blow off valve?

[black06sti]

I just bought an 06 sti and i want to put a blow off valveon an hks ss but i have heard bad things on putting blow off valves on the subbies. please advise on if i should put one on

[MainFrame]

http://www.clubwrx.net/forums/engine...ov-thread.html

[20WRX04]

http://www.clubwrx.net/forums/engine...ov-thread.html

+1.

Welcome to the club. Please use the search function. A lot of your questions have already been covered. Read the stickies as they are very useful. Enjoy!

[Black X Dahlia]

i dont mind answering. Stock=NO. Your STi is tuned to a recirculating valve, meaning the unused air is recirculated back into the intake tract, and the ecu takes a reading on that air...therefore increasing the amount of fuel being dumped by your injectors to compensate for the amount of air. If you put a Blow off valve on a stock Subie, the bov is releasing this unused air into the atmosphere, while your ecu is still dumping out the extra fuel via the extra air. Basically your engine then dumps more fuel than needed, making your car run Rich. Running Rich will waste fuel, make your engine sluggish and in the long run leave residue on valves, sparkplugs etc. reducing effectivness and might lead to repairs.

You can put a bov if you get your ecu tuned to properly run it.