ALL higher performance VW air-cooled engines REQUIRE at least our 1-1/2 qt. sump. This means when you add even dual carbs, an 009 distributor and an extractor exhaust this should be next on your list. Why? The original stock system only provides enough oil for the RPM range, oil pump size, and acceleration rate of the factory stock engine, which is extremely slow. This allows the oil to be pumped through the system at such a slow rate that the spill off has time to return to the pickup tube, providing a continuous supply of oil.
With any higher performance engine it is a completely different story. Using more RPM, accelerating faster or a bigger than stock pump, a greater amount of oil is pumped up to the heads and the top end of the engine faster than it did stock. This oil cannot run by gravity back to the pick up tube fast enough to provide a continuous supply of oil. Sometimes this will not turn on the oil light, however, the pump can have some oil that is mixed with air, so no warning is present that you are having oil starvation. This is particularly prevalent when the oil is cold and/or too heavy of a weight is used in relationship to temperature.
All higher performing engines or one that is subjected to hard braking or cornering will also have greater “G” forces pinning the oil to the back or side of the engine. Also, any larger than the stock pump requires more oil sump capacity as it pumps more gallons per minute (GPM). If the larger pump increases pumping volume by only 2 GPM (some pumps increase volume over 10 GPM), where will that extra oil come from unless you have a larger capacity sump? You must have more total oil available in the engine for its demands. Even a lightweight flywheel on an otherwise stock engine can often accelerate fast enough to cause oil starvation.