Det cans

e28stian · Post by **e28stian** » Sep 19, 2011 2:24 PM

So, how many of the fi crowd are using det cans to detect detonation?.

Just contemplating the optimum point to connect it to the engine, i currently have it bolted to the intake manifolds stud at cyl no5., i am hearing the valvetrains sewing machine sound, but i am unsure if this is the optimum placement, might move it to the block..

Anyone else tried it?.

I recall Kenny mentioning them, but not anything about attatchment point.

Coldswede · Post by **Coldswede** » Sep 19, 2011 6:27 PM

From what I'm hearing, here and other places, the M30 makes too much noise for reliable use of detonation detection. I'd love to find out different though.

marc79euro645 · Post by **marc79euro645** » Sep 19, 2011 8:47 PM

I use stock m106 sensors with megasquirt & a ms knocksense box,that allows me to adjust sensitivity.
I have an red led mounted in my a pillar gauge pod that blinds me at the first knock.
I love it,I have it adjusted to knock I can't hear. I haven't blown a head gasket since tuning with the red light, and I am maxing out my k27@ 18#.
good luck
marc

Lurker27 · Post by **Lurker27** » Sep 20, 2011 12:55 AM

The stock sensors are on the block, right? Any way you could post your msqs? I'd like to compare the timings and AFRs to what I have now, if possible.....

e28stian · Post by **e28stian** » Sep 20, 2011 4:47 AM

The knocksense ms is interesting indeed because the manufacturer custom tunes it to each motors bore, or the expected frequency of the knock or detonation sound.

I am also interested to know the location of the stock m106 sensors.
Would be interesting to know of the m106 sensors are tuned units, designed to pick up a certain frequency

Coldswede
Well the det cans are just stethoscopes mounted on the engine, the instrument for detecting is your ears, might just work on the m30.

While the m30 is noisy i am looking for reliable means to pick up detonation before it is audible in the cabin, as detonation is more damaging the louder it is, from what i gather.

Coldswede · Post by **Coldswede** » Sep 20, 2011 5:20 PM

Please keep us in the loop how this goes, I'm all ears!

Oh Gawd, I crack me up!

Kenny · Post by **Kenny** » Sep 20, 2011 6:35 PM

Det cans are awesome.

As has been said, you are listening to the engine with your ears. Valve train noise is mostly irrelevant since it is consistent.

Someone who knows what they are listening for, and what the engine should sound like can easily differentiate between the normal consistent sound of the valve train, and detonation.

marc79euro645 · Post by **marc79euro645** » Sep 20, 2011 10:07 PM

I'd be glad to share my tune, if you can tell me how to upload.
I don't have a digital camera.
marc

Lurker27 · Post by **Lurker27** » Sep 21, 2011 7:05 AM

I'd be happy to host it, my email is Lurker27 [AT] aol.com

rapidshare or some place like that would work just fine, as well. You just might need an account or something equally annoying to do it.

Post by **Jeremy** » Sep 21, 2011 12:00 PM

I don't think the m106 actually had knock detection. I seem to remember that being debunked as a myth, but I'm not certain and could be wrong. I'm not Kohler, it happens.

Knock detection on anything m30 based is indeed difficult, but doable. Plus it serves other purposes. If the light starts going off when you don't expect it to, for example, you know it's probably time to adjust your valves.

Personally, I think an EGT sensor for knock detection and tuning would be far more useful. If I get into a position where I can build up a car again, I plan to go that route.

Murfinator · Post by **Murfinator** » Sep 21, 2011 9:41 PM

The M106 has two knock sensors: on the intake side between 1-2 and 5-6 cylinders. See photos below of dirty (with sensors installed) and clean (sensors removed).

Post by **Jeremy** » Sep 21, 2011 9:44 PM

Yea, now I remember ... it's M1.3 that some people say has knock detection but it really doesn't.

Don't mind the loony drooling in the corner mumbling (that's just me).

Shadow · Post by **Shadow** » Sep 22, 2011 12:24 AM

Thanks for the pictures, now I know where to put it.
Is that spot tapped, or did you have to do it?

e28stian · Post by **e28stian** » Sep 22, 2011 2:56 PM

Thanks you for posting those pics, nice to know where the stock sensors of the m106 was located, not sure other m30 blocks had those tapped holes.

While the det cans are great for tuning the engine, it is nice to have a system telling the user that detonation is happening after the tuning is done, due to bad fueling, issues with ignition, or any other possible faults a turbocharged engine could experience.Just a thought..

Offcourse one can always develop th habit of driving around with the ear protectors on,and a fat tube sticking out of it, the fuzz will LOve that

Hit Man X · Post by **Hit Man X** » Sep 22, 2011 10:14 PM

FWIW, my other M30s have the pedestals for the knock sensors yet they are not drilled, nor are they tapped for the sensor. Poke your head near the fuel rail and the injector areas, you will be able to see them.

This includes my 3.2L M102 in the '83 and my 3.4L B34 8:1 in the '85 (green motor car).

Now, how the knock detection system works and how well... who knows. I do know the knock system has a totally separate box by the ABS module and utilizes that electric magnetic valve (think solenoid) on the air filter box for some reason aside for more 'rapid' spool up... if you can call a 745i a rapid spooler.

My guess is that the stacked engine/trans -013 in the Motronic 745i (M106 cars) has so little timing to begin with, the system is only there in the event you receive some bad fuel or can only fill up with low octane. Just a WAG.

Pics below of the sensors, box, etc.

Hope it helps.

http://realoem.com/bmw/showparts.do?mod ... g=12&fg=05

http://realoem.com/bmw/showparts.do?mod ... g=13&fg=15

Gunni · Post by **Gunni** » Dec 14, 2011 5:33 PM

marc79euro645 wrote:I use stock m106 sensors with megasquirt & a ms knocksense box,that allows me to adjust sensitivity.
I have an red led mounted in my a pillar gauge pod that blinds me at the first knock.
I love it,I have it adjusted to knock I can't hear. I haven't blown a head gasket since tuning with the red light, and I am maxing out my k27@ 18#.
good luck
marc

how did you setup the knock sense? Did you listen to the engine to determine what amount of noise is detonation?

Also to note.

I work for Cosworth and have seen many a engine dyno facility. Normal det-can all the way at all levels of motorsport.

marc79euro645 · Post by **marc79euro645** » Dec 14, 2011 7:39 PM

I tuned the light with a small pot, in the knock sense box. I started out with knock I could hear, then continued to increase the masking until it only lights occasionally under hard boost.I rarely hear the detonation.
marc

Jared S · Post by **Jared S** » Dec 15, 2011 1:29 PM

http://www.viatrack.ca/

I am using a bosch sensor and one of these units on my '89 turbo Saab 900. It has a sensitivity adjustment on it. I did full throttle runs with zero boost and set it so it was on the verge of lighting up the LED. I consider any lighting up of the LED with boost as detonation. I wanted to run one of these on my turbo M30 but never bothered since everyone said it was pointless on the "noisy" M30.

marc79euro645 · Post by **marc79euro645** » Dec 15, 2011 7:15 PM

That's what I have, & I love it!
marc

Duke · Post by **Duke** » Dec 15, 2011 7:34 PM

Here is the sensor I installed on my M106. Through the boss into the water jacket. The engine proved way to noisy and I turned it off. I was using Electromotive Tec3 ECU.

Shadow · Post by **Shadow** » Dec 15, 2011 8:45 PM

Would the bung on the throttle cable bracket be an ok spot?

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Det cans

Det cans