Just changing the turbo won't increase boost psi. Different wastegates, chips, boost controllers etc. those affect psi.

 

I can't proof you wrong, since I don't have boost logs from before installing the modified turbo. But there is no doubt in my mind that the factory K03 turbo cannot generate 18.5 psi at 4000 rpm no matter what software/chip/boost controller/etc is used.

I am still driving the same setup (with the new custom K04, but everything else (including chip/tune/boost controller, wastegate, etc.) as I had with the K03 OEM turbo (huge difference!)



Once the limits of a turbo are reached (that's why they have compressor maps), there is nothing to you can do to push the turbo beyond its limits.

WITHIN the physical limits of the turbo, the above (wastegates/chips/boost controller, etc.) can and do control the psi.

Still looking for a PC16 chip or chipped ECU to utilize the turbo's potential; and a file for T3T4 (440cc-660cc injectors) for the next step.

 

I had tried a while ago to dig up info on T.A.P. Back then, and now again, all leads came back empty. They vanished.

I am sure VAGcom can provide some input.
Can someone post a list of parameters (modules, channels) in VAGcom that I can try to log to shed some light into my situation?

Particularly:

- can/is the ECU 'pulling back' the boost to avoid running lean (past 4k RPM)? What VAGcom parameters can help in finding an answer?

- how can I check the duty cycle of the injectors over RPM in VAGcom

- since I don't have intake pressure as an ECU parameter (?), is MAF flow the next best thing?

- what would happen if I increase the fuel pressure (via AFPR 3-5 bar) and comparing logs (which parameters) running stock injectors/pressure (4 bar) with 242.5cc (right?) vs. stock injectors with higher (5 bar) pressure for 271.1cc? Worst case, I am running rich (right?) and ECU would through a code?

 

I'm never in this forum so here ya go: the early DBC cars relied on only the maf sensor to judge how much airflow the engine is getting. Later post 2000 cars used map and maf sensors, which is why we can get a "mafless" tune.

The reason your boost peaks midrange, is because the small frame kkk turbos (ko3, ko3s, ko4, etc) cant spool that hard in the upper rev range. It also has to do with the tune. Apr tunes this way also, because they have the n75 (boost control solinoid) tuned to midrange grunt. GIAC on the other hand tuned for higher boost at redline. No 2 tuners are the same.

As far as the new boost, my guess is since the k04 is the more race tuned turbo, the wastegate is setup differently. The k03 series default pressure is 5 psi, and im pretty sure the k04 is set between 7 and 10. So when the tune opens the n75 (because it thinks its still running a k03) its actually higher.

You need to swap your k03 wastegate, or better, get a k04 tune, because your car will pull even harder

 

What limits the 'spool'?
Compressor or turbine side?
Housing or wheels?

What is the T.A.P chip doing in comparison?

I have check the settings on my 'hybrid', not sure what pressure it was calibrated for. Should I increase to say 14 psi?

I have been trying to get a GIAC PC16 to swap into one of my stock ECUs, but nothing found.

General:
I am surprised that no one considers running out of fuel, and the ECU pulling boost back, if that IS possible (my second thought after the obvious: turbo running out of air at higher RPM, likely limit on the turbine side (almost stock K03).