Link KnockBlock G4+ Pro Knock Detection Equipment The easy way to detect engine knock The G4+ KnockBlock is an essential tool for tuning and can aid in the early detection of incorrect timing, lean air/fuel mixtures and mechanical issues. Features Listen to one or two knock sensorsSpecial filtering design improves signal to noise ratioCan be used with ear buds, ear phones and noise cancelling ear muffsLong life lithium rechargeable batteryRugged CNC aluminium enclosureFlying lead headphones connectorCan be used with all OEM knock sensorsCan be used to interface directly to a laptop for recording of engine noise or knock sensor frequency analysis (using PCLink G4+) Included parts and Specifications: Operating Install the knock sensor/s in a suitable location on the engine (typically on a solid mounting point on the block near the cylinder head) If only using one sensor, leave the unused sensor cable disconnected Turn the volume control clockwise until it clicks. The LED indicator will turn blue when the KnockBlock is operating Turn the volume to the minimum setting (most anti-clockwise) Connect headphones to the 3.5mm audio jack Run the engine and carefully increase the volume (clockwise) until engine mechanical noise can be heard. Adjust to a comfortable listening volume Charging Turn off the KnockBlock by turning the volume control anti-clockwise until it clicks Connect the USB charging cable to the KnockBlock's Mini USB connector. Can be charged from any standard USB charger PC, laptop, car or cell phone charger (2.1A at 5V max) The LED indicator will show red while charging. When the indicator turns off the battery is fully charged Charge the G4+ KnockBlock after use and before storage What Is In The Box? G4+ KnockBlock 2 sensor looms (attached) 1 headphone loom (attached) Quick Start Guide 1 USB cable mini 2 Bosch type doughnut OEM knock sensors 2 small Link Engine Management stickers- See more at: http://dealers.linkecu.com/G4PlusKnockBlock#sthash.6N87QbDz.dpuf Knock Sound Recordings Knock sound recordings demonstrate what you would hear when using Knock Ears The following sound recordings were sampled at various RPM at first with correct timing, which does not produce knock; then timing was advanced to induce knock, and finally timing was reduced to eliminate knock: 2500 rpm. 13, 23, 13 degrees 3500 rpm. 17, 27, 17 degrees 4000 rpm. 17, 27, 17 degrees 4500 rpm. 18, 28, 18 degrees 5000 rpm. 21, 31, 21 degrees The following sound recordings were sampled at various RPM to demonstrate heavy knock: 2500 rpm. 23 degrees 3000 rpm. 27 degrees 3500 rpm. 23 degrees 4000 rpm. 27 degrees 4500 rpm. 28 degrees 5000 rpm. 31 degrees Please note, the following sounds are in Microsoft's WMA format which can be played through Windows Media Player and other audio players with WMA support.