Originally Posted by jock
Why is that Chip i have heard it talked about and have seen it on a bunch of graphs i have had from my cars but never been told why ???
Mike
In order to manage peak cylinder pressure points within the cycle.
If you have more boost then it takes longer forthe flame front to propogate which means that you have to retard the timing to avoid detonation occuring.
Fuck, that doesnt read very easily, umm, lol
Attempt 2:
Basically when your car fires, its NOT an explosion of fuel and air, its a burn, as this burn happens gasses are given off (exaust) which pressurise the cylinder.
If the pressure in the cylinder goes past a certain number of PSI then the fuel/air mix can ignite on its own, before the burn gets to it, so the whole lot goes up at once (THIS is an explosion).
So what you have to do is manage the amount of pressure that builds from the burn to make sure it NEVER reaches that point, but you want to be JUST before it, or you are wasting power.
So the more boost you cram in, the more you have to start the burn happening while the piston is further back in the cycle, so that you dont end up with this happening.
Not an easy thing to explain in a post really TBH
Question me further if ive still not made that clear?!