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This is a car blog...Corvette blog...track day blog...a blog which covers the evolving list of modifications I found necessary to use my 2003 Corvette C5 Z06  as a dedicated track day toy,  as well as covering regular maintenance jobs.

I bought the Corvette as a replacement for an aging Subaru WRX, where only the body shell was left of the original car. Engine, gearbox, differential, suspension, engine management - all replaced with JDM STI parts (8500 rpm limit). Unfortunately, road salt ate away the body shell. Can't park an AWD turbo during the winter season, so it was inevitable.

As I retired the WRX, I bought a 2001 Lotus Elise S2. In many ways the perfect track day car, with magical handling (and looks). The magic stopped with the Rover K engine, unfortunately. 

I then tried to be sensible and buy a BMW 1-series, that could work both as a family car and on a track day. The engine broke on the very first track day - no more BMW ever! I also had a Porsche Boxster 2.5 for a few years, but that car was so perfect that it became utterly boring. I enjoyed the engine note though, especially after a muffler bypass mod. I also had a Citroen Saxo hot hatch for the fun of it. Install the transmission for a 1000 cc engine in a car with a 1600 cc engine, and you have loads of fun on twisty country roads shifting up and down through the gears.
Then I found the ad for a 2003 Corvette C5 Z06 on I got it cheap as it clearly had some faults, with oil leaking everywhere. But oil leaks can be fixed. In many ways it reminds me of the Lotus Elise. Light weight (considering the engine size) body shell of SMC, all aluminum suspension with double A arms front and rear, nicely balanced and simple electronics.

I've realized that my use of  a Corvette is quite different to most, a Corvette is typically not used for track days in Norway. On public roads, I find that the Corvette is just tiresome, boring and noisy. So, my kind of fun is to head for a race track, where I can allow the LS6 engine to exceed 2000 rpm without putting others at risk or breaking the speed limits. The C5Z performs quite well on a racing circuit as it came from the factory, but when you add very sticky tires this is no longer true - hence this blog.

Some Corvette C5 Z06 details from the marketing guys

"With a maximum top speed of 177 mph (285 km/h), a curb weight of 3117 lbs (1414 kgs), the Corvette C5 Z06 has a naturally-aspirated V 8 cylinder engine, petrol motor, with the engine code LS6. This engine produces a maximum power of 411 PS (405 bhp - 302 kW) at 6000 rpm and a maximum torque of 542.0 Nm (399 lb.ft) at 6000 rpm. The power is transmitted to the road by the rear wheel drive (RWD) with a 6 speed Manual gearbox. About chassis details responsible for road holding, handling behavior and ride comfort, the Corvette C5 has transverse leaf spring. Double wishbones. Anti-roll bar. front suspension and Transverse leaf spring. Double wishbones. Anti-roll bar. rear suspension. For stopping power, the Corvette C5 Z06 braking system includes Vented Discs at the front and Vented Discs at the rear."

Hydro formed frame rails

Trick suspension setups and big horsepower numbers are meaningless if they don’t have a rock-solid foundation to connect to. GM spent considerable effort in making the fifth-gen Corvette as rigid as possible, and it shows. Grip was high right out of the gate, with basic coupes pulling over .90 g on the skid pad despite being equipped with thoroughly awful run-flat tires.

Utilizing a special process called hydro forming, two 13-foot-long steel tubes were filled with water pressurized to 7000 psi and bent to shape without requiring any heat. The structure proved to be four times stiffer than the C4’s, eliminating much of the shakes, rattles, and chassis flex that plagued that car. Now if only those stock seats held you in just a little bit tighter.


Beginning in 1997, the C5 Corvette’s 6-speed manual and automatic gearboxes were attached to the rear differential at the back of the car. Unlike traditional rear wheel- drive cars that have the driveshaft behind the engine and transmission, the C5’s is located between the engine and transmission. The main benefit of this configuration [transaxle] so that engineers could design a near-perfect 51/49-weight distribution into the new car. 

Head-up display

"After driving around the past week in a vehicle equipped with a head-up display, I’m now convinced that any time engineers have the chance to incorporate fighter-jet technology into an automobile, they should go for it. First offered as an option in 1998, the C5’s HUD projects speed, RPM, oil pressure, and a number of other vitals up onto the windscreen right in front of the driver. Controls for information, brightness, and height adjustment are located on the dash, allowing for easy on-the-fly adjustment.

What could have been an opportunity for GM to market a cheap, gimmicky device, actually turned out to be a very useful piece of tech, one that’s quickly becoming a favorite feature of mine. It must be loved among other owners, too, as the HUD has found its way into the subsequent C6 and C7 generation cars"

Sandwich floor

The floors of C5 (1997-2004) and C6 (2005-2013) Corvettes feature a sandwich of materials, including lightweight, renewable balsa wood

Above information courtesy of Hagerty Media and GM