NefMoto

hi folks
i have a k03 hybrid with RS6-sized wheels in machined housings and 1.0 bar custom actuator. now im drive with 1.4 bar (or 20 psi) and all seems ok. but it can produce about 1.8 bar (26 psi) boost. car pushed really hard with good IAT, knocks and AFR (btw turbine noise more quieter at this boost level)

so now i thinking to buy 3 bar map sensor, make an 5120 hack and run overboost at 3 gear only because it makes no sense at 1 and 2 gear in FWD car and to prevent overloading turbo at 4 and 5. so it will be running only ~5-10 secs with overboost. so the question is how bad it is for turbocharger? and yes nobody know about quality of this hybrid turbo so lets imagine that it is K03

any suggestions? car is 1.8t w stock ex mani; stock catback and 3" downpipe another HW is ok to handle it

Boost = heat.

How effective you can make the turbo boost is the key,  also think about intercooling aswell.  Is a uprated intercooler there?  Whats IATs like etc.

how i can calculate efficiency wo compressor map? maybe comparing air consumption on different pressures?
yep there is a good fmic which gives +10..+20c higher IAT than ambient temp

Regardless of how big your wheels are, the housings of a K03 are way too small. How are your EGT's?

dunno
has no sensor to measure it, only egt model that shows something like ~800 at wot

btw i forget that im running 0.8 bar actuator spring now that can provide only 1.4 bar. to achieve 1.8 i should replace it with 1.0 bar which are very unconfortable at mid-range light loads. so... leaving this

Pre-turbo water / meth injection may be what you're looking for to push this small turbo to its limits.

Don't just rely on just monitoring the IAT. Place a temperature sensor (just stick it under the hose clamp) after the compressor but before the intercooler. As soon as the temperature of the air leaving the compressor is not linear anymore with increasing boost, but rather exponential, you are starting to push the compressor side too much.
Also, measuring back pressure in the turbine housing is a good idea alongside the EGT.

I can tell you for a fact and lots of experience if you run more boost you will end up with less top end bhp as egts and timing will be impacted.

The key is to finding the sweet spot on these , which from experience is around 21psi on the average setup above that the gains aren't that effective. Ie you might run more boost but egts run higher, timing is less and power on a dyno doesn't actually increase .

Getting the setup to flow better is the key on these things, you can end up making more power from the same boost. The rs6 turbine is good but the rs6 compressor will fall out of efficency over the equivalent of 290bhp of air. 

The Hotside as stated is the biggest restriction off all and little you can do about it.

so i made some searching and seems that it is 2277 comp. wheel in k04-022 machined housing. turbine wheel also different
i have no experience in it but believe that hotside has a high backpressure because it can produce 1.4 bar only with 0.8 bar actuator spring  (with 95% WGDC at top-end)
no idea why they used this pretty compressor with useless hotside. it produces ~220 g/s on 1.4 bar.. same level as k04-023 with 1.2 bar and stock actuator... so im leaving this idea, thanks all :