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Autoweek/Andy Pilgrim 991 GT3 vs Z/28 at Barber Motorsport Park

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Old 04-07-2014, 05:32 PM
  #271  
Mercel
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Originally Posted by savyboy
Porsche apologists gamely grasp at tire straws when the real issue is:

... Those with open eyes and minds recognize and appreciate solution-oriented enthusiast engineering as demonstrated on the Z/28. The facts are undeniable and the results are there in lap times and everyday practicality.
Everyday practicality of the Z28? Thanks for the laugh. The Camaro is a pure track car, unless you are willing to change tires like your underwear.
Old 04-07-2014, 05:54 PM
  #272  
handful
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Given GMs current fiasco with the ignition switch where lives were lost, your characterization of Porsche willing to "sacrifise their owner's public safety on the alter of corporate profits" doesn't measure up. GM's cold calculation that a replacement part costing pennies against the value of a human life is the gold standard by which all others will be measured now and in the future.
"Objective eyes can see it no other way."

Originally Posted by savyboy
It's perfectly on topic as one of the differentiating factors between Porsche 991 GT3 and other car manufacturers. There is no doubt in my mind you are spot-on. In the vein of "too much (€) is never enough", the CL on 997.2 and 991 is a perfect example of Porsche being willing to sacrifice their owners safety on the alter of corporate profit.

Objective eyes can see it no other way.

Last edited by handful; 04-07-2014 at 08:05 PM. Reason: clarification
Old 04-07-2014, 06:20 PM
  #273  
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Z/28'is undoubtedly a monster. I just doubt that is such a bargain, 305 Trofeos all around ( good thing for interchanging) given the weight of it will hit hard on the pocket, but the ceramic replacement rotors will just put it into a different financial league and there is no arguing. I saw the numbers in car and driver today and I do not understand that it is mentioned here in the 991 GT3 thread. Please move it to Mustang boss 402 Laguna Seca /next NASCAR for the road thread.
Old 04-07-2014, 06:37 PM
  #274  
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Originally Posted by Metodt
Z/28'is undoubtedly a monster. I just doubt that is such a bargain, 305 Trofeos all around ( good thing for interchanging) given the weight of it will hit hard on the pocket, but the ceramic replacement rotors will just put it into a different financial league and there is no arguing.
Someone posted numbers on GM's rotors way back in this thread. I don't think they were that bad, with an aftermarket BBK of dubious value. Replacement steel rotors may provide the lower running costs you seek.

Originally Posted by Metodt
I saw the numbers in car and driver today and I do not understand that it is mentioned here in the 991 GT3 thread. Please move it to Mustang boss 402 Laguna Seca /next NASCAR for the road thread.
B/c the OP wanted to start a discussion of the merits of the mullet car v. the squashed beetle.
Old 04-07-2014, 07:20 PM
  #275  
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Originally Posted by Metodt
Z/28'is undoubtedly a monster. I just doubt that is such a bargain, 305 Trofeos all around ( good thing for interchanging) given the weight of it will hit hard on the pocket, but the ceramic replacement rotors will just put it into a different financial league and there is no arguing. I saw the numbers in car and driver today and I do not understand that it is mentioned here in the 991 GT3 thread. Please move it to Mustang boss 402 Laguna Seca /next NASCAR for the road thread.
Yeah, you're misinformed. Replacement CC rotors and pads for a full set is about $6,500. I just did this on my C6 ZR1 after 3 years and 35+ track days. 4 pad changes on the first set of rotors (about $900 for a full set of pads for front/rear). I don't drive easy either.

I'm just laughing over here because you're claiming running costs will put the Z/28 in a different financial league than a 991 GT3? Uh, what about the $75k up front price difference?!!? You have any idea how many sets of pads/rotors/tires/gas that will get you? A LOT.

Now, I'm not claiming the Z/28 is as good of a driving experience as a 991 GT3 because I'd take the GT3 cost notwithstanding. Actually, I'd take a C7 Z51 before a Z/28. But, the Z/28 is a pretty sweet car in the same vein as a RS Porsche and that's a good thing. Maybe an RS-like track ready C7 coming down the pipe? Yes, please.
Old 04-07-2014, 07:23 PM
  #276  
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Originally Posted by savyboy
It's perfectly on topic as one of the differentiating factors between Porsche 991 GT3 and other car manufacturers. There is no doubt in my mind you are spot-on. In the vein of "too much (€) is never enough", the CL on 997.2 and 991 is a perfect example of Porsche being willing to sacrifice their owners safety on the alter of corporate profit.

Objective eyes can see it no other way.
Hey Pete- does Movit makes ceramics for the z28? Even if they are $$$$ it mite last the lifetime of the car and even with that upgrade still worlds cheaper than the 991gt3. Only caveat is weight of car. Mike
Old 04-07-2014, 08:53 PM
  #277  
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Originally Posted by Mercel
Everyday practicality of the Z28? Thanks for the laugh. The Camaro is a pure track car, unless you are willing to change tires like your underwear.
Pure track car? Hardly. It's a Camaro at the end of the day. Big flimsy chassis, no cage and cheap additional of AC. Opt for AC (which most will do) ,switch the tires for MPSS and drive on the street, easily. Probably easier than most any GT3.

Can't say I'm buying the Camaro as a better track car than the GT3. It will survive, but even with all of the unproven tech on the GT3, I would still think the GT3 would be a better track car.
Old 04-07-2014, 09:38 PM
  #278  
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Originally Posted by orthojoe
Pete, we love you, but you don't really come off as being objective. The issues and concerns you bring up certainly are valid, but aren't without biased conjecture. Don't be surprised if other brands have problems with track use as well. It's the nature of the sport. I have no doubt that your opinions are based on real personal experience, but there is no such thing as a perfect car. You have had the priviledge of experiencing all of the nectar that Porsche has to offer. Some of us still haven't and need to taste it for ourselves, both good AND bad.
Right on!

I'll note for the record, what can't be seen is the grin on my face when I'm writing 95% of my posts
Old 04-07-2014, 10:20 PM
  #279  
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Originally Posted by savyboy
Right on! I'll note for the record, what can't be seen is the grin on my face when I'm writing 95% of my posts
Old 04-08-2014, 10:11 AM
  #280  
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I can't believe the transmission debate hasn't weighed heavily in this thread. Save for the comments about it being responsible for the Z/28's slightly slower lap time. Even if you can afford the large price gap between the two cars, if you're an MT die-hard, you'll need to look elsewhere in Porsche's line-up (or to GM's) in order to row your own.
Old 04-08-2014, 01:33 PM
  #281  
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Even if the driving experience of the 991 GT3 is better overall (which I think it is), it will be pretty hard to argue against the Z/28 having a more viseral and engaging drive. That 427 screaming to 7,100rpm, banging through the gears, jumping curbs, engaging "flying mode", etc.
Old 04-08-2014, 02:10 PM
  #282  
handful
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I owned a C6 Z06 for a few years and the LS7 is one nice power plant. However, throttle response was poor and heel and toeing was a waste of time (literally). This took away from the driving experience. The new vette power plant has direct injection so throttle response will have improved.
I may have missed this but if the LS7 engine is unchanged, there was an inherant flaw in the engine causing a few to blow along the way.
Old 04-08-2014, 02:49 PM
  #283  
frayed
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In case you hadn't read this. Of note:

1.
So it's a shame that GM's fear of unintended acceleration has the pedal spacing favoring snowshoes over Sparco boots. And when you do manage to connect with the throttle, there's just the tiniest smidgen of slack, engineered in to dial out driveline shunt at the behest of the GM passenger-car guys and against the wishes of the Z/28 team's racers.
This is not good and echos Handful's comments above.

2.
Not as exciting or engaging as the $130,000 Porsche 911 GT3 I jumped into for context days later—arguably the benchmark street racer—but money well spent, all the same.
The Z/28, resurrected: Road & Track Review

http://www.roadandtrack.com/car-revi...d-65-8-roa0514

The Z/28, resurrected
Wicked is as wicked does.

By Chris Chilton April 7, 2014 / Photos by Jamey Price



They call it the "flow tie." In the pursuit of maximum cooling efficiency for the Z/28's 505-hp V8, someone realized that the Chevy's bow-tie-shaped grille badge was acting like a giant stop sign for airflow. Why not take it off? No, the General wouldn't like that. Instead, an engineer whipped out his humble Dremel and cut away the center of the emblem, leaving only the outline. A simple solution, maybe, but that "what if?" attitude sums up the Camaro engineers' approach to the whole Z/28 program, a skunkworks project to create a genuine, no-compromise track car and hang the expense.

Chevy knows the Z/28 will only appeal to a certain type of person, just as the original did in early 1967. Built to homologate the Camaro for the SCCA's new Trans-Am racing series, the first Z/28's party piece was a solid-lifter small-block that helped Mark Donohue run off with the championship in both '68 and '69. But the average customer found it hard to rationalize spending big on a piddly 302 when less money would buy GM's 396-cubic-inch Camaro, with almost 50 percent more torque.

Fast-forward half a century and history is repeating itself. Thus far, the fastest, most powerful, and most expensive Camaro you can buy has been the supercharged ZL1. 35 ponies stronger than a Nissan GT-R and half the price, capable of lapping the Nürburgring in 7 minutes, 41 seconds and ripping 12-second quarter-mile passes at the strip, the ZL1 seems the ultimate Camaro. Who'd spend 20 grand more for 13 percent less firepower?




"The kind of person who wants a car because it looks cool won't appreciate the Z/28," says the Camaro's chief engineer, Al Oppenheiser. "We said we'd only build another Z/28 if it was true to its historical origins. This is not a trailer car, but it's definitely optimized for the track."

No kidding. The list of component suppliers reads like a SEMA exhibitors map: brakes by Brembo, seats by Recaro, rods by Pankl, trick tires by Pirelli, shocks by Multimatic. Every one of the Z/28's 190 unique parts was chosen by answering one question: Will this make it go faster? They obviously do, because despite giving away 75 hp to the 580-hp ZL1, the Z/28 bests that car's impressive Nürburgring time by 3.9 seconds.

You only have to catch a glimpse of that front cowcatcher to know the Z/28 means business. Just one part of a suite of aerodynamic mods designed to reduce lift at track speed, that splitter can withstand 250 lbs of aero force, and it's echoed on the Z/28.R racer that made its debut at Daytona in January. Rocker-panel extensions guide air as it passes along the Z's flanks to a two-position Gurney flap, while an undertray delivers air to a rear diffuser. In total, they provided 150 lbs of positive downforce at 150 mph.

What you don't notice is the lightweight battery, that the rear window is made from thinner glass, that the rear seats have been slimmed down and the tire-inflation kit banished to help the pudgy Camaro shift some pounds. All told, the Z/28 weighs 22 lbs less than a Camaro SS 1LE and 224 lbs less than the ZL1, bringing the total mass down to a still-not-svelte 3856 lbs. Also gone as part of that diet are the heavy cast-iron rotors, replaced by carbon-ceramics, and the ZL1's burly differential, not needed here because the Z/28 is packing a very different kind of powertrain.



While the latest (C7) Corvette Z06 shifts to a supercharged 6.2-liter V8, dubbed LT4, the old Z06's LS7 engine finds a home under the Z/28's hood. The single most expensive device on the whole car, it weighs 64 lbs less than the ZL1's supercharged LSA V8, and it comes stuffed full of titanium rods and a forged steel crank. Those ingredients help produce a pushrod engine that'll happily hang out near its 7000-rpm redline as well as deliver the feel and response that only a large-displacement, naturally aspirated engine can.

From both an engineering and a philosophical standpoint, only one kind of transmission was deemed suitable to handle the engine's 505 hp and 481 lb-ft of twist. The good news is that it's the Tremec six-speed manual from the ZL1; the better news, that it's mated to a 3.91:1 rear end instead of the supercharged car's 3.73, to more efficiently make use of the LS7's torque curve. Zero to 60 mph took us 4.0 seconds on a less than ideal surface, putting the car ferociously close to its ZL1 brother.

But judging a track car by its spec sheet is like reviewing an album based on the liner notes. So we've come to Alabama's Barber Motorsports Park, site of the Z/28's media launch, to try the car ourselves. While too technical and compact a track for us to feel out the car's high-speed aero prowess, there are enough elevation changes and transitions to uncover any car pretending to be something it's not.

Earlier, we did a handful of familiarization laps in a Camaro SS with the 1LE option, a handling package that turns the coupe from ho-hum to ho-ho. But the Z/28 is different almost beyond recognition.

It's obvious immediately. You feel it in the measured precision of the steering and the tautness of the damping that checks every minute body motion. Chevy says the car's bolt-on wheel-arch lips are there to promote stability, but they're also preserving the modesty of some humongous tires. The rear 305/30R-19 Pirellis are an inch smaller than those on the ZL1, but instead of that car's 285/35R-20 fronts, the Z/28 gets 305s at the nose as well as out back. That's an outrageous amount of tire for a front axle to deal with, 10 millimeters wider than the rear rubber fitted to a Ferrari 458. Did engineers worry about winding up with the steering sensitivity of an autistic Audi?

"This was a big debate," says GM's Adam Dean, the lunatic responsible for that 7:37 time on a partially wet Nordschleife. "Of course, the worry is that you'll have tramlining and a loss of sensitivity. I think we're close to that limit, but we have to run a big tire because we don't benefit from a camber change in cornering with a strut-type front suspension."



Translation: Everything's a compromise. And the front rubber is beyond monstrous, and monstrously grippy, so stop complaining.

The tires in question are Pirelli P Zero Trofeo Rs, summer track rubber that frightens in the wet but clings to dry pavement with prejudice. They take a couple of laps to warm up, while the oil pumping through the LS7's dry-sump system does the same. By lap three, the turn-in understeer has gone and the full extent of the car's staggering grip is revealed.

We're told the Z/28 can pull a mighty 1.5 g under braking, thanks in part to four-wheel carbon-ceramic brakes that are as impressive for their pedal feel (a common carbon-brake failing) as their total refusal to fade. But here's the crazy bit: The Z has so much stick that the 19-inch wheels are media blasted to add texture, because they were found to be slipping within the tires during testing. Not by a couple of degrees, or even 10, as Chevy first thought, but a whopping 370.

The electric steering is neither particularly quick by modern standards nor the last word in feel, but it relays all the important signals when you near the outer limits, remaining just on the manageable side of meaty, the weight falling off, tugging at your wrists ever so slightly as you push. Lower-control-arm link bushings stiffened by 50 percent lend a welcome improvement in precision around and just off the straight-ahead.

It's a well-judged setup, but it's the damping that steals the show. Instead of the computer-controlled, magnetorheological shocks fitted to the ZL1, the Z/28 gets a fixed-rate damping system designed to work with springs that are 85 percent stiffer in the front and 65 percent stiffer in the rear than on the SS. A pair of spool valves in each shock allows superior control of oil flow and independent compression and rebound tuning. Normally seen in top-flight motorsport, the only other road car to use dampers like these has been Aston Martin's $1.75-million One-77.



Predictably, they're awesome. You never forget that you're hauling nearly 4000 lbs of car, but the Z/28 manages its weight so well in braking and through transitions that you find yourself taking liberties. Turning in on the brakes late to point the nose. Climbing back on the power early to do the same. I can't think of another track-focused car with this much power and so few vices, so much stability. Whatever your own level of performance, the Z/28 has something to offer, nothing you need fear.

A five-stage Performance Traction Management (PTM) stability-control system is on hand to spare any novice blushes, but the first two settings would rather you just park the Z/28 in the paddock, and even the third feels like a sop to the tires' propensity to give up in the face of precipitation. No, modes four and five are where it's at. Four when the track is damp and you want the comfort of both throttle and brake intervention. Five when you want to go as fast as it's physically possible to go and just need help with the gas. Dean's 'Ring heroics were achieved with the stability system in mode 5. Switch it off altogether and you'll almost certainly go slower.

Fortunately, PTM's subtle nature and the combination of sticky rubber and a new Torsen limited-slip differential means the system never dominates the driving experience. The diff stays relatively open on the approach to a corner to kill understeer, the Z relying instead on its ABS for stability. But hit the throttle at the apex and the LSD hooks up quicker than high schoolers after prom. Chevy's guys say the diff is worth 0.7 second around GM's Milford proving ground and that the whole Z/28 package helps the Camaro lap 5.34 seconds faster than the brilliant last-generation Ford Mustang Boss 302 Laguna Seca—in some turns, achieving speeds an absurd 10 mph higher.

The Z/28's light, short-throw shifter also bests the Boss's, its gate precise enough to make wrong slotting inexcusable. Unlike the latest Corvette, there's no La-Z-Boy rev-matching software on hand to make you look like a hero. If you want to get downshifts right—and on a circuit, if you want to stay out of the sand, you really ought to—you need to do it the old-fashioned way, rolling on that throttle and hearing the growl from what must still rank as one of the best engines to come from America.

So it's a shame that GM's fear of unintended acceleration has the pedal spacing favoring snowshoes over Sparco boots. And when you do manage to connect with the throttle, there's just the tiniest smidgen of slack, engineered in to dial out driveline shunt at the behest of the GM passenger-car guys and against the wishes of the Z/28 team's racers.

But when we leave Barber and venture out on the road, it seems that Oppenheiser is being modest about the Z/28's streetability. The lack of trunk insulation is apparent in the increased tire roar, and those fat front Pirellis like to settle into the grooves in the pavement. But the ride is bearable, the big LS7 tractable, the clutch light. You probably wouldn't want to drive it every day, but you could, in which case you'd want to add a little weight with the optional radio and air conditioning.

Of course, doing so makes a pricey car even less palatable. At $75,000, the Z/28 is $20,000 more expensive than either the Camaro ZL1 or the new Corvette Stingray, brilliant cars both. Worse still, BMW's new M3 will undercut it by at least $10,000. But none are so focused as this.



Stuck in traffic, gazing at the sub-Korean plastic of the center console, the Z/28 feels as convincing a $75,000 car as a Toyota Yaris. But on a track like Barber, it feels invincible. Not as exciting or engaging as the $130,000 Porsche 911 GT3 I jumped into for context days later—arguably the benchmark street racer—but money well spent, all the same.

If you want a quick car, there are better buys, better Camaros. A ZL1 makes more sense for all but a few hardy souls. But for the guy who recognizes the difference between a fast car and one whose every fiber has been optimized in the pursuit of total performance, this Z/28, much like the original, is the real deal.
Old 04-08-2014, 03:04 PM
  #284  
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Just buy a set of aftermarket pedals. Seriously guys.

http://www.lingenfelter.com/mm5/merc...E#.U0Q5v7bD-ig
Old 04-08-2014, 04:59 PM
  #285  
frayed
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My concern isnt pedal placement but the throttle response. It's a pet peeve of mine and I hate it even in my wife's Q7.


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