Detroit 2008: Corvette ZR1 chassis display
As gorgeous as the 2009 Corvette ZR1 may be on the outside, it's what is under the skin that gets our blood pumping. Fortunately, GM stripped down its new supercar to the bare essentials and put it on display here at the 2008 Detroit Auto Show.
You can access our gallery of ZR1 chassis photos by clicking on the photo above. We've also got commentary on what you're looking at after the jump.
The Corvette is rather unique among volume production cars by virtue of its space-frame layout, which uses a self-supporting structure as shown above. Contrast this to the typical modern car, which largely relies on welded and bonded sheetmetal to bear the forces imparted by the suspension, passengers, cargo, powertrain, and other required components.
At the front of the car, tall tubular members help tie the suspension system into the firewall, much like the geometry that would be found at the front of a tube-frame race car chassis (although constructed rather differently).
At the very top of the picture is the large bumper beam that forms a significant part of the crash safety system.
Underneath the front end, a magnesium engine cradle (23) supports not only the powerplant, but also the aluminum lower control arms (22). The radiator is located in front of this; it looks small in this picture because of the angle. The black band running above the "22" and "23" tags is the transverse composite leaf spring, which saves weight and packaging space compared to traditional coil springs.
Just before the exhaust disappears into the frame, you can also see the close-coupled catalytic converters.
This shot clearly shows the front-engine/rear-transmission layout of the Corvette, but the exhaust system hides the large "torque tube" that ties together the two components.
A large plate normally covers the open bottom of the tunnel, which greatly improves the structural rigidity of the chassis.
Another magnesium subframe appears at the rear of the car. While its job of resisting the torque reaction from the driveshaft and differential is made somewhat easier by the aforementioned torque tube, it's still a difficult task to keep the control arms, differential and chassis in alignment when all 595 lb-ft of engine torque are multiplied by the transmission and axle gearing. When the inertia of the rotating mass is considered, the instantaneous torque transmitted to the rear tires is immense - perhaps on the order of 8,000 lb-ft or more, depending on the tires, road surface, and mood of the driver.
Although not obvious here, GM uses unequal-diameter half-shafts in the rear - 40mm on the left, and only 33mm on the right. Although the manufacturer has not explicitly stated why it does this, it's very likely that the left shaft experiences larger torque loads during hard acceleration. Making both shafts the same diameter would result in increased weight, and the Corvette team fights for every pound.
The titanium mufflers of the previous Z06 are gone, but in their place are these stainless-steel pieces with bypass valves (manufactured by Pierberg). Those who get a look at the ZR1's tail - that'd be most cars on the road - at least are treated to the sight of polished 4" tips.
The construction of the Corvette presents an interesting problem - where to store the fuel? The solution is to place twin tanks (15) ahead of the rear axle centerline, with a transfer system linking the two that allows the use of one filler neck.
The transmission (18) and rear diff (20) share a cooling system, which is a rather significant issue to address when one considers that the majority of powertrain losses - on the order of 10-15% - are dissipated in these two assemblies. For a 620-hp engine, that's up to 50 kW of power - enough to run several clothes dryers or electric ovens.
Magnesium is used once again for the roof structure. It's a material that's well-suited to this type of structural task - the strength-to-weight ratio is quite good, and better yet, modern processing technologies allow the metal to be injection-molded in its thixotropic (semi-solid) state - much like the way that plastic is processed. This results in a part with accurate details (like the honeycomb ribbing of the above part), which further improves the part's strength and stiffness.
Despite all the fancy materials used elsewhere, a balsa-wood composite is still used for the Corvette's floor. Don't be too critical, though - the material simply needs to act as a spacer between the two "skins", and balsa's mechanical characteristics and light weight make it perfect for this task.






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Reader Comments (Page 1 of 4)
Autostream 3:07AM (1/30/2008)
It looks to me like its all 'vette' fanboys here, not Nissans'.
The leaf spring setup on the Corvette couldnt be engineered any more wayward or awful. Using two leafs, like a pickup, would've at least been preferable to one, for christ! This links both rear wheels together! Acting exaclty like a solid axle.
And all in the name of cost-cutting. None of the world's premier car company's use leaf spring in their sports cars, or any cars for that matter. Only the company that is constantly in financial trouble. They make zero profit on their cars. The only thing keeping them from shutting the factories is the revenues from their GMAC finance arm, and finding new ways the cheapen their cars and then calling it part of their 'weight saving' target.
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Johnnyangel 11:49AM (2/19/2008)
Actually, selling off 51% of GMAC was probably the smartest thing GM did in a while, financially speaking- sold them off while the mortgage market was booming, and now Cerberus is in trouble with it... And since Cerberus owns Chrysler, they're hurting for cash anyway- they were counting on GMAC continuing to make year over year gains on into eternity. While we all looked at GM like they just sold the goose that laid golden eggs for a handful of magic beans, the markets took a downturn and proved them right. GM isn't broke just yet, boys- they're turning out better cars than ever before, and pulling off the biggest turnaround in the history of the industry.
Oh, and by the way- until your car pulls a G on the skidpad, shut up about the leaf spring. As far as saving money goes, that spring on the ZR1 probably cost as much as your whole car did.
Maverick_Nick 6:01AM (2/13/2008)
To all you guys whom think that the leaf spring construction is something that should go onto an old car or pickup truck, just remember that Ferrari is now also beginning to implement the leaf spring suspension on some of their models. In fact Delphi (owned by GM) supplies that suspension to Ferrari. This just proves that GM is using excellent quality and technology.
By the way the ZR1 also uses an active suspension system, which adjusts according to the style of driving. When cruising the suspension provides a soft ride. As soon as the driver picks up speed the suspension will stiffen up accordingly.
And for those of you whom think that an American muscle car can't corner, just remember that the ZR1 can pull about 1G around a corner.
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Johnnyangel 11:53AM (2/19/2008)
I think he meant the Coupe, Convertible, Z06 Coupe, Z06 Convertible, ZR1, and XLR.
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Scott VanPala 1:00AM (3/13/2008)
Maverick needs to stop doing his research from brochures. The ZR1 has adjustable damps (like lots of cars-porsche,ferrari,bmw), which adjusts, obviously, the dampening, which has nothing to do with the leaf spring setup that only the Corvette has.
BTW, the Corvette pulled 1g 20 years ago, its not a big deal, has little to do with track times, virtually nothing to do with handling, and has mostly to do with the tires and weight.
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Luis 8:01PM (1/14/2008)
Even the skeleton is beautiful!
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tbirdman 12:37AM (1/15/2008)
yes but evidence that this was never ever intended to be worked on. love to ride in one though
naggs 3:12AM (1/15/2008)
work on, what is there to work on
i cant think of a single thing any amount of time and or money could improve
from the sandwich construction floor to the honeycomb magnesium roof, i dont see a single part that is anything but the best that can possibly be done
that only way to improve this car would be to go to a full carbon fiber monocoque pushing the price above 300k.
no wonder they are making the next gen corvette a mid engine, there is no other way to make it better.
Godzilla 8:03PM (1/14/2008)
Ha ha
Nissan Gt-R will kick the crap out of ZR-1
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PandaBeat 8:08PM (1/14/2008)
Truthness.
SilverAero 8:27PM (1/14/2008)
Ummmmm no
Smeagle 8:38PM (1/14/2008)
I'm really enjoying everyones well thought out arguments on this topic.
Yes times infinity squared!
Temple 8:40PM (1/14/2008)
Please don't start another pointless fanboy war. Honestly, we are living in a renaissance of fantastic sports cars, and all we can do is bicker petty arguments about which brand is better?
Ed 8:55PM (1/14/2008)
You must be on something to believe that. The ZR1 weights less and has more power!
Eric Bryant 9:02PM (1/14/2008)
A lot of time was spent putting together this post, and it'd be great if we could keep the comments relevant to the topic. Thanks!
GM786 12:27AM (1/15/2008)
Your joking right? I hope you are because your blowing smoke. The Chevy Corvette ZR1 is going to eat the Nissan GT-R for lunch.
naggs 3:14AM (1/15/2008)
why is it that the gtr guys always bring up corvettes?
oh and i cant wait till the z51 burns the gtr
meshies 9:12AM (1/15/2008)
There should be no argument over GTR vs. ZR1. Anybody that has the slightest understanding of life on earth knows that the Zr1 will perform better than the GTR. The ignorance is comical. You GTR fanboys probably think cold water boils faster than hot water.
mg1942 4:49PM (1/15/2008)
No, the ZR-1 will only keep up with the GT-R in some of the world's most prestigious race tracks... NOT the Talladega ;)
Thetruck454 8:10PM (1/14/2008)
It was stated before that the unequal half shafts are to reduce wheel hope by having different harmonic frequencies due to the different diameters
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