Early Corvettes (1953–1962) were ideal drag cars. In the 1950s, Corvettes were difficult to beat in stoplight races. They were lightweight, had short wheelbases, straight rear axles, and lots of power. All of these advantages helped put America’s sports car ahead of the competition. This drag-racing advantage changed when the 1963 model was introduced. Chief Engineer Zora Duntov was a road racer at heart. He wanted Corvette to become the dominant production sportscar racer and pushed to have an independent rear suspension added to the car. He succeeded in 1963, when the new Stingray was introduced with an independent rear axle. This new design allowed for better cornering speeds on road courses, but it was not as effective on the drag strip. The Stingray was a great design, but suffered from excessive weight and poor brakes. When Carroll Shelby introduced the Ford Cobra in 1962, Zora Duntov knew Corvette was in trouble. He set to work on building a lightweight Corvette to compete with this new production supercar. The Cobra weighed 1,000 lbs less than the Corvette and produced close to the same power with its small-block Ford engine. Zora’s answer to the Cobra was the Grand Sport. It weighed 2,000 lbs and its 388-cubic-inch engine produced close to 500 horsepower.
This Tech Tip is From the Full Book “HIGH-PERFORMANCE C5 CORVETTE BUILDER’S GUIDE“. For a comprehensive guide on this entire subject you can visit this link:
SHARE THIS ARTICLE: Please feel free to share this post on Facebook / Twitter / Google+ or any automotive Forums or blogs you read. You can use the social sharing buttons to the left, or copy and paste the website link: https://www.chevydiy.com/street-race-c5-corvette-win-part-11/
However, GM instituted a racing ban on all corporate products in the summer of 1963. The ban halted Grand Sport development, and GM told Zora to destroy the five prototypes that had been constructed. Zora ignored the order and sold them to private teams. Without factory support, the Grand Sports were raced for a short time and soon became uncompetitive. Meanwhile, the Ford Cobras continued to win every production race they entered. Zora really wanted to beat the Cobras, so he continued working to improve the production Corvette’s road-racing abilities. In 1965, Corvettes were equipped with four-wheel disc brakes and a big-block, 396-cubic-inch engine. In 1967, the limited-production, “off-road” L-88 427-cubic-inchengine option was introduced. In spite of the car’s weight, the L-88 had enough power to overtake the lighter Cobras, and soon Corvette was the king of the hill. The L-88 continued to be the engine of choice through the 1960s and 1970s and was always very difficult to beat.
The fourth-generation Corvette was only available with a smallblock engine. However, the new car was equipped with sophisticated electronics and a state-of-the-art lightweight aluminum suspension system. What the car lacked in straight-line acceleration was made up with racecar-like handling and braking. The new Corvette became unbeatable in showroom stock racing, and, from 1985 to the end of 1987, was never beaten in a showroom stock race.
Other manufacturers complained so loudly about Corvette’s dominance that the SCCA banned them from racing in showroom stock events in 1988. To soothe Corvette fans, the SCCA introduced the “Corvette Challenge” series in 1988. This was the first time Corvette produced a racecar at the factory. The cars were built in Bowling Green with race-prepared engines before being sent to Protofab to have their race equipment installed. The series was cancelled after running for two years. However, the Challenge produced some of today’s best drivers, including Boris Said, Andy Pilgrim, Paul Tracy, and Stu Hayner. The Challenge cars continued to be raced successfully throughout the 1990s. However, a new Corvette was beginning to emerge from the design studio that was going to replace the C4.
The fifth-generation, or C5, was introduced in the fall of 1996. During this time, another program was given corporate approval. This program authorized an outside vendor, Pratt & Miller, located in Wixom, Michigan, to design, build, and test a new production racecar called the C5-R. The car was scheduled to debut at the 1999 24 Hours of Daytona. The C5-R was tested secretly around the country at small, unknown racetracks, and was finally spotted by spy photographers in mid 1998. In the meantime, Corvette engineers were working hard on a new production C5 called the fixed-roof coupe (FRC).This car was a less expensive version of the coupe and convertible, but also stronger and lighter than its cousins. The hardtop was nonremovable, and this strengthened the entire car. Corvette engineer and race driver John Heinricy extensively tested this car in 1997 and 1998, as mentioned in Chapter 4. By the time the car was introduced as a 1999 model, a GM-approved T-1 package was available for the 1999 Corvette. Race teams bought the FRCs and began preparing them for road-racing events.
Heinricy and fellow racer and Corvette engineer Jim Minneker supported a limited-production run of 20 boxcars, available to approved race teams. The boxcars were designed to run in races for modified production cars such as the Speedvision GT series. The rules for this series allowed racers to strip the interiors, and add fuel cells and different brakes to their boxcars.
So, by the beginning of the 1999 season, Corvette had competitive racers running in three series. The first was the international endurance series with the Pratt & Miller C5-R. Next, Corvettes were competing and winning in the SCCA T-1 production-car category.
Finally, Corvette boxcars were competing and winning races in the Speedvision GT pro-racing series. This was a major change for Corvette, and flooding the world with competitive racecars soon proved to be a very wise marketing decision.
Corvette engineering learned a lot of lessons with C5 racing on three very different racing venues. These lessons were used to develop a new hot-rod Corvette called the Z06. The Z06 was an improved version of the 1999 and 2000 FRC and included more horsepower and a revised suspension. Owners drive these cars during the week to work and go to track events on the weekends. The high- revving LS6 engine and crisp, nimble handling made quick work of its competition. Several high-performance driving schools opened using Corvettes. The Justin Bell Driving Experience, Bragg Smith, and Bob Bondurant driving schools all offered Z06s to their students. While Justin Bell and Bragg Smith schools are no longer available, check around for a similar type of school if you want to learn how to drive your car well. Tuners such as MTI Racing also offer weekend driving schools.
Amateur Track Events
Some tuners participate in amateur track days at various racetracks around the United States. Tuners can prepare your car for these events for a fee. This includes car preparation, transportation to the track, driving instructions, and mechanical support for your car. In addition, tracks charge you by the day to use their facilities. Amateur events usually have three racing categories for you to enter.
These classes (usually A, B, and C) help track operators determine your skill level for safety reasons. New drivers are put into the beginner class and are forced to follow a pace car with no passing allowed. Drivers usually have to do this for at least one day. Each higher class is less supervised, until you reach the A class. In this class, you are allowed to run your own pace and pass other cars on the straightway. Passing in the corners in any class is never allowed for safety reasons.
What You Need
Most times, 16-year-olds or older can attend (16/17 require parent’s signature) a track event. A clean, maintained street vehicle (okay to trailer) is required, as is a Snell 85+ helmet (loaners usually available). The standard belt that came with your car is approved for these events. All convertibles must be equipped with a roll bar that is above the driver’s head. Vehicles with factory hoops or pop-up rollover systems are not allowed.
A high-performance driving school is not a competition event. The instructors teach the basics of car control, from experienced road racers at non-racing speeds in a safe, closed-course environment. At no point should you go faster than you feel is comfortable. At no point should you go faster than your instructor feels is comfortable. There is nothing to prove. The point is to learn.
Damage to your car is not covered by any insurance at the track. It is between you and your insurance company. Track Insurance is liability only, typical of racetrack and racingevent insurance.
When You Arrive
Complete the registration process. Complete the safety review of your car. Secure your gear in your pit area. Be at the mandatory driver’s meeting on time.
Any C5 automatic or stick can be taken to a track event. No matter what options are on your C5, taking your car to the track can teach you valuable driving lessons in a safe, controlled environment. Participating in track events does not make you into a racecar driver; it does, however, teach you the limits of your car’s suspension and braking system. Track events also teach you the difference between over-steer and under-steer and how to correct for it. Most importantly, it helps you become a better driver because you have learned what your car can and cannot do in emergency situations.
The biggest change you can make to a stock car’s handling at a track event is varying your tire pressures. With EMT run-flat original-equipment tires, a good place to start is to add air to each tire, 3 lbs over the factory recommendations. The stock Z06 F1 Supercar tires respond well to 32 lbs front and 33 lbs rear. If your car is over-steering (the rear swings out in a corner), lower the rear-tire pressure in one-pound increments after each session. If your car is under-steering (front wants to go straight in a corner), increase rear-tire pressure in one-pound increments after each session. Before any track event, make sure you check the condition of your engine’s serpentine drive belt.
If any cracking appears on the top or underside, I recommend replacing it. Check the level of your brake fluid and its color. If it is dark and cloudy, you should have an expert bleed the system and install fresh brake fluid. Also check your radiator level (cold engine). Make sure your coolant is fresh and is not showing any signs of rust. I also recommend a fresh oil change and checking your transmission and rearend oil levels. Tire condition, tread depth, and alignment should also be checked. Make sure your suspension’s castor and camber are set to factory settings. Racers set their cars up outside factory specs to maximize their car’s handling. But for normal, non-modified cars, I recommend staying with the factory settings.Once you have completed your preparation, you are ready to head to the track. Remember, the more stock your car is, the less track time you get. Stock C5s without oil coolers tend to overheat their oil quickly. My advice is to closely monitor your oil temperatures when on course. When you see your oil temps approaching 280 degrees, it is time to come into the pits and cool your car down. Open the hood, turn off the engine, and check your car over while you wait for the temps to return to normal. If you have a portable fan and spot an electric outlet, direct the fan under the front of the car for faster cooling.
Once you have become comfortable driving road courses, you might want to begin thinking about modifying your car to improve its reliability, performance, and safety. Oil coolers are an excellent investment for component reliability. I recommend frequent oil changes and paying close attention to all of the car’s fluids. Performance improvements should not be restricted to the engine. Performance shocks, stiffer composite springs, and thicker sway bars all dramatically improve your C5’s handling. I have found that C5s respond well to 35-mm, hollow-front sway bars and to 25-mm, rear-hollow sway bars.
Cars equipped with plastic sway-bar links benefit from the addition of metal sway-bar end links from a Z06. Stock LS1 engines produce 295 to 305 rwhp. LS6 Z06 engines produce 336 to 344 rwhp. With the addition of a top-level air intake like the Callaway Honker and a good cat-back exhaust system, a stock LS1 now produces around 330 to 335 rwhp. An LS6 with similar modifications produces around 360 to 365 rwhp. The horsepower is felt on the track coming out of corners. If this power is not satisfactory, your next step could be installing a headand- cam package or a supercharger. Head-and-cam packages usually add about 80 to 100 rwhp, and a Supercharger adds around 120 rwhp. The head-and-cam installation requires that the heads, intake, and enginedrive accessories be removed during installation.
A supercharger installation requires removal of the intake and the engine-drive accessories during installation. The pros and cons of each installation are: the head-andcam package is more expensive and produces a little less power; the supercharger is a little less expensive, produces a little more power, but has more mechanical parts to maintain; a supercharger usually requires a higher hood, which needs to be repainted to match your color. The sky is the limit when you begin heading down the trail for more power. You can combine a supercharger with a head-and-cam package or convert your LS1/LS6 block into a 383-cubic-inch or 427-cubicinch engine. Always remember, you have to get this power onto the track. A 500-rwhp provides a nonprofessional race driver with plenty of thrills on a racetrack. When adding extra power, don’t forget to upgrade your car’s brakes, wheels, tires, and suspension. I also recommend changing your automatic transmission’s torque converter. If you have a 6-speed, add a high-performance flywheel, pressure plate, and clutch for better reliability.
Most tracks require safety equipment in the top classes such as a roll bar and six-point seat belts. In the case of an off-course excursion and your car flips, a roll bar will probably save you from serious injury. Sixpoint seat belts hold you securely into your seat and allow you better car control, because they keep you from bouncing around during hard cornering. Another big safety item is brakes. Stock C5 brakes are very good, but under hard use, the pads wear out quickly and the rotors overheat and warp. I recommend adding a set of high-performance brake pads like Hawk Ceramic or HP Plus pads. The HP Plus gives you a very aggressive brake pedal, but leaves a lot of brake dust on your wheels and tends to squeal during street use. The ceramic is not as dusty and is quieter on the street, but the brake feel is not as aggressive as the HP Plus. I also recommend cryo-treated slotted brake rotors.
If you are going to do a lot of weekend track events, I strongly recommend the HP Plus pads on a stock C5 brake system. If you are only going to do occasional events, then go with the ceramic pads. If you modify your car’s engine to produce more power, then you need to do the same thing to your braking system. Aftermarket suppliers like Wilwood, Brembo, Baer, AP, etc., offer excellent aftermarket braking packages for your C5. Expect to pay $3,000 to $6,000 for a high-performance brake package. This might sound expensive, but if you want your car to stop from 160 mph, it is well worth it
As you head out onto the track, if it is your first time, you follow either a pace car or are placed into a line of fellow drivers. Things to look for are the lines or routes they take around each corner. It is also important to notice how they move as far to the left as possible before entering a right hand. Then notice how close they get to the curb on the righthand corner. Coming into a corner, try to do all of your braking in a straight line. Braking in the corner upsets the car’s suspension. Gently feed the car as much power as it can take as you exit the corner, until you are in a straight line.
The pace car has been around the track enough to know the best line. Learning its route helps you to quickly start turning good lap times. As you become more comfortable with your car and the track, your lap times drop. It’s easy to become hooked on this kind of racing.
When you go to the track, I recommend taking simple tools like screwdrivers, pliers, wire, wire cutters, electric tape, duct tape, flashlight, portable air pump, air gauge, small jack, and a lug wrench. This assortment of tools allows you to make minor repairs to your car that might prevent you from leaving the track. Track time is expensive, so you want to utilize every minute that is available to you. If you have room, pack a couple of one-gallon jugs of water. A ground cloth, small cooler with drinks, blanket, and portable chairs make waiting between track sessions more comfortable.
Check with your local Corvette clubs to determine what track events are scheduled for your area. Most of the major racetracks offer these events. I suggest using Google to search for events that might interest you. Good luck!
SCCA T-1 AmateurRacing
Participating in track-day events can sometimes give you enough confidence and desire to make you want to participate in an actual race series. The SCCA is a huge racing organization dedicated to amateur racing. The SCCA is divided into many regions around the country. Each region has a series of races covering multiple categories of production and all-out racecars. Each year, the competitors who finish in the top three in each of their regional categories are invited to the national runoffs. Corvettes that are less than 10 years old are eligible to race in the T-1 category. According to the SCCA rulebook, the T-1 category “is intended to provide the Membership with the opportunity to compete in commonly available, recently-produced automobiles in as near the legal, street-driven form of those automobiles as is practically and safely possible under racing circumstances.”
John Heinricy, director of highperformance vehicles at General Motors, won his fifth consecutive SCCA National Championship in 2005. John won the Touring 1 race in his Phoenix Motorsports/Goodyear Chevrolet Corvette C5 Z06. His margin of victory was 1.649 over a Dodge Viper driven by Scotty White. The C5 Z06 continues to be very competitive in this category against the Vipers and Porsche GT3. The 2002 Z06 is the car of choice for a beginner building a T-1 racecar. The 2002 to 2004 cars have the same horsepower ratings (405) and the same mechanical specifications.
Car setup and construction have to be done according to the SCCA rulebook, which is found online at the SCCA website. The engine must remain stock, but can be blueprinted and balanced. Exhaust must remain stock from the engine to the catalytic. The exhaust can be changed from the cats to the rear of the car. Transmission, cooling system, brakes, and suspension must adhere to factory specifications. A full roll cage must be installed around the stock interior. You are allowed to change the driver’s seat to a race seat, but the passenger seat must remain. The SCCA allows the installation of GM Motorsports T-1 suspension package (PN 12480062). This includes new springs, sway bars, and shock absorbers. In addition, GM Motorsports transmission cooler kit (PN 12480080) is permitted. The other good news is that the SCCA allows updating and backdating within models and years listed in this classification. Basically, you can install Z06 parts into a non-Z06 like an FRC.
Rules that govern this category are available from the SCCA. You can go online and print a copy or write the SCCA to ask for a hard copy to be mailed to you. T-1 races are usually 30 minutes in length. You need two complete sets of spare tires, plus the ones on your car. One set should have rain tires mounted in case of bad weather. You need a pit cart filled with tools and a proper tow vehicle and trailer to pull your racer to the track. An SCCA competition license is required to compete in T-1 races. The SCCA offers regional driving schools that you can participate in to get your competition license. Check with your local region for dates and times for these schools.
There you have it. These are a few tips if you want to road race your C5. It is a great foundation that lends itself well to this type of racing.
Written by Walt Thurn and Posted with Permission of CarTechBooks