UnhandledException

Three different cases to analyze:

1) C7 ZR1. Official VIR lap time. Start watching at exactly 1:19. You can see that WOT run beginning 140 mph and ending 160 mph takes precisely 4.20 seconds (begins 1.17:30 ends at 1.21:50 - these are times off of PDR lap time).
2) C8 Z06. Indy PDR video. Start watching at 10:44. It takes nearly 9 seconds to do the same. I bet its 2x slow maybe tiny bit worse than 2x slow.


3) 992 GT3 Autobahn run. Start watching 0:42 seconds. It takes 5 seconds to go from 225 km/h to 258 km/h (which is same as 140-160 mph).


Something is seriously wrong here. This will be a problem in a lot of high speed tracks like COTA, VIR, Nurburgring.

Could this be why the car is delayed? Transmission redesign/gearing changes?

ZR1 weighs 3670 lbs and makes 750 hp. Z06 weighs the same and is down 80 hp. 80 hp does not explain the 5 second gap between two cars. Something else is at play here.

GT3 has only 502 hp. Its down 170 hp. Yes it weighs 3250 lbs, but Z06 still has substantial hp advantage.

Yes Z06 isnt a roll racer but neither is GT3. GT3 is its direct competitor. At the very least it should match GT3.

555ctsv

Yeah the pdr shows he's at WOT. I gotta say that's freaking lame above 130mph in 5th gear... you've got 3 gears to go, why is 5th so long??

I'm believe the LT6 does not have cylinder deactivation, could having 3 or 4 overdrive gears help them hit mpg/emissions targets?

UnhandledException

Updated OP to include GT3 autobahn run.

Iker

The car has a combination of bad gearing pulse inefficient aero (Cd = 0.47) = 9 second from 140–160 mph but who cares! you still can enjoy the sound lol

UnhandledException

I dont think you understand how slow 9 seconds is vs 5 or 4 seconds. Its several bus lengths (someone can do the math). Also the slowness is visible as low as 128 mph. I just couldnt do an apples to apples comparison with ZR1 due to how ZR1 was in turns and not WOT.

555ctsv

^oh I agree there was another thread but as far as I recall there was no.way to confirm he was at WOT. I swore there was no way he was based on how slow it was and this confirms it.

What happened to the reveal video,, "it just keeps pulling and pulling and pulling in all gears/rpm".. BS, maybe in gears 1-3

Any chance they would have geared these cars differently for oval track duty? Seems very unlikely

frodoz737

C8 Z06 will not and was not designed to beat the C7 ZR1. That comes with a later C8 ZR1, Zora or whatever they end up calling it.

SharkDiverZ06

This is going to play havoc driving to C&Cs if true.

UnhandledException

Z06 was advertised to beat or match a ZR1 as per Tadge. He said that in a track it is just as fast and can pull the same lap times consistently vs ZR1 heat soaking after 3 laps. His words not mine.

There is no way thats happening in every track. I also dont see mathematically Z06 beating even the GT3 in those tracks where you reach over 130 mph. And I would completely stop asking for Nurburgring time, it wont come.

Z0HS1CK

I have to wonder because this GT4RS has heavy aero, "only 493hp", yes only 32xxlbs, but was able to do a low 7 second 100-200kph run. What does a C7Z do 100-200?

I really think aero plays a big part in the C8Z Z07 package. The GM engineer said it multiple times in these ride along videos about, "feel that? How it squishes you down?"

So i think their focus was on big downforce. We have to accept this C8Z isn't a roll racer. But we have to give it one more shot when we see videos of the base z06 making straight line runs like this.

I still think it's amazing though lol

555ctsv

Itd be nice if it could at least keep.up with a C7 Z06 though! Freaking disappointing

z28lt1

No doubt if this is the final product, it is going to be slower than we want up there. The shift point is above 140 though, so I would ignore anything from 130-140 done in 5th gear because on the track that would all be done in 4th. No excuse after that.

UnhandledException

GT3 and ZR1 both make 1000 lbs downforce.

I also believe C8 Z06 does not make more downforce than the ZR1 if one simply does not factor in reduction of lift. In other words, take those channels under the body out, the wing and splitter together will not come close to the downforce ZR1 produces splitter + wing. Just look at the size, shape, height of each. I’m pretty sure its some marketing trickery they are using. So perhaps somehow Z06 has better drag, less lift, and considering those two factors, net downforce and at only lower Z06 speeds it may have more downforce (but I still fail to see how).

Nevertheless GT3 has 950+ lbs (or around that number) downforce. Do you see it hitting a brick wall in that autobahn video?

Z0HS1CK

The video i posted? It's not a GT3, it's a 718 GT4RS. So i was watching this.


I counted around 9 seconds for this C7Z to go from 124mph to 160mph, give or take milliseconds which does seem odd. Since the C7Z in this video has a stage 3 aero.

I don't know. Maybe you guys are right about the gearing. Or because the pace car has under 500 miles maybe all the HP wasn't unlocked yet? lol

z28lt1

Pulled up one of Poor-sha's VIR videos in his C7 Z06 with level 2 Aero. On the lap I pulled up he is off the throttle on the backs straight at 153, so I compared 140-153. The C8 Z06 is a tick quicker in that range than the C7 Z06, HOWEVER, there was a shift (manual) in there on the C7 --he's very quick on the shift -- but no doubt it is impactful, so if we could eliminate the shift, they would be awfully close. Best I've got with a quick search is that they aren't too far apart.

EvanZR1

At about 11:03 he goes from full throttle 4th to 5th and it looks like about a 2300rpm drop. That seems like an excessive spread, my '12 ZR1 with the more fuel-efficient 5th & 6th is about a 1900rpm drop from 4th to 5th.

UnhandledException

You didnt even watch the video clearly. PDR shows driver was 100% WOT. Did you actually go to 10:44 in the Indy video posted? PDR is very sensitive and wont show all green unless you are truly WOT.

555ctsv

I tried quoting to say the same thing.

I'm not sure how accurate the pdr is with braking/throttle input but I would hope it's accurate

z28lt1

In fairness Tadge said on a single lap it would "hang" with the ZR1 (his word) but be quicker in average lap over a session. In my mind "hang" does not necessarily mean just as fast, but almost as fast. We'll have to wait and see and I'm parsing semantics here and we'll all have our own opinion on how close it needs to be to "hang" ( 1 second on a 2 minute lap? 2? 4? ) Between tires, slightly better aero, and the architecture enabling the power to get down better/quicker, Maybe the Z06 gets bit of a head start out of a turn onto a straight, say a 4-5 MPH, which probably keeps it close or ahead on a short straight but then on the long straights the ZR1 would blow right by it -- so if the Z06 has enough advantage on the tight parts, perhaps (and we need to wait and see) maybe it isn't too far off on the big tracks with long straights.

No idea really, just think we'll need to see. It's not like GM isn't aware of VIR....

WalterSobchak

Considering top of 4th ends at 145 he was in 5th at 125 there was not an all out run. This car traps faster than GT3 and will be faster in a straight line when actually being driven.