Camshaft education, please?

[95BlueStallion]

Ok guys, could you educate a rookie on some camshaft info? If I decided I wanted to add a supercharger shortly after an H/C/I upgrade, should I just use a cam that is made for boost from the get go? I hear random talk of cams ground for boost aplications, but what is the difference? Im not looking for a huge scientific answer, but some basic things. Is the idle smoother, are they not as high a lift, things like that. Also, can you run a cam that is made for a boosted application without a supercharger for a while until the funds are available for the boost? Im wondering this because I think I might start looking for some used parts such as intake, maybe even heads if they arent too old, and other whatnots. But I will have a cam ground for boost so its done the first time, and doesnt need to be removed for a new one 6 months later... Thanks for any info you can contribute to a newbie!

 

[BlownFiveLiter]

A supercharger cam will have less overlap between the valves (higher lobe separation angle), so you're not blowing boost out the exhaust. It could still have a pretty choppy idle, with a high duration, but the valve separation needs to stay above around 112-114° or so in order to be efficient. Peak lift isn't as essential with a supercharger because it's forcing air in versus the engine drawing it in. You could absolutely run a supercharger cam without having one. I've read that the stock cam is actually pretty good with boost. I'd recommend talking to a cam grinder and let them determine what sort of cam you should run. Jay Allen at Camshaft Innovations or Ed Curtis at Flowtech Induction are the usual guys recommended around here, and have built up a pretty good reputation, so those are the guys I'd recommend talking to based on word of mouth. Many guys here have run cams from both of those guys and they've been very happy and impressed with the results.

 

[95BlueStallion]

Wow, thats exactly what I was looking for. Great easy explanation, and even recommendations! Thanks for the help. I think I might have the right cam ground right off the bat based on my projected combo, and then build up around it as $$$ allows... Thanks again

 

[5spd GT]

Looks like StangGT1995 has got you covered. After all, the incoming air has it's beginnings from the combusted gases exiting out of the exhaust valve. It begins pulling air in and with a tight lobe seperation angle (LSA) some of the fresh air may actually exit out of the exhaust valve, especially with added pressure, via the blower.

Typically they do have a wider lobe seperation angle....

 

[Rick 91GT]

A supercharger cam will have less overlap between the valves (higher lobe separation angle), so you're not blowing boost out the exhaust. It could still have a pretty choppy idle, with a high duration, but the valve separation needs to stay above around 112-114° or so in order to be efficient. Peak lift isn't as essential with a supercharger because it's forcing air in versus the engine drawing it in. You could absolutely run a supercharger cam without having one. I've read that the stock cam is actually pretty good with boost. I'd recommend talking to a cam grinder and let them determine what sort of cam you should run. Jay Allen at Camshaft Innovations or Ed Curtis at Flowtech Induction are the usual guys recommended around here, and have built up a pretty good reputation, so those are the guys I'd recommend talking to based on word of mouth. Many guys here have run cams from both of those guys and they've been very happy and impressed with the results.

Dead On

I have a few customers that run NA with a boosted custom cam until they add the boost with great results.

 

[go-stang5.0]

blower cams also tend to have more exhaust duration and/or lift because the exiting of the exhaust is not an assisted process like that of the incoming air fuel mixture. Remember to decide on a combo before getting the cam: a twin screw supercharger likes a different cam profile than a centrifugal, afr heads like more exhaust duration than some other heads, and so on and so on. You get the idea.