Cam timing questions

[86Shelby]

Does anyone know what the effects would be on the powerband, idle, etc if you were to adjust only the intake cam timing? How about the exhaust? I've been trying for several days to find good info on it but am coming up empty handed.

[turbovanman²]

I know on my Olds Quad 4, I adjusted the cams, 4 deg advanced on the intake and 4 degs retarded on the exhuast and the powerband moved up and hit so much harder, it would smash into the limiter. The bottom end was affected a bit.
The only way to really know is to hit the dyno and adjust them or go to the drag strip and mess around.

[86Shelby]

I agree with what you had found Simon. Thinking about this more advancing the intake and retarding the exhaust will have the same effect that a cam with more overlap would have on a single cam engine- raise the rpm powerband and likely lower the vacuum at idle.

From reading on other boards it seems like the intake timing has a lot to do with the rpm the engine will do best at. Advancing lowers the rpm while retarding raises it. If the exhaust timing stays the same we have a situation like your Quad 4; increasing or decreasing overlap.

Looks like I'll be doing some street tuning to get the A/F ratios where I want them for 20 psi. Then hiting the dyno and trying different cam timing; likely in 4* increments so there should be a noticeable change.

[turbovanman²]

Awesome, let us know what you find. I might try messing around later.

[86Shelby]

Sounds as though the intake timing plays a big part in where the powerband is, RPM wise. The exhaust cam timing is more of a global effect, raising or lowering power across the board. I'm far too excited to get to the dyno to see how things will turn out.