[hl0m4n]

thanks for ur info man..would u say my theory between bi and twin is accurate?

[hl0m4n]

bump

[hl0m4n]

anyone?

[chbrules]

bi- and twin just mean 2 turbos. The name itself won't tell you how the turbo system is setup, be it two at once or a two-stage turbo system.

[hl0m4n]

got ya so it is just name prefrence..?

[Jay@ATP]

Originally Posted by tctic

There's another thing called sequential turbo charging which is what the OP was also talking about. This sequential turbo charging is in BMW's diesel engines. It consists of two turbos. One smaller sized lower inertia turbo charger for low engine speeds. Then another one is a larger one which spools up at higher engine speeds to provide more boost for more power. The benefit here is that the engine would suffer less from turbo lag in the lower range of the power band with the small turbo providing power initially and then switching to the larger turbo when there is enough 'exhaust power' to spool up the larger turbo. This approach is taken by most manufacturers.

The one in the 335i or the N54 engine take the approach of implementing two small turbos both simultaneously providing boost to the engine. (3 cylinders each) These small turbos should spool up very quickly therefore the driver should experience only very minimal turbo lag.

BTW, bi-turbo and twin turbo has the same meaning.

+1. Bi and twin are the same, however sequential and parallel are different.

[hl0m4n]

in what way?

[Suareezay]

saw a ford commercial for the new F-series (not F-150) and they are calling their new turboed diesels "dual turbo"

[WAYNEBO]

I think a couple of thread contributors have pretty much summed this topic up:

'Bi' and 'Twin' mean the same, it's whether they are setup for sequential or parallel operation.

End of discussion.

[wileecoyote]

Funny that there is so much discussion about this.
------
From the bmwusa 335i features and options:
"3.0-liter dual overhead cam (DOHC), 24-valve inline turbocharged 300-horsepower 6-cylinder engine with twin-turbo technology and Double VANOS steplessly variable valve timing"
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From the bmw.co.uk (UK) 335i prices and specification
Engine
Battery in luggage compartment with jump start facility in engine bay
Catalytic converter
High Precision Injection (direct injection system)
Six-cylinder in-line petrol engine with four-valve technology
Twin Turbo
VANOS
------
Looks like BMW is calling it a twin turbo in all markets. Even though the Euros do seem to like to call most "twin turbo" applications biturbo (ie Porsche and Audi)

[hl0m4n]

what is the difference between sequential or parallel operation? seq turbo go off one after another parallel same time? so 335i are seq right? twin is seq and bi is parallel or is that just the anme?

[shyestsparks]

Originally Posted by hl0m4n

what is the difference between sequential or parallel operation? seq turbo go off one after another parallel same time? so 335i are seq right? twin is seq and bi is parallel or is that just the anme?

Sequential means one turbo kicks in one at a time at diferent RPM ranges but both are powered by all of the engines cylinders; parallel means both turbos kick in at the same time and one turbo is usually powered by half the # of cylinders of the engine and the other turbo by the other half (as in the N54, its 3 cylinders per turbo).

[az335i]

I had a girlfriend in college that was bi, but her twin wasn't!

[hl0m4n]

thanks and nice one