What does 'detonation' sound like?

berettafan · 05-22-2008, 10:48 AM

Pookies recent post looking for diagnosis got me wondering what 'detonation' sounds like. My 911 is the first car i've owned in a LONG time that doesn't think for itself in that regard and i realized i have no idea what the bad sounds are.

Could anyone post up some vid/sound files of various maladies along with a description of what we're hearing? might be a nice sticky.

84_Carrera · 05-22-2008, 10:52 AM

Well from what I've read about the 911... if you really can hear it, it sounds like money leaving your wallet at about the speed of light.

DARISC · 05-22-2008, 10:57 AM

Detonation is not always audible. When it is, it can sound like spraying BBs into a tin can. Whether inaudible or audible, it's sure destructive (e.g., can burn holes through the tops of pistons in very short time).

cgarr · cgarr's Garage

I was going to say a real fast rattle sound...like the BB's in a can, yep.

Steve@Rennsport · 05-22-2008, 11:07 AM

Quote:

Originally Posted by DARISC

Detonation is not always audible. When it is, it can sound like spraying BBs into a tin can. Whether inaudible or audible, it's sure destructive (e.g., can burn holes through the tops of pistons in very short time).

Thats accurate!!

Sub-audible detonation breaks rings just as well as the kind you hear.

burgermeister · burgermeister's Garage

I've heard it as spark knock (too much timing advance) at lower engine speeds - sounds like a pinging sound, sort of like hitting a metallic object lightly with a rock or shooting a glass bottle with a bb gun without breaking the bottle.

I've heard it as autoignition in an 11:1 compression V8 (my long gone 1969 Ford LTD with a 429 engine - I still miss it) refusing to shut off on a hot day because I ran out of tetraethyl lead mix to add to the 94 octane Sunoco gas I put in it. Sounded like somebody banging the engine block with a ball peen hammer as hard as possible.

And +1 on the stuff you can't hear ...