Where Do You Place Your Det Cans?

[jabran200]

I am wondering were peopele have been placing their det cans? I had mine on the rear of the exhaust side where the bracket for the turbo water feed is btu found my tube was vibrating on something around 6800-6900 and was definately not det as well but was overpowering valvetraine etc.

I have now devised a new solution which will utilise the rear knock sensor plugged into my laptops mic input which I hope will work but gonna try and confirm tomorrow.

[Trozzle]

WHAT IS THIS I DONT EVEN

[R31Nismoid]

[Legionnaire]

You sure it's a good idea? Stock knock sensor location is great, I'm not questioning that, but unless it's an RB26 you're trying to listen, you've got a resonant sensor, which doesn't give you any usableable info if plugged directly as a mic. Use round knock sensor which has a hole in the middle of it - it actually is a microphone of sorts.

I have never bolted det cans to a RB block, but since you rely on your own ears/brain to interpret what you pick up with them, I don't think that placement makes any significant difference, just stay away from any vibration sources (i.e. don't bolt it to the head or near ancillaries such as A/C or P/S pump). You can also try to reduce vibration by wrapping your pickup tube with some soft material.

[DCIEVE]

^Was also going to mention it sounds like the tube is picking up vibration elsewhere. I'm interested to hear in more detail how you connected to the block? I would have thought using the normal knock sensor locations would be most appropriate where the bolt has reasonable penetration.

[jabran200]

I am doing it on an RB26, and yes it is the bosch sensor (I have my own new one, not using the cars sensor) which is the round ones with the hole and as you say it is essentially a mic. I have had it work in the past through the stereo aux in as an experiment and worked quite well.

I am definately pickign up vibration and the issue is there isn't much availble space on the block to place a tube, I am going to possibly put the car on the ramp if the knock sensor doesn't work well on the laptop but yesterday I did try to listen to the sensor using a mini diy amp and I could hear the engine but had a lot of noise from alternator and ignition as it was powered of the cars battery. I am hoping it will be clearer on my laptop as it was very clear when I did it on the aux in on my radio a few years ago.

will let you guys know how I get on.

And for those that don't know what det cans are you can google them but they are used to hear the engine for detonation when mapping.

Edited February 15, 2011 by jabran200

[Legionnaire]

Getting to the factory knock sensor location is going to be a bitch if the engine is still in a car, btw.

As for sensor noize, it strongly depends on location on the block, flatness of surface you're trying to pick the sound at, how tight your connecting bolt is, etc. My amplifier is powered by two AA batteries. 

If after all noize eliminating measures you're still not satisfied with the quality of sound, you might consider using some kind of frequency bandpass filter. For a 86-87mm bore the frequency of detonation sound should be about 6.6-6.7kHz