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LS9 cam in a 4.8, what to expect?

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Old 04-26-2012, 07:04 PM
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the 4.8 never had the 6 speed
Old 05-23-2012, 10:30 AM
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Just my 2cts, but I would advise against the LS9 cam here strongly. That cam is designed from GM to have a positive displacement blower behind it. Look at the size of the split between intake and exhaust, and LSA. Its designed to lower cylinder pressure because it has the blower forcing the air in throughout the rpm band. Skoalbandit just put one in his N/A 5.3, and trust me, its a dog under 5k rpm, and then not really that impressive above that.
Old 05-23-2012, 10:37 AM
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yea, expect a really soft bottom end , half decent mid, and a kinda strong top end..

Theres much better cams out there.
Old 05-23-2012, 03:09 PM
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a trailblazer stall would be a decent, cheap alternative for a stall. especially for a 4.8 n/a.
Old 05-23-2012, 07:28 PM
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There are allot of other better cam choices, that cam was designed for more cubes and boost. Based on the specs of it that I have seen it bleeds off some of the dynamic compression due to what it its designed for, with a NA engine you dont really want this.
Old 05-25-2012, 04:40 PM
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If you've already got a LS9 cam for this, I'll trade you strait up for my LS2 cam. its a 3-bolt, angle sensor on the front cover.

The ONLY reason you'd want an LS9 cam in a 4.8 is to boost it.
Old 05-25-2012, 05:32 PM
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Lightbulb Couple thoughts....

Originally Posted by Jake99
Remeber at the same rpm the 4.8s piston is moving slower then any other ls motor, you put more dur in the cam you may move more air but your not letting it build any compression (no torque). What you want is less dur more lift tight lsa.
You are starting to touch on what he needs to pay attention to. But let's elaborate. He needs to pay attention to where the intake valve closes in the piston's compression stroke, as this will affect dynamic compression. As this is the case, you can't just tell him to pick xxx intake duration on xxx LSA. He needs to pick an intake lobe that has xxx IVO, and xxx IVC from which he will be able to determine Intake valve Centerline, and when factored into the overall equation once he figures out the exhaust lobe he will see what the LSA is.

When Jake99 says that you want Less dur more lift, that's a more aggressive ramp rate lobe. That's tolerable to the point of frequency you want to be changing valve springs, and how much money you want to spend on valve springs. But he is absolutely right, as more lift area under the curve equals more potential air flow, which will generate more power/torque. LSA is a "Number" that is a by product of where the lobes are set relative to each other, and it is not necessarily viable to say a tight LSA is advisable over a wider LSA. It's all dependent upon what lobes he uses, what the RPM range of maximum torque production is intended to be, and how it is aspirated.
Old 05-25-2012, 06:15 PM
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Our HT1 cam might be a good choice for a DD 4.8

214/218 .559"/.562" 111 LSA

Run it with a 1.8 rocker and you will have .591/.595. Perfect for a PAC1218. Just a thought...
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