I did a search of the site, but didn't find any info in previous threads. Are S4 turbos compatible with S5 TII engines/manifold. Any modifications needed to bolt them on?

Thanks

 

the s5 turbo is a bolt on for the s4's so I don't see why the other way around wouldn't be true, but a better question is why would you want to? The s5 turbo is known to be better. You probably can just easily come by an s4 huh?

 

Yeah, my turbo is dying and a S4 is available. This is my first experience with turbos with any engine or car. What makes the S5 better than the S4...if you don't mind noobish questions?

 

simply put, it doesn't need the twin scroll system to work as well or better than the S4 turbo.

 

Remember you gotta use the same series combo: S4 turbo/S4 exhaust manifold, same with S5. Exhaust manifold not interchangeable.

 

One look at the flange will show you that there's no way the S4 turbo will fit the S5 manifold (and vice versa).

 

What exactly makes the s5 turbo superior over the s4?

 

It has a divided manifold that lets the rotary's strong exhaust pulses hit the turbine wheel directly. This improves turbo response. To work properly this design needed two separate wastegate ports, which are much bigger than the S4's single port, so boost control is also much better.