Camaro Z/28 Nurburgring time = 7:37.47 !! [VIDEO]

[ZL1-V]

Originally Posted by Bhobbs

People do all sorts of stuff without recalibration but GM has to do it and make sure it will last. The Z/28 was also designed to run 19" wheels. I'm sure that was taken into account when they set up the suspension.

Why would the tires matter in recalibrating the suspension anyway? The car sits on top of the springs and shocks, sprung weight. That is what the ECU is reading along with the speed sensors. Just lowering the CG will not affect the Mag ride. If you lower it excessively then you have an issue. I lowered my ZL1 and have had no recalibration issues.

[TrackClub]

Originally Posted by 2SSRS@Gen5diy

Grow up, the ZL1 is one car and the Z/28 a different car, you are tiring to compare apples and oranges, add tires to this car but not power the outer car, bring what you got and lets see how fast they go, O GM they did that and the Z/28 ran fast, in the rain, and the tires you want to add are not rain tires, if you want to add the same tires and rims the Z/28 has to the the ZL1 then if there 8K in price we get to add 8K in horse power mods, no and if or buts..


Then will see if your 580HP ZL1 that is nose heavy, will out run a NA 7000 rpm 427ci monster.


If any one remembers back in the day that JusticePete said GM had 2 cars that will be coming out, one was good and one was grate? well we now know what the grate car was, and its called Z/28.

Rant over

Agree: "bring what you got" from your local GM dealer! And no, you can't get more power there for either of the cars. And why should a car that already costs 50% more need any additional options? As to the "nose heavy" ZL1: its F/R axle weight distribution is: 51.8 to 48.2. What's Z/28's? If you know it pls post it as I can't find it. Thanks!

[LOWDOWN]

Building the Z/28 with an LS7 AND significant changes to that engine would have made the now-$75,000 price point a REAL bargain. The nominal changes made to the Camaro-spec LS7 did NOT require as extensive a re-test/re-cert/re-validation as H&C/LTs would have...and getting GM to sign off on a 5/100 warranty for LTs would have been prohibitive.

NOT to mention further negative CAFE implications, already a factor in the limited number of Gen-5 Z/28s the world will get to enjoy...

Norm, your learned knowledge of vehicle dynamics, and their implications related to on-track performance, is always welcomed as a share, here...

Pete, your thorough understanding, particularly from an OEM-based "hoops 'n hurdles" standpoint, is our reward for good attendance, here, too.

[TrackClub]

Originally Posted by Bhobbs

People do all sorts of stuff without recalibration but GM has to do it and make sure it will last. The Z/28 was also designed to run 19" wheels. I'm sure that was taken into account when they set up the suspension.

Suspension travel and forces are immense during hard cornering, hitting the curbs, braking and even accelerating, etc.
8mm difference is aboslutely inconsequential to "making sure it will last". Albeit it does lower the CG which is almost always better for performance.
But yes, ideally, we would all like the suspension to be calibrated just so. But in real world of track events it rarily happens. Not to this level of detail.

[LOWDOWN]

Tires, and their ultimate gription, are important for all aspects of vehicle dynamics, ZL1-V. Ultimate cornering capabilities are factors for the StabiliTrak metrics, the T/C metrics, and the ABS metrics, before electronic intervention occurs.

More tire capabilities = more electronic leeway...

[Bhobbs]

Originally Posted by ZL1-V

Why would the tires matter in recalibrating the suspension anyway? The car sits on top of the springs and shocks, sprung weight. That is what the ECU is reading along with the speed sensors. Just lowering the CG will not affect the Mag ride. If you lower it excessively then you have an issue. I lowered my ZL1 and have had no recalibration issues.

Originally Posted by TrackClub

Suspension travel and forces are immense during hard cornering, hitting the curbs, braking and even accelerating, etc.
8mm difference is aboslutely inconsequential to "making sure it will last". Albeit it does lower the CG which is almost always better for performance.
But yes, ideally, we would all like the suspension to be calibrated just so. But in real world of track events it rarily happens. Not to this level of detail.

I don't mean that it has to be adjusted to function, but for the set up to be optimal, it would probably be best to adjust it for the different wheels and tires.

[JusticePete]

The tires on the Z/28 are DOT legal and standard OEM issue on a number of very high performance cars, but technically are not R compounds. The new Z06 has similar tires in the Michelin Sport Comps.

The 305 fitment on the Z/28 drops the car just over an inch. The over all diameter is 2" shorter than the ZL1 stock fitment. You can get into the on board computer and change the tire sizes with a USB or Tech II. It can be done with tuning software too. That will correct the speedo. The ABS cal on the ZL1 is not as aggressive as the cal on the 1LE so there are some extreme braking situations that may arise i.e. ICE warning. Very few drivers will ever encounter that on track. It is at the very ragged edge of extreme braking.

The ZL1 is a highly engineered automobile and specifically engineered to run with the OE GYs. The tire and vehicle development were simultaneous. Changing the tires, specifically the tread composition and side wall construction is far from ideal. The MRC system is magic and will make some adjustments, but the sway bars and spring rates will not be optimal.

The Z/28 is no different. It is an engineered package and was design to be optimal with the wheels and tires that came from the factory. The damping, spring rates and bars are designed to take advantage of the Trofeos. If we switched either vehicle to slick, the spring rates, bars and damping would require revision to take full advantage of the added grip.

The key t the ZL1 and Z/28 is to admire what the factory engineers have put into turn-key vehicles with full warranties. If you want more performance from either one, be prepared to make adjustments in terms of a full package. In that respect, without adding any weight or making other changes to the package, the Z/28 would accept head cam and tune upgrades without any package changes because it is over built from the factory. Adding more power to the ZL1 for track use should be done only with a dry-sump system. Oil starvation is a well documented issue with all LS motors in high G applications.

[Norm Peterson]

Originally Posted by ZL1-V

Why would the tires matter in recalibrating the suspension anyway? The car sits on top of the springs and shocks, sprung weight. That is what the ECU is reading along with the speed sensors. Just lowering the CG will not affect the Mag ride. If you lower it excessively then you have an issue. I lowered my ZL1 and have had no recalibration issues.

There is a difference between needing recalibrations vs possibly benefitting from them. You don't need to replace regular shocks and struts at 20,000 miles, even though they've lost some damping in that amount of use.

If nothing else, your spring rates almost certainly increased and the wheels are now sitting at different points along their camber curves than they were at when your car's existing calibrations were finalized - even if you returned the cambers to the factory preferred settings. The implication here is that the damping requirements aren't quite the same as when your car was 100% OE. If nothing else, I'd expect the low speed rebound to be a little softer than it really ought to be.

Actually, it's even legitimately possible that you might like the ride quality now better than you did before.


Norm

[Norm Peterson]

Originally Posted by LOWDOWN

More tire capabilities = more electronic leeway...

If the electronics are programmed to give it to you . . .


Norm

[LOWDOWN]

Originally Posted by TrackClub

Agree: "bring what you got" from your local GM dealer! And no, you can't get more power there for either of the cars. And why should a car that already costs 50% more need any additional options? As to the "nose heavy" ZL1: its F/R axle weight distribution is: 51.8 to 48.2. What's Z/28's? If you know it pls post it as I can't find it. Thanks!

From GM's announcement release:

The Z/28’s unique exterior is designed like a race car to produce downforce that presses the tires against the track for greater grip – up to 1.08 g in cornering acceleration – and faster lap times. The aerodynamically optimized design helped the Camaro Z/28 log a lap on Germany’s legendary Nürburgring road course that was four seconds faster than the Camaro ZL1’s and beat published times for the Porsche 911 Carrera S and the Lamborghini Murcielago LP640.

Power comes from the 7.0L LS7 engine, with dry-sump oiling, rated at an SAE-certified 505 horsepower (376 kW) and 481 lb-ft of torque (652 Nm). The engine will be built by hand at the new Performance Build Center within GM’s Bowling Green assembly plant.

A close-ratio six-speed manual transmission is the only transmission offered and power is distributed to the rear wheels via a Torsen limited-slip differential featuring a helical gear set, rather than traditional clutch packs, for optimal traction. The differential works in unison with Chevrolet’s proprietary Performance Traction Management system, allowing drivers to adjust the level of throttle and braking intervention to match their capability and driving environment.

The Camaro Z/28 is also one of the first production cars fitted with race-proven, spool-valve dampers, which allow four-way damping control, enabling engineers to precisely tune both bump and rebound settings for high-speed and low-speed wheel motions. The wider tuning range also allows dramatically greater damper stiffness without a significant change in ride quality. Additional chassis changes include stiffer spring and bushing rates for improved cornering response.

Lightweight, 19-inch forged aluminum wheels and Pirelli PZero Trofeo R tires reduce unsprung weight by 49.6 pounds (22.5 kilograms) per car compared to the 20-inch wheels standard on Camaro SS and ZL1.

The massive 305/30ZR19 PZero Trofeo R tires represent the first production-car application in the industry and are believed to be the widest front tire on any production car. To fully exploit their grip, the Z/28 also features Brembo Carbon Ceramic Matrix™ rotors and fixed, monoblock calipers. The large 394 x 36 mm front rotors are paired with six-piston calipers, while the 390 x 32 mm rear rotors are paired four-piston calipers. Compared to similar-size, two-piece steel rotors, the lightweight carbon discs save 28 pounds (12.5 kg) per car.

The combination of tire grip and braking power enable the Camaro Z/28 to achieve at least 1.5 g in deceleration. With standard front brake cooling ducts, the Z/28 is also capable of continuous track use.

I can't put my finger on it, at the moment, but I believe the WD = almost exactly 50-50.

4120 (ZL1 Curb) X 51.8% = 2134. Delete the blower and plumbing (and MRC), add the dry-sump (and Multimatics), delete 14 lb (brakes) and 24.8 lb (wheels/tires) and I suspect the Front weight will be near-1900 lb...on a 3827 Curb.

[LOWDOWN]

Originally Posted by Norm Peterson

If it's programmed to give it to you . . .


Norm

...which WOULD be the case with the Z/28..."track-focused"...1.08g cornering capability, and near-1.5g "ultimate", as per testing...

[2cnd chance]

Originally Posted by Blueclyde

Why are some of you seemingly reacting so heavily to the question of tires on an otherwise stock ZL1? I fail to see why such harsh reactions to this relatively simple suggestion of a comparison are being made. I have a ZL1 and have no issue of which is top dog, even with tires. It's a reasonable question for an enthusiast looking to purchase a track car from the Chevy stable to ask. I think this site gets bashed by being un-objective at times and this appears to be one of those times. I'm as Chevy loyal as they come (4 new Chevrolets that I own) and have had nothing but GM for the past 25 years. This question of putting stickier tires on a ZL1 is rationale one for somebody looking to purchase a trackable Camaro. I'm fairly certain exploration of this question will not discredit the Z/28 or hurt sales in any way.

I'll agree with you. However this has been discussed over and over yet the poster continues to ask the same questions hence my previous deja vu comment. I believe there is an existing thread ZL1 vs Z/28 and that is where this discussion should be. http://www.camaro5.com/forums/showthread.php?t=323245

Regarding a previous post on, when was the Z/28 ever a momentum car? 1Gen.

[TrackClub]

Originally Posted by JusticePete

The tires on the Z/28 are DOT legal and standard OEM issue on a number of very high performance cars, but technically are not R compounds. The new Z06 has similar tires in the Michelin Sport Comps.

The 305 fitment on the Z/28 drops the car just over an inch. The over all diameter is 2" shorter than the ZL1 stock fitment. You can get into the on board computer and change the tire sizes with a USB or Tech II. It can be done with tuning software too. That will correct the speedo. The ABS cal on the ZL1 is not as aggressive as the cal on the 1LE so there are some extreme braking situations that may arise i.e. ICE warning. Very few drivers will ever encounter that on track. It is at the very ragged edge or extreme braking.

The ZL1 is a highly engineered automobile and specifically engineered to run with the OE GYs. The tire and vehicle development were simultaneous. Changing the tires, specifically the tread composition and side wall construction is far from ideal. The MRC system is magic and will make some adjustments, but the sway bars and spring rates will not be optimal.

The Z/28 is no different. It is an engineered package and was design to be optimal with the wheels and tires that came from the factory. The damping, spring rates and bars are designed to take advantage of the Trofeos. If we switched either vehicle to slick, the spring rates, bars and damping would require revision to take full advantage of the added grip.

The key t the ZL1 and Z/28 is to admire what the factory engineers have put into turn-key vehicles with full warranties. If you want more performance from either one, be prepared to make adjustments in terms of a full package. In that respect, without adding any weight or making other changes to the package, the Z/28 would accept head cam and tune upgrades without any package changes because it is over built from the factory. Adding more power to the ZL1 for track use should be done only with a dry-sump system. Oil starvation is a well documented issue with all LS motors in high G applications.

Very well put (again). Trofeos and a large number of other like tires are indeed DOT legal R-comps intended for "competition" albeit legal to drive on public roads (not that anyone would wanna do it after a few track days when they become slicks).

I totally agree a car comes as a well thought out, designed and tested package. Yet ANY sports car's performance WILL increase on stickier tires notwithstanding all the other factors. So, to get a FULL advantage of such increase the car would need to be re-engineered again. But I will take a partial increase which likely averages 2-3 seconds per lap without the latter effort any time JUST for the price of the tires and alignment. As to the Z/28 power, yes, it can and should have more. If Lingenfelter can offer LS7 with 616HP for 6Gs RETAIL, GM should be able to do it even cheaper and better and with a longer warranty vs the tuner. I do hope it happens (within the existing price level).
Maybe a little "surprise" from Chevy, just like the unveiling of the car itself?

[LOWDOWN]

Originally Posted by TrackClub

If Lingenfelter can offer LS7 with 616HP for 6Gs RETAIL, GM should be able to do it even cheaper and better and with a longer warranty vs the tuner.

No one disputes the fact there's more available from the LS7. That is PRECISELY WHY it only has 505-net from GM WITH a 5/100 warranty.

ANY engine from ANY OEM can be enhanced...at a likely penalty to BOTH durability AND fuel economy, two things most aftermarket outfits don't have to concern themselves with.

And LPE's warranty is NOT 5/100... "With our commitment to producing quality products Lingenfelter includes our 3 year / 36,000 mile warranty standard on installed engine packages"