Cams with -1 overlap?
01-29-2012, 05:54 PM
#41
I did an exercise when I bought my last cam. I consulted all of the cam manufacturers, specialty shops and net gurus. Then I asked everyone in the thread to make a recommendation based on their opinions. What the comparison chart showed is that most all recommendations were very similar. In fact, when averaged out, the board members made an almost identical recommendation as the experts.
I think a lot of people think that there is some secret special formula that only a precious few gurus know and if you buy an off the shelf cam or don't get this exact cam formula that your build will be a failure. Are LS engines a little different then old school V8s? Sure, but I think Comp Cams and the others have the knowledge to get you what you need.
01-29-2012, 07:27 PM
#42
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Ok just looked into the ls3 cam test from the mags. Found some interesting stuff!
The best performing cam in my opinion
Katech 224/236 made some of the best numbers from 3-6 thousand and the most peak power! That's a 12 degree split!
Futral was in second, 225/236 11 degree split great down low all the way to the top.
Comp had a 8 degree split and made pretty good numbers also but not as good, the worst performing cam had only 6 degree split! Made great peak numbers but terrible low end and mid range power!
It still looks to me that these heads need a big split, I can't find anything were a small split cam is making the numbers. Also I think a lower LSA is the way to go, 112-113 thats just from what I come up with! Been researching the he'll out of this!
The best performing cam in my opinion
Katech 224/236 made some of the best numbers from 3-6 thousand and the most peak power! That's a 12 degree split!
Futral was in second, 225/236 11 degree split great down low all the way to the top.
Comp had a 8 degree split and made pretty good numbers also but not as good, the worst performing cam had only 6 degree split! Made great peak numbers but terrible low end and mid range power!
It still looks to me that these heads need a big split, I can't find anything were a small split cam is making the numbers. Also I think a lower LSA is the way to go, 112-113 thats just from what I come up with! Been researching the he'll out of this!
01-29-2012, 07:39 PM
#43
Ok just looked into the ls3 cam test from the mags. Found some interesting stuff!
The best performing cam in my opinion
Katech 224/236 made some of the best numbers from 3-6 thousand and the most peak power! That's a 12 degree split!
Futral was in second, 225/236 11 degree split great down low all the way to the top.
Comp had a 8 degree split and made pretty good numbers also but not as good, the worst performing cam had only 6 degree split! Made great peak numbers but terrible low end and mid range power!
It still looks to me that these heads need a big split, I can't find anything were a small split cam is making the numbers. Also I think a lower LSA is the way to go, 112-113 thats just from what I come up with! Been researching the he'll out of this!
The best performing cam in my opinion
Katech 224/236 made some of the best numbers from 3-6 thousand and the most peak power! That's a 12 degree split!
Futral was in second, 225/236 11 degree split great down low all the way to the top.
Comp had a 8 degree split and made pretty good numbers also but not as good, the worst performing cam had only 6 degree split! Made great peak numbers but terrible low end and mid range power!
It still looks to me that these heads need a big split, I can't find anything were a small split cam is making the numbers. Also I think a lower LSA is the way to go, 112-113 thats just from what I come up with! Been researching the he'll out of this!
01-29-2012, 08:26 PM
#45
The Lunati and Livernois were pretty decent sized cams. They are both in the mid 230s intake duration at .050" and they both have around 12 degrees of overlap.
Another thing that is really notable in the test is that the top performers had lifts below .600" on the intake and exhaust.
The 3 aforementioned top performers range from 113-115 LSA. The duration split was 12-14 degrees.
What I did not see anywhere was the ICL and more specifically the intake closing event. They have a chart, but there are so many lines, it is impossible to discern.
I don't have LS3 heads, but it is an interesting test nonetheless.
01-29-2012, 08:32 PM
#46
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I was not impressed with the livernois cam, good peak but it was pretty bad down low. For a street strip cam I think the katech was the best, awesome torque and avg power.
01-29-2012, 10:56 PM
#48
I'm glad you guys are keeping an open mind and also feel research is a lot to do with making decisions and not falling for the Internet myth and "gods" lurking. It's not a black magic like some are hypnotized to think. It's about getting a well thought out build. It's knowing where you want the power? Your goals? How exactly your chosen parts performe and calling Comp or a vendor to get you the cam you'll need. I'm not trying to start a debate just trying to say to keep an open mind and research.
01-29-2012, 11:56 PM
#49
many ways to calculate it..........
take ur IVO and you're EVC numbers off your card and add them.....make sure they are the advertised numbers......this is you're actual overlap period im assuming and looking at the above post you calculated using your .050 duration numbers which is how you got -1......i can assure you that is not your ACTUAL overlap lol....even the most mild cams in stock pickup trucks have 10* or so of overlap......
another way to do it if you dont have that info is with your ADVERTISED (.004 lift) duration numbers.....formula as follows...i will use a 286/294 112LSA cam for example (with a somewhat mild lobe translates to a 224/236 @.050 ish cam)
1. Add your advertised intake and exhaust durations together....
286+294 = 580
2. Divide by 4
580/4= 145
3. Subtract your LSA
145-112= 33*
4. Multiply by 2.....
33*2= 66*
So from the .004 Intake Open point to the .004 Exhaust from closed point there is 66*.....which is 66* of time where there is in theory a non-sealed chamber due to both valves being slightly open.....
take ur IVO and you're EVC numbers off your card and add them.....make sure they are the advertised numbers......this is you're actual overlap period im assuming and looking at the above post you calculated using your .050 duration numbers which is how you got -1......i can assure you that is not your ACTUAL overlap lol....even the most mild cams in stock pickup trucks have 10* or so of overlap......
another way to do it if you dont have that info is with your ADVERTISED (.004 lift) duration numbers.....formula as follows...i will use a 286/294 112LSA cam for example (with a somewhat mild lobe translates to a 224/236 @.050 ish cam)
1. Add your advertised intake and exhaust durations together....
286+294 = 580
2. Divide by 4
580/4= 145
3. Subtract your LSA
145-112= 33*
4. Multiply by 2.....
33*2= 66*
So from the .004 Intake Open point to the .004 Exhaust from closed point there is 66*.....which is 66* of time where there is in theory a non-sealed chamber due to both valves being slightly open.....
You mean .006....?
01-30-2012, 07:39 AM
#50
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I'm glad you guys are keeping an open mind and also feel research is a lot to do with making decisions and not falling for the Internet myth and "gods" lurking. It's not a black magic like some are hypnotized to think. It's about getting a well thought out build. It's knowing where you want the power? Your goals? How exactly your chosen parts performe and calling Comp or a vendor to get you the cam you'll need. I'm not trying to start a debate just trying to say to keep an open mind and research.
01-30-2012, 08:35 AM
#51
I think that actual difference in power will be subtle. It should bring the torque in sooner. The motivations to keep the LSA wide is to: smooth the idle, increase vacuum for accessories, lower emissions and make the car easier to tune. But, if you want a rougher idle on a smaller camshaft, you have got to narrow the LSA.
02-01-2012, 07:49 AM
#55
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Depends on the application though, if you look at the smaller cams with bigger splits they are making more power under the curve. It does not seem to effect top end numbers from what I find though.
02-06-2012, 05:12 PM
#57
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Talked to lunati, they said they can do that new 217/228 ls3 voodoo cam on a 110 instead of the 112 to get the idle I want. What do you guys think, I think I may go with it. I also found Howards makes there own version of the hot cam and ASA cam, that sounds interesting.
02-06-2012, 06:07 PM
#58
Talked to lunati, they said they can do that new 217/228 ls3 voodoo cam on a 110 instead of the 112 to get the idle I want. What do you guys think, I think I may go with it. I also found Howards makes there own version of the hot cam and ASA cam, that sounds interesting.
02-06-2012, 06:57 PM
#59
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To much cam for me right now, pretty set on this lunati now. Staying with a small cam for dependability and easy on the valve train and the rest of the car. I want to get a clutch, axles, one piece driveshaft, tires ect. Before I start to push the power. That cartek H/C setup is looking real good for down the road 