Question for you turbo...

[Jukka Majanen]

><< Heya,
>   Only one point I want to make.  Its not a Blow off
> or Pop Off valve.  They vent to atmosphere.  Its a
> recirculation or bypass valve.  >>

Hi

Todd maybe You`re right, that Pop-off mostly means
blow out and by-pass: blow into suction, but...

It doesn`t matter where it blows the compressed air,
atm or for recirculation. It can cause the same problem
-charger overspeeding, that was the point.

When the engine is loaded hard and the valve opens 
quickly, as those safety valves usually do. Meantime
there is full pressure and flow in the turbine side, of 
course it will accelerate. 

Reason for this situation can, for example, be too tight
setting for W/G spring or a damaged diaphgram. Now
if there isn`t a pressure switch ( or it`s over rided ), the
blow-off, or whateveronewants valve starts to regulate, 
without any pass by in exhaust side. After a certain time
this overspeeding will cause damages. 

Also long, hard run with damaged air hose can mean 
same overspeed problems. But that is easy to hear.

If one wants so high boost, that it`s over the blow-off
valve setting, there must be lots of more modifications,
than only B/O valves setting and it is a different story.

My best

j-pm -91 cq