ECU for 14k rpm V8

[Eric Fahlgren]

Greg Hermann wrote:
> 
> Quite the contrary. A "draw through" turbo stays spooled up better because
> there is no (less) load on the compressor wheel in a (partial) vacuum.

Sure, that makes sense.  I was thinking that the time to fill the IC and
plenum would be the overiding consideration, but when the turbo is staying
at 100k rpm, who cares?  I wonder if it would linearize the throttle response,
too, not having the PR-induced pressure differential across the TB?  I'm
struggling with driveability issues on my Audi right now, the torque grows
exponentially from 2700 rpm to 3100 rpm, when the boost comes on.  You can
be accelerating nicely at 40% throttle at 2500, then you need to back down
to 4% when the revs reach 3000.  Makes it a real pain in ass in traffic.

> The compressor also stays much further away from the surge line in a draw
> through--which would probably be damn hard to stay away from any other way
> with a wheel designed to make a 5 to 1 pressure ratio at any reasonable
> kind of adiabatic efficiency!

Yes, I see that as a very significant item that I hadn't even
considered.  I did wonder about surge on something that's running
5-6:1 PR, but didn't think about the TB position as a curative
measure.  Excellent point.

-- 
Eric Fahlgren                            Mechanical Dynamics, Inc
efahl at adams.com                          Ann Arbor, Michigan, USA
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