When it comes to these questions, I have to stop and think about my education....specifically physics. I'm old, but if I remember correctly, cooling efficiency/capacity is affected by a few factors. Efficiency may or may NOT be directly affected by capacity. Motorcycle manufacturers are looking to shave weight so capacity is quickly sacrificed. Now, how to increase efficiency with lower weight/capacity? Well, add surface area and decrease tube thickness while maintaining air flow across the cooling tubes. Still, reliability must also be protected. How about pressure? Gotta keep an eye on that part of the overall design. Aluminum? Stainless? Titanium? BTU transfer efficiency? Coolant selection? Etc. Geez, my head spins!