I doubt it's possible but...

[Bort62]

Um, the reason a big cam has such a rumpity rump idle is because your car is nearly stalling between each pulse.

This is caused by valve overlap and poor cylinder filling.

a smaller LSA like you say will cause that as well as large intake/exhaust duration.

It's really a pretty complicated situation, and the classic inlines site oversimplies it quite a bit.

 

[falcon fanatic]

Bort,
No doubt. That's why I have a stock cam and ratio rockers in mine - I want a smooth idle and smooth performance with my c-4. However, in the original question that started this thread the poster, mustube, wanted a lumpy idle and I'm telling him it's possible, but that he needs to raise his compression significantly to compensate for the lack of cylinder pressure. And, it's important to note that while the car won't idle that great, it will make considerable power and in a useable rpm range.

Engines run better or worse at certain rpm ranges depending on how they are built and tuned. We all know that. Better or worse is different than good or bad. It's shades of gray, not black or white. You can't say a lumpy idle means the engine runs bad. If so, they wouldn't make lumpy cams. It just means the engine idles poorly, and in this case that might actually be a good thing because that's exactly what he wants. It's not what I want, or apparently what Bort or Kitabel want, but it seems to be what mustube wants, so for him, its good.