Is this a suitable cam
03-31-2011, 09:11 PM
#21
Melting Slicks
Thread Starter
Have crane 1.6's roller tips on it now. Sticking w/2nd choice. The 1.6's does not give the cam much more lift. If it increases the lift and has adverse effect, will go to 1.5 ratio.
03-31-2011, 10:31 PM
#22
Melting Slicks
63Mako,..I don't follow your logic. For starters, yes we do know exactly when the intake valve closes for both cams. Again, here are the cam cards:
http://www.compcams.com/Company/CC/c...ookieSupport=1
http://www.cranecams.com/product/car...detail&p=23892
There's no way the Comp cam you've suggested would provide a higher DCR than the 151 cam (or 962), all else equal.
The problem with your methodology is, any formula that uses "advertised duration" to compare two cams made by different manufacturers is useless. There is no industry standard for AD.
More here about the uselessness of "advertised duration":
From Harvey Crane here:
http://www.4secondsflat.com/Cam_Design.html
is this:
"Advertised duration" varies depending upon who wrote the advertising,.."
From here:
http://www.shenyu-sjz.com/parts/cams...a_camshaft.htm
...is this:
"Advertised duration are not reliable numbers when tryng to compare one brand to another,.."
From here:
http://www.wantlandracing.com/cams.html
...is this:
"...problem is that different manufacturers use different standards for this (advertised duration)."...and,.."Not only that, they (advertised duration numbers) do not have a lot of meaning in the real world,.."
From here:
http://www.hotrod.com/techarticles/1...rminology.html
...is this:
"Most cam manufacturers differ in where they start and finish measuring for advertised duration"
Net-net, we agree to disagree.
http://www.compcams.com/Company/CC/c...ookieSupport=1
http://www.cranecams.com/product/car...detail&p=23892
There's no way the Comp cam you've suggested would provide a higher DCR than the 151 cam (or 962), all else equal.
The problem with your methodology is, any formula that uses "advertised duration" to compare two cams made by different manufacturers is useless. There is no industry standard for AD.
More here about the uselessness of "advertised duration":
From Harvey Crane here:
http://www.4secondsflat.com/Cam_Design.html
is this:
"Advertised duration" varies depending upon who wrote the advertising,.."
From here:
http://www.shenyu-sjz.com/parts/cams...a_camshaft.htm
...is this:
"Advertised duration are not reliable numbers when tryng to compare one brand to another,.."
From here:
http://www.wantlandracing.com/cams.html
...is this:
"...problem is that different manufacturers use different standards for this (advertised duration)."...and,.."Not only that, they (advertised duration numbers) do not have a lot of meaning in the real world,.."
From here:
http://www.hotrod.com/techarticles/1...rminology.html
...is this:
"Most cam manufacturers differ in where they start and finish measuring for advertised duration"
Net-net, we agree to disagree.
Last edited by 73, Dark Blue 454; 03-31-2011 at 10:46 PM.
03-31-2011, 10:53 PM
#23
Race Director
This should be tame enough for your car as is.
This is the cam I recommended initially.
http://www.compcams.com/Company/CC/c...x?csid=97&sb=2
Check the specs across the board with the Lunati you just posted.
http://www.lunatipower.com/Product.aspx?id=1984&gid=287
About as close as two cams from different manufacturers could be.
03-31-2011, 11:28 PM
#24
Race Director
63Mako,..I don't follow your logic. For starters, yes we do know exactly when the intake valve closes for both cams. Again, here are the cam cards:
http://www.compcams.com/Company/CC/c...ookieSupport=1
http://www.cranecams.com/product/car...detail&p=23892
There's no way the Comp cam you've suggested would provide a higher DCR than the 151 cam (or 962), all else equal.
The problem with your methodology is, any formula that uses "advertised duration" to compare two cams made by different manufacturers is useless. There is no industry standard for AD.
More here about the uselessness of "advertised duration":
From Harvey Crane here:
http://www.4secondsflat.com/Cam_Design.html
is this:
"Advertised duration" varies depending upon who wrote the advertising,.."
From here:
http://www.shenyu-sjz.com/parts/cams...a_camshaft.htm
...is this:
"Advertised duration are not reliable numbers when tryng to compare one brand to another,.."
From here:
http://www.wantlandracing.com/cams.html
...is this:
"...problem is that different manufacturers use different standards for this (advertised duration)."...and,.."Not only that, they (advertised duration numbers) do not have a lot of meaning in the real world,.."
From here:
http://www.hotrod.com/techarticles/1...rminology.html
...is this:
"Most cam manufacturers differ in where they start and finish measuring for advertised duration"
Net-net, we agree to disagree.
http://www.compcams.com/Company/CC/c...ookieSupport=1
http://www.cranecams.com/product/car...detail&p=23892
There's no way the Comp cam you've suggested would provide a higher DCR than the 151 cam (or 962), all else equal.
The problem with your methodology is, any formula that uses "advertised duration" to compare two cams made by different manufacturers is useless. There is no industry standard for AD.
More here about the uselessness of "advertised duration":
From Harvey Crane here:
http://www.4secondsflat.com/Cam_Design.html
is this:
"Advertised duration" varies depending upon who wrote the advertising,.."
From here:
http://www.shenyu-sjz.com/parts/cams...a_camshaft.htm
...is this:
"Advertised duration are not reliable numbers when tryng to compare one brand to another,.."
From here:
http://www.wantlandracing.com/cams.html
...is this:
"...problem is that different manufacturers use different standards for this (advertised duration)."...and,.."Not only that, they (advertised duration numbers) do not have a lot of meaning in the real world,.."
From here:
http://www.hotrod.com/techarticles/1...rminology.html
...is this:
"Most cam manufacturers differ in where they start and finish measuring for advertised duration"
Net-net, we agree to disagree.
http://members.uia.net/pkelley2/DynamicCR.html
Maybe I just don't comunicate well.
With this logic what your saying is there is no way to determine DCR.
This is not true. Yes, advertised duration point to point will vary some but it is .004 or .006. on almost every hydraulic cam I have never seen or heard of anything more or less. This is 4/1000 to 6/1000 of an inch of lift. The amount of degrees between .004 lift and .006 lift is a couple at most. The advertised duration in the formula is divided by 2. This gives you a correct intake opening or closing point within 1 or 2 degrees using advertised duration in the calculation. This gets your DCR calc within 1/10 of a point which is close enough for a street build.
Again, the intake closing point listed on the Crane card above is @ .050 lift, Duration @ .050.
The intake closing point listed on the Comp card is @.006 lift. Advertised duration
44 thousands difference is big and apples and oranges different compared to a couple thousands that amounts to a degree or two.
I do agree that duration @ 50 and LSA will most accuratly determine the RPM range and mannerism of the cam for comparison purposes. But I think a fairly accurate DCR calculation is invaluable when selecting a cam and to obtain that knowing the actual intake closing point within a narrow margin of error is a requirement.
Sorry about somewhat hijacking the thread. Oldguard 7 has all the info he needs and then some.
The reality is every cam in this thread and his other thread will more than likely work in his engine on pump gas. 106 LSA works, 114 LSA works, some 217 dur @ .050 works, 234 dur @ .050 works, .420 lift works. .520 lift works, some 268 advertised duration works, 320 advertised duration works.
Opinions are like a$$holes, everybody has one.
Im gone!
Last edited by 63mako; 04-01-2011 at 12:26 AM.
