XXR259HR, XR265HR and Old Men, Oh My
04-16-2009, 10:37 AM
#31
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It might seem a little big but I'd look into the ls2 cheatr cam for A 6.0. I run that cam in my truck and makes power from idle to 6800rpm. I run mine to 6500 but never the less makes awsome torque I noticed a bigger difference from just changing my cam then I did from my 6.0 swap in the first place
04-16-2009, 10:50 AM
#33
It might seem a little big but I'd look into the ls2 cheatr cam for A 6.0. I run that cam in my truck and makes power from idle to 6800rpm. I run mine to 6500 but never the less makes awsome torque I noticed a bigger difference from just changing my cam then I did from my 6.0 swap in the first place
What is their reason for so much more exhaust duration? I assume it is because they spec the cam for stock exhaust manifolds, and the duration is to make up for their poor flow? Being I am running headers (although they have small primaries) I wouldn't think a cam with that much exhaust duration would do me any good. That and a ramp rate/lift like that would be a spring killer even with nice aftermarket springs, I am wanting the springs to last 100k w/o ever having to look at them again.
04-16-2009, 01:10 PM
#34
There is more to the story regarding the "not much more power above .550 lift" statements above. True, not much more air goes in at the highest lift points, but - those higher lift cams usually have more duration at .200, .300, .400, .500. That added duration in the mid lifts definitely makes a difference. If you peak a cam at .525 or .550, then its duration at .400 and .450 will likely be less than a comparable .600 lift cam. Also, with more aggressive lobes usually having less .006 duration, that makes for a better idle and mileage than a lower lift cam with the same .050 duration numbers.
I built a custom Comp cam a couple of years back for my supercharged Silverado SS. I looked at the GT2-3 cams valve events and used it as a template. I wanted the perfect idle and wide powerband, but also wanted more cam. I ended up with a crazy config of a ford lobe and SB chevy lobe ground onto the LS1 journal. The end result was something around 212/218 .591 .589 115 +0 (used 918 springs). It idled perfectly. Gas mileage went up. And it had a wide powerband. After demodding my truck, you'd never know it was cammed by the sound. It ran great with the stock converter then too.
I built a custom Comp cam a couple of years back for my supercharged Silverado SS. I looked at the GT2-3 cams valve events and used it as a template. I wanted the perfect idle and wide powerband, but also wanted more cam. I ended up with a crazy config of a ford lobe and SB chevy lobe ground onto the LS1 journal. The end result was something around 212/218 .591 .589 115 +0 (used 918 springs). It idled perfectly. Gas mileage went up. And it had a wide powerband. After demodding my truck, you'd never know it was cammed by the sound. It ran great with the stock converter then too.
04-16-2009, 01:32 PM
#35
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That is some hellacious lift, probably sound like an angry midget with a hammer under the hood. What is their reason for so much more exhaust duration? I assume it is because they spec the cam for stock exhaust manifolds, and the duration is to make up for their poor flow? Being I am running headers (although they have small primaries) I wouldn't think a cam with that much exhaust duration would do me any good. That and a ramp rate/lift like that would be a spring killer even with nice aftermarket springs, I am wanting the springs to last 100k w/o ever having to look at them again.
What is their reason for so much more exhaust duration? I assume it is because they spec the cam for stock exhaust manifolds, and the duration is to make up for their poor flow? Being I am running headers (although they have small primaries) I wouldn't think a cam with that much exhaust duration would do me any good. That and a ramp rate/lift like that would be a spring killer even with nice aftermarket springs, I am wanting the springs to last 100k w/o ever having to look at them again.
04-16-2009, 02:12 PM
#36
There is more to the story regarding the "not much more power above .550 lift" statements above. True, not much more air goes in at the highest lift points, but - those higher lift cams usually have more duration at .200, .300, .400, .500. That added duration in the mid lifts definitely makes a difference. If you peak a cam at .525 or .550, then its duration at .400 and .450 will likely be less than a comparable .600 lift cam. Also, with more aggressive lobes usually having less .006 duration, that makes for a better idle and mileage than a lower lift cam with the same .050 duration numbers.
Thank you.Comp Lobe Catalog
04-16-2009, 02:47 PM
#37
My engine has alot of valvetrain noise, always has even when it was stock. It got worse after the cam swap though. I swapped out the Comp 915's I had for LS6 springs and it didn't change a thing. I was going to try longer pushrods but never got around to it...
04-16-2009, 02:54 PM
#38
Not a problem.
For a good comparison, look at the duration numbers for a 220* cam in XE, XE-high lift, and XER. The 3720 (220 XER) has the same .006 as a 216 XE cam (3766 lobe) making it act like a smaller cam at idle, but has a much larger .200 duration which compares to a 226 XEHL (3716 lobe) for more power.
For a good comparison, look at the duration numbers for a 220* cam in XE, XE-high lift, and XER. The 3720 (220 XER) has the same .006 as a 216 XE cam (3766 lobe) making it act like a smaller cam at idle, but has a much larger .200 duration which compares to a 226 XEHL (3716 lobe) for more power.
04-18-2009, 01:08 AM
#40
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It wasn't listed on the list of cams you were looking at, but have you thought about this cam?:
Lunati Voodoo Cam
212/218 -.531/.531-113+4
I think this is the perfect cam for what you want. These "voodoo" cams have a neat design on their lobes and in a dyno book on LS1-LS7s I have, it made more power under the curve than the Comp265.
Lunati Voodoo Cam
212/218 -.531/.531-113+4
I think this is the perfect cam for what you want. These "voodoo" cams have a neat design on their lobes and in a dyno book on LS1-LS7s I have, it made more power under the curve than the Comp265.