Turbo Diverter Valves for Audi S4 Vehicles

A diverter valve does two crucial things: seal pressure under boost to deliver peak power, and release pressure when you back off the throttle. In turbocharged VWs that are modified for performance, it also does something undesirable: It loses effectiveness, even failing. USP Motorsports offers OEM replacement and high-performance diverter valves for engines including the VW 2.5T; Audi / VW 1.8T and 2.0T FSI and TSI; Audi 2.7T; and Porsche 3.6TT.

Below you’ll find diverter valves and related products from APR, Assembled by USP, Forge Motorsport, Go Fast Bits, HKS, Integrated Engineering, OEM VW / Audi, Spulen, Torque Solution and Turbosmart.

Stock VW diverter valves don’t hold up under the stresses of heat-generating, high-performance engine mods, especially if you upgrade with forced induction accessories or engine software. On a tuned engine, the valve ends up leaking — which lowers performance — or failing. That’s why USP offers many diverter valve solutions.

On most Audi / VW models, the diverter valve is bolted to the turbocharger housing — the compressor side! The heat from a stock engine is stressful enough, and when an engine is modified, stock VW valves can’t handle the extra heat. USP sells stronger units engineered to tolerate higher temperatures, boosting reliability.

OEM Audi / VW offers an economical diverter valve with a piston design based on that of the TSI and aftermarket turbo diverter valve designs, rather than on a diaphragm. It works with 1.8T, 2.0Tand 2.5T engines.

Among your choices are the Forge 1.8T Diverter Valve and Forge 2.0T Diverter Valve, plus the Forge Blow-Off Valve for both engines. All use stock ECU controls. There are also the APR diverter valve (R1 Diverter Valve); mid-priced Go Fast Bits GFB DV+; USP Assembled 1.8T kit with a sequential HKS SQV Blow-Off Valve; HKS Super SQV 4, which has operating ranges from low to high pressure; Spulen Blow-Off Valve Kit for MK7 1.8T and 2.0T; and Turbosmart Kompact Series Blow-Off Valve, which vents to the atmosphere or air intake.

Another solution is a diverter valve relocation kit — available in black, blue or red — to move the valve from the hot side of the turbo housing to the cool side. The lower heat extends valve life. Block-off plates aid the switch.