Got a 01 s4 still mostly stock besides APR chip. I have an idea that my high rev turbo is going and might need to be replaced. I figure that i might as well replace it with something a bit bigger such as the K04 model instead of the K03. I know they are interchangeable and that its a bolt on, however if i do add on the K04 along with having an apr chip, will that be to much force on the engine that parts will break more frequently.

What are things i can expect if i do get a K04, will i need tuning or can i just bolt on and go? As in things to expect i mean like problems that will occur or common things that break when adding a K04.

Is this a good idea to keep my low rev turbo a K03 since it still operates fine?
Thanks guys!

 

i have a 2005 a4 s-line 1.8t resently did k04 bolt on plus bigger intercoler and had to tune it, my check engin light was on and the car was running under safe mode.

 

you can run ko4s without a tune but its silly, you wont want to keep it like that forever, just do it right.

 

hi rev turbo?? low rev turbo?? wtf are you talking about?? these are not sequential turbos, they both work at the same time, both producing boost for these cars. thats why they run out of breath over 5500...

 

if you have a turbo going bad, go with bigger turbos, dont go k03's again unless you just have no money period. even that will be expensive. so save and go k04's or tial 605's.. they are just a little over the cost of k04's. unless you go RP turbos. and yes, you will have to do fueling, including, injectors, tune, bigger IC's, stronger clutch, upgraded mounts are also wise...