How high can you safely rev an '04 4.8L?
05-05-2005, 06:31 PM
#23
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Originally Posted by SportSide 5.3
Are we talking about making power or simply, the motor hanging on that high?
A stock motor would run out of breath WAAAAAAAYYYY before hitting the 9K mark. However, with the right Heads/Cam/Intake/Exhaust it could be a powerhouse of a motor. BUT is would be kinda nutless down low and a high revving motor is not well suited for a heavy truck.
05-05-2005, 06:59 PM
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It takes a 4.8 roughly 600 more rpm to move the same amount of air given the exact same head/cam/intake as a 5.3L.
Example: Same combos
5.3L: 300rwhp @ 5500-rpm
4.8L: 300rwhp @ 6100-rpm
The only problem is the intake manifold. Take a look where almost every Gen III with a LS1/LS6/Truck manifold makes max peak hp. 6200-6400 rpm
The 4.8 wants more rpm but, the manifold limits it.
So, what does a 4.8 do?
Example: Same combos
5.3L: 300rwhp @ 5500-rpm
4.8L: 300rwhp @ 6100-rpm
The only problem is the intake manifold. Take a look where almost every Gen III with a LS1/LS6/Truck manifold makes max peak hp. 6200-6400 rpm
The 4.8 wants more rpm but, the manifold limits it.
So, what does a 4.8 do?
05-05-2005, 07:21 PM
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Originally Posted by SportSide 5.3
So, what does a 4.8 do?
Because of the RPM potentential of the 4.8 power is not that far off of a 5.3 or 6.0 but the problem is that the torque of a 4.8 will never be there.
05-05-2005, 08:52 PM
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Originally Posted by hirdlej
I got in a hairy drag race yesterday and spun my 4.8 up to 5700 RPM's until it bounced off the rev limiter. Are these things tough enough to do this often or is it hard on these things over time? Will this kind of behavior lead to anything like CSK over time or just speeding tickets? 
How strong are these 4.8L rotating assemblies? Geometrically can these things be consistenly revved up this higher than the old 5.7L or 5.3L for that matter?
BTW: I won
How strong are these 4.8L rotating assemblies? Geometrically can these things be consistenly revved up this higher than the old 5.7L or 5.3L for that matter? BTW: I won
