I have a question to you guys and gals who know something about turbos. There's a guy that machines turbos, rebuilds them and upgrades:
So I emailed him and asked about possibility to do same upgrade for our stock Garrett MGT22S (MGT2256S). He said he no longer has power to his end mill machine to do turbine size machining, but he can upgrade compressor wheel to 50mm one (stock is 47mm). The cost is $750 (including rebuild if needed), I'm not sure yet per turbo or for 2 turbos.
I'm now thinking if upgrading only compressor wheel size by 3mm while leaving as is turbine wheel size - will this be a worthy investment or not - meaning if it will give us more power or not?
So far I researched and found out that 3mm increase - it will indeed give us an increase in air flow by about 20% with only negative been a slight increase in spooling time. 20% increase in air flow is substantial and is all we need imho. Keeping air flow increase on the conservative side is better as we don't want to create a turbo surge and blow up engine or bend rod. The beauty of this is the fact that our setup will stay same - same flanges/mounts - you just unbolt turbos, send it for upgrade and then bolt them back. There are 2 lines for coolant and oil in each turbo. Everything is bolt-on and bolt off. I'm not yet sure exactly how much it costs to take turbos off and then put them back, but if it's reasonable - then this may look like a next step in 50i tuning. I'm guessing any tune can take advantage of 20% increase of air flow - that could simply mean less psi boost will give us same power - so we can extract same power while keeping less boost. Win-Win if you ask me.
Can someone comment if increasing inducer size only (while keeping turbine wheel size same) will be beneficial?