5ktq and boost ...........

[Ken]

Ben, it really seems like you may have the boost valve hooked up incorrectly.  I would perhaps take it completely out of the equation, plugging the holes, and see what kind of boost you build then.

> Ben Swann <bswann at worldnet.att.net> wrote:
>
> I can't see where the bypass could be leaking to the outside
> - I'd see some crack or something, right?

It's probably not leaking to the outside, it's just letting your turbo potentially overspin, since the air is is circulating around and around itself.

> Let's assume the bypass might be leaking (internally) -
> why/how would that effect the observed boost pressure?

Because the turbo is spinning around and around, but the boost isn't "building" because it's not filling cylinders with a fixed volume.  It just circulates, even with the throttle open (if it's hooked up wrong or incompletely)

> > Also, since it wasn't entirely clear in your post, I just wanted
> > to make sure that the bypass is sending it's air to the
> > intake (compressor) of the turbo and not into the actual
> > turbine...I am guessing by turbine you just meant turbo.....
>
> Right - I have a fitting installed in the turbo intake, and
> directed toward the impeller.  I did this so the bypass flow
> would enter already going in the right direction.

Is the little vacuum nipple hooked up to intake manifold pressure?  It has to be to stay closed under boost.  Otherwise it will leak.

If it's a stock valve, it could be that the diaphragm is ruptured.