I own a 2003 1.8t a4 and since owning these have been the modifications...Stage 1 software, k&n hp air filter, 3 inch turbo back exhaust (catless). Recently the bearings in my stock turbo went, so i went and picked up a k04. My question is how will this effect the tune i already have for the set up previous to this new turbo? Will I need to tune again if I don't upgrade my fuel injectors?

I eventuallu want to do a fmic and the bigger injectors but am not in a rush to untill my funds are in order. Also any suggestions for fuel injectors for this set up?

Thanks

 

Generally speaking a K04 can be used as a direct drop-in replacement for a K03. Running the same tuning, power gains won't be much, but should be a little more noticeable in higher RPMs where the K03 "runs out of breath".

You'll definitely notice gains when you jump to a K04-specific tune with higher-flowing injectors, which will require an upgraded intercooler. Note that typically you should only change injectors when you change to a tune which requires them (i.e. if you have a Unitronics 440cc tune, then you'll run 440cc injectors).