01-23-2014, 12:16 PM | #505 |
Drives: 2013 Camaro ZL1 Join Date: Dec 2012
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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.
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01-23-2014, 12:18 PM | #506 | |
Drives: 2020 SS 1LE (previous: 2017 SS 1LE) Join Date: Mar 2012
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01-23-2014, 12:23 PM | #507 |
Downright Upright
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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. |
01-23-2014, 12:27 PM | #508 | |
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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. |
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01-23-2014, 12:29 PM | #509 |
Downright Upright
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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... |
01-23-2014, 12:29 PM | #510 | ||
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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. |
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01-23-2014, 12:46 PM | #511 |
Drives: Camaro Justice Join Date: Jun 2007
Location: Virginia
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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. Last edited by JusticePete; 01-23-2014 at 01:02 PM. |
01-23-2014, 12:50 PM | #512 | |
corner barstool sitter
Drives: 08 Mustang GT, 19 WRX Join Date: Jul 2012
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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 |
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01-23-2014, 12:54 PM | #513 |
corner barstool sitter
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01-23-2014, 12:56 PM | #514 | |
Downright Upright
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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. |
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01-23-2014, 12:58 PM | #515 |
Downright Upright
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01-23-2014, 12:59 PM | #516 | |
Too Many Great Choices
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Regarding a previous post on, when was the Z/28 ever a momentum car? 1Gen.
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Last edited by 2cnd chance; 01-23-2014 at 01:10 PM. |
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01-23-2014, 01:11 PM | #517 | |
Drives: 2020 SS 1LE (previous: 2017 SS 1LE) Join Date: Mar 2012
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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? |
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01-23-2014, 01:17 PM | #518 | |
Downright Upright
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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" |
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