Hey guys! Im reassembling my n/a S5 and it want to make sure the diffuser air port is working well before sealing it up.
how much psi does the air port feed to make sure air it coming out the little hole at the diffuser?

 

i'm not sure about the FC, but the FD is just fed in front of the throttle body, so at idle, the port is like -15psi, and the feed is just 0psi, so big difference

 

thank you. I actually decided to remove the top diffuser. I was afraid to crack them. Luckily i took them out by being really care and taking my time. Then made sure the 3 little holes on the diffuser were not cloggee. Then cleaned the port hole with a skinny brush to make sure its cleaned. After I made sure to use 10-15 ps I and air was pushing through well.
everything seems correct. Also make sure the lower diffuser woth the slight downward angle is faxing away from the wall and toward the inside.
👍