advance in LS6 cam?
07-25-2010, 10:45 PM
#1
advance in LS6 cam? Simple question:
Is there any advance ground into the 02 LS6 cam?
I found this on the CTS board:
That seems to point to the cam having about 1 degree of retard in it.
More difficult question:
To advance or install dot-to-dot?
I found this:
I'm going to be installing it in my 5.3 silverado and I'm trying to decide if I'd like to set if off dot-to-dot (I have a double roller adjustable timing set with up to +/- 8 degrees).
Obviously a 5.3 is going to want to spin a higher than a 5.7 on the same cam. All the dyno graphs I have seen of stock LS6s seem to put the peak torque at about 4700RPM and peak horsepower at about 5700RPM. Thus with the 5.3, dot-to-dot I'd think about 6000-6100RPM horsepower peak.
With all this in mind, I'm thinking I might advance it +2 degrees to bring the peaks back down a bit, but I'm not sure. Everyone I know of just runs it straight up (though this could be for simplicity and not having an adjustable timing set).
Thoughts?
Is there any advance ground into the 02 LS6 cam?
I found this on the CTS board:
02+ LS6 cam
204/218 int/exh @ 0.05" duration
0.551" / 0.547" int/exh lift
117 LSA
02+ LS6 cam - 0.006" | 0.050" | 0.200 "
Intake Duration ID - 270 | 204 | 166.6
Exhaust Duration ED - 275 | 218 | 178
Lobe Center Angle LSA - 117 | 117 | 117
Intake Centerline ICL - 117.4 | 118.9 | 118
Intake Valve opens IVO - 17.6 | -16.9 | -34.7 BTDC
Intake Valve closes IVC - 72.4 | 40.9 | 21.3 ABDC
Exhaust Valve Opens EVO - 74.1 | 44.1 | 25 BBDC
Exhaust Valve Closes EVC - 20.9 | -6.1 | -27 ATDC
Exhaust Centerline ECL - 116.6 | 115.1 | 116
Overlap 38.5 | -23 | -61.7 degrees
204/218 int/exh @ 0.05" duration
0.551" / 0.547" int/exh lift
117 LSA
02+ LS6 cam - 0.006" | 0.050" | 0.200 "
Intake Duration ID - 270 | 204 | 166.6
Exhaust Duration ED - 275 | 218 | 178
Lobe Center Angle LSA - 117 | 117 | 117
Intake Centerline ICL - 117.4 | 118.9 | 118
Intake Valve opens IVO - 17.6 | -16.9 | -34.7 BTDC
Intake Valve closes IVC - 72.4 | 40.9 | 21.3 ABDC
Exhaust Valve Opens EVO - 74.1 | 44.1 | 25 BBDC
Exhaust Valve Closes EVC - 20.9 | -6.1 | -27 ATDC
Exhaust Centerline ECL - 116.6 | 115.1 | 116
Overlap 38.5 | -23 | -61.7 degrees
More difficult question:
To advance or install dot-to-dot?
I found this:
The School of Automotive Machinists (SAM) has done extensive engine dyno testing on LS1s and has come to the following conclusion. Intake closing point is the most important determining factor for where (and how much) power the LS1 makes.
Cams that have an intake closing point of 40 degrees ABDC tend to make peak power around 6000 rpms. Close the intake around 42 degrees, they peak around 6100. 44 degrees, 6200 rpm power peak. 46 degrees, 6300 rpm power peak.
You can vary intake closing point by playing around with duration, LSA and ICL. For example:
TR 224/224 112LSA +4 cam has intake closing point of 40 degrees ABDC (6000 rpm peak).
TR 224/224 114LSA +4 cam has intake closing point of 42 degrees ABDC (6100 rpm peak)
TR 220/220 114LSA +0 cam has intake closing point of 44 degrees ABDC (6200 rpm peak)
2002 ZO6 204/218 117.5LSA -2.5 cam has intake closing point of 42 degrees ABDC (6100 rpm peak)
TR 230/224 111 LSA +2 cam has intake closing point of 44 degrees (6200 rpm peak)
MTI 209/216 116LSA +4 A1 cam has intake closing point of 36.5 degrees ABDC (5600 rpm peak)
Cams that have an intake closing point of 40 degrees ABDC tend to make peak power around 6000 rpms. Close the intake around 42 degrees, they peak around 6100. 44 degrees, 6200 rpm power peak. 46 degrees, 6300 rpm power peak.
You can vary intake closing point by playing around with duration, LSA and ICL. For example:
TR 224/224 112LSA +4 cam has intake closing point of 40 degrees ABDC (6000 rpm peak).
TR 224/224 114LSA +4 cam has intake closing point of 42 degrees ABDC (6100 rpm peak)
TR 220/220 114LSA +0 cam has intake closing point of 44 degrees ABDC (6200 rpm peak)
2002 ZO6 204/218 117.5LSA -2.5 cam has intake closing point of 42 degrees ABDC (6100 rpm peak)
TR 230/224 111 LSA +2 cam has intake closing point of 44 degrees (6200 rpm peak)
MTI 209/216 116LSA +4 A1 cam has intake closing point of 36.5 degrees ABDC (5600 rpm peak)
I'm going to be installing it in my 5.3 silverado and I'm trying to decide if I'd like to set if off dot-to-dot (I have a double roller adjustable timing set with up to +/- 8 degrees).
Obviously a 5.3 is going to want to spin a higher than a 5.7 on the same cam. All the dyno graphs I have seen of stock LS6s seem to put the peak torque at about 4700RPM and peak horsepower at about 5700RPM. Thus with the 5.3, dot-to-dot I'd think about 6000-6100RPM horsepower peak.
With all this in mind, I'm thinking I might advance it +2 degrees to bring the peaks back down a bit, but I'm not sure. Everyone I know of just runs it straight up (though this could be for simplicity and not having an adjustable timing set).
Thoughts?
Last edited by 2001CamaroGuy; 07-25-2010 at 10:53 PM.
07-25-2010, 10:53 PM
#2
TECH Regular
iTrader: (12)
Join Date: May 2010
Location: Waxahachie, Tx
Posts: 445
Likes: 0
Received 0 Likes
on
0 Posts
Z06 has higher CR and the cam is set up for it.
TC stretch will retard ~1 deg.
You'll want to advance the cam to get more cylinder pressure from the smaller cid and lower static cr.
Play with a DCR calculator and you'll see what I mean.
Also, asymmetrical cam lobes will move the open/close points around as compared to the LCL & duration method of calculating points vs. actual measured point. How much and where depends on the lobe series. Ex the actual measure vs calculated IVO can be 3 deg different and the exhaust might be 5 deg from what I've been told.
Do you know if those numbers you posted came from a cam doctor or???
TC stretch will retard ~1 deg.
You'll want to advance the cam to get more cylinder pressure from the smaller cid and lower static cr.
Play with a DCR calculator and you'll see what I mean.
Also, asymmetrical cam lobes will move the open/close points around as compared to the LCL & duration method of calculating points vs. actual measured point. How much and where depends on the lobe series. Ex the actual measure vs calculated IVO can be 3 deg different and the exhaust might be 5 deg from what I've been told.
Do you know if those numbers you posted came from a cam doctor or???
Last edited by TurboS10; 07-25-2010 at 10:59 PM.
08-11-2010, 06:03 PM
#4
On The Tree
iTrader: (1)
Join Date: Oct 2003
Location: Roswell, GA
Posts: 173
Likes: 0
Received 0 Likes
on
0 Posts
I'm looking at the posted LS6 duration numbers.
The durations @ .200" seem very high compared to the same lobe's [reported] duration at .050".
Compared to the [equivalent .050 duration] Comp Cams XFI exhaust lobe 3034: 218 @ .050, 141 @.200, the LS6 exhaust lobe appears to crush the XFI lobe in terms of duration @ .200, 178 to 141.
Am I reading this right? Can these LS6 specs be confirmed? I feel like I'm taking crazy pills.
Experts please chime in.
The durations @ .200" seem very high compared to the same lobe's [reported] duration at .050".
Compared to the [equivalent .050 duration] Comp Cams XFI exhaust lobe 3034: 218 @ .050, 141 @.200, the LS6 exhaust lobe appears to crush the XFI lobe in terms of duration @ .200, 178 to 141.
Am I reading this right? Can these LS6 specs be confirmed? I feel like I'm taking crazy pills.
Experts please chime in.
