richierich14608

From what I have seen so far it seems that cams with higher lift seem to lower the power band of a specific duration. For instance, the thunder racing 220/220 on a 112 lsa cam advertises 1500-6500 rpms with .551 valve lift. Texas Speed's 220/220 on a 112 lsa cam advertises 1200-6200 rpms with .581 valve lift. Now is this false advertisment or are the facts right? Anyone have any thoughts or answers? I listed the links below for a look at the two different specs.

http://www.thunderracing.com/catalog...&vid=9&pcid=51

http://www.texas-speed.com/shop/item...d=164&catid=44

00ChevyScott

iTrader: (10)

they could put 0-6800 rpms on those cam sheets and people would beleive them.

AgFormula02

iTrader: (9)

what the heads flow will have much to do with this. Your cam must be matched to the head flow for peak power. I mean, who wants a 650 lift cam if the heads can't take advantage of it?

budhayes3

iTrader: (19)

Duration and LSA determine the powerband, lift affects the horsepower numbers, if the heads will accomodate. On older cam designs, increased lift would usually increase the duration also, which would affect the powerband. Today's computer designed cam profiles and modern lobe designs can allow for more lift without affecting duration as it used to.

MPFD

iTrader: (5)

You can say that again.

BlackGMC

iTrader: (31)

One thing that is missing in those cam specs are the lobe design... you need the cam lobe specs to really determince the valve events...

00ChevyScott

iTrader: (10)

comp lobes FTW

InchUp

iTrader: (2)

I agree 100%. The cam ramps must be taken into account when determining valve events.

Another thing no one has yet to mention is cylinder pressure increase by means of higher lift cams. Any takers on explaining that one to the original poster? It will answer his question flat out as to why the higher lift pulls the power band down 300 rpms. Any takers before y'all make me explain it in full?

budhayes3

iTrader: (19)

I'm foggy as to why the "powerband", (I refer to this in horsepower terms), would come down, but I could see a slightly stronger torque curve being a result...correct me if I'm wrong, but generally speaking, more cylinder pressure=more torque, and a higher lift cam of the same duration will have a more agressive ramp that will fill the cylinders faster, creating more cylinder pressure. Unless we're just using different terminology...

richierich14608

I used the word "powerband" in describing the rpm range of the cams hp. According to my original post, the higher lift cam lowers the rpms in which the cam starts making power. Thats what I meant by "powerband" if that makes since. The overall point to my original post is the fact that I was wondering if the higher lift cams would bring more hp and torque down lower in the rpms vs. a lower lift cam with the same duration?