I've recently had my WRX flashed and put a hks BOV on. Today I took the BOV off and put the stock one back on and I notice theres a huge HorsePower Decrease. It felt like I've lost 30HP or something. So I'm going to put it back on. But what is going on in there that takes all the HP away?
wait a second...I thought blow off valves add horsepower? If so, it makes sense kidding What nate said....probably a leak somewhere. BTW- What kind of flash? And what prompted to take the BOV off and replace it with a stocker?