Top speed question?
04-26-2011, 08:39 PM
#1
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Top speed question?
I can only speek about what I have done to my red Superhawk and my mods and setup. I know my bike tops at 175 range. However the Orginal ower may have done interinal engine work. Where I live we don't have canons or twisties, it long straight highways. Typical busa ville, the inner city is drag racing and outskirts are for the distance runners. Not every biker is like that, but you dont have to look to far to see it. The local police dept, sheriffs and state police received large cuts into the staffing, causing a free for all type of attitude for street racers. I wish we had mountains and green forests to venture thru. It's flat and the home of the motor city. Racing is in the blood here. Just look up Woodward dream cruse.
I am not making a drag bike nor will I be extending the swing arm. But offen you might see my trends looking to increases my straight line and top end. I ride with a group when I can, but for the most part I attend school and do homework. I'm not out looking to be put into a body bag.
What I really would like to know is.. what is a real top speed of a modified Superhawk. What kind of numbers can your bikes put up. Please list your mods. "straight line is boring I understand that"
I am not making a drag bike nor will I be extending the swing arm. But offen you might see my trends looking to increases my straight line and top end. I ride with a group when I can, but for the most part I attend school and do homework. I'm not out looking to be put into a body bag.
What I really would like to know is.. what is a real top speed of a modified Superhawk. What kind of numbers can your bikes put up. Please list your mods. "straight line is boring I understand that"
04-26-2011, 08:48 PM
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evil man of nothing
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I have to ask...175 on your speedo or measured on gps? If it's 175 on gps then congrats-you're putting down some SERIOUS power for a superhawk. If it was on the speedo then yes you were still hauling *** but you were probably going more like 155-maybe 160.
04-26-2011, 09:46 PM
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Yea i agree. First of what gearing are you running. I ask because we all know the hawk stock gearing will not reach red line in 6th gear unless u have a very long straight to ride down. With me, i am running 16/43 and i can hit redline all day and the max my speedo read was 180 and i was neck and neck with a GSXR 600 on a straight. He was running a speedo healer and it read 170. and that was pushing the hawk to keep neck and neck on the top end since he had more to go on top. but like chaos said u would be having to make some serious power. we got power thru out the powerband but like 8541hawk said we dont make much on the top end. so unless u wanna dump huge cash into engine work to go faster, i would also suggest a I-4.
philip
philip
04-26-2011, 10:46 PM
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Speedo error
On my 07 GSXR1000 at a speedo indicated 186mph ( was pretty easy to do really) was going 163mph on the gps unit! Most bike speedo's are quite far off.
All of the above was on a closed course! of course?
All of the above was on a closed course! of course?
04-26-2011, 11:05 PM
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04-27-2011, 06:13 AM
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They might actually be off from factory too, but that's never the whole story...
The Speedo takes the signal from the engine output shaft, so it has no idea what's happening in the real world... It says you are going 55 mph weather you are tooling down the interstate or sitting on a dyno... And that's obvoiusly a lie...
The thing is, a lot of stuff happens after the point where the speedo is measuring... And all of them varies heavily with speed...
One, you can change gearing... That throws the speedo off because it relies on the fixed ratio of the final gearing to calculate the speed of the wheel...
Two, changing the tire to another size tire, throws the speedo off, same reason as above...
Three, at speed the tire expands, that throws the speedo off, since it calculates the speed based on a fixed ratio based on the relation between the speedsensor, gearing and the circumreference of the tire...
Four, at high speed the wheel "slips" a certain amount, ie it's actually rotating faster than the actual roadspeed...
Five, the speedo has no concept of wind resistance or road resistance... These are a lot higher at high speeds...
All of these varieables are different at different speeds rpm's and road conditions... But the manufacturers can only work off of the data they have and make a best case guessing table, ie compensate % at speeds above X and it works out fairly true in most cases...
In the end, the speedo is still off by a pretty big margin...
The Speedo takes the signal from the engine output shaft, so it has no idea what's happening in the real world... It says you are going 55 mph weather you are tooling down the interstate or sitting on a dyno... And that's obvoiusly a lie...
The thing is, a lot of stuff happens after the point where the speedo is measuring... And all of them varies heavily with speed...
One, you can change gearing... That throws the speedo off because it relies on the fixed ratio of the final gearing to calculate the speed of the wheel...
Two, changing the tire to another size tire, throws the speedo off, same reason as above...
Three, at speed the tire expands, that throws the speedo off, since it calculates the speed based on a fixed ratio based on the relation between the speedsensor, gearing and the circumreference of the tire...
Four, at high speed the wheel "slips" a certain amount, ie it's actually rotating faster than the actual roadspeed...
Five, the speedo has no concept of wind resistance or road resistance... These are a lot higher at high speeds...
All of these varieables are different at different speeds rpm's and road conditions... But the manufacturers can only work off of the data they have and make a best case guessing table, ie compensate % at speeds above X and it works out fairly true in most cases...
In the end, the speedo is still off by a pretty big margin...
Last edited by Tweety; 04-27-2011 at 06:16 AM.
04-27-2011, 07:35 AM
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Tweety- very true
I know the speedo can't be correct. The idea crossed my mind to see what others have done and their type of mods. I did put a gps on the tank with a suction cup for a minute, but didn't trust it would stay and quick removed it. I am sure my bike tops around 160-165. A friends r6 hits his limiter before I do. His bike has some mods and +2 on the gearing, my gearing is -1+2. I'm going to have to open this motor up before I choose to sell it. I want to see what's been done to the top half. Its faster then the black 98 but not by much. The original owner was a mechanic at Am General and works on prototype vehicles. As far as I know he did put a new clutch in it, cans, air filter, jetted it and some tweaks.
I know the speedo can't be correct. The idea crossed my mind to see what others have done and their type of mods. I did put a gps on the tank with a suction cup for a minute, but didn't trust it would stay and quick removed it. I am sure my bike tops around 160-165. A friends r6 hits his limiter before I do. His bike has some mods and +2 on the gearing, my gearing is -1+2. I'm going to have to open this motor up before I choose to sell it. I want to see what's been done to the top half. Its faster then the black 98 but not by much. The original owner was a mechanic at Am General and works on prototype vehicles. As far as I know he did put a new clutch in it, cans, air filter, jetted it and some tweaks.
Last edited by lukenukem47; 04-27-2011 at 07:42 AM.
04-27-2011, 07:58 AM
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The two 98's I have are organ donor's for my 02 that I'm building. I have 4 motors to choose from and I was going to just take one of the two running motors. I have no clue what is in this engine. I got je hc short block I'am going to put together with a top half of one this winter.
04-27-2011, 10:27 AM
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Sorry to burst your bubble but with that gearing the most you are going to see is between 147-150. There is no why around that unless your engine can turn more than 10300 RPM.
04-27-2011, 10:40 AM
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Theoretical top speed on that gearing is 161 hitting the limiter... It will hit the limiter at that gearing even if bone stock, and you usually account the wheel slip at around 5% at that speed, and with the other factors, a good number is around 7% to knock off...
So it can reasonably hit 150 mph in the real world... If conditions are good... 139 at redline...
Anything more than that is just a pipedream... Makes no difference what's done to the engine...
So it can reasonably hit 150 mph in the real world... If conditions are good... 139 at redline...
Anything more than that is just a pipedream... Makes no difference what's done to the engine...
04-27-2011, 10:45 AM
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I'm taking you're word on it. I am not going to go thru the work proving it anytime soon. I moved the speed healer to the red bike. I plan on taking the gps out to make sure its correct. But no high speed runs.
04-27-2011, 10:46 AM
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Well the simple explanation is that in order to create traction the tire must create friction. The amount of traction (and therefore the amount of friction needed) is dependent on how you are riding, where you are riding, the conditions you are riding in.
Here is an example curve, from and excerpt of "The Racing and High-Performance Tire":
So in order to determine true top speed ( or speed in any gear or condition) you can use this formula :
Though the easy way is, if you are over 100mph, just use a 10% constant and you will be very close.
As an example, my bike is currently geared with 16\43 sprockets. If you just use the gearing and RPM limit the bike should be able to do 174 mph which the bike will not do. If you factor in a 10% slip error now the number say the bike will do 157mph which is what it really does (oh and the speedo is buried past 180mph at that point....)
Here is an example curve, from and excerpt of "The Racing and High-Performance Tire":
So in order to determine true top speed ( or speed in any gear or condition) you can use this formula :
Though the easy way is, if you are over 100mph, just use a 10% constant and you will be very close.
As an example, my bike is currently geared with 16\43 sprockets. If you just use the gearing and RPM limit the bike should be able to do 174 mph which the bike will not do. If you factor in a 10% slip error now the number say the bike will do 157mph which is what it really does (oh and the speedo is buried past 180mph at that point....
)
04-27-2011, 11:02 AM
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I have a new found understanding. Base on those facts it was impossible For my bike to be going that fast. Now I want to know is how fast was I going. I will get a mount for the gps and toy around with it.
04-27-2011, 04:38 PM
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