A lot of good advice, @Teammccalla (sorry, I forget your first name?), from Gordon, Mitch, Kelly and Michael. The problem with using the space in front of the engine compartment and above the transaxle for a cooler is there's no air movement- this is also why a hole in the firewall in front of the fan intake doesn't really help. At highway speeds there is a solid bank of air flowing horizontally underneath the pan that goes right by the above the trans airspace (also why our cars run hotter at such speeds if not equipped with sled tins and either heater boxes or the industrial side tins). Earlier I mentioned engine compartment temps was important- both Beetle and Speedster engine compartments (again, at higher speeds) will suffer negative air pressure with bigger engines, starving both the fan and carburetors, with what they are getting being pre-warmed by heat radiating off the engine components. Airflow THROUGH the engine compartment creates positive pressure, will feed enough air to the cooling and intake systems properly, takes away radiated heat which reduces air temps so the systems can work as intended and the engine runs within proper parameters more of the time.
After a long highway drive, stop, quickly run around to the engine compartment and put a hand on a cylinder cover- if you can't keep it there more than a couple of seconds, the engine is running too hot. Or, put a drop or water on the engine case. If it sizzles...
Kirk, when he ran Vintage Speedsters, equipped a lot of his cars with a big hole in the firewall in front of the fan shroud, but because of that layer of air underneath the car at speed, really didn't do anything. But guys on the Samba have proven that if you re-direct air up into that area it goes a long way to keeping even a bigger, more powerful engine cooler.
This guy claimed a 10° reduction in oil temps with this air deflector in his bus. Another fellow in Utah (Salt Lake City?) with a big engine in his street bug (ran mid to high 11's in the quarter mile- may have been turbo'd?) found that removing the front breastplate off the engine made a world of difference in the engine's ability to keep itself operating within normal parameters.
I think the deflector could be bigger...
