Can somone describe what detonation sounds like? I don't think i have any but i want to make sure. I get a poping type sound after i shift gears. I hear my BOV then right after that I hear a deep tone <pop> noise. It doesn't seem to hurt performance but it bothers me cause it was not there yesterday. Today I connected my V-AFC back into the car to supplement by greddy turbo kit, but I doubt thats it. If I floor it in say 3 or 4 gear i hear no abnormal noises just after i shift gears. any ideas?

 

Maybe some sort of your turbo setup is hitting against something (like your hood?) when you shift.

Dustin

 

It's possible that you get a little compressor surge before the BOV opens....

Also the deep tone could simply be a backfire... look around for exhaust leaks...