valve springs

Bernie Benz b.benz at
Thu May 8 17:32:46 EDT 2003

Sounds like nonsense to me!  The intake valve is 32mm, 1.25" dia = about 1.3
sq" area.  At 1 bar boost that's only 18# force on the valve trying to open
it against atmo press in the cylinder.  But the cyl pressure is always above
atmo even during the ex stroke because of the turbo press drop.  I don't
know the valve spring force holding the valve closed, but I'll bet it is
>100#.  Don't waste your time on the Q list, ask the experts!


> From: "Brandon Rogers" <brogers at>

> Hey guys-
> Apparently there is a thread over on the Main Q list WRT valve springs and
> high boost.  Somebody is saying the 10V cars have springs that start to give
> at high boost, thus letting boost escape from the cylinders.  Makes sense to
> me in the sense that if the springs require 15 psi to compress and your
> running 16 psi boost...they give--bye bye boost.  Any comments on that here,
> WRT to 20V engines? maybe the 20V runs stiffer springs already--which would
> not surprise me....
> Brandon
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