Honda S2000 Rigidity
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Originally Posted by SiDriver,Jun 30 2007, 08:47 PM
Also, are those Z4 numbers official or unconfirmed values from scouring over the web? I had driven the Z4 and it did not feel any stiffer. Both cars weigh similarly, yet the S2000 is endearingly tossable and feels much lighter on its feet. Turn in is very direct and the S2000 is a "point and shoot" go-kart machine. Is this a function of just a stiff chassis? Or a combination of that plus suspension tuning plus weight distribution plus low polar inertia?? Sorry, for the lack of understanding but just trying to get to the bottom of this rigidity issue.
I do have 90k miles on the car and those miles have been daily-driven hard on shitty and gouged up NY roads, so I guess it's possible that what Ive been feeling lately is the result of bushing and shock absorber wear. Will ask Billman when I see him in a couple of weeks.
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[QUOTE=jimbogxp,Jul 1 2007, 04:18 PM] The Honda S2000 is well above average torsional stiffness for convertibles, I can tell you that.
We had a GM chassis engineer at a Solstice meet last summer in Kansas City tell our group the torsional rigidity of the Solstice and Honda S2000 were similar and were in the mid 7000s of NM/degree.
He compared this to the current MX-5 in the low 6000s NM/degree.
My recollection is that the BMW Z4 is very rigid in the 9000s NM/degree.
But yes, all of these values pale compared to closed coupes. That is just the price you pay for being topless..
Whoever posted the S2000's torsional rigidity of 22,000 NM/degree is misinformed.
We had a GM chassis engineer at a Solstice meet last summer in Kansas City tell our group the torsional rigidity of the Solstice and Honda S2000 were similar and were in the mid 7000s of NM/degree.
He compared this to the current MX-5 in the low 6000s NM/degree.
My recollection is that the BMW Z4 is very rigid in the 9000s NM/degree.
But yes, all of these values pale compared to closed coupes. That is just the price you pay for being topless..
Whoever posted the S2000's torsional rigidity of 22,000 NM/degree is misinformed.
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Man, I've been looking for accurate numbers for torsion and bending for cars for so long and it is an exercise in futility. It is very frustrating that manufacturers refuse to publish them. I wish auto mags would make it a part of their test procedures. Send every car to a lab to measure torsional rigidity and bending.
You search hours on the web for this information, and a lot more disinformation comes up.
I am not confident about any of my numbers except the ones I was told by the GM chassis engineer at our meet in KC, which was very clear...
MX-5 is low 6000s NM/degree.
S2000 and Solstice are mid 7000s NM/degree and for all his vagueness, the S2000 may well be slightly stiffer than the Solstice, since he wouldn't give specific number for either car.
But since he is one of the engineers who designed and tweaked the Kappa platform for the Solstice, he does know the car's torsional stiffness as well as that of the MX-5 and S2000, so I feel comfortable citing him as a source.
His name is Steve Padilla.
Here is a little about him...
"A few words about me, and the development of the Solstice/SKY.
"My name is Steve Padilla, and I am the Ride, Handling and Steering Development Engineer for the Kappa platform. I have met some of you on the forum over the last couple of years, and lurk occasionally on the forum. I attended the first 1000 party, as well as participating at the press event in Oregon. I was also in England with the Solstices, and did tuning on the Kappa in Germany including the Nurburgring.
"I was assigned in November, 2002, to develop the vehicle dynamics of the Solstice, having come fresh off co-development of the Chevy SSR. As the platform structural design began, I worked with people from the advanced group to do predictive math modeling of the car.
"The limits of the niche and performance envelope of roadster competitors were defined by driving them and testing them. We had to pay attention to where the competition was, like the Miata, the Z3 and Z4, and the Honda S2000. The Toyota MR2 and the Porsche Boxter were also evaluated as part of understanding the market.
"Contrary to popular belief, we did not set out to conquer the Miata. From extensive research, it became obvious there was room in the roadster market for the right combination of style, cost, and performance within the niche. While the Miata is undoubtedly one of the most successful in this niche, there were people who made the choice not to buy a Miata for various reasons, be it cost, practicality, or even size.
"Once I was assigned and began to research the competition, I set out a personal goal that I kept to myself. I observed that some of the cars did certain aspects well, such as the Miata for ride, or the Honda S2000 for responsiveness, but also did not meet personal expectations, such as overall damping or roll stiffness on the Miata, or a minimum amount of ride comfort on the Honda S2000.
"Simply put, I decided to develop the car I would love to own personally, essentially trying to create the ride, steering, and handling that I want in my own personal car. This combination was not, and I believe is still currently not met by the other cars in this niche.
"So, I can say I personally achieved this goal, and luckily, it happens to match the same vision that the program management team had for these performance aspects of the Solstice, (including Bob Lutz).
"I do not currently own a Kappa platform product, but I know I certainly will in the near future.
"However, this assignment was not about what I wanted to do. Accepting the job of tuning the Solstice meant ensuring the ride, handling, steering, and related areas of braking were developed to deliver the promise of the styling of the car. In other words - the performance had to match the look of the car. So, not only did I have to match my own personal expectations, I had to satisfy requirements as determined by the Chief Engineer, the Vehicle Line Executive, my Vehicle Performance Manager, and many other evaluators.
"On behalf of my other engineering team members, from the people who worked with me on tires, braking and chassis controls, suspension and steering, to the electrical and structural people and those people who work on all the different systems of this car, I want to thank all of you for your enthusiasm for this car. Working on this platform required sacrifice and lots of elbow grease, and cohesive teamwork, and it is satisfying and also humbling to see people that support the product and are so passionate about it.
"Fortunately, I got permission from our internal communications people to post the questions and answers that I addressed at the Kansas City Meet on July 14 through July 16. It was a pleasure to meet and speak to so many of you owners, and I hope to see you all again at future events."
You search hours on the web for this information, and a lot more disinformation comes up.
I am not confident about any of my numbers except the ones I was told by the GM chassis engineer at our meet in KC, which was very clear...
MX-5 is low 6000s NM/degree.
S2000 and Solstice are mid 7000s NM/degree and for all his vagueness, the S2000 may well be slightly stiffer than the Solstice, since he wouldn't give specific number for either car.
But since he is one of the engineers who designed and tweaked the Kappa platform for the Solstice, he does know the car's torsional stiffness as well as that of the MX-5 and S2000, so I feel comfortable citing him as a source.
His name is Steve Padilla.
Here is a little about him...
"A few words about me, and the development of the Solstice/SKY.
"My name is Steve Padilla, and I am the Ride, Handling and Steering Development Engineer for the Kappa platform. I have met some of you on the forum over the last couple of years, and lurk occasionally on the forum. I attended the first 1000 party, as well as participating at the press event in Oregon. I was also in England with the Solstices, and did tuning on the Kappa in Germany including the Nurburgring.
"I was assigned in November, 2002, to develop the vehicle dynamics of the Solstice, having come fresh off co-development of the Chevy SSR. As the platform structural design began, I worked with people from the advanced group to do predictive math modeling of the car.
"The limits of the niche and performance envelope of roadster competitors were defined by driving them and testing them. We had to pay attention to where the competition was, like the Miata, the Z3 and Z4, and the Honda S2000. The Toyota MR2 and the Porsche Boxter were also evaluated as part of understanding the market.
"Contrary to popular belief, we did not set out to conquer the Miata. From extensive research, it became obvious there was room in the roadster market for the right combination of style, cost, and performance within the niche. While the Miata is undoubtedly one of the most successful in this niche, there were people who made the choice not to buy a Miata for various reasons, be it cost, practicality, or even size.
"Once I was assigned and began to research the competition, I set out a personal goal that I kept to myself. I observed that some of the cars did certain aspects well, such as the Miata for ride, or the Honda S2000 for responsiveness, but also did not meet personal expectations, such as overall damping or roll stiffness on the Miata, or a minimum amount of ride comfort on the Honda S2000.
"Simply put, I decided to develop the car I would love to own personally, essentially trying to create the ride, steering, and handling that I want in my own personal car. This combination was not, and I believe is still currently not met by the other cars in this niche.
"So, I can say I personally achieved this goal, and luckily, it happens to match the same vision that the program management team had for these performance aspects of the Solstice, (including Bob Lutz).
"I do not currently own a Kappa platform product, but I know I certainly will in the near future.
"However, this assignment was not about what I wanted to do. Accepting the job of tuning the Solstice meant ensuring the ride, handling, steering, and related areas of braking were developed to deliver the promise of the styling of the car. In other words - the performance had to match the look of the car. So, not only did I have to match my own personal expectations, I had to satisfy requirements as determined by the Chief Engineer, the Vehicle Line Executive, my Vehicle Performance Manager, and many other evaluators.
"On behalf of my other engineering team members, from the people who worked with me on tires, braking and chassis controls, suspension and steering, to the electrical and structural people and those people who work on all the different systems of this car, I want to thank all of you for your enthusiasm for this car. Working on this platform required sacrifice and lots of elbow grease, and cohesive teamwork, and it is satisfying and also humbling to see people that support the product and are so passionate about it.
"Fortunately, I got permission from our internal communications people to post the questions and answers that I addressed at the Kansas City Meet on July 14 through July 16. It was a pleasure to meet and speak to so many of you owners, and I hope to see you all again at future events."
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From: Durango, Colorado
I am afraid that there is no way to collect 100% guaranteed accurate objective rigidity figures for our cars, or any others. All I have to go by is subjective feel, according to which my daughter's Z3 feels like driving a rubber band, and my neighbor's vette feels like driving a piece of balsa wood compared with my S 2000.
To the OP, I must say that I am not experiencing any of those complaints. If the dash and cowell are not actually shaking, and no body pannels can be observed as moving, I would suggest a couple of other things. What, and how, are your tires? Tire make and model can make a bog difference on this car, and when the tires are close to worn out, strange things happen. Mine rode and handled like a farm tractor until I got new tires. And how are your shocks? Worn out shocks can cause shuddering that you won't have with good shocks.
Just some ideas, because every S 2000 owner I know thinks his/her car is as stiff as a brick.
To the OP, I must say that I am not experiencing any of those complaints. If the dash and cowell are not actually shaking, and no body pannels can be observed as moving, I would suggest a couple of other things. What, and how, are your tires? Tire make and model can make a bog difference on this car, and when the tires are close to worn out, strange things happen. Mine rode and handled like a farm tractor until I got new tires. And how are your shocks? Worn out shocks can cause shuddering that you won't have with good shocks.
Just some ideas, because every S 2000 owner I know thinks his/her car is as stiff as a brick.
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Originally Posted by jimbogxp,Jul 1 2007, 01:18 PM
Heck, the Z4M Coupe is around 22,000 NM/degree, which is WAY up there as most cars go. (I'm thinking 25-26,000 NM/degree for the Z4M Coupe)
So how could the S2000 be low 20,000s NM/degree? Doesn't pass any sort of reality check.
Nobody on this site will believe it, I am sure, but the Saab 9-3 convertible is actually one of the more rigid common verts out their and it is mid 12,000s NM/degree. 22000 Nm/degree for the S2000 is not accurate in the least. Nice dream, though...
I already posted that the Z4 M coupe has 32,000 Newton-meters per degree of torsional rigidity. So it's a heck lot stiffer than the 25,000 you guessed. I didn't make up that number. It's published by BMW. If you don't trust me you can easily google it and find it.
The Z4 M coupe is the stiffest production car BMW has ever built (this included the E92 M3).
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Originally Posted by jimbogxp,Jul 1 2007, 01:18 PM
The Honda S2000 is well above average torsional stiffness for convertibles, I can tell you that.
We had a GM chassis engineer at a Solstice meet last summer in Kansas City tell our group the torsional rigidity of the Solstice and Honda S2000 were similar and were in the mid 7000s of NM/degree.
He compared this to the current MX-5 in the low 6000s NM/degree.
My recollection is that the BMW Z4 is very rigid in the 9000s NM/degree. Possibly 10,000 NM/degree. Bottom line is, the base Z4 is ETREMELY rigid for a convertible and exceeds the S2000 or Solstice in torsional rigidity.
But yes, all of these values pale compared to closed coupes. That is just the price you pay for being topless..
Whoever posted the S2000's torsional rigidity of 22,000 NM/degree is misinformed. That value is not even close. The car is mid 7000s NM/degree.
Heck, the Z4M Coupe is around 22,000 NM/degree, which is WAY up there as most cars go. (I'm thinking 25-26,000 NM/degree for the Z4M Coupe)
So how could the S2000 be low 20,000s NM/degree? Doesn't pass any sort of reality check.
Nobody on this site will believe it, I am sure, but the Saab 9-3 convertible is actually one of the more rigid common verts out their and it is mid 12,000s NM/degree. 22000 Nm/degree for the S2000 is not accurate in the least. Nice dream, though...
We had a GM chassis engineer at a Solstice meet last summer in Kansas City tell our group the torsional rigidity of the Solstice and Honda S2000 were similar and were in the mid 7000s of NM/degree.
He compared this to the current MX-5 in the low 6000s NM/degree.
My recollection is that the BMW Z4 is very rigid in the 9000s NM/degree. Possibly 10,000 NM/degree. Bottom line is, the base Z4 is ETREMELY rigid for a convertible and exceeds the S2000 or Solstice in torsional rigidity.
But yes, all of these values pale compared to closed coupes. That is just the price you pay for being topless..
Whoever posted the S2000's torsional rigidity of 22,000 NM/degree is misinformed. That value is not even close. The car is mid 7000s NM/degree.
Heck, the Z4M Coupe is around 22,000 NM/degree, which is WAY up there as most cars go. (I'm thinking 25-26,000 NM/degree for the Z4M Coupe)
So how could the S2000 be low 20,000s NM/degree? Doesn't pass any sort of reality check.
Nobody on this site will believe it, I am sure, but the Saab 9-3 convertible is actually one of the more rigid common verts out their and it is mid 12,000s NM/degree. 22000 Nm/degree for the S2000 is not accurate in the least. Nice dream, though...
I also think that the S2000 is more torsionally stiff than a Z4. I've driven both, and they both feel very solid, but the extra trusses and braces in the S2000s X-bone frame along with the higher side sills and center backbone probably make it more rigid.
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So... back to the question of the day - can anyone do this test and publish their findings here on this board? There's gotta be someone here with the technical know-how and proper equipment at their disposal to test this properly. Maybe a fun project? 
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Z4 M coupe is a coupe, not a convertible. From my figures, it's 14,000 for the convertible, and this is the same thing that happened with Aston Martin DB8 Coupe (22,000) when they took the top off of the coupe design to make it a convertible, which dropped it to 15,000 (or so).
as far as Ferrari's, maybe the design of their body doesn't require that much rigidity, since it's a rear mid engine layout and such compare to FW/RD format.
Veyron doesn't have any bushings on it's car.
as far as Ferrari's, maybe the design of their body doesn't require that much rigidity, since it's a rear mid engine layout and such compare to FW/RD format.
Veyron doesn't have any bushings on it's car.