2.5 L Versus 2.3 L Both with E2 Cam
Here is an example of what happens when you stroke the S14 motor without any other headwork. Notice that both of the maximum HP values are similar. Both of these engines have an E2 intake cam installed. But, look at the abundance of torque that 2.5 L has. This is an example of how the area under the curve makes a difference, not just peak numbers. And, this also shows that the head evens things out when all other things are kept stock minus displacement. An E36 3.0 L M3 produces the same HP as it's 3.2 L younger brother as does the E36 325 does when compared to the 328is.
This chart also clarifies the picture when people say that there 2.3 L's are making as much HP as the 2.5's. Why spend the extra cash, right? Well, you don't get the extra torque with the 2.3L. Even on the track, the 2.5's extra torque stays late enough to make a significant difference in track lap times!
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