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Old 15th February 2007, 06:30 AM   #310 (permalink)
fabianGTR34
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well bigger displacment will make more power with the same amount of boost,
The average cilinder pressure is converted to a force by the piston, and the rod and crank convert it to rotating force, (torque) The force is created by the pressure X surface area of the piston (bore) so a biger bore creates a bigger force with the same pressure. A long stroke has a relative small bore ( surface but the pressure doesn't drop as fast during the stroke, resulting in high torque with relative low horsepower. A bigger bore will convert the pressure to a bigger force, but due to the bigger bore the pressure drops relative fast during the stroke, resulting in higher horesepower and relative lower torque.

As for the bigger engine with the small GTSS, It is more commont to mach a turbo to the kind of engine, the exhaust flow rates of the 4,5 liter engine are different ththan a smaller displacement engine, so the small turbines could become a restriction to the engine, I can emagine that the gtss on the 4,5 liter engine restrict the max power due to the small turbines, but if you let that aside, they will make more power at the same boost level due to the bigger displacement.
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