Boost enrichment delay
 

I know I've seen information on RPM triggered boost enrichment delay on this forum before, but I can't seem to locate it now. Once upon a time someone out there posted dyno results demonstrating the OEM over-rich condition in the early stages of manifold pressure and how it was resolved by a delay swith to block the pressure signal to the WUR until about 4000 RPM - I think. Does any of this sound familiar?

It may have been on Rennlist. Try searching for "Brian Leask" or "solenoid"

Leask has a device that performs that function.
I would think it to be more advantagous to delay enrichment to a preset boost level instead of a preset rpm. As you know boost onset is a different rpm in different gears and ambient temperatures. Something like 0.4bar might be a good preset for boost reading delay at the WUR.
A quick data log of A/F ratios throughout your operating rpm range will tell you when it hits under those conditions. You can count on greater lag when the intercooler heat soaks or while driving on a hot humid day.
A simple hobs switch will perform that function.
I am going to do this myself very soon and will post all the dyno runs.

since we are running too rich in the mid-rpm range, would it be beneficial to dial in more boost in those rpms via a ebc?

As the CIS meters the air with a flap it will try to compensate for any extra air being forced into the engine. So I doubt it.

but won't running higher boost in those "too rich" rpm range will actually lean out the afr curve?

I don't know for sure. I wouldn't think so.
Why do you think it would ?

Brian Leask has it available with is adjustable wur. http://members.cox.net/930wur/