Hi There,

Could anybody please explain to be a little bit about when your car engine starts to det?

How do you know it is?, what causes it, what can you do to minimise it?

Also, what is a knock sensor, what is a Dawes?

I am simply asking these questions because I have an interest in Subaru's but dont have any technical knowledge.

Thanks to anybody who takes time out to explain the above to me, I appreciate it.

Michael

Det is when the flame fronts hit each other (i.e. flames ignite too early). A Knock-link senses det (det is also know nas 'knock'), and lights up a series of LCD's to tell you of the situation, which then needs to be rectified (either by coming off throttle/boost, increasing the Octane of fuel used or retarding timing).

Octane is in some ways a rating of at which pressure the fuel will self-ignite, the higher the octane, the more it can be placed under pressure until it ignites - hence low octane rating can be a source of 'det' as the fuel is igniting in the combustion chambers too early (as pressure increases)

Michael, if you have a read of my website I've included a load of info about knock there (scroll past all the info selling you stuff you've already bought ;) ) I've also recommended some books on the topic.