Why 100mph of 2.5L car is faster than 100mph 1.5L car

i mean the speed-o-meter is meant to measure the SPEED; not the CAPACITY of the engine. in a related note, speed-o-meter for each type of car is uniquely designed to match the CAR'S SPEED. that, if u installed bigger wheels for any specific car, then its speed-o-meter wont be not accurate anymore; since one of the way of how speed-o-meter measure speed is by calculating the rotations of the wheel per second, whatsoever.

so, 100mph is a measure of SPEED; not CAPACITY. but why do i keep hearing people say BMW's 100mph is faster than average car's 100mph?

i have asked this question to my cousin who studied mechanical engineering and she told me that it is because CAPACITY influences the strength of the car IN MAKING ITS WAY THROUGH THE CONSTANT WIND FORCES, or PHYSIC FORCES (at least this is how i understand it; i dont know the technical jargon. i hope someone can provide clearer answer)

100 mph = 100 mph. But I think what you are trying to say is that the car with the bigger engine can -accelerate- faster and therefore -reach- a speed of 100 mph (or any other speed) in less time.

This is simple, a 1.5L car has break horse power at about 109hp and a BMW 2.5L has 184 hp.

Therefore the higher capacity engine provides better acceleration and torque require to propel it to 100mph at a shorter time. And therefore it is faster for a BMW 2.5L to achieve 100mph than that of 1.5L Toyata Vious.

One has bigger wheel base causing longer strides or load pull with a smaller than normal transmission balancing out the resistants caused from the larger wheels or maybe the other cars just have smaller transmissions and or wheel base which makes them "normal".