I swore off turbo-charged cars later the mid 1980s, I'd had enough of the lag until 3500 RPM and so the boost would come on with a rush (though it was fun), the nasty side affects of a turbo-charged FWD machine pulling wildly nether power when exiting corners, and the all-around amateur feel of the OEM turbo-chargers on affordable cars of that era. And so the siren song of the N54 bit me . . .

Twenty years after my last turbo-charged motorcar, I bought another. This one equipped with BMW's N54B30 ('N' is for 'New', v = the cylinder count (no, it'due south non five, only because 8 cylinders is represented by BMW every bit a 'six', so 6 cylinders has got to be something else, in this instance 'v'), 'B' = 'Benzine', and '30' = deportation in deciliters). It also employs direct gasoline injection and two tiny turbo chargers in parallel.

If there's one knock on this blazon of turbo setup, information technology's that the twin turbos have to be throttled back at college engine RPMs in guild to avoid spinning themselves to death. Those little turbos have to spin much too rapidly at higher engine RPM to produce the aforementioned boost pressures they did at lower RPM. And that'southward why the torque curve on the N54B30 is a tall mesa between 1400 – 5000 RPM, but falls off the face of the globe later on.

bmw m twinpower turbo 10 655x491

BMW TwinPower Turbo shown here

So, how can that exist fixed, we'll have an approach known equally compound supercharging. In this example, employ the two small turbos for depression RPM operation and apply a third turbocharger for higher RPM functioning. A BMW tri-turbo engine can be done in a couple of means.

One is to plumb the turbos to operate sequentially. This will run the smaller turbos up to a specific engine RPM, heave level where a transition to the third turbo will have place and the intake track is
supplied from the output of the bigger, third turbocharger at high RPM. The drawback to this organization is the Rube Goldberg plumbing necessary to make information technology piece of work (and the system tweaking needed to make sure the transition is seamless).

Another way of accomplishing it is through staged turbo-charging. This would use two turbos (or a combination thereof) of similar size to provide a multiplying effect on boost. If the first (set of) turbo(s) produces iii times compression of inlet air and the 2nd turbo is fed the output of the first phase, and so boosts that 3 times further, you've finer squared the boost (the turbos deliver a total of nine times the input pressure level). The drawbacks of this setup are lag, and an unresponsiveness to fairly rapid RPM changes. This type of turbo-charging was used in piston engined aircraft.

Then of the two types of compound turbo-charging the type that makes the nigh sense for an N54 derivative would be the sequentially engaged turbo-chargers, if they can package the plumbing needed to do it in the existing infinite.

At present if they just fabricated the next M3 FWD, they'd be able to cram the plumbing for the sequential turbos in the nose with no problem . . .Merely KIDDING!!!!