To reduce turbo lag, some manufacturers opt for sequential twin-turbo. At low engine speed, all the limited amount of exhaust gas is directed to drive one of the turbos, leaving another idle. Therefore the first turbo can spool up more quickly. When the exhaust flow reaches sufficient amount to drive both turbos, the second turbo intervenes and helps reaching the maximum boost pressure. The switchover is implemented by a bypass valve, which is controlled by engine management system. Cars employing sequential twin-turbo include Porsche 959, Mazda RX-7 Mk3, Toyota Supra (last gen) and the 1990s Subaru Legacy.
Showing posts with label Twin-turbo. Show all posts
Showing posts with label Twin-turbo. Show all posts
Thursday, May 9, 2013
Sequential Twin-turbo
To reduce turbo lag, some manufacturers opt for sequential twin-turbo. At low engine speed, all the limited amount of exhaust gas is directed to drive one of the turbos, leaving another idle. Therefore the first turbo can spool up more quickly. When the exhaust flow reaches sufficient amount to drive both turbos, the second turbo intervenes and helps reaching the maximum boost pressure. The switchover is implemented by a bypass valve, which is controlled by engine management system. Cars employing sequential twin-turbo include Porsche 959, Mazda RX-7 Mk3, Toyota Supra (last gen) and the 1990s Subaru Legacy.
Parallel Twin-turbo
The simplest twin-turbo arrangement is Parallel Twin-turbo. Both turbos work independently at the same time. Most twin-turbos on the market are this type.
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