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Was chatting with a member here about KR/False KR.
I ran into some info from a GM tech in testing department. Stating how they use a copper tube 8-10mm dia bolted to the block and routed into the cabin. Slightly flared at the end. It emits the knock sound very well and seems to be a fantastic tool when tuning out KR and determining if KR is false or not.
Said the end of the tube is flattened and drilled for bolting to the block. The copper transmits the sound of knock, not the hollow space so it can be bent smooth to route with very little loss of signal.
"We use a copper pipe that runs from the engine block into the cabin of the car for listening to knock. Works really well."
"I can get some more detailed info on our knock tubes if you like. They are basically just a copper tube maybe 8 to 10mm diameter, belled out slightly at the end. They transmit the knock sound beautifully."
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Although it sounds primitive, the knock tubes work a treat
Mounting point for the end of the tube is pretty much anywhere on the block. Further away from the valvetrain helps, otherwise you get a bit of valve noise at high RPM which can be distracting. We just happen to have a couple of spare bolt holes under the exhaust manifold, so thats where it goes. Then it is routed up through a hole in the passenger footwell and into the cabin. You will notice knock VERY easily with this, there is no mistaking it at all.
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What do you guys think or know about this? It seems like a great tool for the performance tuner wanting to advance spark to the very edge. Or tune the spark map with no kr sensor.
I would install a device like this for a track car. Maybe even consider this concept for building a knock sensor pick-up that has better discernment between noise and knock. That is if true knock is magnitudes stronger then the back ground noise, the KR pick up used currently might work well at the end of such a tube in the engine bay.
I ran into some info from a GM tech in testing department. Stating how they use a copper tube 8-10mm dia bolted to the block and routed into the cabin. Slightly flared at the end. It emits the knock sound very well and seems to be a fantastic tool when tuning out KR and determining if KR is false or not.
Said the end of the tube is flattened and drilled for bolting to the block. The copper transmits the sound of knock, not the hollow space so it can be bent smooth to route with very little loss of signal.
"We use a copper pipe that runs from the engine block into the cabin of the car for listening to knock. Works really well."
"I can get some more detailed info on our knock tubes if you like. They are basically just a copper tube maybe 8 to 10mm diameter, belled out slightly at the end. They transmit the knock sound beautifully."
----
Although it sounds primitive, the knock tubes work a treat
Mounting point for the end of the tube is pretty much anywhere on the block. Further away from the valvetrain helps, otherwise you get a bit of valve noise at high RPM which can be distracting. We just happen to have a couple of spare bolt holes under the exhaust manifold, so thats where it goes. Then it is routed up through a hole in the passenger footwell and into the cabin. You will notice knock VERY easily with this, there is no mistaking it at all.
Forum Link
What do you guys think or know about this? It seems like a great tool for the performance tuner wanting to advance spark to the very edge. Or tune the spark map with no kr sensor.
I would install a device like this for a track car. Maybe even consider this concept for building a knock sensor pick-up that has better discernment between noise and knock. That is if true knock is magnitudes stronger then the back ground noise, the KR pick up used currently might work well at the end of such a tube in the engine bay.
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