Pre-assembled P3 Vent Guage B8.5

B8 S4
#1

sorry if this seems more like an AZ caliber qst… but I ordered a P3 vent gauge and am trying to find info about installation of the unit already assembled in the vent. Before purchase I watched the install videos and it all seemed pretty straight forward. Later that day I got in my car and noticed my dash trim was different than the car in the video- which I guess is a nuance of the original vs facelift cars. So I tried doing some research and could only find threads about the challenges with installing the gauge only unit in your own vent & wires not being the same? but nothing about the pre-assembled unit. Any thoughts about whether the unit will even work in a 8.5? The site I purchased at shows it will but…

thanks in advance.

#2

I did the P3 install on a B8.5, but opted only for the board rather than pre-installed vent. One of the major differences was the new vents have the lit knob hard wired, there is no harness you can disconnect (at least I didn’t see one). So I had to do everything with the vent dangling from the car.

So you might want to see if you can disconnect the wires from your current vent. Ideally not splice the wires, but keep peeling the onion till you see where to pull them off. On the new vent, you might end up having to splice the wires after the harness, or I guess you could try and source the other side of the harness (from the B8) and then wire your own. I wouldn’t be overly worried about the wiring there, since it’s not like anything moves in there. But I do suppose it could be exposed to humidity (if you run w/o AC), but I personally would be fine crimping wires there.

The trim surrounding the vents/gauge cluster is also different, but it still will come off with a trim removal tool. I didn’t completely remove it, but had everything to the left of the MMI screen popped off. Let me know if you need any help, mine was a bitch because I exploded the vent fins everywhere.

Also, it will work on the B8.5. Skywagon did it on his car (pre-installed vent).

#3

thanks for the help drob- Justin from UroTuning contacted P3 and it appears the pre-installed is only applicable for the pre-facelift cars as Audi doesn’t sell the vent assembly by itself for the 8.5. I 've decided to scrap the idea for now and UroTuning refunded with no problem, bummed about the gauge but very pleased with the vendor!

#4

I would think about whether you’ll need any of the measurements…

The only things I really use are coolant (was nice to monitor when I upgraded to the AMS intercooler system), battery charge and boost (I have a mechanical boost tap). I thought there was oil temp, but was wrong.

The rest are usually kind of pointless: 0-60 meh, RPM, speed, throttle pedal pos, ignition timing (I believe this is requested, but it’s all over the place), EGT. I haven’t gotten my air temp to work (forget the steps I need to do).

Boost isn’t that interesting since I can hear via intake whine (and it’s not like we have turbos with variable boost settings), battery is just to check if I’ve killed it with the dash cam.

Really wish we could read oil pressure or oil temperature. Oil temp can be found on the lap timer, but that’s always a hassle to access.

What does everyone else use the P3 for that I’m not thinking of? Would be cool if they would allow us to flash some custom PID’s onto there. I know skywagon had an analog sensor put on the outlet of his APR intercooler radiator, which would be nice…but I don’t want to go through that hassle.

#5

You’re probably right- maybe more of a novelty than a tool I’d actually get much use out of. Could have gone the route you did but I lease my car for business and if I decide not to purchase at term I want to be able to easily put it back to stock- hence the reason I won’t do exhaust or suspension mods. I guess if I’m tagged for the tune I’m SOL but I have Revo like 15 minutes away and they’ll flash me back to stock @ no charge if/when I need dealer svc- fingers crossed on that one.

Thanks again!