OnAnySunday
Well-known member
1:55.. Don't need any CC's apparently...
How many of you take your bike to redline?
- Thread starter ISuckAtMath
- Start date
1:55.. Don't need any CC's apparently...
XenoVibe
Well-known member
A piaggio? :B
Roomie
Banned
I said BABY wheelie! That's a "OMFG I'M GONNA LOSE GOTTA CATCH UP...**** I'M IN NEUTRAL" pride ego wheelie lol
When your on it, you are usually always better off using the entire rpm range available, even if peak power tapers off before redline. Like you said peak numbers don't matter, because its the highest *average* power throughout the rpm range that matters. Simply look at a dyno graph and imagine an average of the low and high hp numbers of your power band. Shade in the area under the curve between your start and end rpm in a gear. Shifting early will usually lower the average power available in each gear. Every engine is different though and you can't use your butt you need a graph and some maths.
Also, if your gear ratios don't match a particular track then you may need to shift early to avoid banging the limiter before a braking zone but thats another topic :s
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XenoVibe
Well-known member
Burgman 650
I was close xD
If your not making any more tq, your not going any faster.
qs keeps the rps where they need to be, I have had my bike dyno'd and It makes no more power at 13000 or tq then it does at 15000
so there is simply no point in revving the **** outta it.
tq is acceleration, no more tq gains, no more speed gains.
07/08 R1's do 159km/h on the limiter in 1st, the 2009 and up just a hair slower. An 06 or newer R6 does 126km/h, just for comparison.
Eh.. circumstances will really dictate when you shift, but the main purpose of reving beyond your peak tq/hp is so that your post-shift-revs will have dropped higher in the powerband than outside the powerband.
Maybe the post-shift point enters a super technical section (esses/carousel/bus-stop)that would favor smoothness and more constant throttle vs an outright BASH of power like opening onto straight?--(aiming to reduce chopping the throttle): short-shift.
No real "100%" answer to when to shift.
Again it depends on the characteristics of the particular motor and transmission, and I'm sure you've found what works for yours, but mathematically that statement is incorrect. Torque is not acceleration, and is simply a measure of force at a particular snapshot in time. When you make more trq you make more hp, and when you make more hp then you accelerate quicker and go down the track faster. Hp is a measure of work (power) over time and is what matters for acceleration. Even with a tapering torque curve it is possible to accelerate faster with more rpm.
To express what I mean, imagine two scenarios.
1) A *completely* flat torque curve, allllll the way from low rpm to max rpm. In this scenario, your motor makes the exact same amount of trq all the time at any rpm. In this scenario you will have a completely linear power curve and you will accelerate quicker as the rpms increase, and it would be most beneficial to rev to the absolute limit available.
2) Low end. Everyone has heard the term 'lots of low end torque', but that is huge misnomer, what people mean to say is 'lots of low end horsepower'. An engine that makes lots of torque mathematically makes more hp at a lower rpm, and that is where the confusion comes from. More torque is good, but people do not understand why.
A fat torque curve results in more AVERAGE horsepower for the duration of gear, which is what moves you quicker.
If your torque tapers significantly after it peaks, then it may not be benefical to redline it, but it is almost always be benefical to rev past peak torque, unless it's dropping off a cliff which would indicate some sort of problem.
It's much easier to explain with a picture of a dyno, peak numbers mean nothing, *especially* peak trq numbers.
Here is an example of when you would want to redline to the absolute limit.
And here is an example of when you may want to shift a *little* early (sorry not motorcycle, it is hard to find these examples).
If you were to shift at peak torque in this next one, you'd be losing a ton of speed.. much better off nearly redlining this bike:
First one is FLAT trq curve, common on I4 bikes, and the second is a FAT torque curve more common with large displacement.
But even these graphs aren't useful without knowing the gearing and the available rpm range to work with!!!!
Pretty simple really, you can't argue math, and you can't compare different engines without seeing a dyno, and most peoples butts are not very accurate
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Torque is the only actual power measure on a dyno, horsepower is just a mathematical figure derived from torque and engine speed.
One horsepower is defined as 550 foot-pounds per second. The units of torque are pound-feet. From torque to horsepower, you need the "per second" term. You get that by multiplying the torque by the engine speed. Curves occur as torque drops with increased engine speed at a certain peak point.
Electric bikes have a perfectly flat torque "curve", because maximum torque occurs at near zero RPM.
The variables are traction, incline, head wind.
For the road, hitting redlines on some 600s and 300s is crazy piston speeds, which means crazy forces on those poor rods.
A Ninja 300 at 14,000 is almost 2 metres per second mean piston speed, or max piston speed of 130 km/hr. A Mustang 302 at redline is 85 km/hr piston speed.
Some of these motorcycle engines have piston speeds close to the old F1 engines.
One horsepower is defined as 550 foot-pounds per second. The units of torque are pound-feet. From torque to horsepower, you need the "per second" term. You get that by multiplying the torque by the engine speed. Curves occur as torque drops with increased engine speed at a certain peak point.
Electric bikes have a perfectly flat torque "curve", because maximum torque occurs at near zero RPM.
The variables are traction, incline, head wind.
For the road, hitting redlines on some 600s and 300s is crazy piston speeds, which means crazy forces on those poor rods.
A Ninja 300 at 14,000 is almost 2 metres per second mean piston speed, or max piston speed of 130 km/hr. A Mustang 302 at redline is 85 km/hr piston speed.
Some of these motorcycle engines have piston speeds close to the old F1 engines.
Awesome!!
Yes and no. F1 engines in 2000 ran 2 races, about 600km. The big difference is the power output that strains everything past the crankshaft.
kiwi
Well-known member
lol the one at 4:18 was just awesome!! lol
starboy869
Well-known member
My 93 vfr is around 95km/hr at 11,000 rpm in first. Really comes alive past 9,000rpm. Plenty enough pickup for me. At the end of the day I don't really like going more than 130km/hour anyways. Also I just keep the roads vs 400 series as any 400 series is boring or suicidal.
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