[ANSWERED] Latest MT test at Laguna Seca
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[ANSWERED] Latest MT test at Laguna Seca
The original question is here.
AliZ51 asked:
What is your take on Moto Trend latest head to head test against the ACR and GT3RS? The Z06 performed really well and made Corvette guys proud. MT pretty much loved everything about the Z06 with the exception of rear grip / oversteer issues. Randy said front grip was good but rear was very loose. Was the alignment checked on this car? Do you agree with Randy's comments that softening the rear will bring more grip for better corner entry/exit?
What is your take on Moto Trend latest head to head test against the ACR and GT3RS? The Z06 performed really well and made Corvette guys proud. MT pretty much loved everything about the Z06 with the exception of rear grip / oversteer issues. Randy said front grip was good but rear was very loose. Was the alignment checked on this car? Do you agree with Randy's comments that softening the rear will bring more grip for better corner entry/exit?
Tadge answered:
There are always interesting back stories associated with these tests, so I will share a few things. First of all, the alignment on the car was fine. The car handled great for our engineers performing 10 hard shake down laps at Milford before we shipped the car. The engine ran strong. We had no overheating or other performance issues in Motor Trend’s hands. So, I would like to address the handling comments, and answer the implied question, "Should the car have been faster?"
Regarding handling, we develop the Corvette at many tracks with the objective of finding a sweet spot for all from a vehicle dynamics perspective. It is evident from many other independent tests that the Z07 handling is spot on -- Super-capable without too much over steer or under steer. We do not want to overreact to comments about one vehicle, on one day, at one track at the risk of sacrificing handling for a multitude of drivers at many different tracks across the country.
That is particularly true in this case, as the story makes it clear the track conditions were far from ideal. Consider this quote about the Porsche:
“It says a lot about the GT3 RS that it’s the first and only car Randy’s ever spun while hot lapping MRLS,” Scott Evans says. “Not once but three times.”
Followed by these comments from Randy Pobst:
“I was struck by the wide gap in lap times between the Viper ACR lap record I set at Mazda Raceway with Dodge and the time I set for Motor Trend. The cars felt similar. It’s not a power issue. Top speeds on the straights and acceleration curves were similar. Grip was down. I braked earlier and had a lower minimum speed in nearly every corner. I attribute the difference to the track condition. Our MT test followed a motorcycle weekend, and those skinny bike tires don’t leave a nice layer of rubber the way race cars will. The track felt really green, as we say in racing. Perhaps it helps explain why the ‘Vette Z06 felt so unruly. The Viper had that great stable balance, same as at the lap record run, and data showed good power, just less grip. I blame the track.”
The Viper was set up for that track very well. Randy had just been in it one month earlier with SRT to set their claimed track record at Laguna Seca, so Dodge had the opportunity to fine tune the Viper for Laguna Seca. In the review, Motor Trend mentions that, "Dodge also gave us another ACR set up in Track mode — different compression and rebound settings for the dampers, a larger front splitter, a larger rear diffuser, and a different angle on the wing." One advantage of having a large rear wing, is that small changes in attack angle have a big impact to pitch moment, so you tune the aero-driven under/over steer balance at will. Of course, there are numerous disadvantages as well, such as the reduced practicality of the car.
So could we have gone faster? In a word, yes. In other similar comparison tests the two cars are much closer in lap times, but there will always be test-to-test variation. Bottom line is that the Z06 is one of the fastest cars in the world and can be used in so many more ways than a pure track machine can. That is something we are very proud of.
There are always interesting back stories associated with these tests, so I will share a few things. First of all, the alignment on the car was fine. The car handled great for our engineers performing 10 hard shake down laps at Milford before we shipped the car. The engine ran strong. We had no overheating or other performance issues in Motor Trend’s hands. So, I would like to address the handling comments, and answer the implied question, "Should the car have been faster?"
Regarding handling, we develop the Corvette at many tracks with the objective of finding a sweet spot for all from a vehicle dynamics perspective. It is evident from many other independent tests that the Z07 handling is spot on -- Super-capable without too much over steer or under steer. We do not want to overreact to comments about one vehicle, on one day, at one track at the risk of sacrificing handling for a multitude of drivers at many different tracks across the country.
That is particularly true in this case, as the story makes it clear the track conditions were far from ideal. Consider this quote about the Porsche:
“It says a lot about the GT3 RS that it’s the first and only car Randy’s ever spun while hot lapping MRLS,” Scott Evans says. “Not once but three times.”
Followed by these comments from Randy Pobst:
“I was struck by the wide gap in lap times between the Viper ACR lap record I set at Mazda Raceway with Dodge and the time I set for Motor Trend. The cars felt similar. It’s not a power issue. Top speeds on the straights and acceleration curves were similar. Grip was down. I braked earlier and had a lower minimum speed in nearly every corner. I attribute the difference to the track condition. Our MT test followed a motorcycle weekend, and those skinny bike tires don’t leave a nice layer of rubber the way race cars will. The track felt really green, as we say in racing. Perhaps it helps explain why the ‘Vette Z06 felt so unruly. The Viper had that great stable balance, same as at the lap record run, and data showed good power, just less grip. I blame the track.”
The Viper was set up for that track very well. Randy had just been in it one month earlier with SRT to set their claimed track record at Laguna Seca, so Dodge had the opportunity to fine tune the Viper for Laguna Seca. In the review, Motor Trend mentions that, "Dodge also gave us another ACR set up in Track mode — different compression and rebound settings for the dampers, a larger front splitter, a larger rear diffuser, and a different angle on the wing." One advantage of having a large rear wing, is that small changes in attack angle have a big impact to pitch moment, so you tune the aero-driven under/over steer balance at will. Of course, there are numerous disadvantages as well, such as the reduced practicality of the car.
So could we have gone faster? In a word, yes. In other similar comparison tests the two cars are much closer in lap times, but there will always be test-to-test variation. Bottom line is that the Z06 is one of the fastest cars in the world and can be used in so many more ways than a pure track machine can. That is something we are very proud of.
Last edited by jvp; 02-12-2016 at 06:19 PM.
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#3
Thanks Tadge. The Z is a great car, bottom
Line!
Line!
#4
I suspect those tires are way grippier than even the cup2's.
the V720 ACR tires are very different than the normal V720s probably. The normal V720s have a UTQG 200 and the ACR version has a UTQG 20!!!
"The Ecsta V720 (Viper Edition) has tested to provide lap times that are 1.5 seconds faster than every other competitive benchmark tire due to its unique compound and tread design targeted specifically for the Dodge Viper ACR." "The latest race tire compound technology with massive Kumho® Ecsta V720 high-performance tires (295/25/19 front, 355/30/19 rear), designed specifically for the 2016 Dodge Viper ACR, delivers laps times that are 1.5 seconds faster than off-road only race tires."
Tires can make a huge difference. And aero can make a huge difference. And track tuning can make a huge difference.
I think the real advantages the viper has is a slightly better power to weight ratio and a slightly larger tire contact patch (and maybe double adjustable coilovers?). Other than those things the majority of the track time advantage is stickier tires, much more aero, and track tuning with the aero. These cars have roughly the same core platform, roughly the same weight and power. You take the aero and tires out of the equation and you have the viper gt or gts, which i am guessing would have similar lap times as the zo6.
Put the same tires, aero, and tuning on the z06 and the times would be much closer, maybe even pretty much even. And if you wanted to make it a track monster you can do those other things to it. I just care that the core platform is pretty much just as capable as the core platform of the viper, except much easier to live with. I was hoping tadge would mention the tires.. but he didnt... so maybe the tires are not that big of an advantage? has me wondering. Oh and trackwise, i guess from lots of complaints on this site the viper probably has a big advantage in heat management.
That is my theory anyway. I also have a theory about dinosaurs being small at one end, big in the middle, and small at the other end.
the V720 ACR tires are very different than the normal V720s probably. The normal V720s have a UTQG 200 and the ACR version has a UTQG 20!!!
"The Ecsta V720 (Viper Edition) has tested to provide lap times that are 1.5 seconds faster than every other competitive benchmark tire due to its unique compound and tread design targeted specifically for the Dodge Viper ACR." "The latest race tire compound technology with massive Kumho® Ecsta V720 high-performance tires (295/25/19 front, 355/30/19 rear), designed specifically for the 2016 Dodge Viper ACR, delivers laps times that are 1.5 seconds faster than off-road only race tires."
Tires can make a huge difference. And aero can make a huge difference. And track tuning can make a huge difference.
I think the real advantages the viper has is a slightly better power to weight ratio and a slightly larger tire contact patch (and maybe double adjustable coilovers?). Other than those things the majority of the track time advantage is stickier tires, much more aero, and track tuning with the aero. These cars have roughly the same core platform, roughly the same weight and power. You take the aero and tires out of the equation and you have the viper gt or gts, which i am guessing would have similar lap times as the zo6.
Put the same tires, aero, and tuning on the z06 and the times would be much closer, maybe even pretty much even. And if you wanted to make it a track monster you can do those other things to it. I just care that the core platform is pretty much just as capable as the core platform of the viper, except much easier to live with. I was hoping tadge would mention the tires.. but he didnt... so maybe the tires are not that big of an advantage? has me wondering. Oh and trackwise, i guess from lots of complaints on this site the viper probably has a big advantage in heat management.
That is my theory anyway. I also have a theory about dinosaurs being small at one end, big in the middle, and small at the other end.
Last edited by TripleBlack99; 04-21-2016 at 02:25 PM.
#5
Drifting
Thanks Tadge, interesting to know.
#6
Melting Slicks
Very reasonable response. But it leaves me scratching my head a bit. Two track edition cars competed. One of them won.
One of them is a track edition car that can be driven on the street. By people in their 30s-40s.
One of them is a street edition car that can be driven on the track. By people in their 30s-70s.
We all have to tip our hat to SRT for this one. SRT built a track edition car that competed head to head with a car that appeals to the customer base.
My grandpa drove a Lincoln Town Car. It was pretty much two couches, one in front of the other, rolling down the road on a cushion of air. He made no attempt to force an automaker to compromise it's "track car" so that he could feel young again. He accepted his Town Car.
I'm 34 years old. One reason I love my C6Z. My no excuses, bada$$, N/A brute.
In thirty years I won't write GM poor reviews because my C11 Z06 is too stiff on the road. I'll have a forced induction base model or something. I'll put on shoes rather than demand that the whole world be made of carpet. I will change to the world, to my age, not insist that everything around the world change to me.
Bravo SRT.
One of them is a track edition car that can be driven on the street. By people in their 30s-40s.
One of them is a street edition car that can be driven on the track. By people in their 30s-70s.
We all have to tip our hat to SRT for this one. SRT built a track edition car that competed head to head with a car that appeals to the customer base.
My grandpa drove a Lincoln Town Car. It was pretty much two couches, one in front of the other, rolling down the road on a cushion of air. He made no attempt to force an automaker to compromise it's "track car" so that he could feel young again. He accepted his Town Car.
I'm 34 years old. One reason I love my C6Z. My no excuses, bada$$, N/A brute.
In thirty years I won't write GM poor reviews because my C11 Z06 is too stiff on the road. I'll have a forced induction base model or something. I'll put on shoes rather than demand that the whole world be made of carpet. I will change to the world, to my age, not insist that everything around the world change to me.
Bravo SRT.
#9
Tadge's answer makes total sense! Kudos to him! I totally agree with the approach and explanation around it.
Phil
Phil
#10
Pro
#11
Drifting
SRT pulled out of GTLM racing because Sergio doesn't see the value in spending the money in racing Vipers at the OEM level. As for the GTD Vipers, the 93 car finished on the podium behind two brand new cars - not too bad at all.
Last edited by djpatrick35; 02-16-2016 at 04:12 PM.
#12
Some guys should do a little more research about racing.
In 2014, the two-car SRT Motorsports Viper GTS-R team won at the final race at Petit Le Mans and clinched the GT Le Mans-class drivers’ championship (Kuno Wittmer) and the teams’ championship, beating both Corvette C7R's. That was the top GT class.
In Oct 2014 after their championship win, Dogge pulled Viper out of racing, so they did not even run against the Corvettes and others in 2015, same as in the Rolex 24 this year.
In 2014, the two-car SRT Motorsports Viper GTS-R team won at the final race at Petit Le Mans and clinched the GT Le Mans-class drivers’ championship (Kuno Wittmer) and the teams’ championship, beating both Corvette C7R's. That was the top GT class.
In Oct 2014 after their championship win, Dogge pulled Viper out of racing, so they did not even run against the Corvettes and others in 2015, same as in the Rolex 24 this year.
#13
cough "bop" cough..
#14
Le Mans Master
^exactly....
I think the world who pay attention to racing also know that SRT's sudden victory was a bunch of bs as well. I'll admit the team executed, did what they had to do, but IMSA was trying to keep them in the series, without question.
I think the world who pay attention to racing also know that SRT's sudden victory was a bunch of bs as well. I'll admit the team executed, did what they had to do, but IMSA was trying to keep them in the series, without question.
#16
Good comparison
Very reasonable response. But it leaves me scratching my head a bit. Two track edition cars competed. One of them won.
One of them is a track edition car that can be driven on the street. By people in their 30s-40s.
One of them is a street edition car that can be driven on the track. By people in their 30s-70s.
We all have to tip our hat to SRT for this one. SRT built a track edition car that competed head to head with a car that appeals to the customer base.
My grandpa drove a Lincoln Town Car. It was pretty much two couches, one in front of the other, rolling down the road on a cushion of air. He made no attempt to force an automaker to compromise it's "track car" so that he could feel young again. He accepted his Town Car.
I'm 34 years old. One reason I love my C6Z. My no excuses, bada$$, N/A brute.
In thirty years I won't write GM poor reviews because my C11 Z06 is too stiff on the road. I'll have a forced induction base model or something. I'll put on shoes rather than demand that the whole world be made of carpet. I will change to the world, to my age, not insist that everything around the world change to me.
Bravo SRT.
One of them is a track edition car that can be driven on the street. By people in their 30s-40s.
One of them is a street edition car that can be driven on the track. By people in their 30s-70s.
We all have to tip our hat to SRT for this one. SRT built a track edition car that competed head to head with a car that appeals to the customer base.
My grandpa drove a Lincoln Town Car. It was pretty much two couches, one in front of the other, rolling down the road on a cushion of air. He made no attempt to force an automaker to compromise it's "track car" so that he could feel young again. He accepted his Town Car.
I'm 34 years old. One reason I love my C6Z. My no excuses, bada$$, N/A brute.
In thirty years I won't write GM poor reviews because my C11 Z06 is too stiff on the road. I'll have a forced induction base model or something. I'll put on shoes rather than demand that the whole world be made of carpet. I will change to the world, to my age, not insist that everything around the world change to me.
Bravo SRT.
#17
Burning Brakes
I'm not butt hurt that the Viper won. Dodge built a car with little compromise for it's purpose and it shows. The C7 Z06 is for a different audience and purpose. No harm in that, but it leaves a void for those of us who came to Corvette because of the C5 Z06 and C6 Z06.
Where do we go from here?
Where do we go from here?
#19
Le Mans Master
I'm not butt hurt that the Viper won. Dodge built a car with little compromise for it's purpose and it shows. The C7 Z06 is for a different audience and purpose. No harm in that, but it leaves a void for those of us who came to Corvette because of the C5 Z06 and C6 Z06.
Where do we go from here?
Where do we go from here?
I HOPE the day may return, where Z06 can be somewhat what it was. I don't think that really may happen though. We may truly see C6 Z07 Carbon Edition values hold HARDCORE for this reason, that was the most hardcore NA car they built. Frankly, the C5Z was a beautiful execution of the Z06 concept...lighter, leaner, meaner but affordable, but it did so in a market that wasn't todays.
I currently think, that among the C7 lineup either a cooling modified/aero modified stage 1 Z06 or a mildly modded Grand Sport is the track car of C7. Z07 package is for the old boys and exotic buyers so they can say they have them. Corvette has run iron brakes on the racecar for how long and consumables are cheaper. The REAL Z06 lives within the brand...you just have to find it and finish the last 20% of the car yourself.