Description
1. Suspension: The factory suspension was very hard, caused by the stock Bilstein struts. This caused the car to be unbalanced when cornering on uneven road surfaces. Bilstein and GM recognised this, and offered replacement struts that reduced the stiffness thus offering more stability. These are now on the car and make it more tractable, thus the fillings will stay in your teeth. Exhaust: I replaced the cast exhaust manifolds with American Racing long tube 1 7/ 8" balanced racing headers. This required additional heat shielding under the floor in the area of the headers.
2. Exhaust Valves: Replaced the stock sodium filled exhaust valves with Monel exhaust valves as the stock valves were failing on some engines. Though at the time and to this day, my thoughts were then that exhaust valve failure was mostly due to drivers with inexperience driving push rod high performance engines, which I grew up on. I did this as a preventive measure to solve uncertainty.
3. Dyno Tune to the camshaft: The stock camshaft in the LS7 is aggressive for a road car, being high lift and longer duration as required for a race engine. Stock tuning/ timing was an early advance to reduce the engine roll at idle that the average non-petrolhead would dislike. In stock form this could be done due to the 11:1 compression ratio, thus reduced horsepower and torque. The current profile develops c. 525 hp at the rear wheels (c. 615 flywheel) at Calgary elevation (3, 300' asl) on Shell V-Power premium. One can get more aggressive with the timing with different cylinder heads (brand name Fast) to achieve 650-665hp if one desires, but with an accompanying rough idle.
4. Brakes: The stock brakes were developed by an Australian firm PBR. They were 6 piston callipers, single pads per piston with drilled rotors. They were/ are complicated with uneven pad wear coupled with rotors subject to fracturing. The current brakes are Baer brakes, a US performance brake maker, though the callipers have the tuner, Davenports, brand. The rotors are also Baer and are slotted. These brakes are much superior to the stock brakes.
5. Air Induction: I replaced the stock air induction and throttle body/ mass air sensor with a Lingenfelter (noted Texas based tuner) unit to reduce induction restriction. (Note: GM detuned the LS7 for the road cars thus the stock 505 HP). History of its life !
First some background on the car itself. As you may or not be aware, General Motors has run Corvettes at Le Mans as a factory backed team for over 25 years. This car is a 6th generation Corvette, or C6 as termed in North America. The platform for the GT1 class by the ACO then as today was a production car. The platform for the C6R GT1 race car introduced for the 2006 Le Mans race was the 2006 C6 Z06. To race the C6R car at Le Mans, General Motors was required to build a homologation number of road cars that had parts in common with the C6R race car. This car was built for the homologation build run. It was built in October 2005 in a batch of C6 Z06's at the Corvette assembly plant in Bowling Green Kentucky. At the time, General Motors was not taking direct orders but delivering cars to select dealerships factory spec'd with in this cars case the variance being colour and either chrome or painted wheels. All other specifications were constant.
Under the ACO's GT1 rules at the time, the road car and race car had to have common parts being:
1. The engine, less cylinder heads and intake manifold. For the C7 Z06, General Motors introduced the LS7 (7 litre) V8 specifically to race at Le Mans. In following years, The ACO limited displacement thus the cylinder bore remained constant with a shorter stroke. For 2006, 2007 and 2008 years the race engine was 7 litres. As such, the engine block (alloy), crankshaft, connecting rods (titanium), pistons, camshaft and valve lifters (solid) were/ are common to the C6R race engine.
2. Front wing fenders in the road car are carbon fiber and common to the race car.
3. Roof is made of magnesium, common to the race car.
4. The car frame, constructed of an aluminium alloy developed by Alcola for the race car, is the platform for the 2006 C6 Z06 road car. This is important as the race car required torsional rigidity.
5. The engine is dry sump, common to the race engine.
The suspension of the race car is different, though many enthusiasts converted their road cars to coil over suspensions in lieu of the composite transverse leaf springs at the rear, there was no noticeable difference in handling on the road or the track.
At the time there were a limited number of these cars allocated to Canadian dealers, with dealers offering the cars at a substantial premium of MSRP. Thus I went searching for one in the US. This car was delivered to a dealer in January 2006 to a dealer in Lake Forest Illinois, who subsequently sold the car to a dealer in Las Vegas Nevada as cars like this do not sell in Chicago winters. I purchased this car through a Canadian dealer
