MJ, what do you think about this.
We take a TR220 112/108 cam w/ a 38* IVC.
Put it on a 120* seperation and place the ICL at 116*. Now, we have a 46* IVC. So, the high end has increased.

If you spread the LSA (and keep the ICL/ECL at the same placement from the LSA) then, the intake duration must come down to maintain the same RPM range.

220/220 112/108 = 210/210 117/113 (same 38* IVC)
Which one offers a stronger, mid range curve?

We've totally forgotten about one thing however.

Shaun Perry explains here.

 

I just bought a darn cam with 121LSA.

 

Yeah but your intake duration is probably small and also... The Radix doesn't use the same intake.

 

Great discussion topic, lol this has been what i have wanted to know since i got to these forums... all i want is great lower and midrange torque, im not gonna be racing my truck... i want more grunt down low. but sportside i am cam illiterate like many here and dont know how to answer the question you asked in your last post..

which one of these would offer stronger mid range? or would they be the same due to the same IVC? im still trying to grasp alot of these terms and how they relate... i think i need to find a beginners cam term library....

 

Yes intake duration is small. LPE GT7 208/230 .554/.556 121 LSA. It's the LSA that disturbs me. Worried about all mentioned here. Low end torque loss, soft throttle response, and having to possibly spin it to the moon to make power. Hopefully the intake duration and radix intake are equalizers.

 

Ok. Lets start out with this. I don't claim to know everything about a cam. That is why I started this thread, to learn. Not to say everyone is idiots and i'm right because I said so. I hope i'm not that shallow or stupid.
Now that I have made that clear; What exactly do you mean with the specs you are giving above?... (220/220 112/108 = 210/210 117/113 (same 38* IVC)
Which one offers a stronger, mid range curve?)
What is the 112/108 and the 117/113? Is that the lsa/icl?
Second - I have no clue who Shaun Perry is, but that quote is either not giving all the info in respect to cam or he is just wrong IMO. What I am thinking is he is saying that he either moved the icl or decreased the duration to bring the power band down yet kept the lsa tighter to allow it to peak higher where he wanted it. This is just a hunch. Otherwise, I am saying he is wrong.

 

Yep, pretty much... I've taken two single pattern camshafts. One with a 112LSA + 4* and the other with a 117LSA + 4*. Duration adjusted for the IVC point.

I figured this was your main idea that given the same RPM spectrum, one with a wider LSA will have a broader power curve.

No disclaimers needed... I know.

 

Ok, so I'm thoroughly confused now. A tighter lsa like a 112 will have a narrower power band and something wider will have a broader powerband. What I'm wondering is how you tell when a cam is gonna kick in, i.e. which lsa is better for bottom end? Like say the same cam such as a tr 220 on a 112 vs. one on a 114.

 

To answer you question about the two cams the 220 112/108 vs the 210 117 113 the second one will have a much lower power band for 3 reasons:lower duration, wider lsa, and it is advanced 5 degrees more. All 3 of these aspectst, in their own way, will lower the powerband.

 

There are so many variables there it isn't even funny. When a power band "kicks in" is a matter of opinion in the first place. Second, the effects of lsa and icl position change as you change intake and exhaust duration. Typically a cam with a good low end will have a LSA in the 114+ range, yet a cam with 250* duration w/ 114 lsa isn't going to have good low end unless you have 450+ci. See why so many people scratch their heads about cam wizzadry. The one's that truely know are the ones that have built and tested hundereds of cams themselves. There is nothing written down too the exact science, there are guidelines like some of the quotes here, and you have to figure the rest out for yourself. There are just too many combos and variables out there to write everything down, like an intake manifold design can effect the powerband as well.
Confused I have been for years!