[danhr]

Soooooo again.... saying that LSA doesn't matter and that it's only overlap that makes it chop is contradictory. O e of the factors that determines overlap is LSA.

Here's some food for thought.

This car has a 22x/236 cam with .650+ lift in an ls1. Those are pretty stout duration numbers, especially for an ls1. It falls in the "donkey dick" category, with the ms4, trex, polluter, btr 4, etc, going off those numbers... so you would expect it to be pretty choppy.

https://youtu.be/B1OJU58oof4

(And for a little icing on the cake.. that was a first start up, with the factory tune.... nothing had been adjusted yet either)

117 LSA, just in case you were curious.

Sorry... can't embed videos on my phone..

[Joe's_cool_1le]

Here's mine. Pretty mild but it rocks the car side to side. Link to a quick video.
https://drive.google.com/file/d/0B2I...ew?usp=sharing

[KingLT1]

Originally Posted by danhr

Soooooo again.... saying that LSA doesn't matter and that it's only overlap that makes it chop is contradictory. O e of the factors that determines overlap is LSA.

Here's some food for thought.

This car has a 22x/236 cam with .650+ lift in an ls1. Those are pretty stout duration numbers, especially for an ls1. It falls in the "donkey dick" category, with the ms4, trex, polluter, btr 4, etc, going off those numbers... so you would expect it to be pretty choppy.

https://youtu.be/B1OJU58oof4

(And for a little icing on the cake.. that was a first start up, with the factory tune.... nothing had been adjusted yet either)

117 LSA, just in case you were curious.

Sorry... can't embed videos on my phone..

It's not contradictory. You are missing the point to what I am saying. I am saying LSA as a number doesn't matter but yes you need LSA to determine valve overlap.

Read the thread at LS1tech "why lsa doesn't matter".

https://ls1tech.com/forums/generatio...-t-matter.html

here is a piece taken out of that post for those that do not read that thread.

"I also get the question all the time, "will this cam chop"? Or, "I'm afraid that because this cam is on a 114lsa it won't chop". This is internet myth and I will debunk it here for you.

LSA as I have shown is nothing but a sum of numbers. Overlap is what determines how much your cam will chop in a given engine. Cubic inches and a few other factors can change how much it chops, but for the majority more overlap means more chop and less overlap means less chop."

[danhr]

Originally Posted by KingLT1

It's not contradictory. You are missing the point to what I am saying. I am saying LSA as a number doesn't matter but yes you need LSA to determine valve overlap.

Read the thread at LS1tech "why lsa doesn't matter".

https://ls1tech.com/forums/generatio...-t-matter.html

here is a piece taken out of that post for those that do not read that thread.

"I also get the question all the time, "will this cam chop"? Or, "I'm afraid that because this cam is on a 114lsa it won't chop". This is internet myth and I will debunk it here for you.

LSA as I have shown is nothing but a sum of numbers. Overlap is what determines how much your cam will chop in a given engine. Cubic inches and a few other factors can change how much it chops, but for the majority more overlap means more chop and less overlap means less chop."

So if lsa determines overlap... and overlap determines chop.....

1 + 1 = ???

LSA is a FACTOR that determines OVERLAP. If a FACTOR changes, the end result will CHANGE.

Overlap = Intake duration + exhaust duration / 4 - LSA x 2 (go from left to right, dont use order of operstions).

Overlap is mathematically connected to LSA. I dont know any other way to explain it without using pictures and making a song

[KingLT1]

The point is LSA does not dictate the sound of a cam, overlap does. You can have 2 different camshafts with 2 different LSA's but the same amount of overlap and they generally will sound the same. That is all I was saying.

[Hyper SS]

Originally Posted by KingLT1

The point is LSA does not dictate the sound of a cam, overlap does. You can have 2 different camshafts with 2 different LSA's but the same amount of overlap and they generally will sound the same. That is all I was saying.

You definitely have more lope with a tighter LSA.

[KingLT1]

Originally Posted by Hyper SS

You definitely have more lope with a tighter LSA.

Only if the cam that has the tighter LSA has more overlap. 224/228 114 vs 224/228 112, the 112 variant has more lope because it has more overlap not because the LSA is 112. Now take a 220/224 112 vs a 224/228 114 and they will sound the same because both cams have -2 degrees overlap.


Pulled from the thread I linked:

I also get the question all the time, "will this cam chop"? Or, "I'm afraid that because this cam is on a 114lsa it won't chop". This is internet myth and I will debunk it here for you.

LSA as I have shown is nothing but a sum of numbers. Overlap is what determines how much your cam will chop in a given engine. Cubic inches and a few other factors can change how much it chops, but for the majority more overlap means more chop and less overlap means less chop.

Now that you know what center lines are, think about a camshaft mentally in your mind. Look at how the centers of the lobes are spread apart from one another. If the LSA is tighter they will be closer to one another and if the LSA is wider they will be spread further from one another. If you took those centers and spread them apart further from one another, what would happen to the intake opening and exhaust closing ramps? They would now overlap less. I'll give an example.

Take the SNS Stage 2 cam 107 and 113 centers. If we change the exhaust center to a 115, we now have changed the LSA to a 111lsa. We didn't touch the duration of the intake or exhaust lobes, we just widened the exhaust center line. By doing this, and widening the centers further apart we reduce overlap. The SNS Stage 2 has 11 degrees of overlap @.050 lobe lift. If we change it to a 111lsa by doing the above, we now have 9 degrees of overlap@.050 lobe lift.

Now here is the real eye opener. If two camshafts no matter their duration or LSA both have the same amount of overlap and you put both cams in the exact same vehicle with everything else the same aside from the camshafts they will sound identical.

Let's take another cam for this example. 235/251 116+5. This cam has a 111 icl and a 121 ecl. Now most of you would probably say that because this camshaft has a 116lsa that it will not chop nearly as hard as the 110lsa of the SNS Stage 2. Let's take a closer look at how much overlap this cam actually has.

To determine overlap we add the intake and exhaust durations together and then divide them by two. This gives us 243. We now take the LSA and multiply it by 2 this gives us 232. Now subtract 243-232 = 11 degrees of overlap. So this camshaft has just as much overlap as the SNS Stage 2 with a 110lsa.

If you had the SNS Stage 2 cam installed in your car and replaced it with the 235/251 116lsa cam it would sound 100% identical to the SNS camshaft that you previously had installed. Again, LSA is just a sum of numbers and it doesn't matter!

I will leave this thread with one last suggestion. Do not pick a cam based on LSA. LSA is not the end all be all when it comes to camshaft performance or sound. Don't be lured into a trap by a manufacturer or a vendor when they tell you that, "X companies camshaft won't sound like you want it to because it's ground on a certain LSA". If you really want to know how two different camshafts will sound and want to see which one will chop harder at idle, just compare their overlap figures. If one has more overlap than the other it will chop harder than the other 95% of the time. If one has less overlap than the other it will chop less 95% of the time. Different exhaust systems and tuning can and will affect this, but for the most part overlap is a very good way in determining cam sound AND how drivable a camshaft will be. Don't think that just because a cam is ground on a tight LSA that it will be a pain to drive or because it's ground on a wide LSA that it will be a dream to drive.

I hope I have now instilled in those of you that read this that camshafts are just a sum of numbers. There are no absolutes in cam grinding. Everything is a compromise and not everything is as it seems at face value. Look deeper into your cam selections and compare valve events, overlap figures and not just duration and LSA specs. Compare the known performance of other camshafts with similar overlap and valve events to the cam you're considering purchasing. This will give much more insight into what you're looking for rather than just basing an assumption of LSA and duration.

[oldman]

I will help the rest of you out: http://www.hotrod.com/articles/camsh...ted-explained/

Overlap is related to duration and to LSA, with LSA roughly twice as great of an impact. Yes I can teach Math at any local University....

[oldman]

Originally Posted by KingLT1

Only if the cam that has the tighter LSA has more overlap. 224/228 114 vs 224/228 112, the 112 variant has more lope because it has more overlap not because the LSA is 112. Now take a 220/224 112 vs a 224/228 114 and they will sound the same because both cams have -2 degrees overlap.

This is precisely incorrect. It has more overlap BECAUSE of the decrease in LSA. Overlapped is the derived number from durations and LSA. Since it is derived from two parameters, any change in overlap is because of one or both parameters deltas.

[MP3BOOSTED]

This is very normal.. think your engine moves a lot, imagine my vvt3 cam from TSP

[KingLT1]

Originally Posted by oldman

This is precisely incorrect. It has more overlap BECAUSE of the decrease in LSA. Overlapped is the derived number from durations and LSA. Since it is derived from two parameters, any change in overlap is because of one or both parameters deltas.

You are missing the point as well.. I never said LSA has nothing to do with overlap.
I said the actual LSA number does not dictate how the cam will sound. How many degrees of overlap the cam has dictates the sound of the cam. The thread link I posted clearly explains this.

You also misunderstood my example. Yes when you tighten up LSA overlap increases and powerband shifts to the left. Again take the 224/228 114 vs 224/228 112, the 112 variant will have more chop because overlap went from -2 with the 114 to +2 with the 112. Again power band shifts left with a slightly earlier peak. Either way increased overlap is what changed the cam sound.

I think where we are looking at things differently is it's common to use LSA in correlation with Cam chop because companies like TSP give you the option to pick LSA with most of their cams. Yes when you use the same duration profile of cam but alter the LSA, the tighter LSA variant will chop harder because again overlap increases. However you can't always use that theory to judge all cams. take a 238/242 116 vs a 228/228 110. Guess which one will chop harder? Neither, they both will sound similar because they both have 8 degrees of overlap.

[JFM-jr]

Originally Posted by KingLT1

Only if the cam that has the tighter LSA has more overlap. 224/228 114 vs 224/228 112, the 112 variant has more lope because it has more overlap not because the LSA is 112. Now take a 220/224 112 vs a 224/228 114 and they will sound the same because both cams have -2 degrees overlap.


Pulled from the thread I linked:

I also get the question all the time, "will this cam chop"? Or, "I'm afraid that because this cam is on a 114lsa it won't chop". This is internet myth and I will debunk it here for you.

LSA as I have shown is nothing but a sum of numbers. Overlap is what determines how much your cam will chop in a given engine. Cubic inches and a few other factors can change how much it chops, but for the majority more overlap means more chop and less overlap means less chop.

Now that you know what center lines are, think about a camshaft mentally in your mind. Look at how the centers of the lobes are spread apart from one another. If the LSA is tighter they will be closer to one another and if the LSA is wider they will be spread further from one another. If you took those centers and spread them apart further from one another, what would happen to the intake opening and exhaust closing ramps? They would now overlap less. I'll give an example.

Take the SNS Stage 2 cam 107 and 113 centers. If we change the exhaust center to a 115, we now have changed the LSA to a 111lsa. We didn't touch the duration of the intake or exhaust lobes, we just widened the exhaust center line. By doing this, and widening the centers further apart we reduce overlap. The SNS Stage 2 has 11 degrees of overlap @.050 lobe lift. If we change it to a 111lsa by doing the above, we now have 9 degrees of overlap@.050 lobe lift.

Now here is the real eye opener. If two camshafts no matter their duration or LSA both have the same amount of overlap and you put both cams in the exact same vehicle with everything else the same aside from the camshafts they will sound identical.

Let's take another cam for this example. 235/251 116+5. This cam has a 111 icl and a 121 ecl. Now most of you would probably say that because this camshaft has a 116lsa that it will not chop nearly as hard as the 110lsa of the SNS Stage 2. Let's take a closer look at how much overlap this cam actually has.

To determine overlap we add the intake and exhaust durations together and then divide them by two. This gives us 243. We now take the LSA and multiply it by 2 this gives us 232. Now subtract 243-232 = 11 degrees of overlap. So this camshaft has just as much overlap as the SNS Stage 2 with a 110lsa.

If you had the SNS Stage 2 cam installed in your car and replaced it with the 235/251 116lsa cam it would sound 100% identical to the SNS camshaft that you previously had installed. Again, LSA is just a sum of numbers and it doesn't matter!

I will leave this thread with one last suggestion. Do not pick a cam based on LSA. LSA is not the end all be all when it comes to camshaft performance or sound. Don't be lured into a trap by a manufacturer or a vendor when they tell you that, "X companies camshaft won't sound like you want it to because it's ground on a certain LSA". If you really want to know how two different camshafts will sound and want to see which one will chop harder at idle, just compare their overlap figures. If one has more overlap than the other it will chop harder than the other 95% of the time. If one has less overlap than the other it will chop less 95% of the time. Different exhaust systems and tuning can and will affect this, but for the most part overlap is a very good way in determining cam sound AND how drivable a camshaft will be. Don't think that just because a cam is ground on a tight LSA that it will be a pain to drive or because it's ground on a wide LSA that it will be a dream to drive.

I hope I have now instilled in those of you that read this that camshafts are just a sum of numbers. There are no absolutes in cam grinding. Everything is a compromise and not everything is as it seems at face value. Look deeper into your cam selections and compare valve events, overlap figures and not just duration and LSA specs. Compare the known performance of other camshafts with similar overlap and valve events to the cam you're considering purchasing. This will give much more insight into what you're looking for rather than just basing an assumption of LSA and duration.

I have read that thread in the past I believe thats written by Martin Smallwood of Tick Performance a pretty bright guy in the camshaft arena.

[oldman]

LSA deltas has double the impact of duration change when it comes to overlap. Overlap = lope. Ergo LSA has an effect on lope, in fact it has twice the effect of duration changes on lope.

I read the article and it exaggerates to prove a point that cams of different durations could have the same overlap. Really that is just admitting that LSA has double the impact on overlap vs duration changes... duh.

Standard street performance cams of 220 duration will lope a whole lot at 104 LSA vs 120 LSA... As simple as that.

[KingLT1]

Originally Posted by JFM-jr

I have read that thread in the past I believe thats written by Martin Smallwood of Tick Performance a pretty bright guy in the camshaft arena.

Pretty much...but you come to Camaro 6 and you have guys that can't even figure out what kind of lifters to run questioning those that live and breathe camshaft design.