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NooB Question about turbos

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Old 03-17-2003, 06:44 PM
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HatchVX
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Default NooB Question about turbos

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
Old 03-17-2003, 06:49 PM
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Snoopy
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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.
Old 03-17-2003, 07:33 PM
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DSC
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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.
Old 03-17-2003, 07:48 PM
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ah i see. thanks guy for being patient with me.
Old 03-18-2003, 12:50 AM
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drift
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Originally posted by DSC
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.
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.
Old 03-18-2003, 09:48 PM
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Sportmode
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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.
Old 03-19-2003, 12:07 AM
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drift
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Originally posted by Sportmode
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.
Old 03-19-2003, 10:11 AM
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s1267712
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Oh and btw im pretty sure that anything with an external wastegate is not street legal, not that anyone really cares anyway.
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
Old 03-20-2003, 03:49 AM
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drift
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Originally posted by s1267712
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.
Old 03-20-2003, 07:58 AM
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yeah, a closed loop external is no different than an internal as far as emissions go.



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