I bought the Super Cool tins on an impulse. Further research showed they were designed for the T3 flat pancake cooling system and not the T1 up right cooling shroud. Not sure if that was hear say or results of some study. The positive ads (vendors selling them) say they increase cooling but others say -
Pro - Chirco performance offers both black and chrome plated custom Air Cooled VW super cool tin, these tins mount underneath the cylinders and above the push rod tubes and direct the air coming down the fan to swirl around the cylinder for better cooling . these custom super cool tins fit all Air Cooled VW upright engines.
Con - IF VWs had cooling issues that mandated 10 million dollars of R&D to create the doghouse system, don't you think they would have applied these "super cool tins" to the engine from the factory?
“Cool Tin.”
You shouldn’t need the “cool tin” if all of the other
parts of your cooling system are in place and
functioning. But it is available at minimal cost
(e.g., from Aircooled.Net)and is easy to install
(with the engine removed from the car).
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You have to remove the engine to install the cool tin, and to fit them to the Type 1 Beetle tinware they might need to do a little cutting and bending. They are not really needed for a stock Beetle engine, but if you have a higher performance engine or are experiencing cooling problems, they might help. (We have not personally used "cool tin" and cannot vouch for its effectiveness. It helps, though, according to the experts.)