Let’s review what we’ve learned in the previous posts. We learned that there are many old wives tales about aluminum radiators, most of which are not true. Then we learned that aluminum is lighter and stronger than copper/brass. As hot rodders, we exploit this lighter and stronger aspect of aluminum to build aluminum radiators that cool significantly better than their copper/brass counterparts.
The reason aluminum cools better is quite simple: bigger tubes. Bigger tubes are a culmination of all the positive aspects of aluminum put into action. Bigger tubes means fewer, larger tubes are needed to get the same amount of cooling done. Because there are fewer tubes, there are fewer tube gaps. These tube gaps act like speed bumps and slow down the cooling air as it flows over the core.
Back in the era of copper/brass radiators, snake oil companies started building cheap 4-rows. They did this by using tall fin heights and small tubes. A cheap 4-row radiator would have 32 rows of tubes vertically and only use ⅜” tubes. A good high quality 4-row will typically have 38-40 rows of ⅝” tubes. That’s a huge difference.
Just like the snake oil 4-row copper/brass radiators, there are snake oil aluminum radiators. These come in the flavor of 3-row and 4-row aluminum radiators with ½” cooling small tubes. From our previous discussion on aluminum, you might be wondering why would anyone want to make aluminum radiators with small ½” cooling tubes? Doesn’t that defeat the entire benefit of using aluminum with larger, fewer rows?