Dont race modded bikes! I repeat DONT RACE MODDED BIKES! (my dyno #: 483rwhp 588rwtq)
#82
TECH Fanatic
iTrader: (8)
Join Date: Jan 2003
Location: Maryland
Posts: 1,435
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by NOSjohn
Our bike goes 0 - 185mph in 7.83 seconds... ![Headbang](https://ls1tech.com/forums/images/smilies2/headbang.gif)
Some people are trying to explain coefficient of drag ( the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body)and you're going about it all wrong...at least that's what I'm getting from reading it.
The drag coefficient Cd is equal to the drag D divided by the quantity: density r times half the velocity V squared times the reference area A (wing area, frontal area, surface area).
Cd = D / (A * .5 * r * V^2)
A car has WAY more frontal area than a bike. It takes more HP for a car to maintain 60 mph versus a bike due to the car weighing more, having more frontal area.
A prime example is airplanes, it takes a larger plane MORE power to maintain
cruise velocity vs. a smaller plane. Anyone remember the test piloting Chuck Yeager has done? They weren't in a 747...they were small, slippery Cd (coefficient of drag) styled airplanes.
A bike has a great Cd, I can remember riding home from the track and it would start to rain. I would tuck down and not even get wet - believe it!
...great conversation/topic so far!
![Headbang](https://ls1tech.com/forums/images/smilies2/headbang.gif)
Some people are trying to explain coefficient of drag ( the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body)and you're going about it all wrong...at least that's what I'm getting from reading it.
The drag coefficient Cd is equal to the drag D divided by the quantity: density r times half the velocity V squared times the reference area A (wing area, frontal area, surface area).
Cd = D / (A * .5 * r * V^2)
A car has WAY more frontal area than a bike. It takes more HP for a car to maintain 60 mph versus a bike due to the car weighing more, having more frontal area.
A prime example is airplanes, it takes a larger plane MORE power to maintain
cruise velocity vs. a smaller plane. Anyone remember the test piloting Chuck Yeager has done? They weren't in a 747...they were small, slippery Cd (coefficient of drag) styled airplanes.
A bike has a great Cd, I can remember riding home from the track and it would start to rain. I would tuck down and not even get wet - believe it!
![Mr. Cool](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cool.gif)
Sorry to say bud but you are flat out wrong.
A corvette Cd is .32
A Hayabusa Cd is .561
Now yes the frontal area is much less on a bike than a car but that is not the only factors.
Here is an article from a motorcycle magazine comparing motorcycle Cd and their results.
http://myweb.cableone.net/toddshelton/aero.html
This is where most people go wrong, they relate drag to coefficient of drag. The Cd is a constant used to figure out drag which is a factor of Cd and of frontal area.
Drag is proportional to the square of speed, and to the size of the frontal area. The constant of proportionality is called the drag coefficient, or Cd, and is primarily the function of shape (NOT SIZE). It indicates which shape is superior, but does not define the total aerodynamic drag by itself. The product of the drag coefficient and the frontal area,
A, gives the drag.
The shape of a motorcycle is where it gets killed not the frontal area like people think. The tire out there spinning on distrubs the air tremendously. The elbows and person riding disturbe badly. The forks on the bike kill the Cd.
This is a Very common misconception but the reality is a bike is more like a brick going through the air.
A Land Rover Discovery has a Cd of .55 which is still BETTER than a Hayabusa which is the most aerodynamic production bike produced.
#84
Launching!
Join Date: Nov 2001
Location: Ft. Worth, TX
Posts: 225
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 93LS1RX7
Sorry to say bud but you are flat out wrong.
A
Now yes the frontal area is much less on a bike than a car but that is not the only factors.
This is where most people go wrong, they relate drag to coefficient of drag. The Cd is a constant used to figure out drag which is a factor of Cd and of frontal area.
The shape of a motorcycle is where it gets killed not the frontal area like people think. The tire out there spinning on distrubs the air tremendously. The elbows and person riding disturbe badly. The forks on the bike kill the Cd.
This is a Very common misconception but the reality is a bike is more like a brick going through the air.
A
Now yes the frontal area is much less on a bike than a car but that is not the only factors.
This is where most people go wrong, they relate drag to coefficient of drag. The Cd is a constant used to figure out drag which is a factor of Cd and of frontal area.
The shape of a motorcycle is where it gets killed not the frontal area like people think. The tire out there spinning on distrubs the air tremendously. The elbows and person riding disturbe badly. The forks on the bike kill the Cd.
This is a Very common misconception but the reality is a bike is more like a brick going through the air.
#85
TECH Senior Member
iTrader: (2)
Join Date: Sep 2003
Location: Houston
Posts: 10,591
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
yep, i was about to comment on that, but i am still not sure about the drag coefficients and how it all works out....
i will learn a lot more of this soon in more physics through my degree to becoming a Mech Engineer
i will learn a lot more of this soon in more physics through my degree to becoming a Mech Engineer
#87
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
oh yeah ... especially the webpage that says a 600 bike needs a 600RWHP car to hang in there with it... HAHAH big time.. he ran an 11.9@118 and says he needs a 600 RWHP to keep up with him..
#88
Launching!
Join Date: Nov 2001
Location: Ft. Worth, TX
Posts: 225
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by BigBronco
yep, i was about to comment on that, but i am still not sure about the drag coefficients and how it all works out....
i will learn a lot more of this soon in more physics through my degree to becoming a Mech Engineer
i will learn a lot more of this soon in more physics through my degree to becoming a Mech Engineer
#89
7 Second Club
iTrader: (7)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 2002Z06yellow
oh yeah ... especially the webpage that says a 600 bike needs a 600RWHP car to hang in there with it... HAHAH big time.. he ran an 11.9@118 and says he needs a 600 RWHP to keep up with him..
#90
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
550 RWHP trap 130 miles with low to mid 10 sec ETs what are you on about? a 600cc bike will get owned from a roll by Z06... and i do understand how a car and a bike accelerate belive me.. owned both..
#91
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Again, most of you need to remove your heads from you know what.
Flat out, race someone. Not all bikes are the same, and because one ran shitty, doesn't mean it will do it again with a different rider.
Every bike is different, every car is different. One bike on a certain night may run like crap, but a week later with nothing much done can run totally different. Riders make twice as much a difference when it comes to skill level than it does on a car. Trust me on this, experience first hand has taught this to me.
Bikes at 130mph usually, hit a brick wall....what is it? Yea CD. Whoever posted the CD of bikes, I give kudo's to. Too many people are misconceived on what it takes bikes to run. I've run a few single turbo Supra's here in Austin (almost the Big Single Supra Capital) and right around 125-140 is where they begin to pull good.
Bring my any Z06, Any LS1 for that matter here in Austin...and win or lose, we'll post the vids. I'll be the guinnea pig biker. I want to prove a few people's theories wrong...that's all they are. Theories.
How about it? Anyone in Austin care to take on a bike that runs 10.90/130?
Flat out, race someone. Not all bikes are the same, and because one ran shitty, doesn't mean it will do it again with a different rider.
Every bike is different, every car is different. One bike on a certain night may run like crap, but a week later with nothing much done can run totally different. Riders make twice as much a difference when it comes to skill level than it does on a car. Trust me on this, experience first hand has taught this to me.
Bikes at 130mph usually, hit a brick wall....what is it? Yea CD. Whoever posted the CD of bikes, I give kudo's to. Too many people are misconceived on what it takes bikes to run. I've run a few single turbo Supra's here in Austin (almost the Big Single Supra Capital) and right around 125-140 is where they begin to pull good.
Bring my any Z06, Any LS1 for that matter here in Austin...and win or lose, we'll post the vids. I'll be the guinnea pig biker. I want to prove a few people's theories wrong...that's all they are. Theories.
How about it? Anyone in Austin care to take on a bike that runs 10.90/130?
#92
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 93LS1RX7
Sorry to say bud but you are flat out wrong.
A corvette Cd is .32
A Hayabusa Cd is .561
Now yes the frontal area is much less on a bike than a car but that is not the only factors.
Here is an article from a motorcycle magazine comparing motorcycle Cd and their results.
http://myweb.cableone.net/toddshelton/aero.html
This is where most people go wrong, they relate drag to coefficient of drag. The Cd is a constant used to figure out drag which is a factor of Cd and of frontal area...
A corvette Cd is .32
A Hayabusa Cd is .561
Now yes the frontal area is much less on a bike than a car but that is not the only factors.
Here is an article from a motorcycle magazine comparing motorcycle Cd and their results.
http://myweb.cableone.net/toddshelton/aero.html
This is where most people go wrong, they relate drag to coefficient of drag. The Cd is a constant used to figure out drag which is a factor of Cd and of frontal area...
Hey BUD, did you use to cheat on your Math tests too? Did you even read how they got that number? Let me help:
*Frontal area on the Hayabusa and ZX-12R was measured using Photoshop
images with the pixels set to a scaled size, then counted. The Hayabusa
proves to have a smaller frontal area, but the Cd also shows it has the
superior aeridynamic shape.*
That's real mathmatical ! I would venture to say... it's not very accurate. Of course a 'vette has a low Cd, it was designed (practically) in a wind tunnel. I previously stated F-bod type cars too but I guess you forgot to look on the internet for their Cd?
![Rolleyes](https://ls1tech.com/forums/images/smilies/LS1Tech/rolleyes.gif)
Wait...let me look something up on the internet...here we go:
http://www.motorcycle.com/mo/mcyam/1996_ace.html
...and I quote," Yamaha claims the fairing fitted to the Ace is the slipperiest ever worn by any of their street bikes, with a drag coefficient of only 0.29..."
WOW! that's 3 hundredths less than a Corvette!
![Hail](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_hail.gif)
It goes on to state it does very little for improved top speed. As stated before, a motorcycle with a size of "x" needs a certain amount of power "y", very similar to a car of size "x" needing to make power "y" to sustain speed.
Now we're comparing apples to oranges and I hope we dont discuss which is more round. I hate it when I'm "flat out" wrong.
![Rolleyes](https://ls1tech.com/forums/images/smilies/LS1Tech/rolleyes.gif)
#93
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 929
Again, most of you need to remove your heads from you know what.
Flat out, race someone. Not all bikes are the same, and because one ran shitty, doesn't mean it will do it again with a different rider.
Every bike is different, every car is different. One bike on a certain night may run like crap, but a week later with nothing much done can run totally different. Riders make twice as much a difference when it comes to skill level than it does on a car. Trust me on this, experience first hand has taught this to me.
Bikes at 130mph usually, hit a brick wall....what is it? Yea CD. Whoever posted the CD of bikes, I give kudo's to. Too many people are misconceived on what it takes bikes to run. I've run a few single turbo Supra's here in Austin (almost the Big Single Supra Capital) and right around 125-140 is where they begin to pull good.
Bring my any Z06, Any LS1 for that matter here in Austin...and win or lose, we'll post the vids. I'll be the guinnea pig biker. I want to prove a few people's theories wrong...that's all they are. Theories.
How about it? Anyone in Austin care to take on a bike that runs 10.90/130?
Flat out, race someone. Not all bikes are the same, and because one ran shitty, doesn't mean it will do it again with a different rider.
Every bike is different, every car is different. One bike on a certain night may run like crap, but a week later with nothing much done can run totally different. Riders make twice as much a difference when it comes to skill level than it does on a car. Trust me on this, experience first hand has taught this to me.
Bikes at 130mph usually, hit a brick wall....what is it? Yea CD. Whoever posted the CD of bikes, I give kudo's to. Too many people are misconceived on what it takes bikes to run. I've run a few single turbo Supra's here in Austin (almost the Big Single Supra Capital) and right around 125-140 is where they begin to pull good.
Bring my any Z06, Any LS1 for that matter here in Austin...and win or lose, we'll post the vids. I'll be the guinnea pig biker. I want to prove a few people's theories wrong...that's all they are. Theories.
How about it? Anyone in Austin care to take on a bike that runs 10.90/130?
is ur bike stock? let me konw a day before you come so that my frined can fill his bottle!
#94
TECH Fanatic
Thread Starter
Join Date: Jul 2002
Location: San Antonio Texas
Posts: 1,206
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 2002Z06yellow
okay 929... you show some spirit that i respect... we should get this over with .. do you think you can drive ur bike down to san antonio? if so me and my roommate will race you .. i have a stock Z06 12.9@114 and i will race you from a 60mph punch up to 170 mph and we will get that on tape.. and then you race my roomate with a cam nitrous trans am 480 from a 60 mph punch to 170 mph .. we will post the results either way.. we need to get this discussion over with...
is ur bike stock? let me konw a day before you come so that my frined can fill his bottle!
is ur bike stock? let me konw a day before you come so that my frined can fill his bottle!
![Winky](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_wink.gif)
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
I will also be a true sport. I will meet up at san antonio (cant make it to austin at all) and will get my dyno sheet with me. I dont know about racing to 170mph but I will do it anyway. If I lose and its on tape so be it. The performance will speak for itself and if im not faster then who cares. Keep in mind i will NOT be able to spray in 5th gear (dont want my engine to blow). But if my rpms start climbing in 5th I may spray just a "little" bit. I do not mind having a camera person with me in the car taping me as I hit the button and disarm the nitrous in fifth to prove it.
I make 379.94rwhp without spray - BARELY 380rwhp with a mild cam and bolt ons. I make 482.51rwhp on spray (true 100 shot).
I will give all the details on everything and promise to be a true sport even if I lose. Let me know if you think its fair or not.
Let me know if you can make it to san antonio and we'll plan this out.
Please do not take this in a wrong way. I am not trying to bash your bike. Its an awesome bike and it would be BAD *** if I can beat it WITH nitrous (again I wont spray in 5th).
#95
TECH Fanatic
iTrader: (8)
Join Date: Jan 2003
Location: Maryland
Posts: 1,435
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by NOSjohn
Hey BUD, did you use to cheat on your Math tests too? Did you even read how they got that number? Let me help:
*Frontal area on the Hayabusa and ZX-12R was measured using Photoshop
images with the pixels set to a scaled size, then counted. The Hayabusa
proves to have a smaller frontal area, but the Cd also shows it has the
superior aeridynamic shape.*
That's real mathmatical ! I would venture to say... it's not very accurate. Of course a 'vette has a low Cd, it was designed (practically) in a wind tunnel. I previously stated F-bod type cars too but I guess you forgot to look on the internet for their Cd?
Wait...let me look something up on the internet...here we go:
http://www.motorcycle.com/mo/mcyam/1996_ace.html
...and I quote," Yamaha claims the fairing fitted to the Ace is the slipperiest ever worn by any of their street bikes, with a drag coefficient of only 0.29..."
WOW! that's 3 hundredths less than a Corvette!![Hail](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_hail.gif)
It goes on to state it does very little for improved top speed. As stated before, a motorcycle with a size of "x" needs a certain amount of power "y", very similar to a car of size "x" needing to make power "y" to sustain speed.
Now we're comparing apples to oranges and I hope we dont discuss which is more round. I hate it when I'm "flat out" wrong.![Rolleyes](https://ls1tech.com/forums/images/smilies/LS1Tech/rolleyes.gif)
*Frontal area on the Hayabusa and ZX-12R was measured using Photoshop
images with the pixels set to a scaled size, then counted. The Hayabusa
proves to have a smaller frontal area, but the Cd also shows it has the
superior aeridynamic shape.*
That's real mathmatical ! I would venture to say... it's not very accurate. Of course a 'vette has a low Cd, it was designed (practically) in a wind tunnel. I previously stated F-bod type cars too but I guess you forgot to look on the internet for their Cd?
![Rolleyes](https://ls1tech.com/forums/images/smilies/LS1Tech/rolleyes.gif)
Wait...let me look something up on the internet...here we go:
http://www.motorcycle.com/mo/mcyam/1996_ace.html
...and I quote," Yamaha claims the fairing fitted to the Ace is the slipperiest ever worn by any of their street bikes, with a drag coefficient of only 0.29..."
WOW! that's 3 hundredths less than a Corvette!
![Hail](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_hail.gif)
It goes on to state it does very little for improved top speed. As stated before, a motorcycle with a size of "x" needs a certain amount of power "y", very similar to a car of size "x" needing to make power "y" to sustain speed.
Now we're comparing apples to oranges and I hope we dont discuss which is more round. I hate it when I'm "flat out" wrong.
![Rolleyes](https://ls1tech.com/forums/images/smilies/LS1Tech/rolleyes.gif)
I did search the internet for some of the information because unfortunately I dont have access to a wind tunnel to do real world testing so I need to rely on someone else to do that for me but I sure as hell can extrapolate the data I need from the hard facts they give which is much more accurate than I dont get wet in the rain because the bike has a good Cd (Which is completely incorrect to). Other than research scientists everyone merely extrapolates information from previous information. No need to redo someones work.
Here is a tidbit for you FRONTAL AREA HAS NOTHING TO DO WITH THE COEFFIECENT OF DRAG!!!!!!!!! So the photoshop thing is irrelevant, but it is the most accurate way to measure the frontal area of the object. Again showing your lack of understanding.
The coeffiecent of drag is not something you can figure out with a formula. It is a constant value that you can only discover through scientific testing. Using the formula for drag I will explain why a bike HATES high speeds and where the Cd effects it so greatly.
Now that we have discussed Cd and drag here is the one that will really fry your noodle.
Using the formula for drag we can see some interesting things. Lets compare a corvette to a Hayabusa at 75 mph and at 150 mph.
D = Cd * A * .5 * r * V^2
D= Drag (not including FORM drag for now at least)
Cd= Coefficient of Drag
A=frontal area
r= Air density (1.2 kg/m^3 constant)
V= velocity
Example 1:
A corvette traveling at 75mph (33.582 meters/second) with a frontal area of 2.048 m^2. The drag on this car is:
D=.32 * 2.048 * .5 * 1.2 * 33.582^2
D=443.45
Example 2:
A motorcycle traveling at 75mph (33.582 meters/second) with a frontal area of .313 m^2. The drag on this motorcycle is:
D=.516 * .313 * .5 * 1.2 * 33.582^2
D=118.82
Example 3:
A corvette traveling at 150mph (67.056 meters/second) with a frontal area of 2.048 m^2. The drag on this car is:
D=.32 * 2.048 * .5 * 1.2 * 67.056^2
D=1768.09
Example 4:
A motorcycle traveling at 150mph (67.056 meters/second) with a frontal area of .313 m^2. The drag on this motorcycle is:
D=.516 * .313 * .5 * 1.2 * 67.056^2
D=435.73
As you can see the drag(without form drag) on the corvette is ALWAYS higher than the drag(without form drag) on the motorcycle. Now you are thinking this guy just proved himself wrong. But you are wrong there. The rub is when you bring form drag into the equation which relates to the Cd. The reason why a motorcycle loses to a car when speeds get high is .................turbulence.
At low speeds turbulence doesnt matter a whole lot cause the air is able to flow fluidly wherever it wants now at high speeds turbulence becomes a major concern particularly for a motorcycle. A motorcycle doesn't share the shape of your car: a motorcycle and rider have a very irregular shape and generate turbulence (and therefore additilonal drag) by design! The windshield, front fairing, gas tank, and tail sections of the motorcycle (and virtually every part of the rider) all have aerodynamically abrupt shapes -- these shapes do not taper together like an aeroplane wing. Areas of low pressure behind the abrupt shapes of the motorcycle cause the airflow to collapse into the space, creating vortices and increasing the form drag.
Form drag is the aerodynamic resistance to the motion of the motorcycle through the air. As air flows around the bike, local velocities and pressures change as a function of the motorcycle's shape. The change in flow is apparent from the size and type of wake left by the object. The flow change and wake produce forces that can be summed to determine the total force opposing the motion (this is why drag slows you down!) (TOTAL DRAG INCLUDING FORM DRAG, I told you it was coming.) This source of drag depends on the shape of the motorcycle and is the most-commonly engineered parameter in the drag equation. Form drag is why riders will crouch behind the windshield of the motorcycle while traveling at high speeds.
Form drag is much less significant on a car because everything is smoothly tucked away, relative to a motorcycle. The flow is much less turbulant than a motorcycle.
THUS THE MOTORCYCLE LOSES THE HIGH SPEED BATTLE.
Maybe this can become a sticky so no one ever has to type all that again.
![Chug! Chug! Chug!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_chug.gif)
#96
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
It looks like you're arguing with yourself now...haha. You can talk about Cd, force of drag, drag queen...whatever you want. My point was this:
As stated before, a motorcycle with a size of "x" needs a certain amount of power "y", very similar to a car of size "x" needing to make power "y" to sustain speed.
ANY vehicle will lose acceleration ability at high speed, that is a law of nature. That's all, end of discussion.
As stated before, a motorcycle with a size of "x" needs a certain amount of power "y", very similar to a car of size "x" needing to make power "y" to sustain speed.
ANY vehicle will lose acceleration ability at high speed, that is a law of nature. That's all, end of discussion.
![The Patriot !!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_patriot.gif)
#97
TECH Fanatic
iTrader: (8)
Join Date: Jan 2003
Location: Maryland
Posts: 1,435
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by NOSjohn
A bike has a great Cd, I can remember riding home from the track and it would start to rain. I would tuck down and not even get wet - believe it!
...great conversation/topic so far!
![Mr. Cool](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cool.gif)
![Owned](https://ls1tech.com/forums/images/smilies2/owned.gif)
No **** as speed increases power to increase the speed increases more that wasnt the discussion. But you are still wrong in saying it a motorcycle and car are similar at high speeds. Turbulence comes into the picture on a bike in a big way.
I am not argueing with myself I am just trying to inform people of the facts instead of the
![Bulls#!t](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bs.gif)
![Grin](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_grin.gif)
Now thats all end of discussion
Class dismissed Biatch
![Devil](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_devil.gif)
![Winky](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_wink.gif)