S2000 rolling-start acceleration numbers?
03-07-2008, 02:03 PM
#51
if WOT is what youre interested in, search dyno plots and they will give you the answer, it just takes a bit of work to get it into a usable form. if WOT isnt what youre after, youll have a hard time finding info unless you make it yourself.
from a dyno plot, here are the steps to get your information:
take the torque from the plot at intervals (ie start at idle and find it every +250rpm) and assume power is roughly constant from that interval to the next.
for the gear(s) of interest, take the gear ratio
multiply by the diff ratio
i've heard we also have an extra gearing multiplier, not just diff*gear, so search this multiplier and multiply diff*gear*multiplier if it indeed exists.
diff*gear*multiplier = gearing
TQ*gearing = true TQ at the wheels.
find the tire OD.
TQ*gearing / OD = Force to the ground
mass of the car, 2850lbm or so
F = m*a
(you will have to either convert between lbm and lbf [mass vs weight] using slugs or just dodge the issue by converting everything to metric to make F=ma work out)
alternatively, you can take accelerometer data and skip to this point. the issue seems to be, nobody seems to have accelerometer data that is time dependent, and you'd want tens of data points or so from both cars to really compare them. but we do have hundreds and hundreds of dyno plots, so you may have better luck doing the work to get here.
now integrate the accelerations you calculated by making a spreadsheet in excel. to do this, you type in your accel at (maybe 0.5 second) intervals, and multiply acceleration * time to get velocity increase over the interval. sum these values and you have your velocity at any time in any gear.
incorporate shifting if you want to make it really accurate/useful, and add time with no acceleration to simulate shift time. later, you can add drag, which usually becomes rather significant at about 100mph.
from a dyno plot, here are the steps to get your information:
take the torque from the plot at intervals (ie start at idle and find it every +250rpm) and assume power is roughly constant from that interval to the next.
for the gear(s) of interest, take the gear ratio
multiply by the diff ratio
i've heard we also have an extra gearing multiplier, not just diff*gear, so search this multiplier and multiply diff*gear*multiplier if it indeed exists.
diff*gear*multiplier = gearing
TQ*gearing = true TQ at the wheels.
find the tire OD.
TQ*gearing / OD = Force to the ground
mass of the car, 2850lbm or so
F = m*a
(you will have to either convert between lbm and lbf [mass vs weight] using slugs or just dodge the issue by converting everything to metric to make F=ma work out)
alternatively, you can take accelerometer data and skip to this point. the issue seems to be, nobody seems to have accelerometer data that is time dependent, and you'd want tens of data points or so from both cars to really compare them. but we do have hundreds and hundreds of dyno plots, so you may have better luck doing the work to get here.
now integrate the accelerations you calculated by making a spreadsheet in excel. to do this, you type in your accel at (maybe 0.5 second) intervals, and multiply acceleration * time to get velocity increase over the interval. sum these values and you have your velocity at any time in any gear.
incorporate shifting if you want to make it really accurate/useful, and add time with no acceleration to simulate shift time. later, you can add drag, which usually becomes rather significant at about 100mph.
03-07-2008, 03:40 PM
#52
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Originally Posted by ace123,Mar 7 2008, 03:03 PM
TQ*gearing / OD = Force to the ground
Remember, you only have to use the radius of the tire. Insightful post though. 
03-07-2008, 09:06 PM
#54
Originally Posted by Spectre48,Mar 7 2008, 06:40 PM
Force = TQ*gearing / (OD/2) Remember, you only have to use the radius of the tire. Insightful post though.
Remember, you only have to use the radius of the tire. Insightful post though. 
03-08-2008, 10:46 AM
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Originally Posted by DavidM,Mar 6 2008, 02:30 PM
BULLSHIT. You need to learn how to read. ... I'm sure you are not really foolish enough to think that you can go WOT to redline in first without breaking the law
Not sure why you trying to derail my question, but keep in mind I don't live in the same country as you, and not every country has the same laws as yours. Also as I stated before, I don't really care what is legal or not, just what the acceleration numbers for the F20c S2000 are when rolled off the line with minimal revs.
Is it possible to focus at the question at hand instead of what I do in my spare time, how I drive my car, whether it's broken, or whethe it's legal or not?
maybe you should restate the original question
Here you go, taken from my very 1st post. Let me know if it's confusing and I'll do my best to make it clearer:
"Would someone happen to have the acceleration numbers for a (stock) S2000 where a hard launch is not involved? ie. where the car was eased off the line, cluth fully engaged, and then thottle to the floor from something like 5kph? I would love to see the numbers in 10kph increments ..."
Rest of the details of what I'm after are in the very 1st post.
No the mx5 is never faster and yes it is an NC... We are not even at any point
Thanks for that. Good info.
With out any fancy clutch work the MX5 Does have a bit more power around idle 2k ect. so crank to crank a 2-3 mph run the mx5 will leap infront quickly only to fall back.
How far does the MX5 jump ahead? And at what speeds/revs do you start reeling at in?
Not sure why you trying to derail my question, but keep in mind I don't live in the same country as you, and not every country has the same laws as yours. Also as I stated before, I don't really care what is legal or not, just what the acceleration numbers for the F20c S2000 are when rolled off the line with minimal revs.
Is it possible to focus at the question at hand instead of what I do in my spare time, how I drive my car, whether it's broken, or whethe it's legal or not?
maybe you should restate the original question
Here you go, taken from my very 1st post. Let me know if it's confusing and I'll do my best to make it clearer:
"Would someone happen to have the acceleration numbers for a (stock) S2000 where a hard launch is not involved? ie. where the car was eased off the line, cluth fully engaged, and then thottle to the floor from something like 5kph? I would love to see the numbers in 10kph increments ..."
Rest of the details of what I'm after are in the very 1st post.
No the mx5 is never faster and yes it is an NC... We are not even at any point
Thanks for that. Good info.
With out any fancy clutch work the MX5 Does have a bit more power around idle 2k ect. so crank to crank a 2-3 mph run the mx5 will leap infront quickly only to fall back.
How far does the MX5 jump ahead? And at what speeds/revs do you start reeling at in?
03-08-2008, 11:26 AM
#56
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Originally Posted by ace123,Mar 7 2008, 03:03 PM
if WOT is what youre interested in, search dyno plots and they will give you the answer, it just takes a bit of work to get it into a usable form. if WOT isnt what youre after, youll have a hard time finding info unless you make it yourself.
from a dyno plot, here are the steps to get your information:
take the torque from the plot at intervals (ie start at idle and find it every +250rpm) and assume power is roughly constant from that interval to the next.
for the gear(s) of interest, take the gear ratio
multiply by the diff ratio
i've heard we also have an extra gearing multiplier, not just diff*gear, so search this multiplier and multiply diff*gear*multiplier if it indeed exists.
diff*gear*multiplier = gearing
TQ*gearing = true TQ at the wheels.
find the tire OD.
TQ*gearing / OD = Force to the ground
mass of the car, 2850lbm or so
F = m*a
(you will have to either convert between lbm and lbf [mass vs weight] using slugs or just dodge the issue by converting everything to metric to make F=ma work out)
alternatively, you can take accelerometer data and skip to this point. the issue seems to be, nobody seems to have accelerometer data that is time dependent, and you'd want tens of data points or so from both cars to really compare them. but we do have hundreds and hundreds of dyno plots, so you may have better luck doing the work to get here.
now integrate the accelerations you calculated by making a spreadsheet in excel. to do this, you type in your accel at (maybe 0.5 second) intervals, and multiply acceleration * time to get velocity increase over the interval. sum these values and you have your velocity at any time in any gear.
incorporate shifting if you want to make it really accurate/useful, and add time with no acceleration to simulate shift time. later, you can add drag, which usually becomes rather significant at about 100mph.
from a dyno plot, here are the steps to get your information:
take the torque from the plot at intervals (ie start at idle and find it every +250rpm) and assume power is roughly constant from that interval to the next.
for the gear(s) of interest, take the gear ratio
multiply by the diff ratio
i've heard we also have an extra gearing multiplier, not just diff*gear, so search this multiplier and multiply diff*gear*multiplier if it indeed exists.
diff*gear*multiplier = gearing
TQ*gearing = true TQ at the wheels.
find the tire OD.
TQ*gearing / OD = Force to the ground
mass of the car, 2850lbm or so
F = m*a
(you will have to either convert between lbm and lbf [mass vs weight] using slugs or just dodge the issue by converting everything to metric to make F=ma work out)
alternatively, you can take accelerometer data and skip to this point. the issue seems to be, nobody seems to have accelerometer data that is time dependent, and you'd want tens of data points or so from both cars to really compare them. but we do have hundreds and hundreds of dyno plots, so you may have better luck doing the work to get here.
now integrate the accelerations you calculated by making a spreadsheet in excel. to do this, you type in your accel at (maybe 0.5 second) intervals, and multiply acceleration * time to get velocity increase over the interval. sum these values and you have your velocity at any time in any gear.
incorporate shifting if you want to make it really accurate/useful, and add time with no acceleration to simulate shift time. later, you can add drag, which usually becomes rather significant at about 100mph.
03-08-2008, 11:41 AM
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The problem is that for some reason DavidM doesn't trust dyno plots, and thinks accelerometers will give him "real" information instead of "theoritical." I've tried to explain that given good inputs, you get the same results, no matter how you do the actual performance measurement, but haven't had any luck.
As per DavidM's original request, does anyone have any accelerometer data from an S2000 and/or MX5?
As per DavidM's original request, does anyone have any accelerometer data from an S2000 and/or MX5?
03-08-2008, 04:34 PM
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Thanks guys all good info. Though, I was digging through my older mags and found the kind of numbers I'm looking for in Autorevue (ie. a German mag). They measured and published the acceleration times for the S2000 in all gears (from 40kph) as well as the 'hard launch' times. They did that in 1999 and also 2000 and clocked some pretty average numbers in one article, and really good numbers in the other. So here is what they clocked/listed for F20c S2000. Both the good and average times are listed here ie. 2000 in -7deg C vs 1999 in +7deg C:
In 2nd gear:
- 40 - 60kph (ie. 3,400 to 5,100rpm) = 1.7 / 2sec
- 60 - 80kph (ie. 5,100 to 6,800rpm) = 1.7 / 1.7sec
- 80 - 100kph (ie. 6,800 to 8,500rpm) = 1.8 / 1.9sec
In 3rd gear:
- 40 - 60kph (ie. 2,500 to 3,700rpm) = 2.2 / 2.5sec
- 60 - 80kph (ie. 3,700 to 5,000rpm) = 2.5 / 2.7sec
- 80 - 100kph (ie. 5,000 to 6,200rpm) = 2.6 / 2.7sec
-
In 2nd gear:
- 40 - 60kph (ie. 3,400 to 5,100rpm) = 1.7 / 2sec
- 60 - 80kph (ie. 5,100 to 6,800rpm) = 1.7 / 1.7sec
- 80 - 100kph (ie. 6,800 to 8,500rpm) = 1.8 / 1.9sec
In 3rd gear:
- 40 - 60kph (ie. 2,500 to 3,700rpm) = 2.2 / 2.5sec
- 60 - 80kph (ie. 3,700 to 5,000rpm) = 2.5 / 2.7sec
- 80 - 100kph (ie. 5,000 to 6,200rpm) = 2.6 / 2.7sec
-
03-08-2008, 05:58 PM
#59
Originally Posted by DavidM,Mar 8 2008, 07:34 PM
Interesting thing to note is that the acceleration rate (ie. time to cover each consecutive 20kph) is pretty consistent no matter what the revs (above ~2000rpm) ...
03-08-2008, 06:01 PM
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Given your interest in the time it takes to cover 20km in second gear, we can compare the S2000 (ap2) against the MX-5:
So the honda takes 2.6 seconds to cover 40-60 mph, so we convert this to km (64-96) divide 2.6/32, then multiply by 20 and get 1.6 seconds, with is pretty close to your time
For the 06 Mx-5 we'll have to use 30-50 since 2nd gear tops out at 52. The 30-50 time is: 2.9 same math and we get: (48-80km) 2.9/32 *20 = 1.8
Honda 1.6 seconds for 20km jump in 2nd gear
Mazda 1.8 seconds for 20km jump in 2nd gear
I got my numbers from road and track:
road and track
This showed times like 0-20 0-40 0-60 for the honda and 0-30 0-40 0-50 etc. And the article showed where the gears lined up. For both cars, we're near a shift boundry. The Ap2 has to go into third at 58 and the miata, 30-50 time has a shift right at 31mph from 1st to second. It's a problem for both cars so I'll assume it's fair.
For us americans it showed the honda covers a 20mph distance in 2nd in 2.6 where the mx-5 is at 2.9, and that's with the advantage to the mx-5 since the 20mph window it had to cover was 10mph lower than the honda.
So the honda takes 2.6 seconds to cover 40-60 mph, so we convert this to km (64-96) divide 2.6/32, then multiply by 20 and get 1.6 seconds, with is pretty close to your time
For the 06 Mx-5 we'll have to use 30-50 since 2nd gear tops out at 52. The 30-50 time is: 2.9 same math and we get: (48-80km) 2.9/32 *20 = 1.8
Honda 1.6 seconds for 20km jump in 2nd gear
Mazda 1.8 seconds for 20km jump in 2nd gear
I got my numbers from road and track:
road and track
This showed times like 0-20 0-40 0-60 for the honda and 0-30 0-40 0-50 etc. And the article showed where the gears lined up. For both cars, we're near a shift boundry. The Ap2 has to go into third at 58 and the miata, 30-50 time has a shift right at 31mph from 1st to second. It's a problem for both cars so I'll assume it's fair.
For us americans it showed the honda covers a 20mph distance in 2nd in 2.6 where the mx-5 is at 2.9, and that's with the advantage to the mx-5 since the 20mph window it had to cover was 10mph lower than the honda.