Quote:
Originally Posted by Symaze
I believe the 5th gen's fuel system is the old school return style so fuel is always returning to the tank. Since there is a second filter in the system, it would be returning to the tank much cleaner than it left. As you drive around, that same tank of gas is cycling through two filters instead of one. The tank filter is certainly still capturing all the largest debris from a fresh fill-up, but I'm thinking the aftermarket filter would still be taking close to half the load of filtering each tank of gas and therefore would still extend the life of tank filter.
Doesn't seem like it is a very common setup though, which is why I'm asking about it.
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Yes, fuel has been returned to the tank for a long time, but it is hardly old school. It is an absolute requirement to prevent vapor lock; it keeps cooler fuel in the fuel lines.
I don't see why returning cleaner fuel back the tank is important. If the fuel is clean enough to not clog the fuel injectors, it is clean enough to send back to the fuel tank.
Any additional filtering will cause some back pressure in the fuel lines, thus reducing the fuel pressure needed at the injectors. If the pressure is lower than it should be, the injectors won't put out the right amount of gas.
I can see adding more fuel filtering in countries where the gas is inherently dirty compared to the US, but in the US, the OEM filter works just fine.