When good turbos go bad...

[type53 at gmail.com (Drew Mac)]

On 7/15/07, Eric S <scirocco@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

> How where you controlling the nozzles?

A dual-diaphragm can - vacuum moved the nozzles to no-boost for idle,
and a throttle switch shut the vacuum source down.  This allowed for
no boost at idle/low boost cruising.  The (approximately) 11 psi
spring in the can controlled the boost pretty well, no spikes.
Transition of the nozzles was controlled by the force of the
diaphragm, which was smaller than the stock TDI cannister.

It worked pretty well all told, from the time I settled on that method
(the day before driving to Cincy) to the time the impeller shaft
parted.

I had just completed a long hard pull in 5th from about 1700rpm (a
MAJOR no-no) which put the compressor pretty much smack in the surge
zone, and presumably weakened the shaft  I then immediately followed
that up with a hard launch from a stop sign which resulted in the
catastrophic failure.  Very embarrassing when the cars you just passed
drive by you as you're smoking on the shoulder... And I mean
SMOKING... ;)

Drew

-- 
84 Wolfsburg Ed. Scirocco GTD mit ?berVerteilerpumpe
http://scirocco.cs.uoguelph.ca/gtd
77 Scirocco project - Boom Boom Boom...
99 A3 Jetta GL TDI (hers) 02 Jetta GLS TDI (Bloatware)
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