I'll disagree with you completely on the idea that header coatings' "primary purpose is to keep exhaust gasses speed up thru the header." Again that is the byproduct of attempting to achieve lower engine bay temps. Besides, the scavenging of the cylinder only occurs at the exhaust manifold/header and the increase in temperature creates more vacuum pulling more of the exhaust air out of the cylinder more efficiently. This is the purpose of headers altogether to begin with. Increased heat is not an advantage nor a factor down the line, though. The exhaust temps drop naturally. The STS system is simply taking advantage of this natural drop by moving the turbo further down the line. The STS is not proposing that it lowers the exhaust temp, just that it takes advantage of the lower exhaust temps. Again, further down the line the gases are naturally cooler and cooler air is more dense and dense air acting on the blades are more efficient as compared to hotter air. I think that is the point being lost here.
You are right it is thermodynamics. Cooler air is more dense. If there was some way to spin the turbos with only cold air, it would be more desirable than using hot air because denser air reacts on the blades more efficiently. It's just like airplane wings. Planes get more lift when the temps outside are cooler as opposed to hotter. The molecules are more closely packed together creating the effect of more molecules moving across the wing surface. The same idea applies to the turbo. If there are more molecules moving against a turbo blade it moves the turbo more efficiently as compared to hotter air where there is less molecules in the same volume of air.
It's applying all of this where it will make the difference though. So much R&D needs to be done to achieve the desired results. I agree the H2 needs more torque than extra HP but smaller turbos tend to spool quicker (simply due to having to spin less mass) and create boost at lower RPMS. I don't have all the answers, own a shop, or even tune, but I do like to see the continued innovation.
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