Detecting detonation

When an engine detonates you can hear the exploding mixture in the cylinders. Detonation is often called knock or pinking because when it occurs the detonation sounds like a “pink”, “pink”, “pink” type sound.

If you are driving a car and detonation occurs you may not be able to hear it. The best way to listen for detonation is use a knock analyser pro – click here for info.

What to do if your engine is detonating

There are a number of simple things you can do to stop detonation, if it is occurring:

  • Use high octane fuel if you are not already: Super unleaded, Optimax or Tesco 99

  • If you have a Nissan car, retard your ignition timing – with my Nissan ECU upgrades 14-15 deg BTDC is usually OK. However, your engine may be different and you may be able to get away with more or have to use less ignition advance. If you have to retard it to 13 deg or less then you may want to try stopping detonation using a different method.

  • Reduce your boost pressure – if you run high boost pressure your engine is more likely to detonate

  • Change the components in your engine – these solutions are more expensive but will also help prevent detonation: use a front mount intercooler, use a catch tank breather system (vaporised oil going into the engine effectively reduce the octane rating of the fuel), use water injection (this is a very effective way of stopping detonation – I use it with my engine) or increase the fuel delivery at the point where detonation occurs.

The list above does not contain all the methods to prevent detonation but gives the most common solutions

Once you are sure your engine isn’t detonating, we recommend fitting a KS-3 knock analyser. This device will show if knock is occuring due to unusual circumstances. The following can increase the chance of detonation:

  • Atmospheric conditions (e.g. hot, dry weather)
  • Fuel quality
  • Failing components (e.g. faulty fuel pump, fuel pressure regulator, hose leaks)