Knock...continued

[1G90AWDTsi]

--In mild cases, you would realize nothing, unless you had an EGT guage, in which case you would see way higher EGTs. In monsterously horrible cases you will acctaully hear a 'ping' noise, which is basically your block resonating fromt he insanely high pressures casued by the gas igniting before the piston is ready to begin going back down on the power stroke.--


That's a post I pulled up from another thread...why would your engine do that "ping" in the first place...what actually causes that to happen? Would dsmlink pick that up in a reading? I really want to know what specific things cause knock, when it starts to get damaging to the engine, and what the symptoms are (please clarify). Thanks!

 

[allwheelTSI]

When your combustion charge explodes instead of burning and the piston is usually not on a downstroke . It's caused by IAT's being too high, too much timing advance and or AFR's being too lean.

Also, you will hear it usually at WOT, it sounds kinda like ball bearings getting shaken up in an empty tin can. Your car comes from the factory with a sensor to combat this, it retards timing when it detects knock.

 

[1G90AWDTsi]

alright, thanks. I don't have it but it's good to know your enemies.

 

[disciplekyst]

Ok, since it's possible not to feel it in mild cases, what would be the feeling (in terms of performance) in the car when the timing gets retarded? Sudden loss in acceleration?

I ask because my car creeps to 19 psi from around 5k (i'll port my wastegate next summer), and i feel the car loses a lot of power from 5,5k.