What I think of with heatsoak, is the temp getting hotter after shutdown. You are claiming that the few hours of less than great cool down after shut down is harming them, which I would doubt. Electronic components can run in heat all day for years and not fail, as long as temps are in spec.
With heatsoak thats where I look at it as the heatsink would soak up the heat of the engine that may have been 210* at shutdown. So they would equalize at say 190* after a half hour or something, compared to the FSD was maybe 140* when moving with airflow and fan going. This I have never observed in many temp checks of the FSD and heatsink during runs and post shutdown, when FSD is on the intake. Thats what I mean. I have seen the IP actually go up a little in temps after shutdown, and the IP is always 10-25* hotter without any PMD on it than my FSD is on the intake.
There is absolutely no way on the IP is better, and the data in the reference post also concurs with that. If I had a PMD actually on there there and running, creating heat, the IP surface would just be even hotter.
Things may get worse on the intake when towing 10K lbs, because sustained high IATs may actually get intake metal up in temp and probably affect the FSD heatsink. And with higher fuel rates, with your foot into the pedal the PMD has to increase voltage to drive IP to higher fuel rates, which might make it run warmer.
Running around with just the bed loaded never had an issue, never seen the FSD itself go over 150*, the heatsink is always a bit less, and my intake itself is never hot, and engine only ever is 190* even on long sustained boost, it never goes up or down after its warmed up.
So I agree that out of the engine bay is cooler, no doubt cooler is better for electronics, but I have not observed temperatures on the intake that are out of the new PMD's spec'd range. I had an old Stanadyne on the IP when I bought the truck, and it had been there 2002-2007, but maybe only 25K miles and it still works fine, never a hiccup, but I took it off and bought a D-Tech anyway.
If you load up your truck heavy, in the engine bay will be hotter and PMD more likely to fail. Im also sure that many people that dont tow have failures. I say ask the quality control at Stanadyne, the old ones just sucked at engine temps, they wont survive in the engine bay. And probably 95% of the data on engine bay failures is associated with older Stanadynes, because of all the remote kits already available when D-Tech came out and they just havent been out but a couple years.
