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Can someone explain the plenum and all the check valves to me?
OK trying to underatand as much as I can about these cars.
The plenum right behind the Throttle body has this large circle which I think is called a venturi valve??? Anyway here are my questions.
In the picture below...
1) What does A do? Does it just direct air in more than one direction? Is it a check valve of some sort or does it just always stay open?
2) Where does the air at A1 go?
3) Where does the air at A2 go?
3) Where does the air at A3 go?
4) What is the function of #9? Does it just split or is this a valve that allows air to pass only one direction?
5) What is the purpos of the #16 check valve?
6) Is B a check valve? If so what's its purpose?
7) Is C a check valve? If so what's its purpose?
8) Would a boost leak test at the inlet of the turbo tell me if all these things are good or not? I.E if all check valves and such are operating properly? Or are leaking?
Im trying to understand the entire system to aid me in my issue of not being able to boost over about 1 bar even with wastegates unplugged and tied shut.
OK trying to underatand as much as I can about these cars.
The plenum right behind the Throttle body has this large circle which I think is called a venturi valve??? Anyway here are my questions.
In the picture below...
1) What does A do? Does it just direct air in more than one direction? Is it a check valve of some sort or does it just always stay open?
2) Where does the air at A1 go?
3) Where does the air at A2 go?
3) Where does the air at A3 go?
4) What is the function of #9? Does it just split or is this a valve that allows air to pass only one direction?
5) What is the purpos of the #16 check valve?
6) Is B a check valve? If so what's its purpose?
7) Is C a check valve? If so what's its purpose?
8) Would a boost leak test at the inlet of the turbo tell me if all these things are good or not? I.E if all check valves and such are operating properly? Or are leaking?
Im trying to understand the entire system to aid me in my issue of not being able to boost over about 1 bar even with wastegates unplugged and tied shut.
Thanks!
#16 is the check valve (iirc? ) at the top of the plenum and yes, a turbo inlet boost leak test at 20+ psi will tell you if it's cracked. often the source of a leak and accompanying boost ( low ) issues. you'll hear it hiss, as they crack and are just plastic, as are many of those parts.
(b) could well be the other check valve as I remember it looking like that and similar to a piece of fishing tackle/lure ( really ). not sure about that one as listed in your schematic? but the pet schematic ( unless that's it??! lol ) I remember as being more comprehensive in listing each part in the intake system.
as to what they do or don't do? well, I know that when they aren't working right? they prevent full boost such as in your case.
more informed folks will hopefully explain their function less anecdotally, and more technically.
Your venturi valve is No9, it works on a venturi effect to supply vacuum for the servo. A1 goes to the dry sump tank so it can breath, there is a one way valve to stop boost going to the tank, A2 is part of the breather system for the fuel tank.
05-28-2015 | 12:12 PM
