Some updates on the RS4
I've updated the nav database to the latest maps
The B&O system in my opinion sounds rubbish in the B9. One of the reasons is the subwoofer is wired out of phase with the rest of the speakers. It's well documented online and pretty easy to sort if you are comfortable with soldering or have depinning tools. You could also make a loom to swap the wires. I went down the soldering route:
You have to swap the Orange and Yellow wires over and do the same on the other side for the other coil. I think the wires were black and green on the other side. Alternatively, re-pin the connector on the sub housing.
It's made an improvement, but you still have to crank up the volume to get any meaningful bass from the system. Audi designed it this way to stop panel rattle at low volumes, so the DSP won't send full power to the sub until you're at around 40% volume. IMO it's a cop out for not building the car better but I guess it comes down to cost.
I'm going to add some sound deadening to the front doors and in the spare wheel well to mitigate some of this, but the bottleneck will still be the DSP setup. I've deadened the rear quarter panels already, if you tap them from the outside, they make a tinny noise. I can post back my results of the additional sound deadening if anyone is interested?
Lightning struck twice for me and the fuel filler flap actuator seized on the RS4 as it did on the S3. I learnt my lesson from the S3 and keep a plastic trim removal tool, thin flathead screwdriver and a pair of snips in the car. These actuators are used on nearly all recent Audi models.
Sometimes you can free it by repeatedly locking and unlocking the car whilst applying some pressure to the flap door. If it opens, you will be on borrowed time so replacement is the way to go.
If it doesn't release, you need to wedge open the flap door as much as it will open, slide the screwdriver into the slot on left side of the gap (it's towards the bottom, between the painted flap cover and the black plastic flap itself) and slide the painted cover towards the back of the car, then snip off the tabs holding the actuator to the flap. At this point, you can leave it broken with the tabs cut off (the tank is anti syphon) or replace the actuator.
The official way to replace the actuator is to punch 4 holes in the flap housing (there are 4 small indents on the perimeter of the housing) and replace the whole housing which seems wasteful. As the RS4 has flared rear arches, there is a gap where you can get your hand (you need small hands and strong fingers) behind the flap cover from inside the boot and release the 2 left clips then you can push it out of the car. There is no need to remove it completely, just enough to get to the 2 torx bolts that hold the actuator to the housing. You have to be careful of the drain tube at the bottom, you don't want it to come out as there isn't enough room to put it back on unless you remove the whole flap housing.
My original flap actuator did not have the red emergency release cord, so I bought a new actuator which has the cord. If the motor seizes, this cord is useless, but if you have an issue where the lock for the flap fails, you will be able to release the flap. It's not a bad idea to put some silicone grease on the shaft of the actuator, clean the housing and test everything before you push the housing back into the body of the car. Make sure the perimeter seal isn't folded over when you push it back in.
As I've had 2 OEM actuators fail, I wasn't paying the Audi tax for a new one so I bought a 'Chinesium' one off Amazon for £17 as I needed it ASAP. I've bought another spare one off AliExpress for £5ish so I have it if it fails again. The AliExpress one is exactly the same as the Amazon one. Part number is 8V0 862 153A (there is a B version but that also fails).
