[s-cars] Too much boost

[Joe Pizzimenti]

Hey, try it before you doubt its operation.

Granted, that diagram is for an internal wastegate, not an external,
so you may have to play around.

Try it, report back, lather, rinse, repeat.

Joe

On 8/14/05, Tom Mullane <tmullane at gmail.com> wrote:
> Joe,
> 
> I took a good look at this diagram you sent, and I have some questions:
> 
> http://pictureposter.audiworld.com/47312/manualboostctrl.jpg
> 
> Is this based on theory or actual practice?  I ask because I'm not
> sure it will work.
> I do understand the theory behind it; either the manual controller or
> the WGFV can limit boost.  In other words boost will be no higher that
> the lower setting of the two controls, ECU via WGFV or manual
> controller.
> 
> It looks great on paper, but here's the problem:
> The WGFV takes boost from the turbo and either routes it the WG to
> force the WG open and limit boost, or it just dumps the boost back
> into the intake track just before the turbo, allowing boost to build,
> right?  Wrong...sort of.
> 
> When the WGFV is closed (default, unplugged, failsafe, yada, yada) it
> routes all boost to the WG to open it.  But when power is applied the
> WGFV, opening it, it allows boost into *both* passages of the "T".
> Boost bleeds off into the intake boot and cannot reach the WG with
> enough pressure to force it open.
> 
> My concern is thus:
> Let's say I install a manual controller and set it to 20 psi.  The ECU
> is calling for 30 psi max.  At anything less than 30 psi, the WGFV
> will be bleeding off boost in the control circuit into the intake
> boot.  There will not be enough pressure in the circuit to reach the
> manual controller.  Even if pressure reaches and passes the manual
> controller, won't it just be bled off through the WGFV before it can
> impact the WG?
> 
> Does this make any sense to anyone?
> Has anyone BTDT?
> Pressure may not bleed off fast enough to create a problem, but I have
> my doubts.
> 
> Tom
> 
> On 8/10/05, Joe Pizzimenti <joe.pizzimenti at gmail.com> wrote:
> > Tom,
> > Did you try turning it down via a manual boost controller plumbed
> > inline with the WGFV?
> >
> > http://pictureposter.audiworld.com/47312/manualboostctrl.jpg
> >
> > Joe
> >
>