Camshaft Selection
11-17-2005, 10:26 PM
#1
Staging Lane
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Location: Sterling Heights, MI
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Camshaft Selection I'm looking for ideas on camshaft selection. I've decided on the following;
LS2 aluminum block for weight savings (ordered from my local Chebby dealer)
I'm looking at a Lunati rotating assembly (crank, rods, pistons) with a 4" stroke (402 CI) and compression should 9.0 or 9.1
I'm probably going to get a set of AFR CNC ported heads with 2.05" intakes and 1.60" exhaust valves and the larger 76cc chambers.
Magnuson Magnacharger. These usually spin to 5 PSI on a stock 6.0L. With the added breathing, the included pulley will most likely only give 2 PSI. Will adjust the pulley to gain back the other 3 PSI
My goal is a very streetable engine that I can jump on now and then. A roots-style supercharger is usually only going to work (and make good power) up to 6000-6250 RPM. This is OK because I'm more concerned with off the line torque than ringing out every last little upper end horsepower.
The car should weigh between 3000 and 3200 lbs, as whatever I save off the rolling chassis will be gained back with insulation and all kinds of power gizmos (windows, locks, cruise, seats, stereo equipment, etc.). The target is 3100.
The rear end will be a 3.73 with a double-overdrive T-56.
Now, this is what I'm looking at. It may seem tame, but it's the largest lift GM has put in a Gen III V-8 (yes, a factory cam). It's the LS6 cam and it's also used in the LS2. The specs are;
Lift: 0.555/0.551 (I/E)
Duration (at .050): 204/218
Lobe Centerline: 117.5
A couple of GMPP cams run a longer duration, but the lift is less. The centerline is also smaller (110 and 112) which would be nice for a lumpy idle.
This cam, to me, appears to offer what I'm seeking; a decent idle, a good vacuum signal to operate the brakes, and enough duration to bleed off excess pressure to avoid detonation on pump gas.
I'm not interested in mechanical cams, and I think a .600 lift isn't necessary to get the power numbers I'm looking for (550 HP). I figuire if I need to add a little lift over a chosen cam I can switch from 1.7 ratio rockers to 1.75.
So based on the above, thoughts? Suggestions?
LS2 aluminum block for weight savings (ordered from my local Chebby dealer)
I'm looking at a Lunati rotating assembly (crank, rods, pistons) with a 4" stroke (402 CI) and compression should 9.0 or 9.1
I'm probably going to get a set of AFR CNC ported heads with 2.05" intakes and 1.60" exhaust valves and the larger 76cc chambers.
Magnuson Magnacharger. These usually spin to 5 PSI on a stock 6.0L. With the added breathing, the included pulley will most likely only give 2 PSI. Will adjust the pulley to gain back the other 3 PSI
My goal is a very streetable engine that I can jump on now and then. A roots-style supercharger is usually only going to work (and make good power) up to 6000-6250 RPM. This is OK because I'm more concerned with off the line torque than ringing out every last little upper end horsepower.
The car should weigh between 3000 and 3200 lbs, as whatever I save off the rolling chassis will be gained back with insulation and all kinds of power gizmos (windows, locks, cruise, seats, stereo equipment, etc.). The target is 3100.
The rear end will be a 3.73 with a double-overdrive T-56.
Now, this is what I'm looking at. It may seem tame, but it's the largest lift GM has put in a Gen III V-8 (yes, a factory cam). It's the LS6 cam and it's also used in the LS2. The specs are;
Lift: 0.555/0.551 (I/E)
Duration (at .050): 204/218
Lobe Centerline: 117.5
A couple of GMPP cams run a longer duration, but the lift is less. The centerline is also smaller (110 and 112) which would be nice for a lumpy idle.
This cam, to me, appears to offer what I'm seeking; a decent idle, a good vacuum signal to operate the brakes, and enough duration to bleed off excess pressure to avoid detonation on pump gas.
I'm not interested in mechanical cams, and I think a .600 lift isn't necessary to get the power numbers I'm looking for (550 HP). I figuire if I need to add a little lift over a chosen cam I can switch from 1.7 ratio rockers to 1.75.
So based on the above, thoughts? Suggestions?
11-19-2005, 02:02 PM
#3
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Join Date: May 2005
Location: Blairsville, GA
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I'd suggest more duration with an aggressive valve ramp, to be honest. One that opens the valve real fast, holds it open for awhile, then shuts it real fast. While it's open, your blower can work more effectively. I'd venture to say that with a profile like this, you'll not lose much if any low-end torque, and middle and upper-end will be freaky.