Any advantage to using the GM knock sensor? Or just wire it to the stock sensor?

 

The GM sensor can be advantageous in an engine with forged pistons because of the extra noise caused by them. Generally people with the GM sensor mount it in one of the holes for the a-pipe support bracket. With the positioning of the OEM knock sensor, you sometimes cannot reduce the sensitivity enough for the J&S to not pick up false positives.

I used the stock knock sensor on my B16A2 and had excellent results with the J&S. However, that engine was bone stock. I have the GM sensor already and will use that with the D16A1/ZC going into my CRX because it doesn't have a sensor.

Sonny

 

Is the OEM sensor any better matched than the GM sensor for Honda motors? I'm not sure whether there is a frequency range difference or what...

 

I have a similar problem. I am currently using the stock knock sensor in the stock place with my j&s and it seems to pickup EVERYTHING. Even turned all the way down it sometimes goes off. I used to use the GM sensor and either my motor is about to burst, or the GM sensor is not as sensitive (or placed in a less sensitive place) I could NEVER get a straight answer from anyone regarding this topic either. I dont think there is one. I'm gonna change back to the GM sensor and put it where i had it before. I'm very confident my motor is not pinging when its going off.

 

I don't think it matters. Ask John for a 100% sure answer, but the output of the knock sensors must be similar since the J&S works with either one.

The stock knock sensor is positioned in the ideal place, but the VTEC engines tend to trigger a false knock at the crossover when the VTEC solenoid engages all of the rocker pins.

The main advantage of the GM sensor is that you can put it where you want it to adjust for things like aftermarket forged pistons.

Sonny

 

So where can you put the GM Sensor on a B16A2? rather than the stock locatoin.

 

Install it in place of one of the bolts that holds the A pipe support bracket to the block.

Sonny

 

I've compared both and the outputs from both share a similar output as far as magnitude, but it appears that the stock honda is calibrated for a different frequency range... I have since learned that there are a few different models of the GM sensor, the one i am using now is used in ls1/ls6 engine or v8, and the 4's have a different sensor. I assume that the 4 cyl version may be more sensitive, but have not tried one.

This was pulled from data on the ems unit with both a honda (denso) and the gm (ac delco) sensors. In either case, spikes were obvious, but i have yet to see any audible detonation (knock on wood)

As for location, as long as the sensor was mounted anywhere on the block, sensitivity was the same... however, i have yet to screw it into the water jacket drain bolt which is where stock ones are usually located, and i expect better sensitivity there.

Lastly, vtec engagement does produce a spike on both sensors, and i suspect that is why stock ecu's ignore the sensor in closed loop(ie after a certain rpm)

I still have stock internals but will install rods and pistons over the winter then have a definitive asnwer