Im confused, a lot of people say that s5 turbo is not twin scroll. To me, it looks twin scroll and a better design as a s4. The housing is split into 2 and the wastegate also. Whya re people saying s4 is twin scroll and s5 is not?

 

We just went over this recently...

S4 uses a "twin scroll", while the S5 uses an "independent twin scroll".
The S5 design is superior.

While others will argue the twin passageways in the turbine housing = "twin scroll", most people use the term "divided turbine" housing more often.


-Ted

 

You have made me feel RETarded again. LOL. RETed's schooling newbs. Hope your not offended, I dont need it that way. Thanks for straightening it out.

 

I don't recall anyone saying that. The S5 doesn't have Mazda's twin-scroll control system that the S4 had, but both are twin-scroll turbos, i.e. they have two separate scrolls within the exhaust housing.

The modern aftermarket may commonly use that term, but car and turbo manufacturers have always described them as twin-scroll turbos and still do. Both terms mean the same thing, and it'd be wrong to say the S5 turbo isn't twin-scroll. Mazda's term "independent twin-scroll" really describes the turbo and manifold together, because without the divided manifold the turbo can't be called that.

 

I have heard a few people say that, even my friend that had a rx7 before me. It made me think it was a standard turbo, he was even claiming the s4 spooled up better. But after looking at it, the s5 turbo is way better.