Foot
17-08-14, 12:19 AM
Been trying to make sense of torque and power and how to use the range of revs to it's full advantage and a google search churns a lot of rubbish and besides - thought it'd be easier / more fun to discuss on here.
To avoid any comments about how maybe speed is for the track or perhaps speed comes from corners, I appreciate both points and want a bit more of a technical answer than something like just gain experience. So lets say, to set the scene, we're talking about on a track trying to get the best track time possible (I know the lap time isn't the point of a trackday, and on the whole better track times will almost always be found from cornering, I am curious and just want more understanding :rolleyes:).
Here is a power curve of the SV, max power/torque seems to vary quite a lot from site to site and there's a bit of difference with different models of the SV, but lets just take this as the case for sake of argument, and to keep everyone on the same page lets talk about the 2003 stats - if this curve is even needed, which I don't think it will be hugely. Who doesn't like graphs though..
http://image.sportrider.com/f/8601986/146-0308-sv650-dyno-zoom.jpg
a) Supposing you'd just come out of a corner and onto a long straight, where would want the revs to be at? (Obviously corners aren't done in sections and the whole thing is smooth and continuous increase in power, but use your imagination ;))
Then whereabouts is the ideal gear change rpm? Just at the redline, or so that when the revs drop they drop to either the torque or the power peak?
I figure max torque will allow you to accelerate faster but ultimately the max power will get you to the highest speed - is this the case?
b) In a more day to day situation, if you're about to perform an overtake you obviously want to get around the car as soon as possible, so again - would you ideally have the rpms around the peak of torque?
c) How bad for the bike is it to have the revs go past the redline? (Not that I'd put my engine under than kind of stress).
Is it damaging to keep the engine at high revs (ie. 9000rpm) for extended periods (10+ miles)? So then to combat this it's best to alter your speed to keep the revs changing?
I'm under the impression it's damaging to an engine to keep it at constant rpm regardless of how high - is this the case?
d) On the road, if you're taking a spirited ride and you've come onto a long straight, personally when-ish would you change gears? Before I come into criticism, I do listen and feel how the bike is behaving and act accordingly, I don't scream the bike's t!ts off everywhere, and as explained above I'm just curious about ideal situations.
If you were on a track and frequently getting to the redline - could this be damaging? Or would this only be a problem if you were doing a couple of trackdays a month?
A lot of these questions could be easier to answer if the question was about an inline four with a much smaller power band - feel free to talk about that instead, whichever way.
All of this is inspired by me having just left the 33bhp club. With the ECU restrictor in, you need a landing strip to get the revs passed 8k rpm which is where the top power is knocked off. But it still held its own. The difference in power is quite considerable, with the derestricted version not running out of steam as soon as you get to around 7-8k rpm.
However I was surprised to not feel any difference in the acceleration/torque (other than the fact there is still accessible acceleration at higher speeds), but I guess that's just the nature of having an ECU restriction.
If you've read all of this you definitely deserve some praise, a real monster post. I labelled questions so that you don't need to rewrite lots of stuff and also because it's late and I didn't want to repeat myself, which I'm pretty sure I did anyway :cool:. I'm sorry for all of the disclaimers which have to go with every question but I don't want people getting the wrong idea, I am an inexperienced rider and I'm slowly increasing my skill in a safe manner and learn things well by reading as well as practising.
And now it looks like an exam paper which I am far too familiar with. I will mark and return your answers, if you don't make the grades I'm afraid you'll have your account suspended. Instant pass for reading everything.
To avoid any comments about how maybe speed is for the track or perhaps speed comes from corners, I appreciate both points and want a bit more of a technical answer than something like just gain experience. So lets say, to set the scene, we're talking about on a track trying to get the best track time possible (I know the lap time isn't the point of a trackday, and on the whole better track times will almost always be found from cornering, I am curious and just want more understanding :rolleyes:).
Here is a power curve of the SV, max power/torque seems to vary quite a lot from site to site and there's a bit of difference with different models of the SV, but lets just take this as the case for sake of argument, and to keep everyone on the same page lets talk about the 2003 stats - if this curve is even needed, which I don't think it will be hugely. Who doesn't like graphs though..
http://image.sportrider.com/f/8601986/146-0308-sv650-dyno-zoom.jpg
a) Supposing you'd just come out of a corner and onto a long straight, where would want the revs to be at? (Obviously corners aren't done in sections and the whole thing is smooth and continuous increase in power, but use your imagination ;))
Then whereabouts is the ideal gear change rpm? Just at the redline, or so that when the revs drop they drop to either the torque or the power peak?
I figure max torque will allow you to accelerate faster but ultimately the max power will get you to the highest speed - is this the case?
b) In a more day to day situation, if you're about to perform an overtake you obviously want to get around the car as soon as possible, so again - would you ideally have the rpms around the peak of torque?
c) How bad for the bike is it to have the revs go past the redline? (Not that I'd put my engine under than kind of stress).
Is it damaging to keep the engine at high revs (ie. 9000rpm) for extended periods (10+ miles)? So then to combat this it's best to alter your speed to keep the revs changing?
I'm under the impression it's damaging to an engine to keep it at constant rpm regardless of how high - is this the case?
d) On the road, if you're taking a spirited ride and you've come onto a long straight, personally when-ish would you change gears? Before I come into criticism, I do listen and feel how the bike is behaving and act accordingly, I don't scream the bike's t!ts off everywhere, and as explained above I'm just curious about ideal situations.
If you were on a track and frequently getting to the redline - could this be damaging? Or would this only be a problem if you were doing a couple of trackdays a month?
A lot of these questions could be easier to answer if the question was about an inline four with a much smaller power band - feel free to talk about that instead, whichever way.
All of this is inspired by me having just left the 33bhp club. With the ECU restrictor in, you need a landing strip to get the revs passed 8k rpm which is where the top power is knocked off. But it still held its own. The difference in power is quite considerable, with the derestricted version not running out of steam as soon as you get to around 7-8k rpm.
However I was surprised to not feel any difference in the acceleration/torque (other than the fact there is still accessible acceleration at higher speeds), but I guess that's just the nature of having an ECU restriction.
If you've read all of this you definitely deserve some praise, a real monster post. I labelled questions so that you don't need to rewrite lots of stuff and also because it's late and I didn't want to repeat myself, which I'm pretty sure I did anyway :cool:. I'm sorry for all of the disclaimers which have to go with every question but I don't want people getting the wrong idea, I am an inexperienced rider and I'm slowly increasing my skill in a safe manner and learn things well by reading as well as practising.
And now it looks like an exam paper which I am far too familiar with. I will mark and return your answers, if you don't make the grades I'm afraid you'll have your account suspended. Instant pass for reading everything.