Join Date: Dec 2017
Thanked 2 Times in 2 Posts
I'm not a supercharger expert, but here's what I've observed. There's debate going both ways, and although the water is much more efficient at removing heat than air is, the water needs to be cooled by air, so logic indicates that the benefits would cancel out... Then again, the same applies to water cooled engines versus air cooled engines, and I think we know which formula wins in most cases. Heat exchangers in industrial applications also seem much more effective using liquid cooling, and especially for a greater temp drop, although generally more expensive for initial cost of the system.
So we could also say that packaging design is a factor, CFM and temp differentials are a factor, weight is a factor, flow path is a factor, engine behavior is a factor, heat soak time is a factor, cost and reliability are a factor, forced induction system design is a factor...there are offseting factors for both arguments even further.
No easy answers, but people these days have figured out better ways to get more temp drop in the air charge... I asked about the ESS Gen 1 to Gen 2 Air-to-water intercooler changes (higher flow pump and larger heat exchanger in front) and the answer was about 15 degrees cooler air temps in the plenum. That's perhaps a big difference in reducing heat soak with extended high power operation which is one of the weaknesses of the water system. What sort of Air to Air would do the same I wonder? And if that supercharger has a specific output limitation that's not too far away from the designed engine demand, would it have the overhead to push that air charge through ducting in a 200+ degree engine bay and through a significantly larger charge cooler (tiny one currently). I don't know, they all need airflow and preferably denser air to cool off, positioning the heat exchanger in the best place in front of radiators and power steering coolers and condensers and oil coolers there's only so much room to get the limited cooling resources to cool either type of intercooler. If they say that the air to water system provides a much better air charge cooling than they can manage another way, I can accept that. Air to water is more expensive so it's not corner cutting. Packaging, probably a factor for sure.
On a humorous but somewhat related note to think about with regard to packaging... I've heard it said that water cooled engines on an airplane make as much sense as air cooled engines on a submarine. :-)
07 M5, 6spd, Sapphire Black. 06 M5, SMG, Sapphire Black.