Re: BOSCH blow off valve

[Avi <Avi@cosmoslink.net>]

>1.  Does your data mean that two Bosch valve will start to bleed off
pressure at
>the additive of the two (10-12psi) or that they will bleed off pressure
twice as
>fast at 5-6 psi?  My assumption of you analysis is that there would be twice 
>much bleed at 5-6psi making it more difficult/slower to build boost on the
>engine.

OK, first a disclaimer I did not check the valves in parallel, but I think
it is fair to assume that if I was  to supply the same amount of air
DIVIDED by two outlets (two valves), the pressure will double, meaning 12,
at 12PSI both will start bleeding, did that make sense?..... I know that
there are other factors involved so you must take this test ONLY in
relation to the set up of the test.

>2.  Have you tested any units, such as the much talked about HKS unit to
see if

No, because:
it is "way big" needs twice or three times the space of a Bosch,
needs to be mounted on a flange
too costly, the best i was able to find is $200 although Eric has a source
at $170 (don't know where) 

>>From your data, which I would consider a pilot study of this devise, it
would
>seem that the Bosch unit is designed for low boost applications, not the
higher
>boost levels that many on the list are using.  

not necessarily so:
even if it bleeds, at all pressures above 6PSI, there should be enough
volume in our turbos to NOT MISS THAT LOSS,
the important factor is that when there is vacuum, the valve will
POSITIVELY  open.... 

>Too bad you do not have access to
>a large enough sample 8-10 units to make a more definitive claim on the
function
>of these units and put the blow off valve controversy to rest.

if you will get them, I WILL TEST THEM (just kidding)

Remember, a positive shut off requires a heavier duty valve, that maybe why
the HKS is so much more heavy duty......the Bosch is OK for what it is
designed for.....
Avi  
>Great work! Thanks,
>
>--
>
>Randall C. Markarian
>
>1990 V8 Quattro
>1996 Merc E320
>
>Saint Louis, Missouri
>
>
>