Alright, I'm looking at different Garrett turbochargers, specifically their new GT lineup. I noticed a couple had internal wastegates as opposed to external, and while I know Hahn sells turbocharger kits with internal wastegates, I was wondering:

What're the advantages and disadvantages of each? I wanna learn what I can before I go out and buy parts...

Thanks,
Corey

internal wastegates are easier to deal with. it's all built right in and you don't need to have a manifold with a flange and a downpipe with a flange to accomidate a dump tube (or, if you don't mind infinite wastegate noise which happens to sound cool but is very loud, you can just leave the wastegate dump open) internally gated turbos can have issues with boost creep if they're used at boost levels that they weren't really designed for. for example, if you have a wastegate the size of a penny, if you try to spool the whole setup to 25 psi it will just keep going up and up, because it's actually easier for the gases to go through the turbine instead of the wastegate.

external wastegates typically are able to handle more power because of this. being able to upgrade wastegate sizes and spring levels with ease is pretty nice. some argue that external wastegates can produce more power too, because internally gated turbos dump the excess exhaust gas back into the downpipe which disturbes the spiral-ish flow of air that comes from the turbine blades.