What is the size of the knock sensor threads on a S4 and S5 TII engine? Also, what is the better location to use? I have a S4 with S5 housings, so I have a choice of 3 locations. Running a standalone, and I have a full range, or whatever they are called knock sensors, its the type that look like a dougnut and have the bolt going through the middle of them, and I have to tune my standalone to the correct frequency, just need an adaptor, or way of attaching it to the engine.

 

I'm not entirely certain but I believe the rotor housing thread size is M10x1.25.

 

Elite Rotary will sell you 2 studs for $25. https://www.eliterotaryshop.com/home...nock&results=3


or you can find your own M10 to M8 stud for a few dollars.

 

M10 to M8 stud off eBay or drill out the knock sensor to suit M10 bolt, or put in an M8 helicoil. See: Stock RX7 Knock Sensors - AusRotary and here: Syvecs Forums ? View topic - Bosch knock sensor and here: Knock Sensor 10mm - Engine Tuning - Link Engine Management

Most people seem to use the Bosch knock sensors which are often recommended by aftermarket ECU manufacturers (but noting these are broadband sensors and you need some sort of signal filtering to ensure it properly detects knock, which most ECUs probably now have anyway), eg https://www.haltech.com/product-cate...knock-sensors/