It’s easy once you look at the graph a bit.
Maybe look at some other cams using the graph. You can use my numbers.
281/281 255/255 105/105 620/620
Put it at 0 advance and look at the overlap triangle. You’ll see it’s centered over TDC.
Then add 1 degree advance and watch it move the triangle to the left. That is advancing the cam. Keep adding a free of advance and watch it move further left.
That shows you where true “straight up” is for any cam you want to graph, regardless of what the cam card says.
The anomaly I’ve found is using the math I do to get cam timing.
Almost always it will call for the LSA and the ICL to be two different numbers. Like 110/107.
Using the numbers from the math I use on the graph you’d think that the 110/107 would show the triangle to the left of TDC (advanced) but it doesn’t. It centers the triangle.
Running your cam, the 110/106 advanced the cam so it’s technically straight up. It’s advanced.
I moved it 2 degrees (2 degrees retarded from the cam card) and it looked centered.
To me, that’s where I’d install the cam and not where Comp wants it.
At home I have an interview with Billy Godbold where he says to center the triangle.
The reason the card says to install it advanced is because Comp is betting (and probably betting correctly 90% of the time) that the end user picked a cam that’s too big. So the advance it.
There is a common misconception that big cams “bleed off” cylinder pressure. That’s not exactly what happens.
What’s really happening is you are moving the IVC point either earlier (advanced) or later (straight up or even regarded which moves the triangle to the right of TDC and there are some rare instances where you need to do that but you are likely not one of those cases) and what that does is it changes how soon you start to build cylinder pressure.
It may sound like tomato-tamoto but it’s a difference that matters.
If you think about it, until the intake valve closes you aren’t building any cylinder pressure. As soon as it closes you start making cylinder pressure. Follow me here. At that point you can now calculate your Effective Compression Ratio.
It is always the same, unlike dynamic compression ratio which is dynamic, meaning it changes with load/rpm/temperature and some other stuff I’ve forgotten.
That’s why I don’t use DCR and my cam math doesn’t either. It’s too hard to calculate where ECR is easily calculated and never changes.
So getting your cam straight up, which in your case looks like (on my phone) you’ll be 110/108. That centers the triangle. If you do 110/110 it’s 2 degrees retarded. 110/106 is 2 degrees advanced.
It will start making sense when you look at multiple cams on that graph.