Next Corvette (C7) MID-Engined

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This isn't a guarantee, but what if this came to be? Good idea? Bad idea?

Someone at GM has been wanting to do this for a long time.

http://www.corvettes.sk/images/Prototypes/XP819/1964%20XP-819_01.jpg

posted by  What

Certainly different, but Corvettes have always been front engined, so it could spark some controversy between enthusiasts....

posted by  Cliffy

Eh I don't like the reasons for the shift really. I think they should stick to the corvettes front engined setup unless going mid engined results in gains. Im not sure it would, it very well could though. I like the looks of a long hood, that looks right to me. Maybe they could just move the driver and passenger and engine back to achieve the same result.

I think they should move the engine back and make the driveline more of a stressed structural components to save weight. I like where they were going with the engine solid to the rear of the car. Great idea. I think they should build on it.

posted by  rudypoochris

come again?

posted by  windsonian

Well if you look at the driveline of a C6 it is solid from engine to rear axle. The driveshaft is inside a metal case that bolts to the engine which bolts to the transaxle. This helps keep good balance and provides rigidity. I was suggesting they slide the engine even farther back and go with a longer hood and make the driveline more of a structural member to save weight elsewhere.

posted by  rudypoochris

I don't really believe any of it.

posted by  Mathew

So you want to use the drivetrain to take the stresses of the car's weight and inertia?? Don't you think you're going to drastically reduce the life of your drive components doing that? Can you imagine the cyclic stresses/strains? The necessity to over-design to remain under infinite fatigue life would hugely increase the weight of the drivetrain, thus defeating the purpose.

[Disclaimer]: obviously I'm making these comments without any calcs, but intuitively it seems (to me) crazy to use your transmission components for transferring non-drive related stresses.

Out of curiosity, by using this method, where would you make the distinction/joint between suspended and non-suspended transmission components?

posted by  windsonian

The transmission in the C6 is mounted in the rear and connected to the engine via "torque tube". It was designed to keep the 50/50 weight ratio to the front and rear. The torque tube is mounted to the the engine much like the manner of a bell housing would be. A ball and socket type of joint called a "torque ball" is used at one end of the torque tube to allow relative motion between the axle and transmission due to suspension travel.

http://www.vnexpress.net/Vietnam/Oto-Xe-may/2004/03/3B9D0C45/C6_chassis_1B. jpg

The torque tube is hollow and houses a more traditional driveshaft. There is consequently no stress on the "drive line". The design has been used in Porsche 944 if you're somewhat familiar with that setup.

posted by  DSMer

Ummmm... I know exactly what he was talking about... but it seemed from his post that he wanted the driveline to be structural..... In fact, that's exactly what he said.
So, saying "There is consequently no stress on the "drive line"." contradicts what he said.

Chris, I'm interested to hear your ideas. Were you, in fact, referring to what DSMer's talking about, and maintaining the rigid shaft housing, but using it for structural reasons? Or did you actually want to transfer structural stresses through the drivetrain components?

posted by  windsonian

Stop attempting to be a stickler. If you knew what he was talking about then you would have assumed that he was not using proper terminology. Its a bit too semantical to get hung up on a phrase of words that are so closely related together.

Unless you didn't know what he was talking about to start with. Somehow I find the latter of the two to be more probable. "What do you mean stress on the driveline, thats dangerous!"

No shit sherlock. Congratulations for pointing out the obvious. :clap:

*EDIT*
In case you didn't read this.

"The driveshaft is inside a metal case that bolts to the engine which bolts to the transaxle. This helps keep good balance and provides rigidity."

That SHOULD have cleared up any doubts you may have had.

posted by  DSMer

Don't try to answer for him. I wasn't being a stickler. He's talking about a proposed new design.... not the old one.

I don't assume he's not using proper terminology. I assume he knows what he's talking about, and I want to discuss it with him.



You make a "quote" that I didn't say, then say "no shit sherlock" ??:screwy:
You sure showed me not to make a point .... that I didn't make.



duh..... like i said, I knew exactly what he was talking about. But my doubts are not with the OLD design. He was talking about a NEW design. Extend your quote to read this (in case YOU didn't read it)

I'm not arguing what they DO do, because that would be kind of stupid. Notice that he's proposing that they do something different?? I'm discussing/debating HIS design, not the old C6 design.

posted by  windsonian

Ugh why do these threads degenerate so. The torque tube is part of the drivetrain. I wrote driveline, sorry. I used incorrect terminology since I interchanged the two although they probably are interchangeable, whatever). Yes I do mean increase the rigidity through modification of drivetrian components (such as the torque tube, obviously not the prop. shaft). Basically make the drivetrain double back as more of a spine of the car. No I haven't thought about all the details or the best way to do it. Yes I realize minimal torsional gains are to be had. I think its a good idea thats all. Whenever you can kill two birds with one stone you gain.

posted by  rudypoochris

ok ok....
so you want to keep the idea of a "shaft within a pipe".
So, as you understand it, the current design uses the "torque tube" for stiffness / rigidity, but not for structural strength??

If you're using it as a structural "spine" of the car, the whole thing would have to be suspended, would it not?
If so, then you'd have to either suspend the diff (or gearbox if it is in fact in the rear also) and put a couple of CV's on the axles, or have a break in the drive shaft just before the diff/GB.
I suspect you would go with the latter, which seems to be pretty much what they're doing with it now.

I guess it sounds (in general) pretty much exactly what they're doing with it now. If you're going to strengthen the spine, you just have to make sure your 1 stone is killing your birds. Where can the weight then be eliminated i guess? Is a structural member down the guts of the car the best chassis design? Because if it's not, are we really making any gains by using it that way? I understand you just want to give something 2 uses, but if it's not the most efficient chassis solution, then are we just doing it for the sake of it??

hmm.... a lot of questions .. not too many hard and fast answers yet. Interesting concept though.

posted by  windsonian

:sleep:

The torque tube ALREADY acts as a main part of the Corvettes structure. The rear end pushes on the torque tube, which in turn pushes on the engine which is mounted to the subframe that is a part of the cars frame.

The structural rigidity of the frame is already taken care of with the seamless tubes on the C6. Over engineering an already simple design won't fix anything.

posted by  DSMer

why are you telling ME this?

posted by  windsonian

Because you wasted several bytes of valuable bandwidth trying to elaborate and understand a theory that didn't need to be explained simply because it was faulty in logic from the get go. That is WHY.

Because I can tell you anything I want to. WHY are you reading it? Thats the more important question.

posted by  DSMer

Go easy. For the intelligent learned engineer you try to portray yourself as, you sure do get into alot of petty disagreements. I know you think you know everything, but the fact of the matter is that GM is already using it as a structural member to an extent. Thus it is possible that by furthering its importance as a structural member more weight may be saved or more stiffness may be had, either results in the same goal. Obviously there are limits. For instance maybe GM didn't go all out with it for cost reasons... comes to mind immediately.

No, a torque tube is not necessarily the best, or even a very good design at all for torsional rigidity. I was thinking more along the lines of a webbed "torque tube" that would be less tubular in shape and more planar. To it would be bolted the rest of the body. It would still be a unibody I guess, but it does go a little bit back to the old "frame" idea. In this case the spine as I have been calling it would be stressed. Basically the engine would become a cross member, so would the torque tube, and the transmission. Etc. Removing the drivetrain wouldn't make the car fall apart, but it would be severly weakened to the point that you wouldn't want to drive it at all if it did have an unstressed drivetrain in it.

These are just dreams of mine and penciled ideas though. I don't know if it will actually work. Was just a thought. Sorry I didn't think it all the way through or explain thoroughly.

posted by  rudypoochris

what about maybe your "tube" is not a single piece, so it could be made so important as to be necessary for the car to "not fall apart". if it wasn't a single piece, you could potentially still get the drivetrain out without destroying the car.

Like you said, it doesnt need to be a tube as such. It's only there to avoid having a bare rotating shaft (and for the afore-mentioned stiffness etc)

posted by  windsonian

Trying to copy european design i see...gay!

posted by  newyorker

This is all a WASTE of time. Explain to me. How can a planar shape properly house a circular tube giving it play equally in every direction? It can't. Thats the simple answer. Don't try to justify YOUR bullshit logic AGAIN. You can't even properly understand how a simple combustion works. What makes you think I would take your word on complicated chassis design?

"Removing the drivetrain wouldn't make the car fall apart, but it would be severely weakened to the point you wouldn't want to drive it"

Really? So I guess you have a car that drives without a drivetrain? Right.. and I suppose you also drive a hovercraft. F*cking pitiful. Just stop now. Please..

Of course I think I know everything. I was here before the creation of human life and I'll be here long after all of you are gone. I've accepted this FACT. Why can't you? Congratulations you've discovered the truth of life. :clap:

posted by  DSMer

Wrong question champ. It doesn't need "equal play" in all directions, it needs sufficient play in all directions. Which is completely feasible.


We're talking about the structure, not the transmission.... wow.
They not bother with reading comprehension for $30k?

posted by  windsonian

I think all you nerds are missing the point.
......................


If Chevrolet does this and keeps the Corvette affordable and "pretty", this will be an amazing image manuever for the Corvette. If the mid-engine design is successful and they keep improving the interior quality AND they maintain a good bang for buck...why buy a Ferrari? Well I understand the reasoning for buying a Ferrari but *this* Vette could make Ferrari/Lambo buyers think. 400+hp...mid-engined...decent interior...excellent performance...what will the Europeans bitch about?

If only GM worked so hard on its other cars like they do with their Corvette.


.......
Go ahead nerd posters...continue explaining engineering shit you don't really know.

posted by  What

Wonder if this next corvette will have a cheap interior and leaf springs too :banghead: goddamn GM needs to get their head out of their ass

posted by  newyorker

Apparently the leaf springs are working and at an affordable price. Let me guess you want a way better interior, and better suspension pieces all around and better this and better that. Okay then it will be the price of a ferrrari.

This is supposed to be a bargain priced supercar that why it uses some of the things it does.

posted by  Enthusiast

The corvette is a super car, but nowhere close to being a supercar. Using a non leaf suspension and better interior will not up the price of the car 120,000 dollars to put it in f430 territory...everything else on the corvette is fine its a great performer but for me the leaf springs are stone age, and honestly my civic uses a higher quality material for the interior than the vette. Not talking seats or head up display w.e it is, but just the dash I think mine would be worth more in scrap parts. If I was looking at a plastic car, id get an evo that performs just as well, handles better, uses modern technology, and is 1/2 of the cost of a vette

That or id get some Mattel toys..they probbably have less recalls than the corvette will also

posted by  newyorker

The interior really isn't that bad at all. It is ALOT better than even a new civics interior. Maybe you should try driving a C6. Yes, it has leather or atleast something close to it. Last time I checked the civic didn't. I wouldn't call the Z06 a supercar though. It does perform as one, but it isn't rare enough.

The fact of the matter is that those stone age leaf springs work. They are light weight an effective. Are you suggesting that by switching to coils which place more weight higher up there would be some sort of performance gain? The rear suspension is still fully independant with the monoleaf...

As for my idea being completely retarded and such regarding the use of the driveline as a structural member... Okay, I guess. They already do this to an extent though so I am not sure how you can complain that it wouldn't work... thats okay though, I didn't expect you to really be open to new ideas after your gross display of "knowledge" regarding the EFI system.

posted by  rudypoochris

Fact of the matter is its underengineered...I would never pay 60k for something that uses 25 year old technology in something as vital as the suspension.

posted by  newyorker

Pure ignorance.

I don't think you even know what a leaf spring is. What's wrong with the design? Where is it located? You'll struggle to answer these questions. Stop listening to Jeremy Clarkson or other anti-Americans hating on the Vette and go drive it yourself.

The C6 Corvette interior is excellent. It isn't Audi good, but it's better or on par with Boxsters and Lotus. Have you sat in one?

Evos are good, but I'd rather the FASTER, more refined, smoother riding, more powerful Corvette. Get real. These aren't the same leaf springs from 25 years ago, don't be ignorant. How old is the combustion engine?

posted by  What

This has been gone over before. It resulted in ChrisV saying pretty much what 'What' said earlier, just more in depth and some very valid (and technical) points were raised. I do tend to agree with you though, leaf springs are stone age, even buses don't use them anymore! :banghead:

It's all too easy to blame Jeremy Clarkson for why people think leaf spring suspension is old and past it, but that's the way it is. Old. And tired.

posted by  Cliffy

On par with lotus! hahahah the elise doesnt even have carpeting I believe its all plasticy and lightweight. A leaf spring is this...I dont see it on SUVs anymore
http://www.eng.wayne.edu/legacy/images/AEImages/Leaf_spring.gif

Yes I have sat in a vette and it was crap. the only thing I liked were the seats and HUD thats all. A vette cant touch an evo on the track at the strip sure, but dragstrips dont really involve too much driving skill. Its stoneage, I dont care if they are from 25 years ago or not. My ****ing civic has a more advanced suspension for ****s sake

posted by  newyorker

Nurburing Lap Times

7:43 --- 2006 Corvette Z06
7:56 --- Chevrolet Corvette Base C6
8:11 --- Mitsubishi Lancer EVO IX

Reality sucks.

Laps on the Nurburing can vary from driver to driver, but seriously, the Evo machine appears to be at a disadvantage.

The new Evo will probably be slower.

posted by  What

This post is so full of bull shit its retarded.

Im willing to bet a Vette could outrun an evo on most road courses.

And I get so tired of people saying driving at the strip is easy. Your not allowed to say that until after you cut some sub 2 second 60' times on street tires and over 300whp. You probably couldnt run a 14 in a c6.

Have you looked at your civics suspension. haha
Everytime we have one on the lift at work we all come and look at all the shitty looking parts and laugh. Yah your right your civic has such good suspension.

And I have a road and track sittin next to me so we are gonna go to that so I dont have to look anythign up.
skidpad slalom
Corvette Coupe non Z51 .95 67 mph
Evo .88 68.9mph

So looks like the vette has more grip but the evo is slightly more nimble. Id be willing to bet the vette would run just a good through the corners and then power away from the evo on the straights.

posted by  Enthusiast

Uhhh a Z06 will eat an Evo alive. Strip or road course. Even at the AutoX. It has alot more contact patch and it weighs less.

As for the corvette leaf spring... Your logic clearly shows why you own a civic and not a corvette. No offense...

The Corvette leaf spring which is oh so antiquated is actually made of composite. It weighs less than the coils it replaces, it is placed lower in the chassis, it outlast the coil spring, and you can adjust the ride height of the vehicle based soley off the end links with out changing springs. Fact of the matter is that it works, and damn well. It works BETTER than the coil springs it replaced.

Also, please realize the C6 Z06 actually ran a faster lap than the McLaren F1 around the Nuremburg ring. The Evo flat out didn't. Enough said on that Evo v. Corvette debate.

Road and track got this for slalom and skid pad, C6 on the left, Z06 on the right:

200-ft skidpad 0.93g 0.96g
700-ft slalom 69.9 mph 71.2 mph

Corvette is more nimble than the Evo, as I said, weighs less, has more power, and more tire.

posted by  rudypoochris

While that may all be true, and I might have been wrong, I still wouldnt buy one..i just dont like american cars plain and simple..I think I could have just as much fun in an NSX

posted by  newyorker

While thats great for you. I don't think your Chevrolets target audience. Can you afford said NSX or Corvette? If not I doubt Chevrolet cares too much unless your friends looking for super cars really listen to everything you say. In any case, as I was saying, while all that is your opinion, it doesn't change the fact that lots of people prefer the better performance and lower cost of a Z06 to an NSX, hence why Corvettes outsell NSX's.

posted by  rudypoochris

Thats not the only reason. A corvette is an icon, and a name, while an NSX is still a honda. Sure you can get used ones for as little as 25-30k, but still, an NSX is a honda and a corvette is a corvette, it has history behind it

posted by  newyorker

Stop the madness. "Just" a Honda? Thats what you believe people think of the NSX?

The NSX name is legendary. It changedFerrari. People who know cars know that the NSX was arguably the best supercar of its era. People who don't know cars won't recognize it as a Honda vehicle.

Honda was asking potential NSX customers to pay the price of a very good modern sports car for a car that hasn't been new since 1991...and yes, it still has less than 300hp. A 350z might out perform it, all of today's M cars will, but a Z06 would straight up stomp that mutha f'er. Today"s Corvette is way more powerful, more advanced and cheaper than the NSX. Aside from being in different price brackets, these are the reasons Corvettes out-sell NSX. Stick a Honda excuse up your ass.

posted by  What

I've asked you this befor,e but does it physically hurt to be this closed minded? Yore' a retard, pure and simple You don't even know the rudimentary facts behind the vette's composite "leaf" spring and why it works so well.

To repeat what I posted before...

1st... the Corvette uses an extremely lightweight composite monoleaf that is about as high tech as suspension components get. By mounting it on the car in the center of the "leaf," the spring actually carries it's own weight, which is better for suspension response. It weights A LOT LESS than coil springs. One leaf replaces two coils. The two coil springs weigh 3 times as much as the one leaf. Additionally the leaf is placed at the bottom of the car so that in addition to removing weight you lower the CG.

2nd...traditional buggy leave springs were multi leaves and were used as suspension arms as well as springs, which was bad due to being inherently flexible. Plus they had friction as the leaves rubbed against each other. The Corvette's monoleaf only has olne job to do: be a spring. That's what makes it unlike any other leaf spring suspension of old cars.

3rd... you really think coil springs are some sort of new development?

Why doesn't everyone use it?

-Engineers like to stick with what they know. Lots of suspension engineers are familiar with using coil springs. They could experiment with leaves if they wanted or they could stick with coils and get the job done.

-Perception. Just like pushrods, the leaf spring as a stigma attached to it. The reasons for the stigma are legit (a key component to old, heavy and typically poor handling suspension). However the reality is the sum of the older parts was the problem, not a specific part of it. In the older buggy spring type setups (like the rears of older cars) the leaf spring was not just the spring, but all of the suspension. The Corvette is actually a dual A arm suspension that has one half of a high tech composite leaf as the spring, and that's all the leaf does.

Coil race springs are not car specific. You select rates, diameters, length etc but you don’t have a specific spring for a specific car. If you want to order a custom spring Hypercoil will wind it to your specifications on the same machine they use for the next custom spring. A custom Porsche, Formula Ford and LMP car spring can all be made on the same machine. By the time the C6 evolves into a C6-R (they don’t start off with a production Corvette) the suspension geometry is so different that they couldn’t just mount a C6 leaf spring. It’s far too expensive to have a few custom leaf springs tooled up (you would have to buy the tooling as well as the springs) so they use readily available coil springs.

This type of universal tooling isn’t available for the composite leaf spring. Only the Vette currently uses the spring so you are making a Vette only part. This seriously reduces the market for aftermarket composite leaf springs (still there are after market leaf springs available for the Vette). The business case for custom equipment to make Vette springs is harder to justify since it’s a smaller market.

In reviews, such as between the Corvette and say, Porsche, the reviewers are using the stigma as fact. They still equate the leaf with old style buggy leaf suspension and look for reasons to call it out, even if they have to make up those reasons. The differences in the car's "feel" have nothing to do with the spring material, but with shock/spring rates and with car layout (the Porsche is heavily rear biased, the Corvette is evenly balanced, but heavy). But since the dual A arms of the Corvette have a single composite monoleaf half attached to it at the outer end, those reviewers think that the "stoneage leaf spring suspension" is sub par in comparison,and to blame for the differences in feel. It could be tires and tire pressures. It could be in alignment specs, or A arm geometry, or in the bushings in the steering. Assuming it's the composite monoleaf because you equate it with old style buggy springs is ludicrous, but magazine reviewers will do that. And so did you.

Ignorance colors your perception of the world and you think it's perfectly acceptable to BE ignorant and idiotic.

posted by  ChrisV

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