Why BMW making the move to turbo and not superchargers

[Krypptic]

It just seems that superchargers are much better at preserving the NA tendencies of immediate throttle response with no lag.

Clearly, with all the supercharged e9x's they could also maintain the high rpm redline and free revving nature of M engines.

So why is M dept moving to turbo's instead of superchargers?

Are turbo's more fuel efficient? Or is there some other reason?

[swiss_cornholio]

the point of a turbo is to save fuel when not going full throttle. a supercharger is just a way of increasing power without increasing displacement.

[Erhan]

Short answer: To save money.

BMW's answer: Turbo is more efficient. Efficient dynamics. Blah Blah...

Real answer: BMW doesn't want to invest on R&D too much. High revving NAs are gone because they don't want to spend money. If they do supercharger, that'll require more R&D than using a modified version of one of their turbo engines for the M3.

[mdosu]

Turbos give you more top end power than SC.

[swiss_cornholio]

Originally Posted by erhanh

Short answer: To save money.

BMW's answer: Turbo is more efficient. Efficient dynamics. Blah Blah...

Real answer: BMW doesn't want to invest on R&D too much. High revving NAs are gone because they don't want to spend money. If they do supercharger, that'll require more R&D than using a modified version of one of their turbo engines for the M3.

totally disagree. imo the reason is that they changed the meaning of M from Motorsport to Marketing, i.e. with the whole movement towards greener cars, they also want to make the Ms greener.

saving money is bs because all BMW has ever done was developing high revving n/a engines. so the r&d effort there is minimal compared to shifting into a whole new technology.

[mkoesel]

Originally Posted by Krypptic

Are turbo's more fuel efficient? Or is there some other reason?

I think that turbo's will be more efficient, yes.

[kmarei]

Originally Posted by TrackRat

In actual practice... turbo engines currently deliver slightly better fuel economy and the same or more power than a supercharged engine. A supercharger requires power to drive it and this hurts mpg. The window on efficiency is narrowing between the two however and an argument can be made for either design. A lot depends on packaging, costs, desired driving performance, etc.

or better yet do what VW does in Europe
turbocharging AND supercharging
read up on the twin charger
they have it on a 1.4, but it puts out the power of a 2.0
while using less fuel

[aajami]

Originally Posted by kmarei

or better yet do what VW does in Europe
turbocharging AND supercharging
read up on the twin charger
they have it on a 1.4, but it puts out the power of a 2.0
while using less fuel

Alas, poor overly complicated 1.4L VW engine, we hardly knew ye:

http://www.autoblog.com/2011/01/19/r...uld-be-killed/

[W12x]

I believe the efficiency of superchargers are more influenced by heat compared to turbos. The superchargers start to lose a large amount of efficiency once the heat start building up, so that could be a problem.
Plus turbos does save fuels...

[UNNATRAL]

Originally Posted by mdosu

Turbos give you more top end power than SC.

Your right but not necessarily. many turbos die out around 1-2k rpm before redline. case in point, the 335i LOL. Supercharger is constant boost.

[Ken37.73]

I recall many posters on here referencing the 997 TT as dream car in various threads over the years. Doesn't seem to be much wrong with that. Variable veng whatyamacallit etc.

PS - Is is me or does it seem a little bit premature/small minded/daft to write off BMW's chances of producing a successful turbo M3 ? Personally a 450bhp TT straight six sounds like the dogs from where I'm standing,

Ken

[Erhan]

Originally Posted by Ken37.73

PS - Is is me or does it seem a little bit premature/small minded/daft to write off BMW's chances of producing a successful turbo M3 ? Personally a 450bhp TT straight six sounds like the dogs from where I'm standing,

Ken

I don't get what's impressive about a 450bhp turbo engine, assuming (with high probabilty) that it will have much narrower power band than 414bhp S65. That being said, if that said turbo engine delivers that hp at lets say 5000rpm, while S65 does it in 8300rpm, then I think it is safe to say that turbo engine will have ~500ft-lb torque. With that much torque, longer gear ratios can be used...

But which one is better? A lot of torque in short powerband that allows you to use tall gear, or decent amount of torque in a wide powerband where you can fit short gears (which will multiply torque&power at the wheels)..? I think the latter is better.

[mdosu]

Originally Posted by Ken37.73

I recall many posters on here referencing the 997 TT as dream car in various threads over the years. Doesn't seem to be much wrong with that. Variable veng whatyamacallit etc.

PS - Is is me or does it seem a little bit premature/small minded/daft to write off BMW's chances of producing a successful turbo M3 ? Personally a 450bhp TT straight six sounds like the dogs from where I'm standing,

Ken

true, the new turbo engine should have a variable vanes...

[Krypptic]

Thanks for the replies. I'm not sure I see how turbos are more efficient if when you get on them they burn as much fuel as a larger displacement engine. Where if you lay off its like they don't exist.

Now I get that because the supercharger is belt driven there will be parasitic losses, but if you are not getting on it, shouldn't it be just as efficient as turbos?

Also, this is not a thread about if BMW should go FI, just curious why the choice of turbos v. Superchargers.

Audi seems to like both. Fwiw

[rapyoke]

Originally Posted by Krypptic

Thanks for the replies. I'm not sure I see how turbos are more efficient if when you get on them they burn as much fuel as a larger displacement engine. Where if you lay off its like they don't exist.

Now I get that because the supercharger is belt driven there will be parasitic losses, but if you are not getting on it, shouldn't it be just as efficient as turbos?

Also, this is not a thread about if BMW should go FI, just curious why the choice of turbos v. Superchargers.

Audi seems to like both. Fwiw

To be honest, it seems like it's more design preference than anything. With today's blower/turbo technology and tuning, the difference between the two is pretty moot. Jaguar, Land Rover, and Mercedes all seem to prefer supercharging their vehicles. VW and Audi seem to prefer turbocharging (except in the case of the A6 3.0T and the S4 3.0T). They're both just a way of getting the power of a V8 from a V6, V6 power from an I4, etc.

[cracker123]

Currently looks like MB has the lead in the green car race .

Check out those mpg rating on the CLS63 at 23.1 combined @ 518/519 , mercedes number though. Also it weighs less than the E93, but about 500 more than the E92.

http://www.insideline.com/mercedes-b...rst-drive.html

[OC3]

Originally Posted by kmarei

or better yet do what VW does in Europe
turbocharging AND supercharging
read up on the twin charger
they have it on a 1.4, but it puts out the power of a 2.0
while using less fuel

If I had to swallow FI, I'd be down for a twin charger.

[Erhan]

Turbos are more efficient because you get higher bhp/liter. So let's say you get 400bhp from 3liters instead of 4. Now when you're cruising (which is what u do most of the time) you have the "economy" of smaller engine.

In the case of supercharger, that always works and hence always draws power from the engine. Maybe someone can make a supercharger with a clutch so when you're cruising it can be disconnected from the engine. But than, when u want to accelerate it'll have to spool hence lag.

Originally Posted by Krypptic

Thanks for the replies. I'm not sure I see how turbos are more efficient if when you get on them they burn as much fuel as a larger displacement engine. Where if you lay off its like they don't exist.

Now I get that because the supercharger is belt driven there will be parasitic losses, but if you are not getting on it, shouldn't it be just as efficient as turbos?

Also, this is not a thread about if BMW should go FI, just curious why the choice of turbos v. Superchargers.

Audi seems to like both. Fwiw

[duk]

cuz turbos are cheaper?

[Krypptic]

Originally Posted by erhanh

Turbos are more efficient because you get higher bhp/liter. So let's say you get 400bhp from 3liters instead of 4. Now when you're cruising (which is what u do most of the time) you have the "economy" of smaller engine.

In the case of supercharger, that always works and hence always draws power from the engine. Maybe someone can make a supercharger with a clutch so when you're cruising it can be disconnected from the engine. But than, when u want to accelerate it'll have to spool hence lag.

That actually makes a lot of sense. I can now see where the tradeoff is for the lack of lag. Thanks for the input.

[double_j]

Originally Posted by swiss_cornholio

totally disagree. imo the reason is that they changed the meaning of M from Motorsport to Marketing, i.e. with the whole movement towards greener cars, they also want to make the Ms greener.

saving money is bs because all BMW has ever done was developing high revving n/a engines. so the r&d effort there is minimal compared to shifting into a whole new technology.

One note - BMW (and all other manufacturers) are being forced into greener cars. So yes, BMW is most likely looking to save money by keeping all of their engines aligned with the same technologies, etc. but the shift to turbos is really coming from the fact that they need to achieve a certain fleet average MPG.