Aftermarket knock sensor install!

[kaahari]

Hi!

 

Where have you mounted aftermarket knock sensor (without taking engine out ) ? I tryed to find a good place but didnt find any

 

Also, if you have mounted it to a good place, AND got a Phormula unit, what gain is suitable for 2jz?

[Andy Blyth]

At the moment, I have mine mounted on the top of the head. If you look between the two cam sensors on a -GTE head, not too far away from the MAP sensor you'll find a threaded hole. The sensor will foul on the intake cam cover so you need to use a stack of washers and a long bolt. The washers go between the head and the sensor.

 

It's not a brilliant position for a knock sensor. In the next couple of weeks I'm going to try and find a place on the block. I think the lower mounting point of the intake support braket may be a possible point.

 

As for the gain setting, it's really just trial and error: it's specific to your engine and senor mounting. The method to find the gain for your car is to set the monitor to the relevant frequency and start with a medium gain. Do a pull from near idle to max revs at full throttle / full boost. You want the peak "knock" to be around 40. Increase or decrease the gain until you get a max reading of 40.

 

If it helps, I have mine set to a gain of 20 (the max) which peaks at 38 at full boost. The alarm is set to 45 which seems to activate reliably when you introduce any knock.

[kaahari]

Thanks, will look that place tomorrow. I got sensor now where the intake manifold support connects to head, gain 13 and max value ~40... but broblem comes when rpm over 5000 (with no load or boost, no matter), the value goes to 70-80! I think cams etc are fooling the sensor

[Tricky-Ricky]

Thanks, will look that place tomorrow. I got sensor now where the intake manifold support connects to head, gain 13 and max value ~40... but broblem comes when rpm over 5000 (with no load or boost, no matter), the value goes to 70-80! I think cams etc are fooling the sensor

 

I had mine in a similar position, but talking with Ryan G about it at a RR one day he recommended fitting it to the plenum, as it acts as an amplifier for in cylinder noise, never did get around to changing it over before i sold my Supra.

 

As for settings from what i remember i had the gain set about 8 and i generally saw an average noise value of 17-28 the alarm was set to 35, i had mine coupled to a data logger which makes set up much easier, as you can then see the tell tail sharper and higher peaks on the graph which is genuine knock, rather than just noise, in some cases you actually need to induce knock to be able to set the unit reliably.

This is all presuming you have the correct KHz setting for the bore, otherwise you will not get any accuracy.