Re: 'supersonic turbos'

[Brett Dikeman <brett@pdikeman.ne.mediaone.net>]

>I'm interested in 'turbo-stall', and RPM's of the turbo device.. Is there
>anyway ouside of a lab (ie. In my car:) to monitor the turbo's RPMS?

I asked this once and didn't get many answers; the only way I could think
of was to paint half the nut with black paint and polish the other; you'd
have to re-balance the turbo again, but then one could put a reflective
optical sensor in the inlet.

The resulting switch between light+dark would be 1/2 the RPM, making it a
little easier to sense the speed.  You can't pick up on the turbine blades
with a hall effect sensor because they'd be going by too fast(I don't know
how many blades there are, but multiply 20-ish times about 50,000RPM[a
minimum I think] and you get an idea of how fast they are going by.)

I can't think of any better way to measure the speed.  You'd need a fairly
damn good($$$) reflective sensor to pick up the upper RPM ranges, and some
custom(but not hard to build) electronics(or just a standard frequency
counter.)

I don't think a sound pickup would work at all.

You'd have to ask someone who works with turbo balancing and stuff to
figure out how they measure it, but they do have the advantage of a
mechanical linkage to the shaft, so they could mechanically reduce the RPMs
to make them more measurable.

I'd love to hear other's thoughts on the subject...
Brett

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Brett Dikeman
brett@pdikeman.ne.mediaone.net
~)-|
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Te audire non possum.  Musa sapientum fixa est in aure.
Ita, scio hunc 'sig file' veterem fieri.
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