quote:

Originally posted by dwd1985:

quote:

Originally posted by trapper189:
With the three motorcycles you mentioned, it’s not a difference in tuning. The answer to your question is torque and engine rpm. That’s it. More displacement (cc in motorocycle engines) equals more torque. For a given amount of torque, the faster you can rev the engine, the more horsepower it will make.

The 675cc Speed Triple makes 106hp at 11,850rpm, but max torque is 50ftlbs at 9,750rpm.

Next up, the slightly larger 689cc MT-07 makes 74hp at 9,000rpm. Amazingly enough, max torque is the same 50ftlbs as the Speed Triple only at a lower rpm of 6,500.

Lastly, the 798cc BMW makes 90hp at 8,000rpm. Being roughly 20% larger than the other two also produces roughly 20% more torque as well. In this case, 63ftlbs at 5,800rpm.

This almost seemed contradictory to me, but then I think it clicked: making torque at higher RPMs produces more HP than making torque at lower RPMs, correct? This is why the Street Triple making the same torque as the MT-07 but at 1.5x the RPMs is producing 20% more HP? And why the BMW producing 20% more torque but at almost half of the RPMs produces 15% less horsepower?