64drvr

Just add him to your ignore list.

SBC_and_a_stick

The most important lesson here is that the hybrids are hugely under-performing. Without a fraction of the budget the 918 had, and therefore with no hope of having a full carbon tub, the 911 is considerably faster than the hybrid car build by the same company.

In fact, I think with a small bit of GT2 like tuning, Porsche could have gotten the Turbo S to go faster than the hybrid as well many years ago.

And then the hybrid does not have the juice to go for that long nor can it due to extra weight.

I was never really impressed by the hybrids and I'm even less so now.

heavychevy

We are close enough (I think) to the same page to call it an agreement. The 1LE is a beast of a pony car. This does make it seem a bit odd that the Corvette is almost as heavy as a 2x2 chassy.
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I had a chance to drive a 1le at Road Atlanta but ran out of time driving a Gt350r. The torque is ridiculous. A bone stock one did 1:29 in the hands of a very talented amateur. Pretty much same time as the Z06 with factory driver.

johnglenntwo

Did you really need their 'Trolling'?
Your reply says, 'Not So Much!' You're more than qualified!

https://www.roadandtrack.com/car-cul...owing-economy/

Amazing huh! Guess I was kind of right?

Hope to see that extreme 1LE type Corvette validation happen real soon, as You probably know:
https://www.corvetteforum.com/forums...post1597681527

And Yes, GM probably could still put some parts together pretty easy mid year if they wanted in, as I have shown.


And
Data Collection -

SBC_and_a_stick

See:
"Next lap is better, a 1:32.46, downforce from the big wing allowing Randy to hold the Corvette flat over the crest at Turn 1, hitting 141 mph, according to our Vbox data."
https://www.motortrend.com/news/2018-best-drivers-car/

That confirms my intuition that the ZR1 will not go nearly enough on the straights to make up for its lack of grip vs. ACR. Heck, the Viper went 142.1 mph on the straight in MT's test. The laptime solidifies it.

heavychevy

It would IF* it were cooler out. What this confirms is that the ZR1 just doesn't perform well when it's pulling timing. And it clearly was in this case. Corvette engineers knew that at the end of a day of various test, it was in "safe" mode and wouldn't be nearly as fast hence the begging for a shot in the morning. I don't see how people ( not you specifially) can't see how blatantly obvious this is. This is not the same car after its been heated up. There is no way it should anywhere near slower than the ACR when flat down that straight. The ZR1 tested at VIR had clearly not been heated up yet. It was 14 mph faster on the front straight than the ACR.

FOURTEEN!!!!!

It couldn't possibly be more clear. Tadge must have to admit it first for everyone to believe it.

And no its NOT just normal heat degradation. Not even close. Losing 3 seconds per lap like Andy Pilgrim did is like going from a TT1 6lbs to 1hp ratio to a TT3 10lbs to 1 hp ratio. It's like going from 550 whp to 350 whp. It's not even close. You'd have to try real hard to find ANY performance car that suffers this much under not nearly that intense testing.




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Lavender

Hmmm MT doesnt say anything about heat soak. Heres what they got to say:

But he just can't get the big 'Vette to hook up coming out of slow turns. "I have to just roll that power in," he grumbles.

Some more:

Just how much that lack of traction hampered the ZR1 is made plain when Randy hits a staggering 154.67 mph over the crest at Turn 1 on his first flying lap in the McLaren 720S

This one oughta be good. Remember that he drove the ZR1 with PTM off right? Apparently he did NOT turn the nannies off in the Macca...

So we air down the McLaren to 29 psi and set the variable drift control a further two clicks away from the "off" setting before Randy heads out again.

Apparently Randy and MT are turning off the nannies @ some cars but not so @ others. Can you tell me why? C&D test showed the ZR1 being 1.7 sec slower/lap @ VIR (much longer track compared to LS) than the GT2 RS on the Cup 2 Rs (that tire isnt a factory Porsche equipment for those of you who dont know). What does that tell you? You cant just turn the PTM off and then cry about lack of traction yet keep the nannies on for other vehicles. Did he turn the nannies off in the Porsche and the Lambo as well because sure as hell he did NOT in the Macca. Seeing as how they kept the nannies in the Macca on...Id say no.

heavychevy

My expectations of you comprehending this are very low, but here goes.

Watch the video. Variable drift and PTM are simar but not the same. The guy drifts all the way through a turn, tire smoke and all with the drift control on. PTM would not allow that level of slip. And that much slip wouldn't be faster anyways. So in essence the drift mode still gives the driver complete control up until a certain angle. That is not what PTM does.

Simply put PTM does not allow a slip angle that Randy finds acceptable and Drift mode gives him more freedom with slip angles while still being present in case of an uncontrollable slide. PTM intervenes to try and control handling, removing more control from the driver while drfit mode only sets a predetermined boundary.

It's quite simple actually. Two different systems.

Lavender

So its okey to use this particular "nanny" to drop nearly a second off of your lap time because its not PTM. (Insert Star Trek palm here) I thought using nannies made you a bad driver?! Oh wait yeah I forgot...this aint PTM. Im sorry pal but you seem to have an axe to grind with GM and their PTM doohickey. Im done with you here... Hit me up with Randy runs 1:29.7x with all nannies on in t he Macca.

heavychevy

Assumptions......

The difference in speed could be because the tires were over inflated. You only assumed it was because of TC.

Most guys know it's easy to lose a second with over inflated tires sliding all over the place. Especially on a lower grip track like Laguna. Considering the tires were still hot when they bled them, it's unlikely they got all the way back to 32. So probably 5 to 6 lbs less psi that his first hot lap. That can easily cost you a second on a 2.5 mile track.

Case in point.... Lamborghini had a factory test driver there and set a lap, by the time Randy got in the tire pressures were 10psi too high. He was 1.3 seconds slower because of it. They didn't test it again because of the noise restrictions.

Sorry to ruin your theory with actual track facts.
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ViperFan1

For 150k I don't know how you can honestly look at an ACR and ZR1 and choose the latter but different strokes for different folks.

Lavender

So Randy went on the track with over inflated tires? Im sure the McLaren engineers that were present were like o yeah tire pressure is irrelevant. Go go go Randy! Yeah Cool Story Bruh. Hit me up when he runs 1:29.78 with all nannies off because you know...nannies are bad and makes you a bad driver!

Lavender

Yeah well the Gen V Viper went under due to poor sales. Or no sales at all... Looks like only a handful of people shared your opinion. Like it or not thats what killed the Gen V Viper. I'm pretty sure it was the same thing that got the Gen IV Viper as well....

Snorman

You can't be serious.
Tell me again how well Vipers sold.
S.

heavychevy

Can you read dude? Read the whole article and comprehend all the information, not just what you want to cherry pick.

Tire pressure can build a lot or a little usually based on how much moisture is in the air in the tire. Some times you set pressures, go out and after a few laps build 5 psi. Other times 10,15 psi. You try to guess we're you'll end up, sometimes you are way off. Usually you go do a couple laps come in and bleed pressure and go back out. Just like they did. When Randy ran the faster laps, it was after they bled the pressure down. It's one of the most common happenings at the track.

You need to drive more and bench race less. You are showing your lack of real world experience.

SBC_and_a_stick

No doubt, the power loss is drastic.

Hard to put this one on Motor Trend though, at some point you have to admit the car is what it is. Randy went one lap to heat tires, one fast lap, and on the third he set the time. So between 3:30 minutes and 5 minutes it was all done. Even if he were to set the time on the second lap instead, can you guarantee the engine output is not down by 100 hp by then? The fundamental reality of a TVS supercharged C7 on the road course is that by the time you heat up the tire the engine is hot too. Even if you used tire warmers a la Formula 1, the car is heatsoaked from driving slowly to get to the grid and so forth. The car needs half a minute at speed to reduce intake temps, go too slow and your tires cool down, go fast and your engine fluids heat up.

I find it funny that Motor Trend loves the engine but hates the chassis. The reasons I walked away from the C7 platform were almost all powertrain related. Can you really blame a chassis for struggling to put down 755hp on street tires with a single element wing? McLaren's chassis is 500lb+ lighter and still struggles to put down less. If you had a low cog, low weight, non-heatsoaked 600 hp naturally aspirated small block powering the car I think they'd sing praises about the chassis. The engine is so temperamental (pun) that you can't steer the car. What can the poor chassis do?

heavychevy

Correct, you can't really expect it to put down 755 and over 700 torque on streetable tires. This is one aspect where more weight in the back will help for sure with the mid engine.

Turbo power delivery is much more driver friendly than SC. A tad bit of Turbo lag is like using power in stages. Especially out of slow turns and places where surface grip is not ideal. The C7Z felt like it had all the power and torques instantly. That's great for roll racing but not much else. It's easy to tune turbos to an NA like powerband. There is a reason not many road race oreinted cars are SC.

Lavender

Yes he ran 3 hot laps. Let me repeat that for you one more time. 3 hot laps and then they bled the tires and adjusted the nanny. Want me to buy you a pair of glasses? Or are you saying the tires were already inflated before he went for the first 3 hot laps? Also...why is he using that drift control nanny anyway? Didnt you say that using nannies makes you a bad driver?

Lavender

Randy complained about not being able to put the power down. I dont think its a heat soak related issue...more like not using PTM kind of issue.

SBC_and_a_stick

Sounds like a lot of issues. However, I doubt PTM is a major driver here. We're talking about the max speed at the end of the longest straight. The McLaren did 155 mph vs. ZR1's 141 mph. PTM is good, but not that good.