STG

STG

https://www.caranddriver.com/news/a2...le-spy-photos/

StudGarden

The sudden, breathless howls of torsional rigidity as the ultimate automotive standard are pretty much proof that the C8 has blown away expectations (and that's just the base model).

Porsche's back to back efforts of emphasizing that the new 911 base can be had stripped for barley under 100k and that silly app thing clearly show that they noticed and are concerned. Not that Chevy will cause them to liquidate overnight, but they are worried this will nibble into their sales. Oh look! You can display your virtual 911 cutaway build in your living room! Asked no one ever.

But hey, muh rigidity! So if that's what's holding C8 back from the power and the glory of cars it runs with now at multiples of its price, then all they have to do is offer a torsional rigidity package (I think they could put something together for 50-100K extra LMAFO!) and BOOM. Checkmate.

STG

K-A

Yeah, nothing fundamentally wrong with a sports car whose chassis is bolted together and less rigid than a 2014 Cruz. Lmao. Go check out a 60K mile C6 that’s been driven remotely hard and I’m sure you’ll come away thinking “solid as the day it was new.”

GM also had the best intentions with those ignition switches. They can do no wrong.

StudGarden

Every manufacturer has its issues at some point or another.

And I'm not saying C8 wins on rigidity. I'm just betting no one ends up caring. Playing the depreciation card is just silly too, especially against true collectible supercars or even small market GT offerings from Porsche. Drive a regular 911 off the lot and boom! Then when it's no longer under warranty, double boom. Put any real miles on it on top of that instead of bubble wrapping it and keeping it in a garage with a car cover...

I bet the C8 would appreciate immediately...if they only sold a couple thousand a year. That's. It really even the point though. And if it's really just a glorified Chevy Cruze, then Porsche very well just may end up losing some sales to a glorified Chevy Cruz...that just might even beat it on the track/ring.

And what's the rigidity of the 911 convertible again? I guess that makes it a glorified VW Cabrio.

And again, let's entertain the theory that C8 sucks because of this and that's why they will depreciate off a cliff and order will be restored etc. OK cool. So they at that point only need to offer a rigidity package (giggity) for 50-100K or a target delete option...maybe pair it with a few pounds of "lightweight glass" and a fabric door pull for another few grand and BOOM back on top. Easy button.

ZDan

As long as stiffness is sufficient for my needs, I don't care if it's "one of the least torsionally rigid cars available" (if that's even true). Beyond a minimum acceptable level of stiffness, I'm fine. Beyond that, it gets into diminishing returns very quickly.

Neither is the similarly targa-roofed Bugatti I referenced above. Yeah, it's stiffer at 22,000, but 1200hp and ~4200 lb, and of course $$$$$$$ and exotic in the extreme...

Believe it or not I try to avoid convertibles too, but I've wound up owning a few over the years, and they all held up very well over time.

I know, that actually *emphasizes* my point. A 7100 N-m/deg S2000 lasted for well over 240k miles including New England frozen winters and potholes and dozens upon dozens of track days (and it's still going strong with the new owner!) without falling apart or becoming "floppy" due to insufficient chassis stiffness. C8 is more than twice as stiff...

The FD had a 550hp 6.8 liter LS3 in it... FD and the S2000 could and did pull over 1g repeatedly at the track... Probably greater stresses from bounding over curbs at the track anyway, which of course I did a fair amount of...

This is a slightly different subject. I'll state again that additional increasing flex and rattling *over time* is not the same thing as chassis torsional stiffness. Again I'll point to my Honda S2000 with less than half the stiffness, which stayed tight and rattle-free (save for a softtop latch I had to replace) over its long and hard life. If you're worried about those issues and the car's reputation then fine, but IMO this is more of a design and build quality issue than base chassis stiffness issue.But I have instructed quite a few C5 and up Corvette drivers over the years and I haven't heard these complaints from them when talking about their cars.

Again with the fear of bolted joints, I don't get this fixation... There will be a modest weight hit (guess: less than 100 lb.) for this type of construction relative to an all-welded aluminum structure, but it's in the name of repairability of a mass-produced car.

Yeah, like Bugatti touting the extreme torsional stiffness of 22,000 N-m/deg... If 22,000 N-m/deg is *extreme* stiffness for a 1200hp 4200 lb. hypercar, then maybe 15,000 N-m/deg is perfectly fine for a 495hp 3550-3600 lb. mass produced Corvette. I think it is...

I hear you on the fixed-roof vs. open-top, for sure I would much rather they built a true fixed-roof coupe but to *save weight* rather than to increase stiffness.
IMO, the C8's performance is not going to be HURT by a torsional stiffness of 15,000 N-m/degree.

fast1

WOW, I've never seen so many myths exploded in one post. Thanks for sharing your expertise.

K-A

Of course nobody will “care.” That’s because GM markets Vettes with paper stats in mind and skimp on the underbelly. It’s how they get these cars to their price targets (unicorn dust sold separately). But look at how poorly older Vettes hold up and you’ll see where said skimping starts to come into effect, and when people will start to “care,” hence fairly lousy depreciation rates. Someone pointed out that in the first few years, they depreciate similarly to 911’s (which doesn’t hold true for 991.1’s which have outperformed on the resale market). That’s not a good look for the Vette as cars with much higher costs should naturally depreciate at a much higher initial rate.

And again. I avoid 911 cabrios for a reason. Thankfully Porsche give you a hardtop option which is bank vault stiff.

And that’s the thing about rigidity. It’s hard to engineer in a rigidity “package” when rigidity is the basis of how your entire car comes together.

At at least let’s hope they include the “ignition switch package.” Most buyers I’m sure would pay the 2 cents for a switch that doesn’t kill them.

Thing is, IMO none of this exonerates GM. Yes, I understand that torsional rigidity isn’t the only basis for how stiff and tight a car is. But it is certainly one. And when you factor in GM being historically the worst at maintaining frame composure and overall built quality tightness over time + the fact that no manufacturer has more “warning” tags attached to it than GM by NHTSA due to weak structures, and the fact that older Vettes tend to feel “floppy” compared to German or Japanese cars, and the fact that the C8 is mostly bolted together, plus the price point for the car and what it offers for said price: my “alert” flag goes up. Honda isn’t GM. Honda has made cars that are proven far more durable.

Bugatti touts that figure since as we see, it’s hard for a vert to get a high rigidity figure. But the C8 is NOT a vert (I guess both are targas) and you have no option for a stiffer overall chassis. The Bugatti targa is also 50% stiffer than the C8.

And Bugatti hardtops have huge rigidity figures.

What do you predict a hardtop C8 would have? I doubt anything Chevy makes, with the repeated materials compromises they had to make (someone posted a link stating they couldn’t get the sources they wanted so had to make compromises. Not to mention lack of welds which in no way gives confidence, repairs don’t take precedence to me, that’s for insurance companies to worry about) would exceed 25K. And that’s being generous. They just don’t have the construction capability. And 100 lb added due to bolts again
signifies there’s a structural compromise story here. I don’t buy the “easier repairs” excuses. No other high performance manufacturer puts emphasis on that. Conveniently, only GM.

Also, it was shown that they use a partially plastic floorpan under the seats. Which the reviewer pointed out as odd. Is that expected to be spun as a good thing too? Would you rather have a plastic safety cage or ultra high strength steels?

Again. The fact that GM are historically known to skimp on important structural measures, as well are the hallmark “rattle” company, is what exacerbates this subject to me. It would just be a tough pill to go from a 911 built to withstand 40,000 degrees of twist, to a Chevy build to withstand 15,000. And I don’t agree with the “diminishing returns” concept. I’ve driven used cars that have been driven hard and I feel there’s always ways to notice they can be tighter.

A 7,500 deg/nm S2000 is one of the last cars you want to be in, if that frame is put to a high load (read: impacts) situation. Not every accident is one and done. Many test different portions of the frame, and sometimes simultaneously. Whether or not torsional rigidity is the key factor to how it will perform doesn’t diminish the fact that it’s one important measure to see how much stress a car can handle in multitudes of situations.

Bemo

I love my '15 GTS and have no plans to sell it anytime soon.
That said, if I was in the market for a new sports car I would give the new 'vette a very serious look. The price of admission coupled with a massive naturally aspirated V8 a mere foot behind my ears would be difficult to resist.
Would prefer a glorious screaming ~$60k V8, than a new turbo-powered 911, much more expensive and a huge letdown with its fake exhausts, nubbin and pixelated gauges.
Both cars represent compromises except that one sounds better and saves gobs of cash.
Count me in for a C8.

K-A

I actually feel the same way. If given either for free, I’d take the 992 just because I know it’ll be a better engineered car, albeit the bland sound would bore me. If I’m paying, I’d perhaps take the C8 for the N/A V8 behind the ears alone.

Porsche needs to release a 992 Carrera with a 9A2evo to really grab my attention with the new gen.

Noah Fect

As he's explained, it doesn't matter. (I'm still waiting for someone, engineer or otherwise, to explain why torsional rigidity is a primary concern in rear/mid-engine cars.)

I agree with you there. That story about getting no-bids from their suppliers doesn't sit well with me.

That's exactly why the 992 no longer has actual exhaust pipes, just chromed openings in the rear fascia and rough metalwork behind it. They have stated unequivocally that this was done to lower costs due to rear collisions.

Porsche has been using plastic oil pans since the 991.2 generation. Materials tech is pretty awesome, huh.

Historically they've actually used balsa wood in the Corvette flooring, I believe. It's a valid-enough technique. Doesn't seem to be causing a lot of complaints among the C5 people.

Most engineering schools expect tighter reasoning than that. Didn't yours?

K-A

Torsional rigidity is a primary concern for any car. It’s cited as the benchmark basis to tout material and construction quality of a cars “innards” for a reason. Read up on how proud Koenigsegg is of their 50+K figure and what it means (and why it’s important) to them.

Why are track times a primary concern when most drivers will never track or drive their cars at the limit?

Re: the 992, I find their rear highly flawed looking due to that. However, I’ll take fake exhaust pipes over a bolted together chassis. All day.

Plenty have complained about the 991.2 moving to a plastic oil pan. Again, however, GM’s compromises keep coming back to structural integrity and safety. Kind of “funny” from the manufacturer who allowed ignition switches that killed 130 or so people to be used because they saved literal pennies, wouldn’t you say?

The C5 is the last car we want to use as a basis for comparison. Saying they used wood in the flooring doesn’t make using wood smart. It signifies how heavily compromised in construction the C5 is. No coincidence it hails from a generation of GM’s that have the worst NHTSA crash/structural ratings ever recorded.

Dr Chill

While I am a lifelong Corvette fan and currently drive a 911, the issue I see is Porsche is beginning to price themselves out of many people's affordability. The premium for the 992 over the 991.2 is excessive and the 992 is somewhat de-contented to even get to that point. I think the C8 Corvette is definitely going to appeal to many Porsche owners as well as owners of all other sports car marques. Hopefully the reviews after they are released for press use will be favorable.

Bemo

GM moved to a mid engine configuration and here we are hoping for a 9A2 in a 911, but a distant dream!

I'm starting to dig V8s more and more for their sonorous characteristics. Having one and comparing it to the 9A1 is quite interesting. The 911 is mean and raspy while the V8 is deep and authoritative. The 3.8L is still more pronounced than the S65 but I'll fix that with a carbon plenum (Eventuri or Karbonius) at which point I'm fairly convinced that the M3 would be the go to choice for sound theatrics with the 911 reserved for precision runs in the hills of CT.

I wonder if it will be a year or more before we can get behind the wheel of a C8 for a test drive...