Corvette leaf springs

[culver]

While I could see the harmonic issue, I don't think it will be a big deal.
1st. Remember that almost all cars already have a torsion spring between the left and right suspensions. So any issues with cross talk would to some degree be present in conventional systems.

2nd. The spring is a composite. I would assume it has some self damping properties but I have no idea what it's natural frequency is relative to say a metal spring. I'm also not sure what frequency range would be important to consider. For race car dampers the engineers are really concerned with shock velocities around 1"/sec. I assume the natural frequency of any suspension parts would be much higher.

3rd. It has rubber mounts at each end and I think at the points where it mounts to the chassis as well. These would tend to dampen vibrations.

[SlickHolden]

My brother was in a Holden Crewman with leaf springs rear, He told me if he took his cup of tea he wouldnt need a spoon
I remember the old V6 Holden had and no matter how many times that engine got a upgrade they still compared it to the old Buick V6 in the 60's. No matter how far it came along.

[Matra et Alpine]

While I could see the harmonic issue, I don't think it will be a big deal.
1st. Remember that almost all cars already have a torsion spring between the left and right suspensions. So any issues with cross talk would to some degree be present in conventional systems.

no, it works in an entirely differnet fashion.
An anti-roll bar is NOT restrained at the mountinf points, so when one suspension wheel moves up the bar is twistsed ADN TURNS IN THE MOUNTINGS to impart a force to the other side. Yes there is still a harmonic issue but NOW it is at wavelength harmonics of the length of the COMPLETE bar. And as it is NOT require to act as a sprign it is usually torsinoally VERY stiff and hence very HIGH natural frequency beyond the expected movements - because you are loking at the rate of change BETWEEN the wheels NOT between wheel and chassis.

The 'vette spring issue is that it's harmonics are at a much shorter wavelenght/higher rate.
The spring does not TWIST it bends, the bend is perpendicular to the mounting points, so it's not imparting directly to the other side.
As a wheel drops, the INNER section of the spring will go UP, hence imparting a downward force to the other side. So it performs TWO functions.

2nd. The spring is a composite. I would assume it has some self damping properties but I have no idea what it's natural frequency is relative to say a metal spring. I'm also not sure what frequency range would be important to consider.

good point on it being composite, but I can't see how they can build in a DAMPING property for bend, vibration yeah, sure, but bend ?? Because IF they build it in to supres the natural frequency AND it's hamronics then you NOW have it doing 3 jobs at the rear - anti-roll, spring AND damper. I jsut dont' see that being controllabel to have a reasonably wide range of handling for differing surfaces.

For race car dampers the engineers are really concerned with shock velocities around 1"/sec. I assume the natural frequency of any suspension parts would be much higher.

erm, that might be true for something like an oval where suspension transitions are gentler. BUT there is NO WAY a suspension is designed around 1"/sec velocities for a road cricuit
Do you have a link as I'd like to check up on that one as I'm very surprised by it. Maybe we are talking different velocities.

3rd. It has rubber mounts at each end and I think at the points where it mounts to the chassis as well. These would tend to dampen vibrations.

Seriosuly ? it HAS to use poly or metalistic bushes at the ends.
IF it uses rubber mounts soft enough to compress then it will create inherently unstabel suspension movements as the rubber changes compression/rebound. Suspension designers try to minimise these. The are ONLY in road cars to reduce the vibration and nosie fromthe road surface. In race cars they are usually changed to rose jointed steel on steel to retain optimum control.
Can anyoen confirm ???

[johnnyperl]

In race cars they are usually changed to rose jointed steel on steel to retain optimum control.
Can anyoen confirm ???

yes..

[Matra et Alpine]

yes..

aha, so on the ROAD car what size are type are the mounting points ?
How much compliance is there ?
Does the Z06 handling pack replace this with rose-joints ?

[johnnyperl]

aha, so on the ROAD car what size are type are the mounting points ?
How much compliance is there ?
Does the Z06 handling pack replace this with rose-joints ?

dont have specific answers but i would say that on a typical car it would play a small part since the other components are so poor (sidewalls, ARB).
the setups ive seen use a 4cm(?) bushing fit inside the swingarm pivot with the mount passing through the center of the bushing.

[Matra et Alpine]

dont have specific answers but i would say that on a typical car it would play a small part since the other components are so poor (sidewalls, ARB).
the setups ive seen use a 4cm(?) bushing fit inside the swingarm pivot with the mount passing through the center of the bushing.

yeah that's typical jp.

replacing a metalistic bush with a poly one makes a HUGE difference in handling only matched by the change up to rose-jointed.

I'd NOT underestimate how much poor handling comes from movement in the bushes. A 1mm deflection under load in a corner can alter the camber/caster by up to a 5 degrees THAT doenst' make for a car easy to drive on the limit.

The "other" components don't have such a large effect - except the tyre itself which we're kind of stuck with anyway BUT the vector forces on the vette spring woudlnt affect geomotry at all so that's not the major issue. BUT it WILL affect the impact of mid corner bumps and undulations.

[culver]

Mantra, this conversation has become very interesting!
I’m sure much of what we are debaiting is like two people trying to describe the exact same thing. It’s a red car! No, it’s a sports car!


First, from what I have heard from the people I know in race car design (Formula Ford – Infinity Pro Series cars) they have never said anything about harmonic issues when they looked at Vette suspensions. On guy I know is trying to get the company that does the Vette springs to make landing gear springs for tail dragger airplanes.
Again, no one I know in the racing industry sees a problem with harmonics in the Vette’s design.
Has anyone reported this as a problem or is this assessment based on intuition. I ask simply because I’ve never heard this issue before.

OK, a couple of replies:

no, it works in an entirely differnet fashion.
An anti-roll bar is NOT restrained at the mountinf points, so when one suspension wheel moves up the bar is twistsed ADN TURNS IN THE MOUNTINGS to impart a force to the other side. Yes there is still a harmonic issue but NOW it is at wavelength harmonics of the length of the COMPLETE bar. And as it is NOT require to act as a sprign it is usually torsinoally VERY stiff and hence very HIGH natural frequency beyond the expected movements - because you are loking at the rate of change BETWEEN the wheels NOT between wheel and chassis.

The 'vette spring issue is that it's harmonics are at a much shorter wavelenght/higher rate.
The spring does not TWIST it bends, the bend is perpendicular to the mounting points, so it's not imparting directly to the other side.
As a wheel drops, the INNER section of the spring will go UP, hence imparting a downward force to the other side. So it performs TWO functions.

I understand how the conventional anti-roll bar twists instead of flexes. However, you can get torsional harmonics as well as flexing harmonics. I also agree that the natural frequency of the beam makes it unlikely to be much of an issue.
I’m not sure I understand your second point. I think you are saying that when one wheel goes up it tends to pull the other wheel up as well. If that is what you are saying, I would counter that this is intentional. As was mentioned in one of my original links, this was an intentional design trait of the C4-C6 leaf spring suspensions. This is exactly how the leaf spring can handle two jobs at once. The roll spring rate of the Vette is provided by a combination of the leaf spring and the anti-roll bar. I’m not sure why this would be considered undesirable. Certainly unconventional but hardly undesirable.

good point on it being composite, but I can't see how they can build in a DAMPING property for bend, vibration yeah, sure, but bend ?? Because IF they build it in to supres the natural frequency AND it's hamronics then you NOW have it doing 3 jobs at the rear - anti-roll, spring AND damper. I jsut dont' see that being controllabel to have a reasonably wide range of handling for differing surfaces.
Again, I’m not sure if I understand the damping property for bending. I think I’m unsure how much vibration you are talking about. If we are talking about macroscopic levels that start moving the wheels around then I will reiterate, I don’t think the problem exists in the first place. Sorry if I’m still not understanding the issue you are concerned with.

erm, that might be true for something like an oval where suspension transitions are gentler. BUT there is NO WAY a suspension is designed around 1"/sec velocities for a road cricuit
Do you have a link as I'd like to check up on that one as I'm very surprised by it. Maybe we are talking different velocities.
This one is easy, link below. The presentation in the link was put together by a 7 time SCCA national champion driver. He is a senior engineer at Firestone and also happens to be his own race engineer. While he has done some oval stuff most of his driving is on road courses (ovals may look easy but they also take a great deal of skill to squeeze out that last 0.02 seconds). Remember, I didn’t say that was the only frequency in the suspension’s motion, just that is was considered to be the most critical.
http://www.neohio-scca.org/comp_clin...handout%20.pdf

As for my third point, I’m not actually sure exactly what material they use as an interface between the spring and chassis. In the pictures it’s black. I assume it’s somewhat compliant. I’m not talking about the ends of the spring were it attaches to the suspension arms, I’m taking about the clamps that hold the spring to the sub-frames. Even at the wheel ends I imagine there is some sort of rubber layer in between the spring ends and the suspension arms. From the pictures it looks kind of like a, for lack of a better description, a bolt with rubber washers. Remember, the spring mounts at the wheels will always be in tension so a semi-compliant peace like a rubber washer will be under compression the whole time. This is different that say a suspension bushing that will transition from compression to tension under different loading conditions. I also do not know how much compliance we are talking about but having ridden in a Vette, I imagine it’s quite small. Again, I think the issue we are having is one of communication rather than facts. The illustration seems to show an A-arm pivot which is not what I’m referring to. I’m referring to the connection between the end of the leaf spring and the suspension arm. The Vette’s suspension arms and thus it’s suspension geometry are very carefully mounted and controlled.
Hopefully this first post will show what I’m talking about:
http://www.z06vette.com/forums/showt...5&page=2&pp=27
Note what appears to be a semi-compliant mount between the A-arm and the end of the spring. Since this joint is under constant tension I would expect it uses some sort of rubber bushing. This is not an A-arm pivot point. Those look rather conventional. You can also just see a bit of what ever compliant material they use to mount the spring to the chassis in the upper left of the picture.

[Matra et Alpine]

Mantra, this conversation has become very interesting!
I’m sure much of what we are debaiting is like two people trying to describe the exact same thing. It’s a red car! No, it’s a sports car!

Definately agree, we are discussin the issues about a gnat on the back of an elephant. The elephants' still in the room

howver, if you dont' midn I find it interesting as I've not foudn anyone with an undesrtanding of the Vette's operation to share REAL experience rather than datasheet-hype

is it OK to contine ? I'll leve out the pbits we're agreeing on

First, from what I have heard from the people I know in race car design (Formula Ford – Infinity Pro Series cars) they have never said anything about harmonic issues when they looked at Vette suspensions.

Thanks, is that the case on road circuits too ?

I’m not sure I understand your second point. I think you are saying that when one wheel goes up it tends to pull the other wheel up as well. If that is what you are saying, I would counter that this is intentional.

yep agreed, THAT is the benefit of the 'vettes use of a transverse leaf.

As was mentioned in one of my original links, this was an intentional design trait of the C4-C6 leaf spring suspensions. This is exactly how the leaf spring can handle two jobs at once. The roll spring rate of the Vette is provided by a combination of the leaf spring and the anti-roll bar. I’m not sure why this would be considered undesirable. Certainly unconventional but hardly undesirable.

because if you want a stiffer anti-roll bar then by definition you end up with a stiffer spring !!
Equally for softer.
usually if you ask a moving component to do more than one job it is a compromise.
it was only to cover that it HAS to do two that I raised it to see how do the race teams and seriosu road users resolve the need to have say soft spring to handle undulations but stiff anti-roll to hadle camber ?
Surely it HAS to be a compromise ? UNLESS there is some magic in the composite that I dont' grasp which makes a difference - hence why I wondered if fitting a mini-damper on the centre sectino of the spring was used.

Again, I’m not sure if I understand the damping property for bending. I think I’m unsure how much vibration you are talking about. If we are talking about macroscopic levels that start moving the wheels around then I will reiterate, I don’t think the problem exists in the first place. Sorry if I’m still not understanding the issue you are concerned with.

No I think we're OK, waht you're quesitoning is if it woudl results in sufficient MOVEMENT to make a difference. I was coming from the impact it would have on the ability of a wheel to follow road surface changes AND how it waould altar corner weights. harmonics are nasty and are usually avoided OR used to aid. I jsut can't see how that can be achieved in the transverse because of the mamny jobs it has to undertake. BUT as I said before, if there's seomthing clever in the composite I woudl love to know.

This one is easy, link below. The presentation in the link was put together by a 7 time SCCA national champion driver.

That looks to be for open wheel race cars where it is ULTRA stiff and so damping rates are often USED To keep suspension movement below a 1"/sec rate. For road/GT and my broader experience in setups for tarmac rallies you talk in havin to do a full 6-8INCHES of travel in less than 1/10 of a second for some events the norm woudl be more in the 4 inches in less than 1/4 second. A long way from the 1" per second, but that is about open wheelers - which means smooth tracks and reduced transitions and downforce. These alter the "opportunities" quite a lot. We've come at it from 2 different directions. I concur with what you're saying on those examples based on the info give, BUT the 1"/sec seems to be the minimum, the graphs show rates going out to 6" per second. But am not yet convinced in road cars on road events and tracks. A quick mental arithmetic -- if a car is doing 60mph and taking a corner on a rise that drops away by 1" and the tyre damper takes a second to get the tyre BACK in contact with the road then it takes 500 feet of tarmac before that tyre is providing grip again. it needs to do it within an inch to prevent the car spinning out a car with downforce PUSHES the car down in those circumstances. Still I woudl put that the histogram showing the 6" up and 6" down deflection is to handle those situations.
I dont' think using the mean on the chart works because the time you NEED the suspension and damping to work BEST are at the extremes.
Agree ?

As for my third point, I’m not actually sure exactly what material they use as an interface between the spring and chassis. In the pictures it’s black. I assume it’s somewhat compliant. I’m not talking about the ends of the spring were it attaches to the suspension arms, I’m taking about the clamps that hold the spring to the sub-frames. Even at the wheel ends I imagine there is some sort of rubber layer in between the spring ends and the suspension arms. From the pictures it looks kind of like a, for lack of a better description, a bolt with rubber washers. Remember, the spring mounts at the wheels will always be in tension so a semi-compliant peace like a rubber washer will be under compression the whole time.

"metalistic" bushes, yep they're standard to reduce the vibration problesm and NOT adversely affect suspension location and movement.
As I said their is a BIG difference from them to poly and the same again to direct.

This is different that say a suspension bushing that will transition from compression to tension under different loading conditions. I also do not know how much compliance we are talking about but having ridden in a Vette, I imagine it’s quite small. Again, I think the issue we are having is one of communication rather than facts. The illustration seems to show an A-arm pivot which is not what I’m referring to. I’m referring to the connection between the end of the leaf spring and the suspension arm. The Vette’s suspension arms and thus it’s suspension geometry are very carefully mounted and controlled.

yeah it was those pics tat rereaised my interest.
Last time around discussing this we couldn't get such clear pictures.
We're talking about the same joint - ie one likely to be rose jointed in competition.
BUT the debate does make me wonder if they can be 'smart' in the clamps the hold the spring to the chassis and built in maximum damping at the natural harminics of that length of leaf between them. yeah THAT could be done, not sure if it has enough leverage, but is possible. It may be that they have already resolved this for serious performance handling and have devloped a reasonable compormise that matches the chassis performance - after all making one MUCH better than the other is a waste of effort as the worst commponent is the limiting factor

[culver]

My turn to reply:

Thanks, is that the case on road circuits too ?

As for the professional opinions about the Vette’s suspension they are not taken in context of racing, just looking at the suspension of a road going sports car.

because if you want a stiffer anti-roll bar then by definition you end up with a stiffer spring !!
Equally for softer.
usually if you ask a moving component to do more than one job it is a compromise.
it was only to cover that it HAS to do two that I raised it to see how do the race teams and seriosu road users resolve the need to have say soft spring to handle undulations but stiff anti-roll to hadle camber ?
Surely it HAS to be a compromise ? UNLESS there is some magic in the composite that I dont' grasp which makes a difference - hence why I wondered if fitting a mini-damper on the centre sectino of the spring was used.

At some point in the C4 design program the engineers were hoping to use just the leaf spring and skip the anti-roll bar. As you have pointed out this makes it difficult to adjust roll rate independently from spring rate. My understanding is with out changing the spring, you can adjust roll rate by changing the location of the spring mounts. Of course this isn’t very practical and in the end they added an anti-roll bar to supplement the leaf spring. Basically the leaf spring provides 100% of the bump spring rate but only some portion of the roll spring rate (say 50%, I don’t know the actual numbers). I then use the roll bar to provide the rest of the anti-roll. Essentially the leaf provides a base roll rate. The anti-roll provides the additional rate and is used to tune the roll rate. But, for a given roll rate I can use a smaller, lighter anti-roll bar because the leaf spring is helping out. I’m sure this makes tuning the suspension different than with normal hardware but I’m equally certain that people have defined the differences. I many not have the knowledge but I’m sure companies like Lingenfelter Performance Engineering do know how to tune things.


That looks to be for open wheel race cars where it is ULTRA stiff and…
The link is definitely for racecars. The data would hold true for something like a Formula Ford that has very little effective down force. However, you are correct that’s a long way from road car suspension travel rates. On the other hand it’s not way out of line when people are taking a high performance street car to a road course (presumable with a reasonably smooth surface). I have never driven on a tarmac (minus in an airplane) so I’m not familiar with the types of bumps/pavement transitions you would encounter.

"metalistic" bushes, yep they're standard to reduce the vibration…
As I said, I’m just not familiar with the bushing used on the Corvettes. The images were of the new Z06 (505hp, looks to be quite a monster). I would expect that with this version of the Vette ride was back seat to control.
From what I’ve read about Vette’s since the C4 was released the leaf springs have never been a source of any handling issues. The C4 suffered because the suspension wasn’t well mounted. Like a Jag E-Type, the Vette used the drive shafts as one of the suspension links. In addition to limiting the geometry options the car now had some of it’s suspension arms mounted to the chassis and others effectively mounted to the dif housing. When they introduced the C5 they dumped all that and put a lot of effort into making sure the suspension arms were mounted to stiff chassis points. Since the C5 came out I can’t think of anything I’ve read that’s critical of the suspension. The biggest issues have always been visibility (you have that long hood); numb, though precise, electric power steering on the C6 (I can attest to that); shift feel. It would be interesting to talk to some of GM’s suspension gurus about the Vette suspension. I always love it when someone illustrates why conventional wisdom doesn’t always hold true*

*Speaking of defying conventional wisdom, years back Racecar Engineering Magazine had a great article looking at the Panoz front engines LMP cars.
http://www.bevenyoung.com.au/prdt880.htm
The Panoz car was a very unique LMP design. Rather than go with a traditional rear/mid engine LMP design, the car used a front mounted pushrod motor. Basically the guy who was paying the bills said make it this way. Until the dominating Audi’s came out, the Panoz cars were very competitive.
The article said while on the surface this car seams like a bad idea, the designers studied the rules and realized it could be competitive.

Motor: Normally the pushrod motor would be outclassed but in this case the cars use a supersonic air intake. Basically high reving peak hp, isn’t as desirable as a very broad power band. The large displacement pushrod seemed well suited to the restriction rules and the car was never lacking for power (I wish I remembered the details).

Weight distribution and Tires: The Panoz car was more nose heavy than the standard LMP cars (say 45% nose vs say 35% again I don’t know the exact numbers). Well the rules of the class limit the size of the rear wheels to something less that optimal for a rear engined car. At the same time the front tires could be larger than needed. By shifting weight forward, the Panoz car could take advantage of the extra front tire allowed by the rules. I can’t remember why they said it was ok to loose the weight from the back ties. Again, I read this article the better part of ten years ago.

Aero: This was where the car really shown. Because the air intake was in the nose of the car there was no need for the large air scoop behind the driver. This made the rear wing more effective because you didn’t have dirty air coming off the air scoop.

In all it was a fascinating look at how, given a unique set of rules and good understanding of the fundamentals, what seems like a bad idea may actually be a very good idea.
I really need to find that article again.

[Alastor]

*Speaking of defying conventional wisdom, years back Racecar Engineering Magazine had a great article looking at the Panoz front engines LMP cars...

That is an interesting story, sounds like a very good read.

[Matra et Alpine]

I many not have the knowledge but I’m sure companies like Lingenfelter Performance Engineering do know how to tune things.

You dont' see Lingfelter's out on the tracks of Europe !
AS we've already covered there are different expectations and environs that may or may NOT match the design goals fit for US customers.

The link is definitely for racecars. The data would hold true for something like a Formula Ford that has very little effective down force.

True, I also realised there is a HUGE hole in the guys rationale over the 1"/second travel rate. The histogram shows a bell curve and he's right most of the time it's in the 0-1 range. BUT thre are large at the extremeities as well. HOWVER< most of all it doesnt' have any inptu on how CRiTICAL that movemetn is. So for example on a straight it matters littel what you need and get from a suspension ( within some limits ) BUT on a corner that 6"/sec coudl be CRITICAL to the difference between cornering at 60 and coernering at 80
So I've increased the pinch of salt I'm taking those figures with - mainly because they just don't jivbe with my own experiences ( and hence why Iwas trygin to seek reasons ie downforce and circuit ) I've NO experience in cars with large amounts of variabel downforce available

The biggest issues have always been visibility (you have that long hood); numb, though precise, electric power steering on the C6 (I can attest to that); shift feel.

Thansk for the info on the C$.
the "visibility" is the major reason the Biper has been taking a slating in the UK journos. With undualting twisty roads narrow for ordinary cars they alwasy complain about being slow because it's difficult to palce the car in the optimal position for line.

It would be interesting to talk to some of GM’s suspension gurus about the Vette suspension. I always love it when someone illustrates why conventional wisdom doesn’t always hold true*

ditto, it clearly works within some set of constraints.
I'd love to know them.
Partly because having used it in a proven design there MUST be drawbacks or everyone would re-adopt them. After all transverse leaf is where racing cars were in the 40s. I cant' see that it is only materials as you can get composite leaf springs for live axle cars - we were consider the "upgrade" for the MGB GT at one time.

*Speaking of defying conventional wisdom, years back Racecar Engineering Magazine had a great article looking at the Panoz front engines LMP cars.
http://www.bevenyoung.com.au/prdt880.htm
The Panoz car was a very unique LMP design. Rather than go with a traditional rear/mid engine LMP design, the car used a front mounted pushrod motor.

Noel Edmunds led an attempt to win the real Le Mans using an early Panoz. Bing a TV presenter, he used it for exposure AND made a TV show he coudl sell on the trials and tribulations of the effort. I'm afraid the inside view we got the engine was a DISASTER. Gettign it up to competitive power meant it overheated HUGE amounts and ultimately killed the engine during testing, qualifying and racing. Edmonds had full Panoz backing and everyone was trygin to find solutions. The bets they came up with afater trying lots of aero and radiator solutiosn was to run the engien below power and it STILL died in the race
I loved the Panoz as it was simple race car design and deserved to do better for NOT being sophiticated.
That was early days and the Panoz became competitive in the American Le Mans copy series, btu I dont' think the car ever did well in long races did it ?
[/quote]Basically high reving peak hp, isn’t as desirable as a very broad power band.[/quote]
Nice to see it recognised. it's the breadth of the power that matters NOT where it happens. A mathematician friend summed this up nicely when I was discussing the best way of comparing them - area under the graph. A higher powered but narrower band engine is matched by a lower powered but wider band engine with appropriate gearing IF the area under the power curves are hte same. So sensible these mathematicians

By shifting weight forward, the Panoz car could take advantage of the extra front tire allowed by the rules. I can’t remember why they said it was ok to loose the weight from the back ties. Again, I read this article the better part of ten years ago.

excellent input, never realised they took advantage of the corner weights that way.
With power limits and availabel rubber maybe they had reached optimal rear tyre sizes with lower weight and the extra weight up front would help turn-in more than the loss of exit grip.

In all it was a fascinating look at how, given a unique set of rules and good understanding of the fundamentals, what seems like a bad idea may actually be a very good idea.
I really need to find that article again.

I'd love to read it too
I'll try and find if that Edmonds TV show ever got to bittorrent

[labomba]

http://www.mulsannescorner.com/panozlmp1.html
http://www.mulsannescorner.com/panozlmp07.htm

Great tales of trials, tribulation, and going against the grain.

[culver]

No I wouldn’t expect to see many Lingenfelter cars in Europe given the few numbers of Vettes in Europe. Everything I know about the guy and his cars come from magazines. The short take is his cars almost always won the Car and Driver modified car shoot outs. He made a twin turbo 7L C5 Vette that did 0-60mph in something like 1.93 sec with DOT legal cheater slicks (Department of Transportation legal drag racing slicks). His car were generally reported to be very livable. The docile nature of the cars when the weren’t being flogged was what set him aside from his competitors. From what I read he was an accomplished tuner for both motors and suspension. Tragically he died in a drag racing accident a little over a year ago. It seemed his cars were easily capable of playing with RUF Porsches. Mind you all of this is based on what I’ve read.

The shock travel rate is based on research done buy a race engineer I know. The data was used buy Goodyear as well as being used for suspension tuning. Remember the person who put this presentation together is a 7 time SCCA national champion. These two really know their stuff. The data is a histogram of suspension motion speeds. By looking at the data you can get an idea what suspension travel speeds are most critical to work with. Keep in mind that none of this data was reviewed in a vacuum. This is based on lots of track time as well as computer analysis and driver feedback. If you check out Apexspeed.net you can see that the guy who put this presentation together (Dave Weitzenhof) is well respected for his driving talent and engineering knowledge, if often knocked for being an old fart.

I had a chance to drive a Corvette C6 that belongs to a friend in the Air Force. That car is actually now living in the UK. (http://corvette.co.uk , you may have to hit refresh a few times until the non-generic picture come up). The car in the link is the one I drove before it headed over the pond. Compared to the Miata I was driving the forward visibility is some what limited. Not to the point that I would refuse it but not the best. The rear visibility is also less that the best but actually somewhat better than a Miata with the top up. Compared to the Formula Vee I drove a few years back the forward visibility is great. Mind you in all cases I’m talking about seeing what is right in front of the car. If you have ever sat in anything like an F1/Indy/F3000 car understand it’s very tough to see what’s right in front of the car. Either way, if you get a chance to drive a C6 don’t pass it up. I’m not going to claim it’s the best car in the world or anything like that but it is really fun and that’s what matters to me.

I don’t know much about the Panoz LMP history. Know the original coupe wasn’t very successful. When they turned it into a prototype it did pretty well. It did win the ALMS series one year. I think it was one of those cars that could have really done something with more money and development. However, when the indomitable Audi’s came out it was completely out classed (along with every other car).

Please let me know if you find that Edmonds episode, that would be really cool to see. If you happen to know a place that has Racecar Engineering the link above was the issue in question.

[culver]

OK, I know I am pulling up a post that is almost 3 years old but... I recently added quite a bit of information to the wikipedia entry on this topic. Specifically I added a number of illustrations in an attempt to make the operation of the spring more clear. I would greatly appreciate any feedback or suggestions people might have that would make the entry even clearer or would improve people's understanding. That includes changes to the CAD illustrations.

Thanks!

Corvette leaf spring - Wikipedia, the free encyclopedia