are dual pattern cams designed for builds having poor exhaust flow?
would they benefit a build using exhaust manifolds instead of headers?
your thoughts...
That was the main idea behind the split pattern cams. It does work. Crane uses approx. 8*'s on there split. Other companies use 4-6. The amount of division can help or hinder. For the most part, more is better for certain applications while in an engine with very well balanced flowing heads, it can lead to over scavenging. A lot is application dependent and engine dependent.
(Find and read AndyF's article. I was surprised myself when I read this. And it shows what I say and continue to say. Sometimes, you just never expect the result! The way I figured things out 20+ years ago was just to simply purchase the cam and run it! 20+ cams later, LMAO!, you get the feel for things. But just the feel!)
When Crane intoduced its split pattern came, only stock heads were available. Porting technics were not as well developed or advanced as they are today thanks to people extremely interested in this area of engine development.
(See and read David Vizard's book on porting heads and be mindful of the time period!)
The question here today we all face is, "Is a split pattern right for me and how much is needed for the best performance of MY engine?"
First I'll say, and probably get a bit of a roasted my for it is, there is nothing wrong with a single pattern cam. Sometimes, it can out power a split duration cam. I'm m sorry to say that an actual write up and dyno sheet showing this, I don't not know where to find. But be sure it is application/engine build dependent. What works great in one engine may not work as well as you would think in the next engine.
Also a word on "Out powers." Max HP isn't the only thing one should look at in what actually makes an engine powerful.
Also consider intake, exhaust and header design coupled with exhaust pipe sizing and length as part of the issues concerning cam selection.
In general, while I am here at the forums, when someone asks for advice on a cam, I am going to look at off the shelf cams rather than sit down with a computer algorithm to science something out.
(No, I do not have such a thing.)
The balance in intake and exhaust flow is the main target to look at. The poorer the balance the more exhaust duration you may very well want.
To help educate yourself, pick up the simple "Desk Top Dyno" program and start entering known cam specs. Then try adjusting them yourself. Pay attention to th power curves and your cam self adjustments.
Once you get the hang of this, you may just order up your own spec custom cam.
Remember! This is a learning tool!
In the end, I think cam prices are cheap and the deep well of wonderment and experimentation will make them easier to purchase and try out. And that is what I suggest! Try them all out!
