2014 C7 Chevrolet Corvette

[vtmike]

Not to mention the hydraulic set up in the mp4 12c that uses no springs or sway bars.

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[ZDan]

Originally Posted by vtmike

Except you can adjust a sway bar.

Yeah, you can change/adjust sway bars on a Corvette as well.

Not to mention some track set ups run with no sway bar.

Already stated, for ease of changing suspension setups on a track car, coils are preferred. Most of these cars will remain stock street cars. Many of those who track them will stick with leafs, many will go to coilovers.

Also porsches active sway bar disengagement system that takes advantage of the true independent suspension that isn't possible on a transverse leaf spring set up.

Hooray for Porsche. But if Pagani doesn't do that it must be inferior...

A pushrod coil suspension eliminates the packaging advantages of a transverse leaf spring.

Wait, the coil has to go somewhere, doesn't it?! Pushrod suspensions are cool, but not necessarily for production street cars.

Ride heigh adjustability. Individual corner spring rate adjustability.

Easy enough to envision ride height and corner-jacking capability with leafs. Even individual spring rates are possible. Again, coils will have a practical advantage in terms of multiple setups for race cars.

Not much to do with whether for a stock OEM application whether leafs are "inferior" to coils (they're not).

[vtmike]

Originally Posted by ZDan

Yeah, you can change/adjust sway bars on a Corvette as well.

Already stated, for ease of changing suspension setups on a track car, coils are preferred. Most of these cars will remain stock street cars. Many of those who track them will stick with leafs, many will go to coilovers.

Hooray for Porsche. But if Pagani doesn't do that it must be inferior...

Wait, the coil has to go somewhere, doesn't it?! Pushrod suspensions are cool, but not necessarily for production street cars.


Easy enough to envision ride height and corner-jacking capability with leafs. Even individual spring rates are possible. Again, coils will have a practical advantage in terms of multiple setups for race cars.

Not much to do with whether for a stock OEM application whether leafs are "inferior" to coils (they're not).

Coilover set up w/ active sway bar > transverse leaf (available in standard 911)

Pushrod coil set up w/ active sway bar > Coilover set up w/ active sway bar > transverse leaf.

Point proven.

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[ZDan]

Originally Posted by vtmike

Coilover set up w/ active sway bar > transverse leaf (available in standard 911)

Dont' further confound the issue. If you think that having an "active" sway bar is "better", that's fine (I don't necessarily think it is), but it's a DIFFERENT ISSUE than leaf spring vs. coil.

Pushrod coil set up w/ active sway bar > Coilover set up w/ active sway bar > transverse leaf.

??? For all applications? I wouldn't agree with any of those ">" signs as absolutes.

Point proven.

HA! You need to go back to suspension school. You aren't there yet...

There are embodiments of leaf springs that are exemplary and embodiments that are sucky. Same with coil springs.

To categorize them in terms of absolutes betrays a lack of understanding.

There's more than one WAY...

[Dimman]

Originally Posted by ZDan

For reasons already presented. It's a lot easier/more practical to have a much bigger variety of different coil springs than leafs. And it's quicker/easier to change out coilovers than leafs.



You could say the same about Ducati using desmodromic valve actuation.

There's more than one way to skin a cat.

Meanwhile, if you don't know the actual technical ramifications, you cannot really speak to any advantage or disadvantage, now can you?

What the C6.R demonstrates with the springs is that the composite leaf spring is purely a legacy hold-over. If the C6.R doesn't need them, or see a performance benefit from them, then they are also an unnecessary cost on the road car. So legacy is the only rational explanation and the tech talk is purely self-justification.

As to the Ducati analogy, do they change to pneumatic valves or keep the desmo system when they race?

[vtmike]

I do have an engineering degree from a top 15 accredited engineering program and state license. But that's beside the point.

The context for the setup is performance car on a road course. Thought that was self evident.

Until I see other qualified engineers from companies other than Chevrolet specifying transverse leaf spring suspension setups, I see no evidence of their usefulness.

I'm done with this argument. Some people are biased and can't be swayed by empirical evidence.


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[Dimman]

Also, monoshock/belleville stack front suspension > Most others.

[ZDan]

Originally Posted by vtmike

The context for the setup is performance car on a road course. Thought that was self evident.

Not at all. Quite the contrary. The application is the stock OEM suspension on a high-performance sports/supercar. I thought *that* was self-evident. I mean, we *are* talking about the new C7 Corvette ROAD car, are we not?

Plenty of tracked Corvettes still use leafs. Most that are professionally raced use coilovers *for reasons already stated several times*.

Until I see other qualified engineers from companies other than Chevrolet specifying transverse leaf spring suspension setups, I see no evidence of their usefulness.

Essentially, you are saying that you don't understand the essence of how these things work, so you'll assume a given solution must be inferior if only Chevrolet employs it. Brilliant...

I'm done with this argument. Some people are biased and can't be swayed by empirical evidence.

Exactly. You are that "some people".

[ZDan]

Originally Posted by Dimman

What the C6.R demonstrates with the springs is that the composite leaf spring is purely a legacy hold-over.

Not at all. Legacy surely has something to do with it though.

If the C6.R doesn't need them, or see a performance benefit from them, then they are also an unnecessary cost on the road car.

What is best for a pure racing car is not necessarily best for a road car.

So legacy is the only rational explanation and the tech talk is purely self-justification.

Just pointing out that leafs aren't technically inferior to coils as springs, that's all. There are benefits, there are drawbacks.

As to the Ducati analogy, do they change to pneumatic valves or keep the desmo system when they race?

I don't know for certain who is using pneumatic valves in motorcycle roadracing. Aprilia tried it with the Cube in MotoGP a while back. Might be in use in the Ducati MotoGP bike, not sure. Highly doubtful that it's legal in World SuperBike.

For years they've used desmodromics to great success at the track and on the street, where NONE of their competition was using them (competition which also enjoyed a ton of success on road and track). They have benefits, they have drawbacks.

There is no one way! Viva diversity...

[Dimman]

Originally Posted by ZDan

Not at all. Legacy surely has something to do with it though.

What is best for a pure racing car is not necessarily best for a road car.

Just pointing out that leafs aren't technically inferior to coils as springs, that's all. There are benefits, there are drawbacks.


I don't know for certain who is using pneumatic valves in motorcycle roadracing. Aprilia tried it with the Cube in MotoGP a while back. Might be in use in the Ducati MotoGP bike, not sure. Highly doubtful that it's legal in World SuperBike.

For years they've used desmodromics to great success at the track and on the street, where NONE of their competition was using them (competition which also enjoyed a ton of success on road and track). They have benefits, they have drawbacks.

There is no one way! Viva diversity...

What I'm seeing with the composite leafs, is different just for the sake of it.

And from my point of view (although you an LSxjunkie have solid ground to disagree, I'll admit) so is the OHV setup.

But when it comes to character and history, the OHV makes a lot more sense to continue. The leaf springs don't.

The Ducati point was that while they were different, they proved it in competition while using it in their street bikes. They didn't have a unique tech in the street bike and race with conventional tech which is what the Corvette does. This takes some credibility away from them when they tell us it is 'better'.

Ducati showed that they believe their tech was absolutely superior, not equal, not marginally better with some tradeoffs. I think GM engineers feel this way about their OHV setup, which I can respect, but not the leaf springs.

[ZDan]

Originally Posted by Dimman

What I'm seeing with the composite leafs, is different just for the sake of it.

But they WORK, and very well, for their intended usage. So what's the problem? Why do you insist that a different approach, that WORKS, should be abandoned?

And from my point of view (although you an LSxjunkie have solid ground to disagree, I'll admit) so is the OHV setup.

Don't get me started! Again, it's a different approach, that WORKS, and quite well. Why should every manufacturer CONFORM to the same solutions?

But when it comes to character and history, the OHV makes a lot more sense to continue. The leaf springs don't.

What compelling reason would they have to change?

The Ducati point was that while they were different, they proved it in competition while using it in their street bikes.

They won races/championships (with a huge displacement advantage), and they lost them as well (notably when Colin Edwards beat Troy Bayliss).
They didn't prove superiority, they did prove that it was a viable *different* approach.

They didn't have a unique tech in the street bike and race with conventional tech which is what the Corvette does. This takes some credibility away from them when they tell us it is 'better'.

ONce more: What is "better" for a production supercar doesnt' necessarily apply to a pure RACE car that has to be tuneable to the nth degree. There are practical (and possibly rules) reasons that the C6R is on coils.

Ducati showed that they believe their tech was absolutely superior, not equal, not marginally better with some tradeoffs.

No, they showed (and show) that it is a viable, competitive alternative. For many years they enjoyed a HUGE displacement advantage (1000cc for twins vs. 750cc for the 4s). And when Honda decided to run a Vtwin (non-desmo) as well, to get the same advantage, they beat Ducati in SBK.

All this obsession over how one method, one way, MUST be "BEST". It's just not true! There is no one way!

I think GM engineers feel this way about their OHV setup, which I can respect, but not the leaf springs.

Seems a strange distinction to make...

[OrbitalEllipses]

Originally Posted by vtmike

I do have an engineering degree from a top 15 accredited engineering program and state license. But that's beside the point.

If it was beside the point you wouldn't have touted it. I stayed a Holiday Inn tonight, but what do I know.

[vtmike]

Originally Posted by ZDan

Not at all. Quite the contrary. The application is the stock OEM suspension on a high-performance sports/supercar. I thought *that* was self-evident. I mean, we *are* talking about the new C7 Corvette ROAD car, are we not?

Plenty of tracked Corvettes still use leafs. Most that are professionally raced use coilovers *for reasons already stated several times*.

Essentially, you are saying that you don't understand the essence of how these things work, so you'll assume a given solution must be inferior if only Chevrolet employs it. Brilliant...

Exactly. You are that "some people".

What's the point of a 450hp 3200 pound car if you never take it to the track. A car of this caliber should be track oriented. There is no way to enjoy it on public streets responsibly. It has so much grip and power it would be boring keeping it at reasonable speeds on public roads. So I think the C7 should be talked about from a track prospective. That's the reason I bought a frs and am on this forum. It is fun to drive within reasonable speeds on public roads. (also on the track)

I understand the pros and cons of the suspension set ups and the coil spring setup is superior in my opinion when comparing them in any application of a high performance car.

While I am an engineer, I'm not an automotive engineer. I doubt you or any other person replying to this thread is an automotive engineer designing suspension components for any major auto manufacturer or as qualified as those who do.

The best way I see to empirically get results on the matter based on those engineers who are qualified to design such suspensions rather than the theoretical benefits based on our limited knowledge is to see what conclusions these engineers have come to. I don't see how this is not sound logic.

The results: overwhelmingly engineers for companies all over the world for all types of performance cars (mid rwd, front rwd, front awd, front fwd, i6, v8, v6, i4, flat 4, flat 6, v12, v10, 2-5 doors, 1900lbs-4000+lbs) all use coil springs for at least the front and some times torsion beam rear suspension. The only exceptions are the corvette with leaf springs, and Mustang with live rear axle (although still using coil springs. ) seems to me engineers for all major companies (minus Chevy for the corvette, but not on other models such as ctsv and zl1) prefer to specify coil spring setups.

Further more reviews from journalist with race experience such as Tiff Needell, Jason Plato, and Chris Harris normally don't have good things to say about the handling characteristics of Corvettes when compared to their competition (even though they put up good lap times.)

End of rant.

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[vtmike]

Originally Posted by LSxJunkie

Your "empirical" evidence is that nobody else does it so it is automatically bad.

My empirical evidence is compare the lap times of a C6 ZR1 with any other car shod with similar tires making comparable power.


The MP4-12C did it in 7:28 on P Zeros. 590hp, 3084lbs, DCT, fancy hydraulic suspension.
The ZR1 did it in 7:26 on Pilot Sport (not Cups) RunFlats. 638hp, 3405lbs, 6spd and clutch, MSRC magnetic adaptive dampers and leaf springs.

The GT2 RS did it in 7:18 on Pilot Sport Cup Plus N2s. 620hp, 3020lbs, 6spd and clutch, PASM hydraulic adaptive dampers and coil springs.
The ZR1 did it in 7:19.6 on Pilot Sport Cup Zero Pressures. 638hp, 3405lbs, 6spd and clutch, MSRC magnetic adaptive dampers and leaf springs.

You claim to be an engineer. I've seen people fabricate degrees on the internet before. Some guy on LS1GTO went so far as to print a fake degree to sell repackaged wax. If you are an engineer, you should thrive in data, not these sad assumptions that because something is bad simply because it is not popular.

My comment on being an engineer was in response to someone replying go back to suspension school.

You're empirical data of 2 cars with similar tires but with widely varying characteristics (front engine vs rear engine to name one) is not valid. Plus were both cars lapped on the same day by the same driver? No tire data on the mp4-12c plus again significantly different car.

There was an interesting article in motor trend a couple years ago where they tried to empirically measure the best handling car. The don't remember if there was a corvette involved.

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