Peak Hp at lower or higher RPMs

Question

What are the advantages or disadvantages of having peak Hp at lower or higher RPMs…

Say both bikes had 100hp – one peaked at 9k revs and the other 10k revs – what’s better?

Alex Warzynski:

The acceleration is determined by the force your tyre applies backwards to the tarmac. The higher the torque the more acceleration. If this torque happens at lower speed you fire off the line (see a Tesla that can apply max torque at a stand still as that’s how an electric motor works). If this torque happens at higher engine speeds then this makes your bike have a faster top speed as that’s where the max force on the tarmac happens. So for racing where your engine is flat out all the time, a torque higher up the rev range is better. For road, lower is better as you’re not thrashing it all the time.

Si 4 years 15 Answers 926 views 0

Answers ( 15 )

  1. None of those two is better.\nIt s just not that easy…

  2. i would say too many unknown other factors….does better mean faster? id say ecu programming, gearing, compression…are a few factors that would come into play.

  3. The acceleration is determined by the force your tyre applies backwards to the tarmac. The higher the torque the more acceleration. If this torque happens at lower speed you fire off the line (see a Tesla that can apply max torque at a stand still as that’s how an electric motor works). If this torque happens at higher engine speeds then this makes your bike have a faster top speed as that’s where the max force on the tarmac happens. So for racing where your engine is flat out all the time, a torque higher up the rev range is better. For road, lower is better as you’re not thrashing it all the time.

  4. Just more power is better! POWER!!

  5. The one that peaks at 9k revs has more torque, therefore probably more fun.

  6. MASSIVELY subjective, and other things like gearing and tyre size will all have an effect too.

  7. I’d say 9k, you get full power sooner and the engine doesn’t have to be stressed as much to achieve it.

  8. Reason for my Question, just looking a bit of understanding…

    I’ve been studying my recent Dyno after doing a series of mods.

    My previous peak Hp came in a 120 @ 9464, the new peak Hp has come in at 121 @ 10044. Peak torques is at 7479…

    I’m just trying to work out which is better. Might be playing with peanuts here, but for a Gen1 Mille to have peak HP past 10k revs is good going. Seeing that they top out at about 10.2K.

  9. The area under the curve is what is important. Or the average power over the rpm range you use.

  10. All else being equal it means your pumping more air for a given RPM with the correct fueling.

  11. Too deep for a Sunday morning this.

  12. For the road the lower the revs at peak power the better. You’re unlikely to be going everywhere at max revs but having useable power at lower revs can get you out of all sorts of trouble. On a track where you are screaming round at high revs then you’re more likely to be in that power band for longer. We’re only talking small differences but I’d say that’s what would be best

  13. Not much in it 1k revs , more like 9k and 12k you’d notice, my old cbr600rr didn’t get going till after 10k all top end , gotta say mid range where we mostly live on the road is more fun.

  14. Nice torque line!

  15. If your after ultimate acceleration, higher is better…\nThe power goes through the gearbox…. So if peak power is 10%higher you can run 10% lower gearing for the same road speed, so the motor has 10% more leverage…

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