why does the s5 engine have more power than the s4? if its just the different turbo, can i just swap turbos?

 

S5 has lower weight rotors, by about a full lb.

also, the s5 is a 9:1 compression ratio instead of the 8.5:1 found on s4. The turbo is a dual wastegate flapper instead of single, as well as a more efficient compressor side. The s5 is good for 20 hp on top of s4

hope that helped

 

nicely explained gotrotors so yea basically everything he said is why the s5 engines have more hp

 

On the N/A you forgot to mention the VDI system that is on the S5 cars.

 

Turbo II's?
Lighter rotors
Higher compression rotors
Stock ECU boost control
Different intake manifold design

The turbo compressor section is identical.
This means maximum power potential is identical.

The Kouki FC turbo does run an "independent twin scroll" turbo exhuast manifold and turbo turbine section design which make for a broader power band, but this doesn't really affect maximum power output.

If you remove the boost solenoid off the Kouki FC turbo, it runs almost identical boost levels as the Zenki FC turbo.
That stock ECU boost control system is good for another couple psi of boost.


-Ted

 

i just finished installing a S5 turbo and manifold into my S4, how much more power did i gain? before i had the S4 turbo and manifold