Like i said this is proboly a noob question, but what its the wastegate for and the blow off vavle for? Also which is better and why internal or external wastegates. Thanks for the helping an interested mind

Patrick

 

wastegate regulates boost and blow off valve releases built up pressure from the intake pipe when the tb plate closes so it doesnt get forced back into the compressor. external wastegates are better cause they allow you to run more boost. most factory turbo'ed cars have an internal wastegate.

 

The wastegate releases the extra air the turbo generates. For example if you have a wastegate at 8psi it cannot go over 8psi.
When you shift the TB plate closes causing a surge of air back toward the turbo. This is of course bad (its spinning one way @ like 50,000 RPM, then gets stopped). The BOV releases this surge.

 

ah i see. thanks guy for being patient with me.

 

uh, the wastegate vents exhaust gas away from the turbine to regulate boost.

not that it releases pressurised air. big difference, as you described a popoff valve.

 

imagine blowing through a straw (your mouth is the turbo here) if you cover the end of the straw (closing the TB plate) you have a bunch of air with no where to go. A blow off valve opens up when the tb plate closes to release the air. Oh and btw im pretty sure that anything with an external wastegate is not street legal, not that anyone really cares anyway.

 

not street legal for CALI.

there are 49 other states that arent emissions nazis.

 

I think it might be legal if you vent it back into the exhaust, rather than venting it to the atmosphere, but maybe not in CA? I dunno

 

some of the new turbo kits coming onto the market are featuring closed loop, external wastegates and are being applied for CARB certification.

JG's system is one of them.

 

yeah, a closed loop external is no different than an internal as far as emissions go.