cam idling

[dstang01]

different cams produce very distinctive idles, some sound deep and lopey, some are very quiet, some make ticking noises, and some sound like chevy trucks. What spec of the cam determines how it sounds at idle?

 

[Sirone]

different cams produce very distinctive idles, some sound deep and lopey, some are very quiet, some make ticking noises, and some sound like chevy trucks. What spec of the cam determines how it sounds at idle?

HAHA LOLOL!

 

[dstang01]

its a serious question man

 

[trav_19]

so your plan on buying a cam is on idle tone...??? sounds like a really bad way to pick a cam do you not care about performance at all? a lot of cams will hurt performance if not paired right for your application

 

[hookups333]

I dont think hes pickin one cuz of the sound. Hes just curious about what does it.

 

[HGFireHazard]

From my little bit of reading about cams and such on the forum it has to do with LSA and duration. I don't know jack crap outside of that, and even as I type this I'm not sure if I'm write or not.

 

[trav_19]

duration is what will give you that loaping sound...every aspect of the cam determins the sound it will give

 

[parchisi]

with my limited knowledge on cam design, I beleive the sounds has a lot to do with overlap where both the intake and exhaust valves are open at the same time. With a lot of overlap, at high RPMs, the momentum of the fast moving air will keep the flow going the correct way (in the intake valve and out the exhaust valve) creating very efficient filling of the cylinder. At lower RPMs though, the overlap causes problems when the air mass isn't going as fast and it causes the engine to run rougher, causing that "lopey" sound. There is a loss of low RPM power and makes for a not very street friendly car. Somebody correct me if I'm wrong though, but I think's that's what I've read