STI Craig

i am considering doing my 3rd year project on making a det sensor (u know a knocklink)

now what i want to know is what does a car thats detting sound like

is it like this http://users.wpi.edu/~mark944/nested...knockstuff.htm
(go half way donwn the page and click on sound file)

or is that just the background noise?

ive bin told it sounds like tinfoil but that doesnt sound like it.

JTaylor

Try technical mate. You may get a better response.

highlander68k

Listen around the 23 & 25 second mark. There are some non-uniform clicks - that is det.

My PC speakers aren't quite suitable for the job and I've just been moaned at by the wife because of it.

Sounds like an interesting project - If you manage to make a decent looking, cheap unit you might make a few sales

ZEN Performance

det sounds like a drawing pin being dropped into a tin can, although if you listen through det cans (think stethoscope) you can hear some "sparklyness" before real det starts.

Paul

G00ner

Can a non turbo charged car det? I'm sure my Legacy is pinking or has a dodgy plug, is that the same thing?

I'm deffo getting a tinny rattle at low revs and w.o.t, pretty sure it's not a heatshield etc.

RON

Hell yeh, but then your car always has a lot to lug around doesn't it Shane..

ZEN Performance

Det and pinking are not the same thing. Det is an event that occurs after the point of ignition, where as pinking is spontaneos and occurs before sparking.

highlander68k

For a full explanation, call Zen Performance on 0845 055 93.....

alternatively look here: http://www.streetrodstuff.com/Articl...tion/index.php

STI Craig

thanks for the help lads

i was thinking of recording the sound as he has done in that link

then i can play it back and use that as something to work on

so my next problem would be where to record the noise
in other words i think i would need a tuning company to let me sit in the back of a car while they map it and i have a det sensor bolted to the engine and pluged in to my lap top.

any takers

if not i think ill try RC as they are only round the corner from me

vulnax999

iTrader: (7)

Confused...
So what does the Knock link / Apexi PFC detect as "knock" ... detination or pre-ignition?

G00ner

Thanks Ron.

Job for Triton to see if it's detting/pinking/missing/dieing etc, can't trust those fools at Olympian to sort it.

Roojai

STI Craig, it is worth paying attention to the following line from highlanders link:

Resonance, which is characteristic of combustion detonation, occurs at about 6400 Hertz. So the pinging you hear is actually the structure of the engine reacting to the pressure spikes. This noise of detonation is commonly called spark knock. This noise changes only slightly between iron and aluminum. This noise or vibration is what a knock sensor picks up. The knock sensors are tuned to 6400 hertz and they will pick up that spark knock.

STI Craig

thanks for the info bud

ive found a few different places that have said that but i didnt know it was different for a iron block

Scott.T

iTrader: (2)

Nice description... I'd go with that.

fujiyama

Det IS pinking; it's Pre-ignition that is spontaneous.