[cartech]

We read about max HP @ some RPM. What does this mean for us in our day-today driving? What is actually available HP when we are driving? I have done a calculation for Swift,Getz Prime(1.1L & 1.3L) and Palio Stile(1.1L & 1.6L). If you see power/rpm curve it rises with rpm, peaks at some rpm & drops. I feel that this curve can be aproximated by a straight line through 0 RPM. Then we can get actual power at various RPM. Here is data:

HP/RPM----------------- @1K------------ @2K----------- @3K
sw)(87/6000=0.0145) ----14.5------------ 29.0---------- 43.5
GZ1)(67/5500=0.0122)--- 12.2------------24.4----------- 36.6
GZ2)(83/5500=0.0150)----15.0------------30.0-----------45.0
PL1)(57/5250=0.0109)-----10.1------------20.2-----------30.3
PL2)(100/5500=0.0181)---18.1-------------36.2-----------54.3

It is intersting to see that Getz1.3(GZ2) has actually more power available than Swift. Also Getz 1.1 (GZ1) is not that badly off wrt Swift in city driving. Ofcourse this make sense only if we can aproximate HP curve by straight line. This also can explain why diesel cars with low power (e.g. Indica diesel) do well in this rpm band.

[Shan2nu]

Sorry dude, didn't really get what you're trying to say here.

Without knowing the torque curve, how can horsepower be calculated?

Moreover, you're calculating power produced at the crank. This does not include the effects of gearing (which is crucial for acceleration). Lack of torque can be compensated by altering gear/final drive ratios.

Lastly, if the HP curve could form a straight line, it wouldn't be called a "curve" in the first place.

Shan2nu