Preamble: I'm not arguing against divorced systems at all, nor am I arguing for an air to air setup. You guys are doing it how I would, but living with the siamesed system in my Jaguar, I see both sides of the conversation. I'm not trying to tell you what to do; I was just throwing it out there and like I said- "maybe." You guys are the real engineers here and are going to do what you see fit, anyway.
But as for your temperature comment, I thought the same thing too back when all I ever messed with were air to air setups. But after monitoring my IAT2s for the past year in everything from 22°F to 100°F ambient and never seeing the delta between the two stay at about 45°F, I started to wonder. When I did the pulleys, heat exchanger and tune I asked the guy about divorcing the systems and he said exactly what I posted previously- that the gains are not there. He said it was because there is no flow of water between the two systems; only pressure fluctuations due to thermal expansion, and because the intercooler put far less heat into their part of the system than the engine while having a relatively larger heat exchanger given the amount of heat generated. I still wasn't 100% on board because I thought that there still has to be heat and fluid transfer through that 1/2" coupling, so I called a few other tuners and they all said the same thing with the caveat that the Mercedes guys do have some luck with it, but mainly because their systems are such garbage to begin with. Mind you, these arent some kids working out of a storage unit putting ebay turbos on their buddies Civics here... these are established, renowned brick and mortar tuners that make a living making $100,000+ cars go faster, and having them all say the same thing is good enough for me. With the pulleys, I roughly doubled the boost over stock on my Jaguar that uses an Eaton TVS R1900 supercharger, and the delta between ambient and IAT2 is still a just hair under 5°F more than stock on the track and in the canyons. It heats up around town, but that's a lack of airflow issue from not having a pusher fan (an issue you guys won't have), and it still doesn't get close to my coolant temps, which are consistently between 195°F and 225°F.
70°F water? Not unless it's 55°F out and you haven't boosted yet. You'll never get the water below ambient, even if the compressor, intercooler and heat exchanger were 100% thermally efficient. without seeing the map or knowing core sizes, flow rates, ect., I'm spitballing here but figure about 75% for the compressor, 90% for the intercooler and 85% for the heat exchanger if you get good stuff... you're still going to have IATs +40°F over ambient. It's just how it is with these things. The great part about W2A is that they have a much higher thermal capacity and are much slower to change temps from the fluctuations in post-compressor temps. Consistent temps are good. So is a reservoir to throw ice in if you want to take a 6500 lb. pig drag racing.
But if you wouldnt mind... please satiate my curiosity- what have you done to calculate the proper heat exchanger and intercooler sizes as well as the water pipe diameter and pump flow rate requirements. That's a genuine, not-a-pissing-match question. You guys are putting a lot of work into this and really sound like you have your ducks in a row, so I'm just assuming you've covered those bases already.
Now I get it, thanks for this post.
