Miata Turbo Forum - Boost cars, acquire cats.

- Prefabbed Turbo Kits (https://www.miataturbo.net/prefabbed-turbo-kits-3/)

- - BEGi bypass valve VTA (https://www.miataturbo.net/prefabbed-turbo-kits-3/begi-bypass-valve-vta-18439/)

Quote:

Originally Posted by wes65 (Post 229436)

hmm... i think i may see the problem here, i didnt have the idle air tube hooked up, that would mean that the motor was not sucking idle air through the piping but from outside, therefore making a little bit of positive flow in the piping. That also means it was sucking unfiltered air.

That would make me feel better i KNOW that there was air blowing out of the bypass valve.

yeah, i mean, i know, i will be fixing it and see if that changes the situation any.

Thank you for the gay-ality check
ive had two root canals done today, and im more than slightly impaired
the only thing that comes to my head for that stupidity is 'SIR!, NO EXCUSE, SIR'

Its possible for a turbo to pressurize the intake piping and intercooler, if equipped, against a closed throttle-plate but there will most likely be low load situations when this isn't the case.

I think it should be open.

There is a spring that sits atop the valve and presses down to keep it shut. The MAP signal pushes in the same direction as the spring, and competes against the pressure in the charge pipe.

If charge pressure > spring + map, the upward force wins and the valve opens.

If charge pressure = map (open Throttle), the is charge pressure below the valve is canceled by the map signal atop and the spring keeps it shut.

At idle the throttle is closed, the turbine is spinning, and the MAP signal is a strong vacuum. It's no surprise the valve is open.

Even with a fairly large turbo (certainly by most of your standards: a holset hy35), I have noticed it moving air at idle. On a 1.8 idling at about 800rpm I've placed my hand in front of my compressor outlet, heard the air fight to pass through the suddenly disconnected charged pipe (this one happened a lot), and placed a finger in front of the BOV. Things we all can do, right?

GOD DAMN stupid fucking rash of NOOBS today opening up 3 week old posts for no fucking reason!!!

Sam, I read Opek's post and immediately thought of your response to that other guy yesterday.

We all can confuse the current board and our search, especially when unrelated threads like this sneak in.