Is that regulator/filter direct fit for A4? That would be a very simple upgrade (my filter is probably partially clogged by now anyways) and would allow for much more fuel. Is it fairly easy to scale the fueling for higher fuel pressure?
Is the stock 1.8t fuel pump up to the task of maintaining higher pressure?
Maybe, we should create a new thread in the vehicle tech section for the B6 A4 and not clutter this one that does not apply to most others??
The filter should work, 2.0t guys have been installing the 1.8t filters on accident... The B6 1.8t filter has 3 and some times 4 ports. When I replaced mine it had 4 ports, the 4th port is a vent line that can be blocked off when using a 3 port version. This an interesting thread with good information about the 4 port fuel filter,
click.
Tuning wise we would be modifying KRKTE and TVUB. Using some online calculators the flow values are:
B6 1.8t injectors 282cc @ 3bar or 398cc @ 6bar
TT225 injectors 386cc @ 3bar or 445cc @ 4bar
The stock pump probably would not be up to the task however @ 105K miles I am thinking of replacing mine with a DW300.
I think increasing the fuel pressure especially considering the the B6 dose not have a manifold reference would provide beneficial results (Bosch EV12 information indicates that maximum system pressure of 8bar) .
Edit: B6 fuel injector information.