Not 1, not 2, but 3 !!!! turbos...

Another online news source has revealed that BMW is about to offer a new turbo diesel. The 3 liter inline 6 cylinder diesel will have 3 turbos. 2 of the turbos will be the usual exhaust driven type, while the 3 turbo will be ELECTRICALLY DRIVEN. The electric turbo is used to aid low speed response. The new turbo diesel will appear in the 550dx (for the somewhat uninitiated, that's a "d"iesel with AWD) before appearing in other BMW models like the X5 and X6. 0 to 62 KPH times are reported as being about 5 seconds, with horsepower up 70 horses over the current two turbo 6 cylinder diesel and torque of OVER 500 lbs/ft.

No word on whether the 3 turbo will be sold in the U.S.

Isn't that an electric supercharger and not a turbo?

BMW ran triple turbo diesels in Dakar last year IIRC...

Oh good. Not 2, not 4, but 6 grand worth of replacement turbos at 100k!

I also thought the electric turbo would be a supercharger, but BMW and the news source are calling it a turbo. Perhaps it's a supercharger if it's belt driven, and this is not belt driven but an electric...? ...fan? that is powered by electricity but not a belt on the engine (like many newer power steering systems are electric).

pres589 wrote: Isn't that an electric supercharger and not a turbo?

Technically a turbo is an exhaust-driven supercharger, so... yes.

Don't they sell those on E Bay for 50.00?

ReverendDexter wrote:

pres589 wrote: Isn't that an electric supercharger and not a turbo?

Technically a turbo is an exhaust-driven supercharger, so... yes.

my '86 volvo turbo had a sticker on the IC (factory) saying something or other about the exhaust driven super charger...

Giant Purple Snorklewacker wrote: Oh good. Not 2, not 4, but 6 grand worth of replacement turbos at 100k!

yup...

Id be happier if it had only one conventional turbo and the electric versus having 2 conventional and no electric, or worse, all 3.

This is all perfectly viable stuff. It's just that the amount of power it would take to drive a turbo compressor into the speed range it would need for high-rpm and -boost ranges is pretty prohibitive. However, i do see it having a place in future performance hybrids which would have the electrical flexibility to incorporate something like this much more efficiently.

Look at this old turbodyne stuff. If you look at the graphs for this model it's apparent that it's only really efficient or useful for providing boost at low-flow rpms, not replacing the conventional turbo. http://www.vondrachek.org/automotive/tech/turbodyne/turbopac2500.htm

Or do what seems like the best thing and run a motor inside a conventional turbo like the turbodyne dynacharger. You can use it to spool the turbo at low rpm, generate electricity off the exhaust at higher rpm, and slow the turbo to regulate boost at high rpm and load, effectively replacing a wastegate.

I love it. You are under warranty for a long time so flog the heck out of it and try to make it break. I've a feeling that it's pretty stable. How many factory turbo issues do you hear of nowadays?

They are thinking out of the box and it sounds as if it has some merit.

If they have one electric turbo how long before we can adapt something like that to our cars?

Instead of whining you need to be applauding!

If you look at how far brushless motor tech has come in the last 5 years, you wont discount the electric supercharger very long. This has a ton of potential for other vehicles too. Imagine installing a turbo without having to do more than cut a section of intake pipe out and insert 5 psi of boost.

It's an electronically driven compressor wheel, not a positive displacement device. Essentially an electric centrifugal supercharger.

A supercharger (unless centrifugal) gives X displacement per RPM, while a compressor wheel relies on spinning fast enough to "fan" the air forwards. This is the latter.

cwh wrote: Don't they sell those on E Bay for 50.00?

Yes, but they don't do E36 M3. I'm pretty sure they are re-assembled hair blow dryers.

Imagine that, BMW making a car more complicated than it needs to be.

Hope Chevy keeps making the LSx motors. This BMW sounds like the perfect candidate for a transplant in 15 years. For the price of the replacement turbos, a swap should be cheap.

Strizzo wrote: If you look at how far brushless motor tech has come in the last 5 years, you wont discount the electric supercharger very long. This has a ton of potential for other vehicles too. Imagine installing a turbo without having to do more than cut a section of intake pipe out and insert 5 psi of boost.

Well, and some extra fuel. Otherwise motor go boom

carguy123 wrote: I love it. You are under warranty for a long time so flog the heck out of it and try to make it break. I've a feeling that it's pretty stable. How many factory turbo issues do you hear of nowadays? They are thinking out of the box and it sounds as if it has some merit. If they have one electric turbo how long before we can adapt something like that to our cars? Instead of whining you need to be applauding!

Exactly what I thought when I read about the electric super charger. How do I cram one on a 1.5 litre?

mr2peak wrote: It's an electronically driven compressor wheel, not a positive displacement device. Essentially an electric centrifugal supercharger. A supercharger (unless centrifugal) gives X displacement per RPM, while a compressor wheel relies on spinning fast enough to "fan" the air forwards. This is the latter.

And with the electric driven motor you can control how fast it spins. It doesn't have to be limited to motor speed.

carguy123 wrote: And with the electric driven motor you can control how fast it spins. It doesn't have to be limited to motor speed.

Most electric blowers that can push enough boost take massive batteries and usually only last a few seconds. My only thought is that it is to maintain a base level of boost while the turbos aren't doing their job. Lessen the lag time?

A supercharger (unless centrifugal) gives X displacement per RPM, while a compressor wheel relies on spinning fast enough to "fan" the air forwards. This is the latter.

Ehhhh... a PUMP moves x displacement per rpm and has no internal compression. I.e. roots blower. Other superchargers like lysholm/twin-screw, and centrifugal (like a turbo) do have internal compression. the lysholm is a pump and a compressor, but the centrifugal is just a compressor, and the roots is just a pump. I think.

Time is marching on and obviously there have been some improvements in electric turbochargers PLUS there will be even more now that some factory is using them.

This could be just the ticket to combat lag and allow you to use a larger flowing turbo to hit the high end with the electric to help prior to the turbo kicking in.

N Sperlo wrote: Most electric blowers that can push enough boost take massive batteries and usually only last a few seconds. My only thought is that it is to maintain a base level of boost while the turbos aren't doing their job. Lessen the lag time?

they mentioned it was done for throttle response reasons.. so yes.. it's to combat lag

On one hand that sounds like a very heavy, complicated engine. On the other hand, if it were a single conventional turbo and the electric one, why not?

Manufacturers have experimented with variable vane, variable inlet, electric assist turbos, etc... It is interesting if BMW chooses two conventional turbos AND one electric turbo. It says to me that BMW believes the other technologies are not quite ready. (or that this will be their method of hybrid technology?)

Wouldn't it have been easier to admit the engine has issues rather than triple turbo it?