I'm doing some comparisons to the non-RS6 4.2 single in-tank pump fueling and the RS6's internal and external/transfer pump?
First off, I'm wondering if the actual pumps that are part of the in-tank assemblies are different between these items:
4B0906087BF (RS6)
4B0906087P (non-RS6 4.2)
After this pump, the RS6 also has a transfer pump (P/N 4B0906089A) that's external to the tank.
From what I can tell, the pumps are in series with the in-tank pump feeding the external pump then through the filter up to the FPR.
Wouldn't the second pump either starve the first pump or cause back pressure to cause premature failure?
Not sure if it's ever been discussed here, but I'm guessing that these pumps have to be matched pretty well in order to not wear out prematurely. With that said, am I asking for trouble if I want to change one of these out to something else or just use one alternative pump?
Adding another monkey wrench to this is that they are both normally running at 10V except when certain conditions make them run at 12V. From what I can tell, both pumps are always at the same voltage, though.