DD_545i

Peak Torque at 1200 rpm? From a petrol engine? How TF do they manage that? That's diesel engine's party trick.

eurotunerM3

now correct me if i'm wrong, but my from my understanding this is how things work...

thats the difference between a bi-turbo and a single turbo
bi turbo's are able to create better fuel efficiency because they are able to spool at lower speeds yet still compress the same amount of air since there are two of them, hence BMW (and most other automakers) using relatively small bi-turbos. Unless you get into the whole sequential / simultaneous spooling argument thats usually what you'll get: efficient, smooth power across the entire power band, with a kick towards the higher rpm's.

when they throw a single turbo in there, it creates the opportunity for a larger turbo, which can spool longer and faster right off the start (much like a single turbo diesel) without having to wait for a second turbo to spool for added power. Therefor the power band created by using single vs bi turbo's is geared toward low end power all the way through, rather than a big kick at the end. A larger turbo, spooling faster from the first push of the throttle allows for such an increase in peak torque.

my knowledge isn't that great on the subject, especially since I have never owned a turbo vehicle. But I do have a lot of friends with Toyota Supras, subaru's, and vw's, and this is all i hear about 24/7. Those gear heads are always tearing something apart with their turbo's. lol

DD_545i

Well, I'm not going to "correct you", I don't know anything either, although I have had half a dozen turbo cars. The first 5 of them were single turbo'd and certainly weren't tuned to produce power low in the rev range (hence the feeling of turbo lag). It would only be when you get to 2 or even 3,000 rpm when they really started to produce the goods. The bi-turbos, I believed, were the solution to this. The second turbo kicking in earlier, lower down.

This engine we're discussing above is a single turbo but produces boost from 1200rpm, so I'm still confused.

eurotunerM3

i believe that all depends on how the turbo is set up.
i've seen and driven set up's where the single turbo is set to spool automatically, trying to eliminate turbo lag as much as possible.
For instance, a friend of mine has two fairly identical Supra's, though one is single turbo, one is twin.

The twin turbo car has a much larger pull in the higher rpm's ie once he hits 3000 rpm's he is gone. The single turbo one, has a very large garrett t66 in it (the thing is massive), it pulls very hard right from the get go and will fry tires through three gears. Im not saying it wont pull hard at high rpm's, because it does, but the majority of the power is prevalent at the lower rpm's.

a way to force the turbo's to spool much earlier on any turbo car is by aftermarket boost controllers.
so there comes to play, the idea that BMW is tuning their single turbo set up to spool at a much lower rpm at a very high boost level. of course without the boost controller sitting anywhere.
much like the new GTR's where you have 'programmable modes', essentially the OBC is controlling how much boost each turbo is creating, along with changing rev limits, etc etc.

I know this is a 5er forum, and i'm talking Supra's, but i'm just going from my own personal experience.

E60714

Just throwing it out there, but doesn't Porsche have something that keeps the turbo spooling lightly when the car is idle at a stoplight or something, to prevent turbo lag?

pinguhk

I like it this would be very good for HK roads

BMWMB

My 530dA is 5 years old and has 200.000km's on the counter, so it's time to buy a new one.
That's why i allready ordered a new 530d/535d. I'm the third one, so i 'l have one off the first ones after presentation...

The next 9 months are going to be long months...

pjinca

The next 6 series looks a lot like the current Pontiac GTO - which is a HUGE mistake!!! Hopefully they change that quickly.

m630

You should read up more on the details already released, though the new GT turbo may be a "single" unit, BMW has developed a new technology called "twin scroll" tech, which is like a twin turbo in that it has two scrools, but only 1 unit housing them...thats how they do it down lowwwwwwwww

lawguy

I tend to agree, however, its too early to know for sure.

Perhaps I am lucky that my lease ends in time to get one of the last e60s!