Optimal Tubular Tire Pressure - RACE?

Here's some guidance Zipp gives for their Tangente tubular tires:

http://www.zipp.com/Portals/0/Shopping/Images/tire_pressures.jpg

Not sure if these would be good recommendations for the Vittoria's or not but, generally, unless you are on a track surface you don't want to be anywhere near the max pressure rating.

No.  It doesn't.

Hmmm, interesting.  And what information do you have to support that statement?  Besides my own 20 years of bicycle racing that formed this opinion of mine (and yes it's only my opinion), within a minute of searching found at least 20 research articles that confirm this.  I've cited only a few below...

http://www.rouesartisanales.com/article-1503651.html

http://www.sheldonbrown.com/brandt/rolling-resistance-tubular.html

http://www.sheldonbrown.com/tires.html

http://www.diablocyclists.com/bicyclescience.htm

http://www.nimble.net/subpages/tirepressure.html

Now granted I am not suggesting "over-inflating" tires, but simply running them at the highest reccomended rating on them.

Anyway, I'm definitely interested in anything you could share as perhaps I've been missing out on the low pressure advantage all this time. 

I don't have time for each one, but the citation you used from Nimble includes this:

"We find absolutely no performance reason to inflate tires beyond 130 PSI (9 BAR)." 

and:

"The Negative consequences of high inflation pressures include: (1) elimination of the principal shock absorber on a bicycle significantly impacting rider fatigue and equipment wear, (2) degradation of handling from the smaller contact patch (increasing slip rates and side wash out), (3) loss of traction (loss of rear wheel acceleration, and braking skids) , (4) marked increase in flat tires (less tire to road conformance, greater puncture load behind road hazards), and (5) more rapid catastrophic flat tires."

and:

"...exactly the same advice pertains to tubular tires.  Do not over-inflate tubular style tires, for the same reasons, it offers no performance benefits and carries the same detriments of increased shock, and worse handling, traction and flatting."

The Sheldon Brown site points to this on tire inflation:

Tire widths are in millimeters, pressure recommendations in pounds per square inch. (Divide by 15 if your gauge reads in bars/atmospheres.)

Check the footnote in the Zipp link above too.  I don't know if they have more info on their website anywhere, but I've heard from someone at Zipp that their testing confirmed the types of recommendations they provided there. 

My uderstanding of the matter is that unless the surface is very smooth (i.e., track or maybe some very newly paved roads), the higher inflation will result in more "bounce" on the road and less contact with the pavement.  Therefore less energy transfer from the wheel to the road (and more absorbed by the rider).  Therefore, poorer performance.  Even though the tire will have lower "rolling resistance", the total resistance to forward movement will be greater.  Moderate pressure will provide better "deformation" when you need it and acceptable rolling resistance for a faster overall ride.

Keep doing some searching and next time read through your "evidence" too.  

See #4 in the Nimble reference above.  The exception would be pinch flats.  But this is only relevant for clinchers.

I don't think any of the references you cited actually discuss the issue about greater overall resistance specifically (sort of indirectly referenced in that Nimble write-up).  But that's the reason for the recommended pressures that Nimble, Zipp & Sheldon Brown all provide.  Technically, you are right that higher pressure yields lower rolling resistance.  But the "bounce" effect generates more overall resistance to forward motion on most surfaces, despite that lower rolling resistance.