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      09-25-2013, 12:38 PM   #1
BRAISKI
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Question Bi Turbo vs Twin Turbo?

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Ok now that the new M3/M4 will have a "bi turbo".

What exactly is the difference? Is there a difference, since technically bi=two so 2=twin.

Is one turbo for a first range of RPM and second is the the next range of RPM. This would be interesting comparison since BMW now has a car with a Twin Turbo (N54) and a car thats called Bi Turbo (S55).

Tried searching around Google but nothing no satisfactory answer everyone seems to have some different opinions.
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      09-25-2013, 12:41 PM   #2
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Quote:
Originally Posted by BRAISKI View Post
Ok now that the new M3/M4 will have a "bi turbo".

What exactly is the difference? Is there a difference, since technically bi=two so 2=twin.

Is one turbo for a first range of RPM and second is the the next range of RPM. This would be interesting comparison since BMW now has a car with a Twin Turbo (N54) and a car thats called Bi Turbo (S55).

Tried searching around Google but nothing no satisfactory answer everyone seems to have some different opinions.
Same thing. Bi=two. What you are thinking of is a sequential twin twin turbo system in which one turbocharger (smaller of the two) is specified for a lower set of RPMs to provide fast boost/response, then an actuator let's the second pre loaded turbo spool for the higher RPM range. At least that's how I remember it working. M4 appears to use a parallel twin turbo setup (two of the same turbos)
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      09-25-2013, 12:42 PM   #3
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The term twin turbo has been often given to vehicles that use sequential turbos, a small one for low rpm torque, and a larger one for higher rpms and power. The biturbo system uses two equally sized turbos, one fed by cylinders 1-3, and the other by cylinders 4-6. They are not sequential or in series, but in parallel.

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      09-25-2013, 12:44 PM   #4
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Really?? Already with these threads!?
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      09-25-2013, 12:56 PM   #5
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BMW uses the phrase "Twin Power Turbo" for marketing speak. Either referring to a twin scroll single turbo or two turbos (a bit confusing).

This has Twin Turbo, which just is two turbos (as seen in the photos). BiTurbo or Twin Turbo is basically two turbos. Sometimes in paralell, sometimes serial, but still two separate turbos.

The exception being BMW's "Twin Power Turbo" which can be one or two turbos as explained above...
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      09-25-2013, 01:06 PM   #6
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Quote:
Originally Posted by Boss330 View Post
BMW uses the phrase "Twin Power Turbo" for marketing speak. Either referring to a twin scroll single turbo or two turbos (a bit confusing).

This has Twin Turbo, which just is two turbos (as seen in the photos). BiTurbo or Twin Turbo is basically two turbos. Sometimes in paralell, sometimes serial, but still two separate turbos.

The exception being BMW's "Twin Power Turbo" which can be one or two turbos as explained above...
I suspect that 'Twin Power' just means forced induction. Even the single turbo - single scroll Diesel engines are branded 'Twin Power'

Regarding the twin turbo / BiTurbo, both terms can be swapped as they mean the same. For me I would expect Twin to mean two the same(same size in the case of Turbo's), but this is not always the case.
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      09-28-2013, 12:38 PM   #7
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This thread seems silly but I could see there being a difference. If there was two separate turbo systems that handle 3 cylinders each, you could call that a (identical) twin turbo. If there is two serial turbos of different size on the same circuit, you would call that a bi-turbo.
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