C8 Z51 beats C7 Z51 by 1 second on VIR full - track settings
12-02-2019, 02:43 PM
#1
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C8 Z51 beats C7 Z51 by 1 second on VIR full - track settings
https://www.motortrend.com/cars/chev...nt-understeer/
So... the C8 with track settings with Pobst goes 2:01.91 (with a passenger).
@Jim Mero did a best of 2:02.9 at VIR with a C7 Z51 with track alignment as well as a Sparco race seat and harnesses (how GM always tests their cars). Granted it was on MPSS tires which are not the latest and greatest as are on the C8 Z51. Mero had no passenger.
So... a casual CORVETTE driver (Pobst) who doesn't have as much seat time as a GM development engineer bested the lap time by 1 second... all doing it in stock seats and belts as well. 1 second a lap at VIR full is a lot; especially when you get close to the 2:00 mark. I'd be very curious to know what GM's engineers have run in the car.
Gives me a new benchmark for my lap timing in "as delivered" trim... 2:03 with nothing.
His VIR lap time in the stock alignment? 2:03.68. Time in the track alignment? 2:01.91.
So... the C8 with track settings with Pobst goes 2:01.91 (with a passenger).
@Jim Mero did a best of 2:02.9 at VIR with a C7 Z51 with track alignment as well as a Sparco race seat and harnesses (how GM always tests their cars). Granted it was on MPSS tires which are not the latest and greatest as are on the C8 Z51. Mero had no passenger.
So... a casual CORVETTE driver (Pobst) who doesn't have as much seat time as a GM development engineer bested the lap time by 1 second... all doing it in stock seats and belts as well. 1 second a lap at VIR full is a lot; especially when you get close to the 2:00 mark. I'd be very curious to know what GM's engineers have run in the car.
Gives me a new benchmark for my lap timing in "as delivered" trim... 2:03 with nothing.
Last edited by RapidC84B; 12-03-2019 at 09:17 AM.
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Popular Reply
12-03-2019, 07:12 AM
We never advertised the time. Actually when it comes to the VIR full course, the C7 ZR1 full course time is the only one we posted. I tried to convince the advertising folks to publish our full course time because the full course is what most of the track folks here drive and can relate to.
Each C8 model will be faster than the C7 it replaces. The Corvette platform will accept nothing less.
"The C7 Z51 was a significant improvement over the C6 Z51. I don't recall acceleration or braking numbers, but, if i recall correctly the lateral acceleration of the C6 Z51 was about .9g and the C7 Z51 was about 1.07g.
Relative to track performance
VIR Full, I believe the best I could muster in a C6 Z51 was 2:11ish. The C7 Z51 was 2:02.9
VIR Grand the C6 Z51 was north of 3 minutes, the C7 Z51 was 2:51
For reference we always had a C6 on hand at VIR so the times were compared on the same day.
At the Nurburgring, the C6 Z51 was well north of 8 minutes, probably closer to 8:15-8:20, and the C7 Z51 was 7:39 (with 2 offs)
Relative to the Grand Sports, the C6 was 8 minutes and the C7 was 7:27.
I suspect (hope) the C8 will produce respectable lap times if nothing else because of the DCT. On the Nurburgring in both the C7 Z51 and C7 Grand Sport, the entire lap was run in 3rd and 4th gears with the exception of 2 5th gear areas, where the acceleration rate dropped dramatically because in the ratio change. The Grand Sport essentially stopped accelerating because of the downforce."
Thank you, Jim
12-02-2019, 02:52 PM
#3
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12-02-2019, 02:54 PM
#4
Okay, I'll be the bad guy and the first to say what is on a lot of peoples' minds: not very impressive. I like the C8 a lot and have a deposit on one so don't confuse me for a hater, but the lap time and performance improvements were certainly overhyped.
12-02-2019, 02:55 PM
#5
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It's a huge amount at that speed. Anything under 2:10 at VIR full is fast, anything under 2:05 is really fast. I'll bet GM's folks have gotten near 2:00 flat in ideal weather.
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12-02-2019, 02:56 PM
#6
Drifting
Now to get the comparison time from the same drivers, possibly on the same days. Although the C8 is faster in the end anyway.
12-02-2019, 02:56 PM
#7
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So, stock from the factory it is not faster than the C7? I've got to be missing something.
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12-02-2019, 02:56 PM
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12-02-2019, 02:57 PM
#9
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Knocking ~2 seconds off a FAST lap at VIR just with extra camber is huge. Lots of potential there.
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12-02-2019, 02:58 PM
#10
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These things seem trivial to non-track folks, but seat an alignment are the two largest things second to tire compound.
Last edited by RapidC84B; 12-02-2019 at 03:04 PM.
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12-02-2019, 03:02 PM
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I'm honestly not sure if their new factory driver has turned an (un)official lap at VIR yet. I'm applying all of the pressure I can to get them to do that, though. Mind you: that's not much pressure. ;-)
12-02-2019, 03:04 PM
#12
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Ask your friends if the C8 track alignment settings can be achieved with the LCA eccentrics, or if the UCA washers have to be removed as well.
12-02-2019, 03:18 PM
#13
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EDIT - Lap times compared both had passengers.
Last edited by RapidC84B; 12-02-2019 at 03:29 PM.
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12-02-2019, 03:36 PM
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Casual in that his seat time is far far far far less than GM development engineers. Or someone like Mero who's job was to literally drive a Corvette.
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12-02-2019, 03:43 PM
#16
No, it is not. Same car (C8), same day, same driver (Pobst), same weight, same tires was 1.77s faster by just changing alignment.
So obviously 1sec when comparing different cars, with different alignments, different drivers, different days, different tires means next to nothing.
So obviously 1sec when comparing different cars, with different alignments, different drivers, different days, different tires means next to nothing.
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12-02-2019, 03:50 PM
#18
Melting Slicks
1.) Both cars had passengers.
2.) Both cars had "track alignment" settings.
3.) C8 had much newer and better tires.
4.) C8 had the power advantage while carrying more weight.
5.) C8 had the transmission advantage.
6.) Both cars were driven by highly experienced drivers who are faster than 99.999% of everyone on this forum (gotta leave that .001% since I am pretty sure Jim posts here).
One second seems pretty minimal in terms of improvement.
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12-02-2019, 03:51 PM
#19
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No, it is not. Same car (C8), same day, same driver (Pobst), same weight, same tires was 1.77s faster by just changing alignment.
So obviously 1sec when comparing different cars, with different alignments, different drivers, different days, different tires means next to nothing.
So obviously 1sec when comparing different cars, with different alignments, different drivers, different days, different tires means next to nothing.
1:59.2 (in a C5 Z06 ST2 race car), 2, 14 years. Now you go.
1 second is a lot of time. You must have missed that that 1 second was over a C7 with comparable GM recommended track settings driving by GM's best test driver in recent years.
No... sure haven't... but I'm guessing they're better than what Pobst put up. They have some really fast guys... the C7 ZR1 video where it did a mind blowing 1:51 was done by Mero's replacement. Mero was a few tenths off that best time. If I had to bet, I would bet that GM has a lap time better than Pobst's best.
Last edited by RapidC84B; 12-02-2019 at 03:52 PM.
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12-02-2019, 03:54 PM
#20
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The "different tires" part is really interesting in this. They alone could account for a significant difference. What's unclear is if is Mero's time was with "track alignment" on the C7 (my bet, it was). So reducing it all down as:
1.) Both cars had passengers.
2.) Both cars had "track alignment" settings.
3.) C8 had much newer and better tires.
4.) C8 had the power advantage while carrying more weight.
5.) C8 had the transmission advantage.
6.) Both cars were driven by highly experienced drivers who are faster than 99.999% of everyone on this forum (gotta leave that .001% since I am pretty sure Jim posts here).
One second seems pretty minimal in terms of improvement.
1.) Both cars had passengers.
2.) Both cars had "track alignment" settings.
3.) C8 had much newer and better tires.
4.) C8 had the power advantage while carrying more weight.
5.) C8 had the transmission advantage.
6.) Both cars were driven by highly experienced drivers who are faster than 99.999% of everyone on this forum (gotta leave that .001% since I am pretty sure Jim posts here).
One second seems pretty minimal in terms of improvement.
Pobst's time was with an OEM seat, 3-pt belt, and a passenger.
You keep downplaying 1 second... going from a 2:12 to a 2:11 is way different than going from a 2:03 to a 2:02.
Last edited by RapidC84B; 12-02-2019 at 03:55 PM.
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