Hello dear members.

I'm asking for help and maybe we can find the solution for this problem together.

I upgraded my 1999 Audi S3 1.8t (narrowband) with a K04 upgrade turbo, big FMIC
2,75" downpipe and exhaust
JBS K04 exhaust manifold (i ported the collector as good as I could)
98 octane Gasoline with 386cc injectors and 4 bar fpr

Turbospecs are:

compressor: 47mm
turbine: 44mm
manufactor: Boosters

Compressor and turbine is bigger than stock k04 but unfortunately I can not generate more power.
At 6500 rpm it is surging the same amount of air thru the MAF as before with the old stock k04.

Further the ecu turns back timing at first on cyl. 1 and 2 at mid rpms and at higher revs on all cylinders. (Up to 3°)

I'm running a good tune file for normal k04 on the ECU.
I did not have these problems with ignition retard before I started the turbo upgrade and using the stock k04 and stock exhaust manifold.
MAF reading was 205 g/s at 6500 rpm and now with bigger turbo its less than before....

There are no leaks in the fresh air or exhaust system.


I dont know what to do anymore. I even tried out using E85 in combination with Deka 630 and 3 bar fpr to get rid off the ignition retard in measuring block 020
But I was not lucky...
With E85 I cant see any retard in block 020 but there are noticiable ignitioncuts starting at 4000 rpm WOT
wideband lambda gauge shows 1.08 at idle and city cruising and 0.78 - 0.80 at WOT with E85


Maybe someone has an idea where I can start.


Thank you very much
BR Oliver

Sorry nyet

My smartphone is a little bit buggy