stunt2

iTrader: (8)

first of all I'm interested which det can is better to use for newby between these two: old school mechanical can or some electrical DIY one, like these for egsample
http://www.autospeed.com/cms/article.html?&A=0353
http://www.d-series.org/forums/diy-f...5-dollars.html

ok, let's say fabricated one of the cans above, attached it to the engine block and went for some pulls.
what next, what kind of sound should I aim for, is it easy to determine knock sound between other engine/drivetrain sound
also what mods should be done to rom (96530706) to hear clearly the detonation, remember posts from here, to disable or enable some periphery bits

so, long story short, interested in everything about this subject, to get started tuning vith cans

sorry for long post, any inputs are appritiated

Raptord

iTrader: (10)

This page has sound recordings with and without knock to show the difference:

http://theknockbox.com.au/the-knock-...nd-recordings/

stunt2

iTrader: (8)

great info, thanks

chetrickerman

iTrader: (7)

there is also this video

http://www.youtube.com/watch?v=GGJZ6...132E0D715992D8

but in reality, the engine is much louder and its harder to hear knock

stunt2

iTrader: (8)

is it a good idea to attach flat copper end to knock sensor's place ? and torque the sensor over it

chetrickerman

iTrader: (7)

I wouldnt

stunt2

iTrader: (8)

^^

why ?

so all the way to intake mani's center bolt ?

chetrickerman

iTrader: (7)

I would not want to hinder the knock sensors performance in any way. Even though bolting a piece of copper between the sensor and the block may not hinder it that much, I still would not do it.

Personally, I made the electronic det can and I like it. It takes a little bit to get used to and "learn" the sounds of the engine, but its very useful.

stunt2

iTrader: (8)

also built electrical one but it picks up very nasty electical interference from the engine

can you share how have you built one and from which parts ?
I've built exactly like this http://www.d-series.org/forums/diy-f...5-dollars.html

chetrickerman

iTrader: (7)

That's the one I did, except on the other side of the mic, I put a sound deadening material so it doesn't pick up as much ambient noise as much as the noise from what its clipped on.

studioface

iTrader: (10)

Check this one out,zero wires and you can hear it from you car radio and uses a regular 9 volt battery.
http://www.ebay.com/itm/SPY-GEAR-SPYGEAR-HIGH-TECH-WIRELESS-HEARING-AID-MINI-SECURITY-LISTENING-DEVICE-/151029228460?pt=US_Surveillance_Gadgets&hash=item232a0b23ac

Raptord

iTrader: (10)

I've built this one:

http://www.miataturbo.net/ecus-tunin...example-61616/

Have yet to try it out, should be within the next week or 2.

ExViTermini

iTrader: (25)

How did it work?

Raptord

iTrader: (10)

I first tried mounting it on one of the bolts on the top of the IM that secure it to the head, but figured I was getting to much valvetrain noise, so I'm not trying on one of the bolts under the IM that bolt it to it's bracket. Seems slightly better.

As a test I've been increasing cruise timing while at a steady speed on the highway, but I've yet to hear knock. I'm not sure if it's because I'm simply not getting any yet, or if I am but not hearing it (went as high as 47 degrees IIRC). I'll do some more testing as I have time.

merlin.oz

Some Det-Can tips:

Use screened twisted pair cable from the mic to the amp module, the screen to be connected to the crocodile clip at the mic onto the engine block or inlet manifold.
This will reduce/eliminate ignition electrical noise pickup - the regular loud clicking you get on some setups.

Try to eliminate wind noise from the mic - tape it over with gaffa tape would be a start.

The small electret mics that are typically used are very sensitive and pick up sound over a wide area - think how effective your mobile phone mic is.
A better mic for this application is an old style dynamic microphone, which works better on sound/vibration close to the mic. This is what I use.

When you start using det-cans you will hear all manner of stuff from the engine - valve train, bearings, piston slap, and knock.