WRX vs. 1.8t

[nealtovsen@yahoo.com (Neal Tovsen)]

I'm not quite sure I follow this, but I know this is
getting over my head technically so I could be plain
wrong...

I think you're saying the early 1.8t measured the MAF
and adjusted the wastegate via the ECU instead of a
self-controlled mechanical wastegate. But mechanical 
wastegates are driven by a diaphram...isn't that
basically the same thing? Boost is pressure, which for
the same fluid should equal density. Thus, for a given
volume/path and speed boost should be directly related
to MAF. Or am I missing something important? 15psi in
the manifold at 5000rpm is 15psi at 5000rpm,
regardless of what the air pressure was *before* it
was compressed.

Neal

--- Dan Bubb <jdbubb@ix.netcom.com> wrote:
> The early 1.8T's didn't actually measure and control
> boost pressure.
> They measured mass air flow and adjusted boost
> pressure to control that.
> I don't know if the later 1.8T's control boost the
> same way or measure
> and control boost directly.
> The net upshot is that at higher altitudes the VW
> engine will run higher
> boost to attain the same mass air flow the engine
> would have at sea
> level. So, power declines at altitude (mostly due to
> turbo inefficiency
> at higher pressure ratios), but not much. If the
> Subaru directly
> controls boost then it will loose more power than
> the VW at altitude.
> Maybe that explains it. Or maybe the Suby driver was
> lost in turbo lag?
> Dan
> 
> -------- Original Message --------
> Subject: WRX vs. 1.8t
>    Date: Thu, 24 Oct 2002 12:59:12 -0600
>    From: "Brandon Smith" <SCIROCCO_SPEED@msn.com>
>      To: "SCIROCCO-LIST" <scirocco-l@scirocco.org>
> 
>  Okay to make myself clear, here in tha Mountains of
> Colorado (well not
> really, but still over 6,200 ft above sea
> level...like the base of Pikes
> Peak) its just been my experience that the 1.8ts are
> faster than the
> WRX....why??? assuming because of the turbo lag of
> the WRX.   Up here
> the 1.8t pulls harder.  guess maybe VW had visions
> of their european
> customers driving around in the Alps a lot.? but for
> some reason, a
> 150hp 1.8t in a VW seems to pull harder in the first
> few gears than a
> 180hp Audi ???-Brando
> 
>  
>
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