im in the process of researching turbo upgrades and im trying to figure out all the turbo options and the related benfits, heres what i have learned so far...

stock k03's - 3mm shaft

k03/k04 hybrids - 3mm shaft k04 commpressor wheel

RSK04's - 5mm shaft 440ish hp

k04/16 - 5mm shaft rs6 compressor wheel 550ish hp

zero clearence is an option on the hybrids...
anyone care to add to the list or comment...

they all have the same shaft size. My K04/16's use a true K16 compressor wheel. The RS6K04 hybrids use a RS6 compressor wheel. I can't speak for anyone else's K04/16 hybrids though.

so what size shaft do they all have?


4mm


there seems to be mis information on AW cause thats where I found the 3 and 5mm shaft sizes

of which both are the same on the K03 and K04 shaft.

The obvious advantage over K03's is their increased reliability due to the larger compressor wheel. The K04 c-wheel lowers the shaft speed of the turbo greatly. They also retain the stock spoolup of the K03, yet have the increased air of the K04 compressor wheel.

The drawback to the K03/K04's is they will not flow quite as much as K04's in the upper rpms. The smaller turbine wheel causes some restriction as you climb higher into the rpm range and start to flow more volume through the turbine housing.

And of course, the all important advantage...they're CHEAPER ;) A set of K03/K04's are around $1400.

of hp/tq curves with hybrids vs. straight K03s and K04s? Even a few numbers would be nice -- I'm kind of curious.

Is there anyone who's been running hybrids for long enough to give some real-world feedback on their long-term reliability?