Which adds more power twin turbo or single turbo?

Answer 1

It's generally agreed that twin turbos spool quicker (less turbo lag) with more low end power. Single turbos usually have better performance in the upper half of the RPM range i.e. drag racing, but twin turbos are also usually smoother i.e. city driving. Twin turbos also generally larger and take up more space than a single turbo. Designed and implemented properly, they have comparable power.