2014 C7 Chevrolet Corvette

[Mango22]

Excerpt from Wikipedia on the use of transverse leaf springs

[ame="http://en.wikipedia.org/wiki/Corvette_leaf_spring"]Corvette leaf spring - Wikipedia, the free encyclopedia[/ame]

Advantages:
Less unsprung weight. Coil springs contribute to unsprung weight; the less there is, the more quickly the wheel can respond at a given spring rate.
Less weight. The C4 Corvette's composite front leaf weighed 1/3 as much as the pair of conventional coil springs it would replace. Volvo reported that the single composite leaf spring used in the rear suspension of the 960 Wagon had the same mass as just one of the two springs it replaced.
Weight is positioned lower. Coil springs and the associated chassis hard mounts raise the center of mass of the car.
Superior wear characteristics. The Corvette's composite leaf springs last longer than coils, though in a car as light as the Corvette, the difference is not especially significant. No composite Corvette leaf has ever been replaced due to fatigue failure, though steel leafs from 1963 to 1983 have been. As of 1980, the composite spring was an option on the C3.
As used on the Corvette, ride height can be adjusted by changing the length of the end links connecting the leaf to the suspension arms. This allows small changes in ride height with minimal effects on the spring rate.
Also as used on the C4 front suspension, C5, and C6 Corvettes, the leaf spring acts as an anti-roll bar, allowing for smaller and lighter bars than if the car were equipped with coil springs. As implemented on the C3 and C4 rear suspensions with a rigid central mount, the anti-roll effect does not occur.
Packaging. As used on the C5 and later Corvettes the use of OEM coil over damper springs would have forced the chassis engineers to either vertically raise the shock towers or move them inward. In the rear this would have reduced trunk space. In the front this would have interfered with engine packaging. The use of the leaf spring allowed the spring to be placed out of the way under the chassis and while keeping the diameter of the shock absorber assembly to that of just the damper rather than damper and spring.

Disadvantages:
Packaging can be problematic; the leaf must span from one side of the car to the other. This can limit applications where the drivetrain, or another part, is in the way.
Materials expense. Steel coils are commodity items; a single composite leaf spring costs more than two of them.
Design complexity. Composite monoleafs allow for considerable variety in shape, thickness, and materials. They are inherently more expensive to design, particularly in performance applications.
Cost of modification. As a result of specialized design and packaging, changing spring rates often requires a custom unit. Coil springs in various sizes and rates are available inexpensively.
Susceptibility to damage. Engine fluids and exhaust modifications like cat-back removal might weaken or destroy composite springs over time. The leaf spring is more susceptible to heat related damage than conventional steel springs.
Perception. Due to its association with spring-located solid axles, the leaf spring has a stigma unrelated to the spring itself.


Racing concerns:
Running stiffer springs left-to-right would require either asymmetrical spring mounts or an asymmetric spring. However, a few companies such as VBP offer kits that allow independent adjustment of spring rate and ride height at all four corners of the car.
Regulations often prohibit the use of leaf springs; NASCAR does not allow them.
The more compact shape of a coil spring can allow for variation in more suspension design and spring placement. Because a transverse leaf spring must span the width of the car, open-wheel cars are too low to use them. The leaf spring would have to pass through the gearbox or the driver's legs.
Coil springs are not car-specific. A Porsche, an LMP, and a Ferrari can all use a spring custom wound on the same generic equipment. Custom composite leaf springs require expensive retooling and cannot be used across car models.
The characteristics of coil springs in a performance environment are known, and racers will use what they know. Most race teams do not have adequate experience with leaf springs to use them in this capacity.
Carroll Smith is quoted in his book, Engineer to Win
If I were involved in the design of a new passenger vehicle, however, I would give serious consideration to the use of a transverse composite single leaf spring of unidirectional glass or carbon filament in an epoxy matrix. This would be the lightest practical spring configuration and, although space constraints would seem to limit its use in racing, it should be perfectly feasible on road-going vehicles, from large trucks to small commuter cars.

[Gixxersixxerman]

Originally Posted by Ryephile

YAY, navigation is optional on the 1LT and 2LT trim levels.

Curious that the car comes with a full-painted roof, and the visible center section roof is optional. We have yet to see a full painted roof, right?

The way they have things phrased with the seats implies the base seats are perhaps vinyl, as it's not until the 2LT it says "Performance Leather GT seats". Of course, figgin' typical, the good seats with actual bolstering are late availability.

Anyone notice the carbon fiber interior trim is optional? I wonder what the base trim looks like? Kinda scared it'll be awful cheap plastic. Please Chevy don't make it look like base/rental-car trim.

Super disappointed that GM is perpetuating the use of chrome wheels. I was hoping the lip service about pandering to a younger generation wasn't strictly cheap talk. The dealer installed matched luggage is cute to impress the soon-to-be ex-Mrs.

Looks like waiting for a 1LT with "competition" seats and Z51 is the way to go for the performance enthusiast. From what I can tell, all the reveal press cars were 2LT with Competition seats + Z51 + Mag-ride + visible carbon roof + carbon interior pack. Ka Ching no doubt.

According to the new car and driver interview. Even the base model is fully wrapped interior quote:

"The Interior is probably the single most upgraded area of the car. It's a fully wrapped interior; you won't see any molded color plastic anywhere. Even the base car is fully wrapped. Even without the leather option or the carbon fiber trim option, you get high quality vinyl, cut and sewn, and premium painted surfaces and aluminum trim, with upgraded soft touch materials"

[Ryephile]

Originally Posted by Gixxersixxerman

According to the new car and driver interview. Even the base model is fully wrapped interior quote:

"The Interior is probably the single most upgraded area of the car. It's a fully wrapped interior; you won't see any molded color plastic anywhere. Even the base car is fully wrapped. Even without the leather option or the carbon fiber trim option, you get high quality vinyl, cut and sewn, and premium painted surfaces and aluminum trim, with upgraded soft touch materials"

Thanks. I must've missed that tidbit in the press frenzy. I'd still like to see the real deal, which will happen in due time.

[swift996]

Originally Posted by Gixxersixxerman

I am not a Porsche fan.. So I am biased.. But please tell me from a design aspect anything "fresh" from Porsche.. It's a slight evolution in every model since the first.. Heritage from the beetle .. Blah... Yeah they are fast around a track.. But I think Porsche fans hate the fact a cheaper vette beats them all the time with that "boat" technology

Porsche has kept to it's heritage in the basic shape and flat-6 over the rear axle with the 911. Otherwise they continuously make improvements and integrate new technology into the 911.

Just my opinion but I have a great deal of respect for engineers that can pump at least 100HP/L which no American car manufacturer has accomplished naturally aspirated. Keep it small, light, and low.

Chevy has the engineering capabilities and technology but they are driven by accountants. They have made some strides but still lack the use of alternative technology (developed in the 1970s and on) that would produce a better performance solution. Things such as DOHC, Variable Valve Timing, and Direct Injection.

I'm not trying to start some long battle on the internet. It's just my opinion. If you look at the ALMS, the 911 GT3 RSR or 911 GT3 Cup isn't too far removed from the streetable 911 GT3. The C6 is a completely different beast. They lower the engine and mount it further back, they rip out your leaf springs, and drastically reduce weight.

[Ryephile]

Originally Posted by swift996

... they rip out your leaf springs....

Wow, that's crappy they steal his springs to make their racecar.










Seriously man, P&M build the cars according to the rule books, it has almost nothing to do with GM except purchase orders. It wouldn't matter if Chevy used anti-matter springs in the production car; if the rules say no, they're not used.

[ZDan]

Originally Posted by swift996

Porsche has kept to it's heritage in the basic shape

Funny, when it's Corvette styling, you say:
"They think this gimmick retro look will wow baby boomers with discretionary accounts"

Not that the C7 is particularly retro. If anything, it looks *less* like older Corvettes than the C6.

and flat-6 over the rear axle with the 911. Otherwise they continuously make improvements and integrate new technology into the 911.

Ditto Corvette.

Just my opinion but I have a great deal of respect for engineers that can pump at least 100HP/L which no American car manufacturer has accomplished naturally aspirated.

Power/engine weight = WAY more important than power/liter. And this is coming from someone who daily-drives an n/a car with 120hp/l.

Keep it small, light, and low.

Small-block aluminum OHV V8 is quite compact, relatively lightweight, with a low c.g.

Chevy has the engineering capabilities and technology but they are driven by accountants.

Have to make money, or car goes away. This is also very true for BMW and Porsche.

They have made some strides but still lack the use of alternative technology (developed in the 1970s and on) that would produce a better performance solution. Things such as DOHC

Adds size, weight, cost, raises c.g. height.
BTW Deusenberg had DOHC 4vpc engines in production cars in the '20s. I'm sure there are other implementations predating theirs.

Anyway, if you're building maximum usable power under a displacement limit, DOHC/multivalves rule. If not, there are alternatives that work just as well. Maybe *better*.

I haven't seen anything to make me think that DOHC/multivalve applied to the Corvette would make it "better", and actually I'm pretty glad they stuck to the compact, lightweight, elegant-in-its-simplicity OHV V8.

, Variable Valve Timing, and Direct Injection.

C7 has these.

I'm not trying to start some long battle on the internet. It's just my opinion.

And my opinion is that the struts on your cars are a bigger performance drawback than leaf springs or OHV V8 in the Corvette.

But then *every* design is a compromise, of course.

If you look at the ALMS, the 911 GT3 RSR or 911 GT3 Cup isn't too far removed from the streetable 911 GT3. The C6 is a completely different beast. They lower the engine and mount it further back, they rip out your leaf springs, and drastically reduce weight.

See previous commentary regarding leaf springs. That they don't use them on the C6R race car is NOT due to inherent inferiority.

Regarding "drastic weight reduction", the C6 Corvette (just over 3300 lb. for base and Z06) was *barely* any heavier than the 997 GT3 (just under 3300 lb.)

And modern Corvettes are WAY lighter-weight than modern-era 911 Turbos. Or M3s.

[LSxJunkie]

Originally Posted by Ryephile

YAY, navigation is optional on the 1LT and 2LT trim levels.

Curious that the car comes with a full-painted roof, and the visible center section roof is optional. We have yet to see a full painted roof, right?

The way they have things phrased with the seats implies the base seats are perhaps vinyl, as it's not until the 2LT it says "Performance Leather GT seats". Of course, figgin' typical, the good seats with actual bolstering are late availability.

Anyone notice the carbon fiber interior trim is optional? I wonder what the base trim looks like? Kinda scared it'll be awful cheap plastic. Please Chevy don't make it look like base/rental-car trim.

Super disappointed that GM is perpetuating the use of chrome wheels. I was hoping the lip service about pandering to a younger generation wasn't strictly cheap talk. The dealer installed matched luggage is cute to impress the soon-to-be ex-Mrs.

Looks like waiting for a 1LT with "competition" seats and Z51 is the way to go for the performance enthusiast. From what I can tell, all the reveal press cars were 2LT with Competition seats + Z51 + Mag-ride + visible carbon roof + carbon interior pack. Ka Ching no doubt.

They still have to pander to people in a situation to actually spend 65k on a car as well. Sales are sales. That's why you can get the wheels in either black, silver, or chrome. Before black, it was competition grey. Old men don't like black or grey wheels.

[RogerR]

Originally Posted by swift996

Porsche has kept to it's heritage in the basic shape and flat-6 over the rear axle with the 911. Otherwise they continuously make improvements and integrate new technology into the 911.

Just my opinion but I have a great deal of respect for engineers that can pump at least 100HP/L which no American car manufacturer has accomplished naturally aspirated. Keep it small, light, and low.

Chevy has the engineering capabilities and technology but they are driven by accountants. They have made some strides but still lack the use of alternative technology (developed in the 1970s and on) that would produce a better performance solution. Things such as DOHC, Variable Valve Timing, and Direct Injection.

I'm not trying to start some long battle on the internet. It's just my opinion. If you look at the ALMS, the 911 GT3 RSR or 911 GT3 Cup isn't too far removed from the streetable 911 GT3. The C6 is a completely different beast. They lower the engine and mount it further back, they rip out your leaf springs, and drastically reduce weight.

Forgive me. I suspect you are a very nice person, have a good sense of humor, good taste in significant others, fine fashion sense etc. I'm an engineer. That means I probably lack most of those things especially a sense of style. However, I do know engineering. I just put down the copy "The Anatomy and Development of the Formula Ford Race Car" I was leafing through to take a look at the activity on this thread.

I saw your post.

I suspect you have many skills and strengths but I don't think an engineering mindset is one of them. Fortunately ZDan covered many of the bases so I don't have to. I can say that the difference between the racing versions of the 911 and the street legal "racing versions" is immense. The changes to both the 911 and the Corvette as they migrate from the showroom to the track are extensive and expensive. For the price of those changes you could buy an F1000 car and lap the track as fast and still have money left over for a street legal Corvette or 911 depending on your preference.

Anyway, you really have missed many of the interesting and subtle yet surprisingly sophisticated design characteristics of the Corvette. The pushrod motor might look dumb but that's just a disguise. It's combination of power, efficiency, light weight and compact size is all but unmatched. Here's a older Corvette motor sitting next to a Porsche flat 6.


Some totally random (and likely drunk) guy posted this somewhere on the web

Originally Posted by ZDan

4.6 liter DOHC Ford mod motor vs. 5.0 liter OHV engine it replaced:


4.0 liter DOHC Toyota 1UZ V8 vs. 5.7 liter LS1 (same external dimensions as current 6.2):

I hope that at least illustrates the point that GM seemed to have traded large displacement for small engine.

[swift996]

^ Fair points

[Dimman]

@RogerR

I've thrown a bit of a challenge @ZDan a couple times, with regards to what may be a practical displacement limit to a V8 engine, but got nothing from him.

We've seen the Ford Coyote put some nice power and weight numbers recently. Now with the low lift flow advantage of multi intake valves, and ease of implementing cam phasing (particularly LSA control) and even lift and duration lobe-switching (not on the Coyote, afaik) of DOHC, giving it a head start on power to displacement and emissions, is it possible that the OHV GM setup will no longer be able to 'grow' itself competitively? Rotating inertia increase, heavier internals, physical block size increase, higher mounting due to longer stroke, could start to have rapidly diminishing returns on a V8 over 7 liters or so. A DOHC rival may decide to look at that and just make an efficiently sized smaller displacement with far higher specific output. (Say a 99x86 5.3L putting out a somewhat conservative 550bhp and 425 lb-ft.)

Is there a realistic practical displacement limit on the OHV V8?

[RogerR]

It's been far too long since I did anything with engines and honestly my area was more gas turbine related when I was there. As for details like that, I have certainly heard some people claim there is an idea displacement per cylinder but I'm not sure that's a hard and fast rule.

I would really have to spend a long time brushing up on fundamentals to answer that sort of question. Sorry.

[Gixxersixxerman]

I personally don't think chevy is close to maxing out pushrods technology on their engines.. The infamous R07 runs 9k + rpm, making between 850 to over 1000 hp all from 358 C.I. Carbureted... Now fuel injected.. I'm guessing if it went D.I. It make more.. These engine last 800miles plus at close to redline, and at the least full throttle.. True that's a tuned race engine. But the technology is there to trickle down when they need it

[Gixxersixxerman]

According to the info.. Only two in the country.. Now one is wrecked

[dem00n]

Two in the country? I keep seeing pics of them on the web.


Vettes get wrecked all the time, this is common knowledge to any car guy.