Is there a difference between a twin-turbo and a bi-turbo?
Depending upon the manufacturer, it may be two terms for the same thing. For some, “twin-turbo” means two turbos – one for each bank of cylinders(V6, V8, etc.). “Bi-turbo” means it likes both men and women. OK, just kidding. Bi-turbo typically means two turbos in series – one spools up at low RPM and the second kicks in at higher RPM. The intended effect is to reduce low RPM turbo lag.
Bi-turbo was most used by Maserati for a car that had a V6, with the turbos in a ‘twin-turbo’ configuration, one per bank blowing together (in parallel). They used a carburetor in a ‘blow through’ setup, resulting in terrible running and a reputation that almost killed the company.
If I remember correctly, BMW currently refers to their single-turbocharger engines as “biturbo.” I can’t explain why.
The Maseratti bi-turbo from years ago had two turbochargers, one for each bank of the V6 engine.
That was then, this is now.