K04 Uograde - In Stages

[Saki Ashraf]

Hey All,

I have been accumulating all the required parts to upgrade to a K04 on my 2007 FSI GTI.

The reason for doing the upgrade in “stages” is simple - time and money and I need this car as my daily.

Car is currently APR S1 with intake/DP/catch can.

I know I need intake carbon cleaning done (98K miles) and I have a contact who can do the walnut shell cleaning.

While doing the carbon cleaning I was thinking of just replacing the stock injectors with the S3 injectors, installing RS4 PRV and an IE hpfp.

Question is can I upgrade these parts and be OK with the APR S1 tune? Has anyone any experience with this?

Thanks in advance for any info to help me make a decision.

 

[golfballer78]

Injectors will prob be too rich for stock turbo. Hold onto them for the swap & reflash

 

[vwengineer]

Injectors will prob be too rich for stock turbo. Hold onto them for the swap & reflash

Not sure what's the difference in size but the stock ecu can trim up to -20% without CEL

 

[Not_Sean]

I'm also waiting for confirmation but you might even be able to bolt on the K04 with the stock map, the boost controller will just hold it where it wants the boost levels to sit, well thats the theory, as I said waiting for someone to confirm this for me.

 

[vwengineer]

Even though that may work it's not a good idea. The flow characteristics are different. For example the K03 spools at much lower RPM and build pressure sooner than the K04 and the ECU will expect that

 

[GIACUser]

Even though that may work it's not a good idea. The flow characteristics are different. For example the K03 spools at much lower RPM and build pressure sooner than the K04 and the ECU will expect that

I don't think that area is a problem, I would expect the top end to be the problem where the K04 flows more than the fuel system can provide for and a 2.5 bar MAP can manage.

Even if the ECU can provide fail safe and drop to limp mode etc. it doesn't seem like a good way to drive around. When I went K04 I bought it piece by piece over time and put the pieces on the bench until I had them all of them and had the install done all at once.