Snrub
Snrub HalfDork
10/17/19 8:59 p.m.
JG Pasterjak said:

I'm not quite ready to call it just yet after a bunch og magazines tested a car on stock rubber that's criminally undersized in the front and no camber. I think the architecture is sound and I'm going to attribute a lot of this early grumbling to setup. There's a TON of adjustability in that suspension.

Sounds like you've identified some ingredients for a piece we'd want to read! When will you guys be testing it?

JG Pasterjak
JG Pasterjak Production/Art Director
10/17/19 9:35 p.m.
Snrub said:
JG Pasterjak said:

I'm not quite ready to call it just yet after a bunch og magazines tested a car on stock rubber that's criminally undersized in the front and no camber. I think the architecture is sound and I'm going to attribute a lot of this early grumbling to setup. There's a TON of adjustability in that suspension.

Sounds like you've identified some ingredients for a piece we'd want to read! When will you guys be testing it?

Man I'm still bitter that every other magazine in the world apparently got track time with these things in teh last couple weeks and we got F-all. 

But suspension-wise, they're very similar in design to the last few generations of Corvette. Lower a-arms with eccentric bolts and upper a-arms with chassis-perpendicular mounting that can be shimmed. Plus the aforementioned tiny front tires. Also, Z51s get threaded coilovers in the rear. There's definitely plenty of adjustability available.

b13990
b13990 Reader
10/17/19 9:49 p.m.

"The biggest enthusiasm gap I’m seeing seems to be between current Corvette hardcores and non-owners, with the latter being more excited about the new version."

That was something I wondered about myself. I posted a thread about it; the title was something like "Do quantum leaps within a model provoke a backlash?" Most of the people here answered "no," but they are (to paraphrase the article) probably more car enthusiasts / owners than Corvette enthusiasts / owners.

I think the bottom line is that when you fundamentally change what a model is, you're kind of expecting different people to buy it anyway- it's fundamentally different, after all.

Brett_Murphy
Brett_Murphy UltimaDork
10/18/19 11:36 a.m.
JG Pasterjak said:
Man I'm still bitter that every other magazine in the world apparently got track time with these things in teh last couple weeks and we got F-all. 

 

I'm hoping that eventually one will show up at GRM HQ for a long term test. Maybe the factory is just getting the short tests out of the way first?

It also wouldn't surprise me if somebody loaned you their personal one if the factory decides not to let you have a loaner.

z31maniac
z31maniac MegaDork
10/18/19 12:04 p.m.
JG Pasterjak said:
Snrub said:
JG Pasterjak said:

I'm not quite ready to call it just yet after a bunch og magazines tested a car on stock rubber that's criminally undersized in the front and no camber. I think the architecture is sound and I'm going to attribute a lot of this early grumbling to setup. There's a TON of adjustability in that suspension.

Sounds like you've identified some ingredients for a piece we'd want to read! When will you guys be testing it?

Man I'm still bitter that every other magazine in the world apparently got track time with these things in teh last couple weeks and we got F-all. 

But suspension-wise, they're very similar in design to the last few generations of Corvette. Lower a-arms with eccentric bolts and upper a-arms with chassis-perpendicular mounting that can be shimmed. Plus the aforementioned tiny front tires. Also, Z51s get threaded coilovers in the rear. There's definitely plenty of adjustability available.

I know, it's funny to watch non-car guys on other forums, "Oh the car is setup for understeer, so it obviously sucks."

Uh, hey guy, fix the alignment just like every enthusiast does on every car. 

But these are the guys that never use the cars, they just read and parrot R&T, Motortrend, etc. 

frenchyd
frenchyd UberDork
10/18/19 12:20 p.m.

In reply to JG Pasterjak : I just saw the convertible version, and it's price(74K)  

Until then I was thinking nah!   Let them depreciate a little before I get excited.  
 

With  the convertible ?  Lust  is great.  
for the record, I owned 2 Corvettes in the past  

 

MrFancypants
MrFancypants New Reader
10/18/19 12:23 p.m.

As someone who doesn't own a Corvette I don't really find this car to be more appealing than a C7. If anything I find the C7 to be more appealing because I can get it with a manual clutch. 

At the same time I have to admit that the Corvette just isn't for me as I don't really care about having a car that can run with Ferraris on a track. A base Porsche Boxster speaks to me in a way that no Corvette seems to, in that the engineers who developed it were concerned with the finer points of driving engagement beyond spec sheet performance numbers and Nurburgring lap times. 

When I'm up in the mountains enjoying a nice drive I find that my 10 year old GTI with its modified suspension goes around corners on my favorite roads faster than I'm comfortable with from a safety standpoint, so when I look at this car all I can think is "what's the point? What would I actually use this car for?"

 Very cool car though, and I am happy that it exists, but I wish GM had taken the brand in another direction. 

z31maniac
z31maniac MegaDork
10/18/19 2:14 p.m.

In reply to MrFancypants :

Just out of curiosity, what direction would you have preferred GM take the Corvette? 

MrFancypants
MrFancypants New Reader
10/18/19 2:57 p.m.
z31maniac said:

In reply to MrFancypants :

Just out of curiosity, what direction would you have preferred GM take the Corvette? 

Before I answer, I want it to be clear that I know what the Corvette is about, and has always been about.  So I don't want this to be taken as a criticism of the car.  It is what it is and it's wildly popular for a reason.

I think we're seeing the last generations of these kinds of high performance internal combustion powered cars.  If the idea of the Corvette is big performance at a low price, we're at a point where you can buy a sub-compact EV that'll do 0-60 in just over 3 seconds and the quarter mile in the mid 12's for half the MSRP of a C8.  It's only a matter of time until someone installs that kind of propulsion in a relatively light weight, stripped down two seat sports chassis and basically destroys the Corvette at its own game.

What I would like to see with the Corvette is perhaps some extra refinement perhaps at the expense of overall performance.  Give me the best, most visceral mechanical dino juice burning experience possible.  Give me telepathic steering that informs me of every pebble on the road, communicative brakes that make me feel like I'm touching the road, a rifle-bolt manual gearbox make it as joyful at all speeds as a Miata, and back it all up with the shove and sounds of one of the best naturally aspirated V-8s ever built.

Like most people I haven't even sat in a C8, much less driven one.  So maybe I'm wrong and it's actually all of these things and insanely fast.

NickD
NickD PowerDork
10/23/19 12:19 p.m.

Anyone see where Motor Trend put a C8 on a dyno and it turns out that GM was maybe be extra-conservative on their power ratings? As in 558hp and 515lb-ft of torque at the tires?!

Dave M
Dave M Reader
10/23/19 12:50 p.m.

In reply to NickD :

That's the charitable explanation. Less so would be giving the press more powerful cars. Didn't the article mention that the official HP figures were SAE certified and as a result in production the engine should be close to the official figure?

accordionfolder
accordionfolder Dork
10/23/19 12:57 p.m.

In reply to Dave M :

I read an article stating that the SAE certification process involves slowly moving the engine up the RPM and waiting for stabilization rather than just running through a single gear. I.e. heat soak/etc are problems. 

NickD
NickD PowerDork
10/23/19 12:58 p.m.

In reply to Dave M :

I know that in testing by a number of people, the Supra has been making a fair bit more than advertised. Billy Godbold, cam wizard at Comp, says that the numbers that Motor Trend published would be more than 98% VE, so the thinking is either that the dyno settings were adjusted to get those numbers, or GM slipped them a car with some serious skunkworks bits hidden onboard

"When MotorTrend Group tries to tell you the new 6.2L Vette makes 600+ Flywheel HP, you should probably run some sanity math. For a given displacement engine, you only have three "knobs" to make more power (RPM, VE and BSFC). To pass emissions, you cannot play all the race car games to get well past 90% VE at peak power. A really good BSFC is about .45 lbs/hp-hr. Maybe they should read their sister Hot Rod articles"

STM317
STM317 UltraDork
10/23/19 1:00 p.m.

I think there's an issue with the Motor Trend dyno tests. Maybe it's testing methods, or equipment setup, or the way that it's being reported but something is off.

When they tested the new Supra, (which Toyota rates at 335hp/365ft-lbs at the crank), the Motor Trend dyno test resulted in 332hp/387ft-lbs at the wheels.

When they tested the GT350, they showed 55hp and 20 ft-lbs extra at the flywheel.

Their 2019 Porsche 911 test showed 44hp and 88 ft-lbs more than advertised.

 

 

NickD
NickD PowerDork
10/23/19 1:09 p.m.

In reply to STM317 :

I haven't seen said video or article or whatever. Does anyone know where they are doing their testing? Hot Rod/Roadkill always seem to do all their testing at Westech Performance and all their data seems to be pretty spot-on and realistic. It seems like Motor Trend would use the same location, but then why are their numbers off so bad?

Keith Tanner
Keith Tanner MegaDork
10/23/19 1:10 p.m.

Imagine a car magazine testing a new car on the dyno and sidetracking the internet conversation because they didn't quite understand what they were doing. Man, that would be weird. 

z31maniac said:
Uh, hey guy, fix the alignment just like every enthusiast does on every car. 

You say that, but I've had SO many conversations with brand new ND owners who don't understand why they should change the perfect, robot-set factory alignment with something developed by a bunch of guys in a garage. Never mind the fact that the robot-set alignment is "about in the middle" and that the car improves dramatically with a proper alignment, and this has been the case for every Miata built for three decades.

So not every enthusiast does it on every car. Certainly not on new cars. And journalists never do.

Keith Tanner
Keith Tanner MegaDork
10/23/19 1:13 p.m.
NickD said:

In reply to STM317 :

I haven't seen said video or article or whatever. Does anyone know where they are doing their testing? Hot Rod/Roadkill always seem to do all their testing at Westech Performance and all their data seems to be pretty spot-on and realistic. It seems like Motor Trend would use the same location, but then why are their numbers off so bad?

Well, for one they're testing at the wheels and then (unclear) to get expected flywheel numbers. If you test at the wheels, report at the wheels. And something definitely fails the sniff test on the Corvette runs. 

STM317
STM317 UltraDork
10/23/19 1:18 p.m.
NickD said:

In reply to STM317 :

I haven't seen said video or article or whatever. Does anyone know where they are doing their testing? Hot Rod/Roadkill always seem to do all their testing at Westech Performance and all their data seems to be pretty spot-on and realistic. It seems like Motor Trend would use the same location, but then why are their numbers off so bad?

I didn't see it specifically mentioned in a quick scanning of the articles, but this photo was included with the story on the 911 test, and it looks like the same place in the other stories too.

STM317
STM317 UltraDork
10/23/19 1:26 p.m.
Keith Tanner said:
NickD said:

In reply to STM317 :

I haven't seen said video or article or whatever. Does anyone know where they are doing their testing? Hot Rod/Roadkill always seem to do all their testing at Westech Performance and all their data seems to be pretty spot-on and realistic. It seems like Motor Trend would use the same location, but then why are their numbers off so bad?

Well, for one they're testing at the wheels and then (unclear) to get expected flywheel numbers. If you test at the wheels, report at the wheels. And something definitely fails the sniff test on the Corvette runs. 

It sounds like they're assuming a 15% drivetrain loss across the board for every car they test. They mention it in the Mustang GT350Supra and Porsche 911 articles.

So their formula is something like Wheel hp/tq X 1.15  = Crank hp/tq. But I just ran their numbers for the GT350 with that 15% assumption, and they're reporting even higher numbers in their articles than a 15% increase. And instead of considering that perhaps their estimates for drivetrain losses are really high for a modern vehicle, or that they could be different for different vehicles, they just report numbers that are high and hammer out articles like "You won't believe how underrated the new ________ is from the factory!"

iansane
iansane New Reader
10/23/19 1:27 p.m.

Those horsepower numbers make me immediately thing the car was an engineering special of hand picked parts but the article states that the car was originally dropped off for MPG testing. I can't imagine a MPG ringer being the same setup as a hp ringer, or am I crazy?

Knurled.
Knurled. MegaDork
10/23/19 1:45 p.m.

In reply to NickD :

Except the OEMs have been beating 100% VE since the 1980s when they were first really able to play with intake runner lengths instead of having to make a carburetor happy.  Heck a '86 5.0 Mustang had peak VE of 102% in stock form.

 

 

Snrub
Snrub HalfDork
10/23/19 1:49 p.m.

It's one thing for a turbo car like the Supra to be a bit under rated. BMW makes a regular habit of it and they have higher rated versions of basically the same engine. Thus the numbers seems plausible and the acceleration figures seem to align with the dyno.

I don't believe a n/a pushrod V8, with only intake manifold changes over the previous version, gained ~150hp (~1/3!) and now makes just shy of 100hp/L without extra revs, etc. Earlier in this thread I posted some acceleration figures from the C6 Z06 which has similar rated power, which out performs the C8 at higher speeds. I don't think that would be the case if the C8 truly made that much power.

I suspect Motor Trend decided to publish this because it creates a compelling story. They must know this doesn't seem right and there was likely an issue.

Vigo
Vigo MegaDork
10/23/19 1:50 p.m.

Well, for one they're testing at the wheels and then (unclear) to get expected flywheel numbers. If you test at the wheels, report at the wheels. And something definitely fails the sniff test on the Corvette runs. 

Unlcear = 99% bullE36 M3. The drivetrain loss figures people use are almost ALL ridiculous. Just the thought that the losses scale linearly with added power is ridiculous. Then you get to the raw percentage % people are using and that's ridiculous. It seems like noone applies even the most basic sniff test before posting up extrapolated CHP numbers. 

On the other hand, it's also probably frustrating and sad to be in a publishing position that trends ever more toward 'Clickbait or perish'.  frown

Keith Tanner
Keith Tanner MegaDork
10/23/19 2:43 p.m.

I once saw a respected tuner (well, respected by himself and with a surprisingly durable reputation) add in a bunch of "correction factors" and manage to double the actual measured horsepower to come up with a power number he liked as his final result. 

I 100% agree that it's not a fixed percentage. That's, like 115% at the flywheel! 

 

nderwater
nderwater UltimaDork
10/23/19 3:30 p.m.
Vigo said:

Just the thought that the losses scale linearly with added power is ridiculous. 

Totally agree. If between dyno runs I take off my air filter and muffler, I might see a 5% power bump. Has the friction in my driveline suddenly increased as well?

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