Just bought an S4... Need Help

[Holmesy316]

Just bought a 2000 red S4 tiptronic... Wanna make it sweet... Fast and nice lookin which both already come with the car. I want to do some performance mods to the car but I'm not sure yet. What is best and is anybody selling anything. Im thinkin of full exhust, air intake, and some bov's or bpv's...Now... I hear the blow off valves are bad for the car bc of the ecu... but I also heard that the car runs fine if with Turbo XS Type H BOV's if you make sure they arent shooting air when the car is idle... so what is the truth here... Anybody know about the DBOV's on www.lltek.com

[Dippy]

Holmesy,

I presume you are US-based?

I'm not sure if BOVs will be bad for the car, but because the ECU bases it's fuelling on air flow measured by the MAF on the assumption that the air is recirculated, there must be a risk that it would cause incorrect mapping. If all you want to do is make some noise then there are electronic units which will do it for you.

The Bosch BPVs fitted by Audi can be unreliable, expecially after tuning. Using aftermarket solid-piston valves is a good idea. However if the engine is tuned for extra boost, the springs must have a higher tension.

Because the S4 uses a closed-loop ECU control system, without a remap there will be limits to the advantage of a free-flow exhaust, and non for air intake mods (such as an air-filter). In fact the stock air-intake system is perfectly adequate for a tuned S4 which still has the K03 turbos, because the turbos will max-out on airflow before the intake does.