So if I hypothetically swapped my 3.0 for a 4.2 would I need to do anything about the fuel pump?
I’m pretty sure but not 100% but i think they might be the same part. But that’s the least of your issues when swapping.
And like EVERYONE else is going to say, SELL THE CAR and buy an S4 if you want a 4.2. They are getting cheap these days you can pick one up for like 10k I’m sure that one for 10 or just over is going to need some work but still your much better off with a S4 that needs some maintenance vs a 3.0 swapping to 4.2, 2.7, 3.0T, etc…
Some 3.0 cars had a return style fuel system all the S4 4.2 cars had a non return style… Power wise if you keep the 4.2 stock you should be good. Etca doesn’t show enough to say if it’s the same…
02 to early 05 A4 1.8 8E0919051BM
early 05 and up A4 1.8 8E0906087P
3.0 8E0919051BM
B6 S4 to 05.5 B7 8E0906087R
2006+ B7 S4 8E0919051BQ
Isn’t that interesting. 3.0 and most 1.8 share the same pump. Then there are some bastard child 05 B6 1.8 cars out there running around with an S4 fuel pump
Also, fuel tanks changed a few times
02-03ish have their own tank unique to the A4
04ish-05 A4 got the same tank as the B6 S4. …I say “ish” because the change did not definitively happen for the 04 model year. Could be some 03 cars with an S4 tank. However since they clearly changed tanks when the B6 S4 came out, it is safe to say that ANY 04+ car will have a tank compatible with an S4 pump.
Fuel tanks are not specific on A4 models. So the 1.8 and the 3.0 always had the same tanks as their same-year counterpart
You’d also want to swap out the front shocks/springs if you dropped in a 4.2. If you really wanted more power, the 2.7T would be a better swap option as there would be less weight difference for similar power output as the V8.