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2ndGenTeg · 11-15-2002, 01:24 AM

With a shorter stroke, you have to use a higher domed piston to get the same CR. Remember what CR stands for- compression ratio. If the stroke is shorter, the volume in the combustion chamber with the piston at TDC has to be less to accomodate the difference- hence the higher dome on the CTR piston. Since the pistons are interchangeable, swapping the same piston into an engine with a longer stroke results in a higher CR. This is also why the ITR pistons starts with a higher compression in its stock motor and ends with a lower CR in the same motor, when compared to the CTR- the ITR has a longer stroke.

Keep in mind this also changes with the head you use, since the combustion chambers have different volumes from one head to the next. Finally, which cam you use has no impact on the CR.

11-15-2002, 01:24 AM	#7
2ndGenTeg 4th Gear Join Date: Aug 2001 Location: Boulder, CO Age: 45 Posts: 830	With a shorter stroke, you have to use a higher domed piston to get the same CR. Remember what CR stands for- compression ratio. If the stroke is shorter, the volume in the combustion chamber with the piston at TDC has to be less to accomodate the difference- hence the higher dome on the CTR piston. Since the pistons are interchangeable, swapping the same piston into an engine with a longer stroke results in a higher CR. This is also why the ITR pistons starts with a higher compression in its stock motor and ends with a lower CR in the same motor, when compared to the CTR- the ITR has a longer stroke. Keep in mind this also changes with the head you use, since the combustion chambers have different volumes from one head to the next. Finally, which cam you use has no impact on the CR.