K&N Replacement Air Filter (33-2483) Audi > TT > Mk1 (1998-2006) > 1.8T 150/180BHP Whilst the stock valve will

Whilst the stock valve will operate as designed

Z4 E89 (01/2011 — 08/2016)

this uses counter balanced springs and dual pistons to prevent the valve from leaking air into the intake system at idle

this has a positive effect on accelerating your vehicle after long deceleration or in between gear changes due to more air being kept within the inlet tract to the turbo charger

K&N Replacement Air Filter (33-2483) Audi > TT > Mk1 (1998-2006) > 1.8T 150/180BHP Whilst the stock valve willK&N washable, reusable High Flow Air Filters feature a state of the art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide an increase in horsepower. Each performance air filter is reusable, engineered to last for the entire lifespan of your vehicle, and backed by K&N's No Hassle Lifetime Limited Warranty. K&N drop in replacement filters are designed to install easily into your