I've had a buzzing/minor vibration sound around -5inHG to 0psi in the 4000rpm range since I installed the turbo in January. It used to buzz in the -9 range before I calibrated my map sensor. I always thought it was something minor in my ecu settings or maybe a faulty wastegate or bypass valve since it was close to boost.

I didn't think it was knock since it didn't sound like a knocking sound, wasn't in boost and my settings were supposed to be conservative, but I recently saw a thread where someone said knock could sound like buzzing. My timing is at 18-19 in that map/rpm range and I've tried lowering it to 15-16 to get rid of the knock to no avail. My AFR is around 12.5, when it runs a little leaner 12.8 is when I hear it more often. I thought 12.8 was pretty rich for 0 psi.

Do you think it's knock or something else? If something else, whats a common buzz that happens at -5inHG to 0psi?

 

knocking = pinging or rattling.
not buzzing.

With the timing set that low, and no load, and fuel that rich there is no possible way the car is knocking unless something is majorly wrong with your engine.

 

Buy or make DET cans.

 

I don't need det cans if I can hear it without it.

Are bypass valves known to buzz if faulty?

 

Sure it's not something rattling?

 

$10 says it's a lose something. I had an annoying and intermittent buzz for years that one day developed into a high pitched squeal that led me to a new speedo cable.

You ain't knockin, definitely not with those AFRs. You'll know if it's knock.

 

That's what I figured but what's throwing me off is that it happens exactly at the right map value and rpm. Only when it was warmer it occured at a couple inhg sooner. Also calibrating my map sensor changed where it buzzed.

 

urrong

 

not sure if this helps identifying the noise ur hearing

http://www.theknockbox.com.au/content/view/8/8/