Re: Popped

["linus d. toy" <linust@interramp.com>]

At 08:00 AM 02.28.96 -0500, PDQSHIP@aol.com wrote:
>In a message dated 96-02-28 04:51:40 EST, you write:
>>
>>I've always thought of a pop-off valve as a pressure-relief valve that opens
>>if manifold pressure rises to a certain point--which means it operates on an
>>OPEN throttle and only if it's relief point is reached.  A closed throttle
>>would quickly drop manifold pressure and keep the PO valve closed.  
>>
>That is the wastegates job...  A pop off valve or bypass valve are the same
>thing....  the pop off valve can be routed to the intake side of the turbo or

I realize i didn't make that very clear--i should have said that the pop-off
valve is mounted to the INTAKE manifold (in contrast to the WG on the
exhaust side) PAST the throttle plates.  in this position, if you are
stubborn and keep your foot into it beyond sanity (i.e. safety for the
engine), the PO valve does control boost level.

>to atmosphere, it's function is the same AT CLOSED THROTTLE, to 1) let the
>turbo freewheel and 2) to prevent pressure spikes at the IC.....  Venting it
>to atmosphere is the easiest and usual racers way of installing the valve
>(big farts), the return to intake of turbo is the more quiet and sane method
>used by most production cars.....  The same valve can be used for either set
>up.....   BTW, most atmosphere pop off's I've seen have a K&N filter attached
>to them to prevent oil blow and the possibility of sucking crap in the hose
>during transition....

i see now what you're referring to as a PO valve and bypass being the
same--it would be the same kind of a valve but mounted BEFORE the throttle
plates.  again, this is the second function we've been discussing, the
closed throttle situation, especially for when it's snapped shut.

--linus
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* linus toy           email:  linust@interramp.com                   *
*                                                                    *
* "...it's stuff that does things people want, but they don't know   *
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*                            --4 year old explaining 'technology'    *
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