Cam Design...
06-12-2012, 08:05 PM
#21
This is a question but kind of ties into yours:
Why such wide LSA's on most LS cams?
1. Is it what works good for making power with pump gas and stock ecm's?
2. A sales and marketing type thing, ie peeps get steered that way by forums, and its hard to sell them if they are not ground wide?
3. Its the real deal and makes LS motors make big power?
4. some combo of the above?
Your program is showing you little change from 102 to 114 lsa, wow I wouldnt think that would hold true in real world. The 102 to 114 is 12 degrees different, But your actually spreading both lobes by that 12 degrees so 24 degrees total. LSA is intake CL to exhaust CL divided by 2. I do not see how you could be moving around lobes by 24 total degrees and not be effecting your results more than that on your program.
Why such wide LSA's on most LS cams?
1. Is it what works good for making power with pump gas and stock ecm's?
2. A sales and marketing type thing, ie peeps get steered that way by forums, and its hard to sell them if they are not ground wide?
3. Its the real deal and makes LS motors make big power?
4. some combo of the above?
Your program is showing you little change from 102 to 114 lsa, wow I wouldnt think that would hold true in real world. The 102 to 114 is 12 degrees different, But your actually spreading both lobes by that 12 degrees so 24 degrees total. LSA is intake CL to exhaust CL divided by 2. I do not see how you could be moving around lobes by 24 total degrees and not be effecting your results more than that on your program.
06-16-2012, 10:51 AM
#22
Damn I work 3rd shift and I am fading fast...
The other day I was driving home from work and thought of this. IS there any input in the program that might deal with how fast the air is flowing in the heads, not just total airflow. Like maybe they flow this many cfm and the ports have X amount of cross sectional area in inches squared? I ask because I would like to see the numbers tweaked to represent a lazier flowing intake port, like same flow but good bit bigger port. I would like to see if it still showed such a small change to moving the lobes around.
Another thing would be lower compression ratio and see if it still has a small effect.
I was just wondering if the program is estimating that really good port velocity and a good base compression ratio is making it not so sensitive to moving the valve timing events around.
The other day I was driving home from work and thought of this. IS there any input in the program that might deal with how fast the air is flowing in the heads, not just total airflow. Like maybe they flow this many cfm and the ports have X amount of cross sectional area in inches squared? I ask because I would like to see the numbers tweaked to represent a lazier flowing intake port, like same flow but good bit bigger port. I would like to see if it still showed such a small change to moving the lobes around.
Another thing would be lower compression ratio and see if it still has a small effect.
I was just wondering if the program is estimating that really good port velocity and a good base compression ratio is making it not so sensitive to moving the valve timing events around.
07-31-2012, 12:26 PM
#23
sounds to me like you may have a bottle neck somewhere in your specs in the program. you should be getting change. Look at custom intake and exhaust flow numbers and calcs. I've used EAP and found it to be pretty close to real world numbers compared to some of the other programs out there that seem to be more just games. numbers are usually closer to rear wheel dyno numbers.
07-31-2012, 07:09 PM
#24
sounds to me like you may have a bottle neck somewhere in your specs in the program. you should be getting change. Look at custom intake and exhaust flow numbers and calcs. I've used EAP and found it to be pretty close to real world numbers compared to some of the other programs out there that seem to be more just games. numbers are usually closer to rear wheel dyno numbers.
Thanks!
