what does detonation sound like?

[Dreamspeed]

what does detonation sound like, i know it's a knocking sound but what kind of knocking? is it really loud or is it soft i mean is it straight out noticeable or do you have to really listen for it, car makes this clicking/knocking sound like two metal beads hitting each other, is this detonation?

[EdwardETraylorIII]

Dude, the two metals *balls" hitting each other is THE Sound. you've got detonation. Either drop the boost and or up the octance ! :P Hope that helps!

Ed

[134K]

It varies at rpm but usually you can feel your car "hiccup" when it detonates. You can usually feel it if you just sit at a stoplight (the car shutters). OR...you can pop the hood and listen with the backend of a screwdriver touching the valve cover. You can here a thud sound. Pinging sounds more like metal balls hitting each other. This is like pre-ignition that causes the sound. Your fuel detonates ahead of TDC. It's caused inside your combustion chamber on top of the piston. Detonation occurs near TDC also. Detonation occurs at the top of the piston as well but it usually isn't as serious as pinging. Detonation can be caused by bad fuel, or water in fuel. Pinging is usually the last sign of bad piston rings, or even the piston?? wearing out. Pinging and Detonation are the same though.

[SE-Rage]

Originally posted by 134K
It varies at rpm but usually you can feel your car "hiccup" when it detonates. You can usually feel it if you just sit at a stoplight (the car shutters). OR...you can pop the hood and listen with the backend of a screwdriver touching the valve cover. You can here a thud sound. Pinging sounds more like metal balls hitting each other. This is like pre-ignition that causes the sound. Your fuel detonates ahead of TDC. It's caused inside your combustion chamber on top of the piston. Detonation occurs near TDC also. Detonation occurs at the top of the piston as well but it usually isn't as serious as pinging. Detonation can be caused by bad fuel, or water in fuel. Pinging is usually the last sign of bad piston rings, or even the piston?? wearing out. Pinging and Detonation are the same though.

Pre-ignition is a bit different from detonation. Detonation is due to "auto-ignition". When the spark plugs ignite the air/fuel mixture, the flame starts burning the mixture, but as the mixture is burned, it increases the temperature and pressure of the rest of remaining mixture. If the pressure is too high, the remaining mixture starts to decompose before the initial flame from the spark gets to it. This decomposition produces auto-ignition, and the remaining mixture then burns without the flame or spark. Now the mixture is burning too quickly and there is another wave of pressure from the auto-igniting mixture. This causes the multiple flames from the auto-igniting fuel to hit, leading to a sharp rise in pressure - then let the pinging ensue!

Pre-ignition is when the mixture burns before the spark.

It's not necessarily due to bad piston rings or the piston, but because the octane of the fuel isn't high enough. You might want to try higher octane fuel, but if you're already using 92 octane, then maybe retard the ignition timing. Detonation could happen because of a bad EGR valve, but that's usually not too common. It's usually due to a lean fuel mixture, over advanced timing, low octane gas, or high compression. Forced induction detonation problems could be solved by lowering the boost or using an intercooler as well as the problems for the NA engines.

[Dreamspeed]

well sometimes i hear the noise and sometimes i don't, and i already pump 92 octane so... i'll check later to see is the sound is still there, but how do i change the timing? thanks for all the info so far, and if anyone has anything else to add it'll help thanks

[SiN-6]

FYI:
1. NEVER use low Octane Fuel when running high boost, it will pinging like a bitch( i would recomment 95RON rating or higher at over 17psi, i am using 98SUL with slightly more then 20 psi). ur 4 umberllas will melt like an icecream sooner or later.

2. Use of Intercooler doesnt help. or if u mean bigger intercooler so the boost pressure lowered when entering the banging room?

3. Injector and Fuel Pump upgrading, its NOT good to use stock injectors for a NA when u add a wind sucker on it.