Knock Sensor Upgrade?

[StuckeyOG]

I was wondering if anyone has ever substituted their knock sensor for a different manufacturers? From what I understand, the generic Nissan knock sensors used on multiple vehicles/engines aren't very good at detecting knock and just generally aren't the greatest lol.
I tried looking it up and reading threads that seemed even remotely related to knock sensor upgrades. It would appear as though nobody has done it or question it yet. Or maybe I just suck at searching, who knows lol.

My plan was to change it out for a different 2 wire sensor off of a Subaru but from what I understand different knock sensors operate on different voltage ranges to detect knock? So I'll probably look into a 2 wire sensor that is close to the same operating range. Though I'm not sure it makes much of a difference either way?
I'm just wondering if this is even plausible? I don't see why it shouldn't be, since it's just a 2 wire sensor that measures vibrations. Thoughts on the matter and any advice would be appreciated.

[cotbu]

Its a microphone, not a vibration sensor. Tuned to a specific frequency
That the ecu senses as knock.

[StuckeyOG]

Its a microphone, not a vibration sensor. Tuned to a specific frequency
That the ecu senses as knock.

Fair enough, thanks for the information. Any input on whether you think its feasible or not?

[cotbu]

The ecu would probably detect a fault if the wrong sensor was connected. So if you can get past that and or you're OK with not running a knock sensor or being sure if it actually works? It could be feasible. Why though? Just use a stock knock sensor or have knock sensing turned off. The upgrade to a knock sensor is a good tune or flex fueling not a sensor replacement, mo

[StuckeyOG]

The ecu would probably detect a fault if the wrong sensor was connected. So if you can get past that and or you're OK with not running a knock sensor or being sure if it actually works? It could be feasible. Why though? Just use a stock knock sensor or have knock sensing turned off. The upgrade to a knock sensor is a good tune or flex fueling not a sensor replacement, mo

Man, no sense of adventure. I'll just get a stock one I guess. Lol thanks

[Kingtal0n]

Knock sensor are tuned to specific frequencies that the original engineers found to be associated with the onset of engine knock (before it becomes audible). Those frequencies are specific to that engine; You can't expect a knock sensor from a random engine to work on another random engine.

The same goes for making internal modifications, i.e. if you change the piston/crank/rods/flywheel/pulley it could change or absorb some of the knock frequency that the original knock sensor is tuned to detect. A knock sensor is a great tool, but it does not confirm or deny anything by itself, we need to use common sense and approach the problem carefully.

For example, If I am getting some knock spikes around peak torque with 25* of timing in a random engine application, lets say a random V8 using 93 octane. If I reduce timing to 20* it goes away. That sounds like real knock to me, peak torque area and all that. However, when I adjust timing back to 25* and use race fuel octane (ex. 105 octane) I still get the same exact knock pattern. Well now we are highly suspicious that the engine was not knocking before. Now we need to hit a dynometer and verify the torque output drops significantly going from 25 to 20* and that EGT rises significantly going from 25 to 20* to confirm that 25 is much closer to the actual, desired timing number, and re-adjust our knock sensor sensitivity in the ECU (or at the sensor) to be compatible with our more correct timing number.

[StuckeyOG]

Knock sensor are tuned to specific frequencies that the original engineers found to be associated with the onset of engine knock (before it becomes audible). Those frequencies are specific to that engine; You can't expect a knock sensor from a random engine to work on another random engine.

The same goes for making internal modifications, i.e. if you change the piston/crank/rods/flywheel/pulley it could change or absorb some of the knock frequency that the original knock sensor is tuned to detect. A knock sensor is a great tool, but it does not confirm or deny anything by itself, we need to use common sense and approach the problem carefully.

For example, If I am getting some knock spikes around peak torque with 25* of timing in a random engine application, lets say a random V8 using 93 octane. If I reduce timing to 20* it goes away. That sounds like real knock to me, peak torque area and all that. However, when I adjust timing back to 25* and use race fuel octane (ex. 105 octane) I still get the same exact knock pattern. Well now we are highly suspicious that the engine was not knocking before. Now we need to hit a dynometer and verify the torque output drops significantly going from 25 to 20* and that EGT rises significantly going from 25 to 20* to confirm that 25 is much closer to the actual, desired timing number, and re-adjust our knock sensor sensitivity in the ECU (or at the sensor) to be compatible with our more correct timing number.

Makes a lot of sense. Thanks for chiming in.

[kruked]

Um, aren't nissan knock sensors a single wire sensor to begin with?
I know 240s area single wire sensor.

[StuckeyOG]

Um, aren't nissan knock sensors a single wire sensor to begin with?
I know 240s area single wire sensor.

Yeah sorry, it would be considered a one wire sensor.. I said two wire because there's a ground coming off it also. And I was half-asleep while typing this up.

In fact, I botched up my question and sort of asked the wrong thing in the first post, though it was not too far off from what I wanted to know. The information about knock sensors was enough for me to figure out what I need to do though.

Thanks for clarifying.