What cam should I get?
mullinax95 said
The XE268 (the one I'm looking at) has a Basic Operating RPM Range: 1,600-5,800 RPM. So that is close to 6000 but I'm still concerned about the starting RPM range which is 1,600. I've looked at other cams that start at Idle or 600 RPM and they seem to be like RV or Tow cams. So I think that I am on the right track far as a good performance cam. I still have to learn more about cams before I purchase. So I still have plenty of time and will learn somethings along the way. Lunati has a cam that has 268 duration on the intake and 494 lift on the intake with a staring RPM of 1,800. The Comp cam has 268 duration on the intake and 477 lift on the intake and a starting RPM of 1,600. So I'm like would 200 RPM make a difference and also why is the duration the same but the lift is more on the Lunati? Will the Lunati cam make more horses? Questions, questions??
That basic operating range is just that. Realize smaller engines will not operate in that zone exactly, but more probable, about 200 rpm's higher. Small engines will idle more radicaly than a bigger engine with the same cam.
At 1600 rpm, it is very much like a operating range of 7 - 10 MPH when the power starts coming in due to the cams profile.
(An autos stock stall converter can handle that OK fine, a manual would almost not notice it at all.)
Another thing, the RPM ceiling acts the same way. A large stroke motor like the 360 or stroker 400+ cube engine will make peak power way before that 6000 rpm comes around.
Between cams listings you posted, various manufacures will grind more aggresive ramps into the cam. The same 270 advertised duration cam can have very far different duration @ .050 lift numbers.
The higher the number @ .050 at the same advertised duration is showing you that this cam is a more agressive lifting cam.
On lift, more the merry. But with this and the oether specs, theres limits to it. Even how it performs in identical motors.
In theroy, the Lunati should make more power. (And I thik it will.) It will not if the overall combo is not up to snuff for the cam or the parts used are not up to snuff. A more agressive cam doesn't allways mean more power. If such was the case, the eveyone would be running 1.8 rockers.
Over aggresive lifts can mimic roller cam profiles, but produce less top end power than a milder Hyd. cam.
Hyd. lifters have there limits as well.
Better to error on a smaller cam and be happier over all with the combo not MAXED OUT than be maxed out and unhappy with what becomes overkill for your needs or engine combo and parts.