Hey guys,

Trying to find, here and google, a good explanation on this.

Let's say you run at 9.0:1CR with 25-deg advance (don't bother on RPM and load yet unless you say it makes a huge difference in my question) and that is the max before detonation. Then you change your CR to 8:1.

How much more timing can you put in before detonation?


I know this varies A LOT depending on everything (engine, air, fuel type, etc..), but I'm looking at some generic numbers just to give a general idea.

For example, maybe on a stock LS7 if you lower CR by 1 without changing anything else you can add 5-deg and go up to 30-deg.
On a 2.5 Subbie doing the same maybe you can add 3-deg and go up to 28.

That's what I'm looking for. Can you generally add 10-deg or 1-deg?
How sensitive is the timing increase with regards to the lowering of CR?

This will help me start up with something, cuz I needed to drop my ratio by 1 point due to failling to find some parts for my rebuild.