Lloyed Elliots cam specs hmmm.....
08-07-2008, 11:38 AM
#22
no real back to back comparisons with cam change only so who knows on that part but the duration and LSA are different on the new cams to not step on the toes of Bret or Joe O but designed to work in the same RPM range.
Most agree Intake Valve Closing point (when comparing lobes with same ramp speed) is what will determine RPM range for xxx cubic inch (as well as measurements in the cylinder heads, ability of cam and exhaust system to get the exhaust out of cylinder and ability of intake and TB and CAI to feed the engine also) the DCR also. You can get there with xxx duration on a moderate ICL, a lil bigger duration on a lower ICL or a lil smaller duration on a higher ICL. This all effects how much of the lobe is before TDC at end of exhaust stroke and begining of intake stroke and changing the valve opening point and amount of overlap.
What size intake lobe and where you place it (ICL) depends on your beliefs of what the engine needs in relation to IVC and your beliefs on what the engine needs on exhaust lobe side and how much overlap you want or can tolerate (emissions) for the EVO, EVC.
Pretty much just look at all the cam specs you can and when you find a car that really runs hard is it because the intake lobe is at X centerline?, because exhaust is on X centerline, there relationship together? because the intake closed at X degree?, because the exahust opens/closes at X degree?, etc, etc. . . . . . lots of variables but when you find a theme in cams that are all making good power, you try and use that theory when designing your own cams.
Lots of completely different theories in cam designs that work so there is really no 'wrong" way and some cam people will come to blows with another calling each other off based and in left field with there cam designs but while both cams are designed COMPLETELY different, they can still end up making the same HP and TQ curves and running the same E.T.
A good example would be to look at Pro Stock and the COMPLETELY different theories in porting, valve job, intake design, camshaft design, tune up, etc, etc, and you still have a 16 car field separated by only .005 or so.
Lloyd
Most agree Intake Valve Closing point (when comparing lobes with same ramp speed) is what will determine RPM range for xxx cubic inch (as well as measurements in the cylinder heads, ability of cam and exhaust system to get the exhaust out of cylinder and ability of intake and TB and CAI to feed the engine also) the DCR also. You can get there with xxx duration on a moderate ICL, a lil bigger duration on a lower ICL or a lil smaller duration on a higher ICL. This all effects how much of the lobe is before TDC at end of exhaust stroke and begining of intake stroke and changing the valve opening point and amount of overlap.
What size intake lobe and where you place it (ICL) depends on your beliefs of what the engine needs in relation to IVC and your beliefs on what the engine needs on exhaust lobe side and how much overlap you want or can tolerate (emissions) for the EVO, EVC.
Pretty much just look at all the cam specs you can and when you find a car that really runs hard is it because the intake lobe is at X centerline?, because exhaust is on X centerline, there relationship together? because the intake closed at X degree?, because the exahust opens/closes at X degree?, etc, etc. . . . . . lots of variables but when you find a theme in cams that are all making good power, you try and use that theory when designing your own cams.
Lots of completely different theories in cam designs that work so there is really no 'wrong" way and some cam people will come to blows with another calling each other off based and in left field with there cam designs but while both cams are designed COMPLETELY different, they can still end up making the same HP and TQ curves and running the same E.T.
A good example would be to look at Pro Stock and the COMPLETELY different theories in porting, valve job, intake design, camshaft design, tune up, etc, etc, and you still have a 16 car field separated by only .005 or so.
Lloyd
08-07-2008, 01:41 PM
#23
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lol, not a book worthy person by any means, just posting my beliefs and I am sure others disagree with my thinking on the cam designing. Just base my beliefs on what I have seen that works over the years and what compromises are made when chnaging things a lil. I have sampled from alot of them and come up with my oewn theory on what needs to happen.
If you wanna read, you should look into David Vizards stuff. I do not agree with everything he says but he can shed some light on ideas and make you open your eyes as to why he thinks things need to be certain ways.
Lloyd
If you wanna read, you should look into David Vizards stuff. I do not agree with everything he says but he can shed some light on ideas and make you open your eyes as to why he thinks things need to be certain ways.
Lloyd
08-08-2008, 09:53 AM
#24
lol, not a book worthy person by any means, just posting my beliefs and I am sure others disagree with my thinking on the cam designing. Just base my beliefs on what I have seen that works over the years and what compromises are made when chnaging things a lil. I have sampled from alot of them and come up with my oewn theory on what needs to happen.
If you wanna read, you should look into David Vizards stuff. I do not agree with everything he says but he can shed some light on ideas and make you open your eyes as to why he thinks things need to be certain ways.
Lloyd
If you wanna read, you should look into David Vizards stuff. I do not agree with everything he says but he can shed some light on ideas and make you open your eyes as to why he thinks things need to be certain ways.
Lloyd
