I just bought the ZL1 from the August carpack and it won me $200k in the S class World Championship.
I will post my upgrades and tune settings below. First off, wow. This thing drives so much better than the SS. Although it still feels like driving a boat at times, it is a much more planted boat than the 2010 SS model. The S class Championship pitted the ZL1 against the Ferrari 599 GTO, Lexus LFA, GT-R, Lambo Reventon, Mclaren MP4-12C, and some others--but the ZL1 still won. My main goal with using the ZL1 against these exotic supercars was to reduce as much weight as possible and THEN add a little bit of power, to achieve a similar power-to-weight ratio that those supercars already have. The ZL1 weighs more than the SS, so weight reduction is PRIORITY.
So here is what I did:
Upgraded to [S/700] class.
ENGINE & POWER
Intake:
Race
Fuel Sys: Stock
Ignition: Stock
Exhaust:
Race
Camshaft: Stock
Valves: Stock
Displacement:
Race
Pistons:
Race
Supercharger: Stock
Intercooler: Stock
Flywheel: Stock
PLATFORM & HANDLING
Brakes:
Race
Springs & Dampers:
Race
Front & Rear Anti-Roll Bars:
Race
Chasis:
Race
Weight Reduction:
Race
DRIVETRAIN
Clutch:
Sport
Transmission: Stock
Driveline: Stock
Differential:
Race
TIRES & RIMS
Tire Compound:
Race
Front Tire Width:
295/35R20
Rear Tire Width:
345/30R20
Wheel: ATS Classic (or your choice)
AERO
None
CONVERSION
None
Tuning:
Tires: 30PSI Front, 30 PSI Rear
Gearing: Stock
Camber: -0.5 Front, -0.5 Rear
Toe: 0 Front, 0 Rear
Front Caster: 4.0
Anti-Roll Bars: 29.23 Front, 23.50 Rear
Springs: 828.0 Front, 812.1 Rear
Ride Height: 5.5 Front, 5.8 Rear
Rebound: 8.7 Front, 8.5 Rear
Bump: 6.6 Front, 6.5 Rear
Aero: n/a
Braking Balance: 60% Front
Braking Pressure: 150%
Differential Accel: 75%
Differential Decel: 75%
The race difficulty settings:
ABS: On
Steering: Normal
Stability: Off
Traction: On
Shifting: Manual w/ clutch (or just manual)
Sugg. Line: Off
Damage/Tire/Fuel: Simulation
Rewind: Off
Opponent Difficulty: Hard (Professional will win you more cash)
Opponent Upgrades: Yes
Class Restriction: Limited
Payout=+120% Earnings
Specs:
60 MPH Lateral G's: 1.14
120 MPH Lateral G's: 1.15
(And that's without aero kits)
Top Speed: 207 MPH
It is a great car in the game. And for anybody who is in the Camaro5 club on Forza, I will share the car in the garage so you can try it out.
