Audi S2 Avant running a CompTurbo CT355 0.63A/R turbo (2.1 bar till red-line with around 500 HP), ADU cams re-clocked and VEMS ECU mapped by Pro-Mo Racing. Full 3" exhaust with 2 silencers and a separate wastegate pipe. Car is not lightened and fully equipped with Wagner Tuning cast EM, EVO IC and short-route IM. The fluttering noise is from my airbox flow which is not yet optimized and it leaks somewhere as you can hear. Also the turbo surges with the too small K&N air filter in the box
Audi, S2, VEMS, 500, HP, 20VT