Thread: Mixing & matching cams

Sorry had a couple beer muscles in me at the time, but still never heard of this cory cat. Ben's the f'in man.

It's cool Bud, I have lots of friends who are mean drunks, lol.


Now, back to the original topic. I’ve mixed and matched cams all the time. It's one way to find out what the engine likes. Some engines like a bigger exhaust cam than intake and vice versa. A poor flowing exhaust port can be helped with a bigger exhaust cam. I can see why some turbo engines liking a bigger exhaust cam. The compressor wheel would be the major restriction in the exhaust system.

The VE engine is a good example of using multi camshaft profiles to get the best power curve. The small cam is good for the low end and the big cam for the high end. At some point in rpm range, both cams make the same hp and this is where you would have the big cam take over.

So, why would a big cam be better than a small cam higher up in the rpm range? At high rpm, there is less time to open and close the valves. The bigger cam, with more duration and lift or time/area, allows the valves to remain open longer, if only for a fraction of a second longer to allow the air to get in to the cylinder.

The engine needs less time/area in the low rpm range and more time/area higher up. You can equate the camshaft degree as time and the lift as the area.