Fuel Cooler using A/C Lines

[sigchuck]

Hi guys, I posted this in the 930 forum, but thought it might get some additional traction here.

I regularly drive my 930'ed 911SC year round, including in heavy traffic with 95+ degree temps. Last summer I noticed that on very hot days during stop and go driving, my AFRs at idle would creep up slowly throughout the course of a drive to around 16.5 or so after coming to a stop.

The CIS system is in tip top shape, I have a relatively new single -044 pump, and AFRs are normal during driving and come back down at idle if I apply a little throttle (say go from 1000 RPMS to 1200).

It seems that the likely culprit is warm gas, and in researching the issue a bit, it's likely exacerbated by the high volume pump I have (as well as the hot asphalt heating the tank and all the fuel being returned to the tank at idle).

It looks like Bosch has developed a fuel chiller for some makes using CIS, and that Porsche used one on A/C equipped versions of the 928. It seems like it just routes the fuel return line through a valve that's in series with the AC lines coming out of the evaporator and heading back to the compressor.

Has anyone ever run into this issue and had it bother them enough to attempt to cool the fuel, maybe even adapting the 928 cooler to the 930 (or 911) CIS?