One of the risks of raising the inlet temperature with a turbo is detonation. Higher octane fuel is indicated but that may be be enough and not all owners may spend the extra. I believe that the air fuel ratio is different for a turbo motor under significant boost to help control detonation. They run rich under heavy boost. Which does not help gas mileage. NA engines do not need to be run rich at high output. If you get on them a lot, you may also have to replace the catalytic converter early for the same reason.

Jim


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## tagheuer (Jun 10, 2004)

if adding turbos are less expensive than adding two cylinders, do you think BMW will pass the savings along to their customers? :rofl:

of course not.

Plus, BMW doesn't look to do anything cheaply...if they wanted a cheap, reliable direct injection 4 cylinder turbo charged motor that generates more hp and torque than their own motor, they could buy one in a $24,000 Kia/Hyundai.

But of course BMW will make their motor more expensive, less reliable...and claim its "better"...and maybe it will be a little smoother, and suffer from a little less turbo lag...but the fact remains that BMW is getting closer and closer to its rivals, and is nothing really special any longer...


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## Munich77 (Jul 16, 2008)

I doubt that turbos are really that much cheaper than adding two cylinders. To withstand turbo charging, the block has to be stronger. Also, the turbos themselves are not that cheap. Yes there are a lot more parts to go from a 4 cylinder to a 6 cylinder - additional valves, injectors, pistons etc. However, I think there are even more parts to go from a 4 cylinder to a 4 cylinder turbo charged engine such as the turbo chargers, intercoolers etc. Of course economies of scale come into play. 

BMW will never pass the savings onto their customers. I just read a letter to the Roundel and a BMW customer asked to have the spark plugs changed at 45,000 miles as required by the manual on BMW's time (under the free maintenance). BMW took the stance that spark plugs are not due until 60K!!?


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## Jashley73 (Mar 28, 2011)

Munich77 said:


> I doubt that turbos are really that much cheaper than adding two cylinders. To withstand turbo charging, the block has to be stronger. Also, the turbos themselves are not that cheap. Yes there are a lot more parts to go from a 4 cylinder to a 6 cylinder - additional valves, injectors, pistons etc. However, I think there are even more parts to go from a 4 cylinder to a 4 cylinder turbo charged engine such as the turbo chargers, intercoolers etc. Of course economies of scale come into play.


This. People don't realize the added expense of the turbocharger, intercooler, additional oil cooling (possibly) charge-pipes, and various other turbo-specific components not needed in an otherwise naturally aspirated engine. The cost of 2 extra pistons, connecting rods, 8 extra valves and springs, all made on high-volume multi-tasking CNC machines that require almost no additional secondary operations or assembly, is not that much greater than it would be for a 4 cylinder engine...


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## mujjuman (Feb 2, 2009)

I'm surprised they aren't adding electric motors to every line up to make hybrid


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