[MIKE 04 GT]

how do you do this.

[limited]

comp cams website gives you the way to do a centerline method for a 4.6L

[MIKE 04 GT]

thanks man

[PAzYearazzUP]

Here is a little theory for setting cams and when you see the card and it says to set it here with these open closing or split-differences, you stick with the cam manufacturer's numbers.
You should first call your cam maker. Tell tech line you are going to street or mild race or all out race is they have that cam profile that sticks with performance right on the ragged edge of going over to all out race.

So, when you see the splits like 106/108 for argument sake, say the intake is 106. The exhaust is 108. Now, say you mess with the open and closing ramps and swap the intake to 108, and the exhaust to 106. Let us see what happens on valve open/closing times...

Say at 106 the intake opens later at 6 than at 108. For argument sake, 108 opens the intake sooner on the intake side. On the exhaust side, 108 opens later. Got that theory down? Now, lets walk what is called compression or for our example, we want the word, "pressure" used.

So, now we open the intake at 106 is late in the crank degree. We lag the intake charge with 106 as opposed to opening the event of the suck, sooner. The sooner we let the intake fill that charge, the sooner we can close the intake valve and begin to build pressure.

Now we peak at say for argument sake, 10° ATDC, we better have all that fuel spent so it makes max pressure or max BTU burning of that fuel. So, with that max pressure is all she burned, she is not about to push that piston down for the power stroke. Say, we want to keep that crank moving. We do not want to open the exhaust too soon. If we do, we open the exhaust valve, the pressure is out the hole and the power stops.
Therefore, when you start to dial-in the cam, your engine is going to work in so much an efficient manor with that modded cam, you need to know if it wants more 08 at the intake opening, or you want the 108 to open on the exhaust side up to the point of, "diminishing returns" does the power go off song at 107 is open that now at 107.

The sooner you open the intake, the more bottom grunt. The later you open the intake, the more top end you have. Make sense is cam theory and numbers to chase?