What boost can I run with a K04? [original map is for a K03)

[AdzCM]

In the process of running in my engine......

For those who don't know, my car is originally mapped to suit a K03 with 17.5psi of boost, GT inlet manifold, g60 injectors [250cc], a standard head and a standard bottom end.

I've now done enough running in miles that I want to add a little boost for a while before I get it mapped.

My setup now is a K04 with a big valve head, ported GT inlet manifold, 1341cc bottom end but obviously still using the same 250cc injectors [until I get it mapped].

My question is, what boost can I use? I assume 17.5psi of boost from a K04 is not going to be the same as 17.5psi of boost from a K03? And if I add a little boost, will my car run really rich or will it adjust in anyway to compensate for the lack off boost? Probably not. No real idea of the mapping side of things.

Any suggestions? ... just worried that if I run in my engine with no boost and suddenly get it mapped running massive boost/power, it will not got down too well.

Adrian

[Andy]

What K03 and what K04?

[AdzCM]

K04-023 [bigger exhaust housing than the 015 I believe] and the K03 is the normal one from the 1.8T Passat's most use. Sold it already so don't know the exact code.

[Andy]

If it was a Passat K03-005 then I doubt you'll get away with it, but if it was an A4 190PS K03-073 (near as damn it a K04-015) then you might. The compressor and turbine wheels on a K04-023 are larger than a K04-015.

[AdzCM]

If it was a Passat K03-005 then I doubt you'll get away with it, but if it was an A4 190PS K03-073 (near as damn it a K04-015) then you might. The compressor and turbine wheels on a K04-023 are larger than a K04-015.

Ah ok. Sack that then. Ill just have to get it mapped before I get to play with boost again.

Thanks

[Alexiskayak_7]

Andy, do you know the vw part number of the K03-073?