What is the gain when you install K04 without changing anything else ?

 

only if you are using the pc-16 or th J31 file will you need the adjustable FPR along with injectors and a FMIC but the regular GIAC file E05 you just use the 5 bar FPR

the TT 225hp comes with a K04 but it is a K04-23 not a K04-15 not sure if you can use this or not I know of only 1 person that has used this turbo

 

I'm pretty sure it's more trouble than it's worth.

 

yeah, the ko4-023 is only for the audi TT, whereas the ko4-015 is for the other makes..i.e volks 1.8T and our motors, fitting a ko4-023 turbo would be quite difficult...so get the 015.

 

The ko4-025/023 flow along the same lines as a t28/gt28r.