[edizio]

So I spent the weekend making my own 'det cans' using a microphone amplifier attached to some speaker cable with a whole fun time of soldering. I'd post some pictures but I'm still new to the forums (under 15 posts) and can't really justify spamming your forums with junk posts until I can provide links/images.

So basically, I'm wondering where the best place to put the crocodile clip where I attached the microphone. I read in some specifications that the standard knock sensors on the RB26DET engine are under the inlet manifold. This is quite tricky to get to so is there any specific place that I should be placing the device? i.e. should the microphone really be touching the block?

I did attach it to as close to the block as possible but there was definitely a lot of background noise, i.e. the sound of the clutch, gear changes and general engine noise. If my understanding is correct, I should hear a crackling/popcorn sound for det?

 

[edizio]

Anyone got any input on this?

I'd really like to know where the best place to mount the electronic mic is on the RB26 for hearing knock.

It may be worth me actually making one out of copper and ear muffs instead as just below the exhaust manifold seems like a great place although I can imagine the heat causing major problems for a microphone and wire surrounded in plastic.

 

[matt j]

 

[edizio]

That's incredibly useful Matt! Thanks!

That's actually the opposite side from the exhaust manifold and turbo so potentially less heat. Might be quite tricky to get to, may have to re-position the catch can!

 

[matt j]

Those are the standard knock sensor positions, can't remember if 1 or both are occupied standard as I don't use them on mine now.

 

[ForgingEngineer]

Matt, take it you have a full set of 6. Where are they mounted?

 

[matt j]

Matt, take it you have a full set of 6. Where are they mounted?

Hi, no, I don't have 6, I think I have just 1 or possibly 2 as I run the MoTeC SKM.

 

[edizio]

I'll give that a go tonight, I assume the common analogy of marbles in a tin can is what I should be looking for if DET occurs? The problem is that I can't really hear anything other than the amplified sound of the engine however these electrical DET cans are supposed to be just as good as a copper tube attached to some ear muffs.

I'm pretty much getting nothing higher than 10 on the knock sensors as indicated from power fc with my current tune although it is, admittedly, overly rich and the timing maybe not as advanced as it could be. Don't really understand whether this means it's getting 10 counts of knock or a knock of 10 severity. I read that there is a knock threshold and anything under 40 is safe enough, although mine is set at 20. Isn't any knock bad at any time? I'm told that the knock is just noise from the valve train.

I'm not overly trusting of the default knock sensors for tuning which is why I built my own set of DET cans with an amplifier and microphone. It will probably be somewhat tricky to actually get to the side of the engine but, no doubt, not impossible.

 

[ForgingEngineer]

Aww ok, be interested to know how you determine without crank angles which cylinder ie with microphone rather than the ECU / SKM. but assuming you believe there's no faulty parts I guess it doesn't matter?
Interested because I had a single injector pop which caused issues!

 

[edizio]

Engine was built 5000 miles ago and run in well. Runs very cleanly, no idle problems, no strange noises.

I'd just like to run the car with my own tuning skills so that I can better myself and potentially help others in the future. I don't want to do this, however, without the correct equipment so that if DET occurs, I can retard the ignition timing or increase the fuelling, or investigate what exactly is wrong, I.e. Plug too hot, hot spots, etc.

 

[ForgingEngineer]

Sounds good, be interesting to see what develops.