vtknight

This site has had its share of excitement to say the least with the C7 Z06 release. This is I think normal for a new car release.

That said - I believe the extremism on both sides has created a dynamic that isn't useful.

Haters simply put the car down and fanboys heap on praise - neither of which is helpful in producing any positive change or potential improvement to the platform.

Racers and "Waxers" - obviously the racers want the fastest platform they can get - but some "waxers" state that they could care less about the cars performance. My question to those that feel that way; wouldn't you want the brand you own and cherish to be the best it can be - even if you don't use it? If you truly love your car and manufacturer - wouldn't you want them after 1000's of hours of design, testing and effort to produce the car they intended? The best car that they are capable to make?

This latest NISMO versus Z06 review had people focusing on the GTR.
That is a mistake in my opinion - we should forget the other car. The Z06 should be the focus.
The Z06 produced pre lap numbers that were literally some of the best Motortrend had ever seen and recorded - in this and in their last review of the C7 Z06.
Those numbers were worth a 1:25 or better lap time. They ran a 1:27 plus.

It's not only those moderates on this site that are wondering why - MT spent most of the video asking that very same question.

The reason is - IF everything were running at full capacity - I think everyone believes this car will be a world beater.
It has all the parts to be truly extraordinary.
I do not think it is a negative thing to try to find out why - and then challenge GM to find a solution.

This is what moderate, logical and civil discussion is for.

I hope this site will allow it and people will be open to it.

455230

[QUOTE=vtknight;1588887570

....wouldn't you want them after 1000's of hours of design, testing and effort to produce the car they intended? The best car that they are capable to make?

[/QUOTE]

They already did....based on their design and cost targets......

Flyboy22

I own a 15 Z06 and love it. That said, I'm disappointed with the latest result at Willow Springs just like you. I partly question the specific car and the test (ie running in Sport). Randy didn't call it loose over and over at Road Atlanta, and it certainly doesn't look loose while Mero drove it at VIR. Something seems off. Alignment? MRC settings?

I think more data points are needed. Heat may or may not be a problem. Drag almost certainly is, but the data seems to indicate much of it is inherent in the body and not due to the Stage 3 spoiler (ie only slight top speed gains by removing it). I do feel that GM put a lot of time into getting the fastest combination of drag and downforce, and still have faith that they weren't idiots in this regard.

I'd like to see more pro drivers wring it out on other courses. If other cars repeat less than stellar performances with other drivers, we can more confidently claim a DESIGN problem versus a specific circumstantial problem. A good amount of data still indicates the car is great (VIR & Road Atlanta time, multiple dyno tests, Milford results). Perhaps it's not as world beating as other super-corvettes have been in the past, but let's face it... nowadays the competition is far far stiffer than ever before.

tracyda

How many other comparisons would you need to believe there is a problem?

Seriously, Randy did try the car in track mode and said it was not stable/comfortable and too loose, so he went to the other mode to get the best time he could. As a note, he did the same with the Viper a year ago. I think unfair to assume the track mode is the fastest for all drivers as it can be too stiff.

There has now been several heating/pulling power comments, drag concerns, acceleration in the 100-150mph range, etc. I am not sure we need more data, but instead ask GM why/what is happening. GM should state the downforce/drag numbers, HP issues when hot, etc. and give us their solution vs suggesting no problem exists.

vtknight

So you believe it is performing as expected?

I will have to disagree with you.

GM hit it out of the park in regards to downforce, grip and braking and produced a more torquey engine.

They were (and I believe are) shooting for a world beating car.
The pre lap tests from Motortrend (both reviews) and Car and Drivers own reviews show extremely impressive track-specific data.

There seems to be other issues preventing the car from achieving what it is capable of.
I don't think the GM engineers planned (or are happy with) that.

M_C7

I think Motortrend went above and beyond to do everything to try to allow the Z06 to win the comparison. they literally removed the center of the wickerbill hoping to reduce drag. it did but made the car unstable it seems. first ive heard of a magazine having to modify a car from the way it was given to them to try to best another car. that shows you how much they thought it should have won in the first place. so I promise you if there was any thing humanly possible on their end to make it do better than it did they would have done it.

all im saying is the Z06 got beyond fair treatment and it seems the issue is something in the design itself and not something that can be chalked up to the testers or the conditions.

the lateral G was great which not to talk about the other car as this isnt what the thread is about but the other car having a bit less maximum G doesnt mean much in of it self as RWD and AWD get the jb done differently. but back on topic it didnt have the drag there so it excelled. braking again good but much lighter than the other car and much stickier tires so no surprises.

so from the outside looking in you have 2 separate issues. #1 is the aero package on the Z07 creates too much drag ( .37 I think vs the other cars .26 even with a massive wing) but its a catch 22 as it needs that aero to be halfway controllable as notice how randy commented time and time again about how he had to wrestle the time out of it and drove the other car at times with one hand

#2 is the heat soak timing from the conservative tune (how else are you going to warrant a 650hp S/C car for 100K miles)

I think they went too far possibly with the car and it resulted in a car that has brute but no balance. so it brakes well and pulls Gs well and accelerates well but maybe 650hp is too much.. maybe it needs a wing where air flows across vs a air dam spoiler.

I think this is why you guys havent seen a ring time. just think of the drag with stage 3 aero on the long final stretch there. if its killing this car at 140mph.. lets try 180+

Steve Snake Driver

While its nice to have other auto brand users on the forum, you'll excuse me if I suggest through your various activities that you have a certain bias. Now you appear to set yourself up as a spokesperson for MT. Just an observation.

vtknight

Again - FORGET about the GTR.

Concentrate on the Z06.

It's pre-lap data was better than any car tested by MT (including the NISMO) - and it went out and ran a 1:27 plus.

The pre-lap data and the lap time do not jibe. There appears to be an issue (heat, power loss and too much drag was mentioned by MT).

MT spent much of the video trying to understand what went wrong. The other car is irrelevant here.

M_C7

Also observe my neat 10 year member badge. Ive had a C5 a C6 and speced out my fathers C7 for him. Ive got a lot of experience with the last 3 generation platforms so I'm fairly well versed in the corvette world atleast enough to call it as I see it. With out bring accused of bias.

Sure I bring a unique input to the convo about the other side of the coin and I didnt even mention by name the other car that I have said unique input on in this thread. I think any Z06 moderate will agree my assessment is on point


Not a spokesperson for MT but the tone of the article and video was almost oh god how could this happen and there was almost reluctant praise for the other car. I'm just saying they bent over backwards to give the Z06 all it needed to win..so we can remove that variable

Shaka

One thing I can't stand are control freaks. In an attempt to have it their way, they must start a new thread.

jbondfl

I didn't go back and watch the video again,,, but I don't recall them complaining about heat soak or pulled timing.
Yes, they pulled the wickerbill to try to reduce drag. But I'm going to bet that the wickerbill, in itself, would not be enough difference in downforce to either account for a noticeable difference in speed or handling (to most). This car was handling badly for some reason and it is the FIRST test I've seen where handling was a problem. In all other tests it has been said that the driver couldn't find the handling limits.

I'm going to bet that the tires were TOAST. In any case we should take our "loss" and move on the the next comparo...

M_C7

heat soak timing comment was a general statement about the other known issue with the car as I thought this thread is more a state of the Z06 discussion.

With that said the editor of MT Scott Evans noted in the forums that Randy's best lap with the Z06 was the first hotlap. and Pobst also stated the car didnt feel like 650hp.

im not really down on the heat soak in itself as that would be hypocritical as the 2014 GTR track edtion in last years Best drivers car Leguna Lap was plagued with it and came in slower than the previous year model. but the exact car set the all time streets of willow record( at the time) with Pobst at the wheel too a few months before when it wasnt suffering.

but I will say when you want to warranty a 650hp S/C motor for 100K miles you are gonna be on the convervative side in tune and maybe it was a little overboard..thats all

KneeDragr

I agree with this post, and I want to add that I think the problems are fixable with the Z06, to where its track performance can match its skidpad, dyno, and brake numbers. Its just going to take some work. Hopefully there will be a mid-cycle refresh that tailors the engine, aero and engine tractability mid corner to get the car to live up to its potential.

I was reading the other day how in the new M3, when you set the highest track setting, it defaults the throttle mapping to the softest. The posers driving around on the street get upset, they want their sport+ throttle to be super sensitive, but it makes sense for the track. Its stuff like that the GM could tweak that makes the car hook up better for guys like Randy.

quick04Z06

Okay, Mr. VTK, let's talk.

Last highlight first:

You said some pretty harsh things to me in the Willow thread, which the moderators appear to have deleted. If you want "moderate, logical and civil" discussion, then by all means.

Now, on to the first highlight:

Just because a car can get it done on a low speed handling (almost autocross) figure-8 circuit does not mean it will tear up a road course at speed, so I am not sure it is fair to say the new Z "underperformed" based on its low speed handling numbers. But, the Z does seem to be cutting timing, which is the real issue with the car and may be related to heat issues with a supercharger, which are not uncommon. We'll see, as Chevy can certainly do something about this with a combination of improvements for both cooling and ECM management. If there are high-speed drag/friction issues, then they can be addressed, too. It is only money....

As to Randy Pobst's "oversteer" comments, he is literally the only writer/driver I have heard make such a statement. Neither CD nor Top Gear said such a thing. I would suggest either this unit was out of alignment, had overworn tires, needed tire pressure adjustments, or would have been more comfortable with more electronics left on. Plus, all pros have preferences and the pros that tuned the Z may like easier rotation than Randy likes when he sets up a car. I would say we leave this one alone until we get a few other pros who agree with Randy, as right now he is in a minority of one, best as I can tell.

I also have no faith that the NISMO test car was "stock", if you can call any car where 50 units are sold in the USA each year "stock". Unless a tester buys cars anonymously from a dealer, has them carefully set up to factory specs by an independent garage, and then tests them, you never know. You resolutely defended the GT-R and Nissan, but that is really neither here nor there. Nissan has a long heritage of manipulation and sandbagging relative to testing and I posted a link to an article about Nissan and the GT-R to that effect, but it was deleted. Whatever.

I personally wish the new Z with the ZO7 option were a bit more track-ready, good as it is. Most street cars have brake and cooling issues on track, and track rats are a minority, so I can see where GM made some executive decisions about options, cost, etc., that compromise track performance. I just hope that some track-oriented adjustments are made to the Z07 package, as it has gotten very close--just not quite there.

harlold

The numbers are disappointing, lets be honest.

But, I never have cared much about the rags anyway. This car will outperform most drivers of it by a long shot.

If I were a serious track rat, I'd be questioning the performance from what has come out. But for most, they'll never touch 3/10ths of the cars abilities.

I do think Chevy needs to address the issues, because how they billed the car and how it is doing are two different things.

Mr. Gizmo

on the Randy P. track time Z07 vs Gtr. It looked like the GTR was bettering the Z06/z07 by 5 to 8mph on the straights. That track had short straights compared to the "ring"

I will say the stock C7 Z06 sounds better under acceleration than any factory or Exhaust modded performance car I have ever heard. --- except for a high revving big block chevy with open headers.

vtknight

...

vtknight

Again - forget the NISMO.

To your points about the pre-lap data not necessarily being applicable to the cars longer lap performance (figure 8 specifically).

I disagree. Braking, lateral G/skid pad, and the figure 8 testing are very applicable to a cars lap performance - this is why reviewers do the tests.

Does it tell the whole story? No.
But it does help tell me that GM needs to make improvements to their heating and ECU tune (power). They are not going to create an active aero system - so that is what it is.

Hopefully the heating and power issues will help to push through the drag as road holding is not an issue. Apparently the tune has been tweaked and was on the VIR record lapping car.

That said - it's my understanding that in order for a new tune to be released GM would have to go through the emissions process again. I hope this is not true.

quick04Z06

Perhaps. But if GM told the g**d***** EPA and the NHSTA that a new ECM flash was a "needed repair", well, then maybe all is well.

You appear to be a track rat. If so, then you know setting up a car for a 60 mph autocross and a 150 mph road course are different. Low speed is all mechanical grip and aero/drag are not that significant; at track speeds mechanical and aero grip and drag become big factors and the balance can change. Plus, low speed cars are almost always set up to rotate more quickly and easily than track cars. Anyway, we can debate this all day, so we'll just say the Z is not as fast on a high speed road course as we would have liked.

vtknight

I agree with you post.