Corvette owners are very proud of how well our cars handle and accelerate. The rush of speed that they can provide is hard to describe. Unfortunately, at every traffic light you pull up to, someone invariably wants to “race” you. It’s tempting to go for it, but if you do it routinely, the long arm of the law will eventually catch you. Illegal “street racing” probably still occurs in your town, usually late at night on some deserted back street. However, this type of unsanctioned racing is dangerous and sometimes fatal. So what can you do? Well, if you like drag racing, I recommend taking your C5 to one of the many hundreds of drag strips located around the country.
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:
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Top-flight drag-racing cars are usually trailored to events, because they are so highly modified. In building a competitive drag-racing Corvette, owners spend a lot of time and money shifting weight over the rear wheels. This ensures that the rear tires get maximum traction as the car leaves the starting line. This re-engineering usually makes these Corvettes more difficult to use as everyday drivers. Unlike a front-wheel-drive car, a Corvette benefits from this weight transfer because the drive wheels are in the back. Power increases vary, depending on the extent of the engine and chassis modifications the Corvette receives. A stock LS1 6-speed runs the 1/4 mile around 13.3 at 109 mph, and an automatic LS1 runs the 1/4 mile around 13.8 seconds at 103 mph. With proper preparation, a C5 LS1 automatic has the potential to turn the 1/4 mile in a little over 10 seconds. The path to that goal is not cheap, but if you are a dedicated drag racer like Paul Smith, it is well worth the investment. Paul purchased a red, automatic LS1 Corvette coupe new in 1998. Paul originally had Mallett Cars in Berea, Ohio, modify it for drag racing, including installing a roll bar.
The LS1 automatic was a consistent winner in bracket races. With constant tweaking, Paul got the car to move from the low 13- second 1/4 mile times to the low 12s. Paul wanted his LS1 to break the 10-second mark. To do this, he turned to MTI Racing to work out a plan to modify his car. Owner Reese Cox put together a modification plan that Paul accepted for this car. The MTI Racing team added more bracing to the roll cage to strengthen the chassis.
Next, they massaged the LS1 motor with a set of Air Flow Research heads and a more radical cam. The stock 346-cubic-inch LS1 is now producing 415 rwhp. MTI Racing also installed a Callaway Honker air intake and new set of headers. Next, a 4,500-rpm high-stall converter was inserted into an MTImodified automatic transmission. The transmission was installed with no lockup. The new torque converter produces 520 ft-lbs of torque. MTI installed strengthened DynoTech Engineering rear axles and a rearend cradle to prevent torque from shattering the axle case.
The front sway bar was removed from the C5 to reduce weight. The standard front factory brakes were replaced with lightweight Strange calipers and rotors. These lightweight units work well, while saving a lot of front-end weight. Low-resistance front shocks were installed to help shift weight to the rear on the starting line. The battery was relocated to the back cargo compartment for additional weight transfer.
Base front and rear springs remained in the car. These soft springs help the car squat in the rear and rise in the front under hard launches for good weight transfer. The headlights were removed and the covers were fixed into a nonopening position.
Lightweight, M&H Skinnie tires ( P185 x 16 inch) were mounted on Complete Custom Wheels (CCW) 5.5-inch rims. On the rear, M&H 275/55R16- inch drag radials were mounted on 11-inch CCW wheels. Finall,y an MTI heat-treated rear axle with 4:10 gears was installed. Paul was happy with MTI Racing’s completed work. The real proof to see if the car improved was on the track. Well, it did. Paul’s son, Paul Jr., routinely clocks a 1.373 60-foot time, which really helps get this car to the timing lights quickly. Paul Jr. launches the car between 1,800 to 2,000 rpm, and the red C5 usually lifts both front tires 6 to 10 inches off the ground. Paul Jr. runs consistent 10.58s at 125+ mph. This car is strictly a bracket racer and, with his amazing 1.373-second 60-foot time, Paul’s red C5 takes home a lot of bacon. Paul runs his C5 in the Sportsman Pro ET class with great results. 90% of today’s drag racing falls into the bracket category. In Chapter 2, I told you that almost 119,000 C5 coupes were built from 1997 to 2004. This is a great car to look for if you want to go drag racing. I recommend finding a car with minimal accessories for weight reasons. These are great cars to take to the weekend drags.
Here is another example of a stock C5 that is used for drag racing. This car is a 2002 Z06 6-speed, and the times are shown with stock tires and a new air intake and Drag radials.
Stock Engine, Stock Tires: 11.81, 117.26, 1.78, 60-foot times. Non-factory air intake and Drag Radials: 11.52, 120.21, 1.64, 60-foot times.
The drag radials and the air intake make this a worthwhile change to improve this car’s performance. Again, as we have mentioned in other parts of this book, C5s respond well to bolt-on additions to its engine and drivetrain. If you really need a fast C5 drag Corvette, call Lingenfelter. I witnessed an automatic 2000 Lingenfelter twin-turbo 427 FRC turn an 8.89 @156.5 mph. The late John Lingenfelter started out his career in drag racing and he was hard to beat. A 1,000-hp twin-turbo Lingenfelter Corvette retails for over $225,000! It’s only money.
The National Hot Rod Association (NHRA) and the International Hot Rod Association (IHRA) both offer sanctioned drag races at approved racetracks. Sanctioned racetracks have to follow the rules of their governing body to hold events. These rules typically cover registration, track safety, emergency medical personnel, car classification, protests, and timing equipment.
These tracks also must provide competitors with properly designed racetracks that include adequate stopping areas. A drag race is an acceleration contest from a standing start between two vehicles over a measured distance. The accepted standard for that distance is either a 1/4 mile (1,320 feet) or 1/8 mile (660 feet). NHRA tends to support 1/4-mile racing and IHRA supports 1/8-mile events. Drag racing is a series of two-vehicle, tournament-style eliminations. The losing driver of each race is eliminated, and the winning drivers progress until only one, the winning driver, remains. Each race is started by means of an electronic device commonly called a “Christmas Tree.” It was given this name because its multicolored starting lights resemble a Christmas Tree. On each side of the Tree are seven lights: two small amber lights at the top of the fixture, followed in descending order by three larger LED lights, a green bulb, and a red bulb. Two light beams cross the starting-line area and connect to trackside photocells. These photocells are wired to the Christmas Tree and electronic timers in the control tower.
When the front tires of a vehicle break the first light beam, called the pre-stage beam, the pre-stage light on the Christmas Tree indicates that the racer is approximately seven inches from the starting line. When a competitor rolls forward into the stage beam, the front tires are positioned exactly on the starting line and the stage bulb is lit on the Tree, which indicates that the vehicle is ready to race. When both vehicles are fully staged, the starter activates the Tree, and both drivers focus on the three large amber lights on his or her side of the Tree. All three large amber lights flash simultaneously, followed 0.4 second later by the green light; or, the three bulbs flash consecutively 0.5 second apart, followed 0.5 later by the green light. Two competitors are monitored for their elapsed time and speed on each run. Upon leaving the staging beams, each vehicle activates an elapsed-time clock, which is stopped when that vehicle reaches the finish line. The start-to-finish clocking is the vehicle’s elapsed time (ET), which serves as a performance measure. Each lane is timed independently. The first vehicle that crosses the finish line wins, unless, in applicable categories, it runs quicker than its dial-in (dial) or index. A racer also may be disqualified for leaving the starting line too soon. This could also occur if a competitor leaves his or her lane by crossing the track centerline or hitting anything such as a wall, guardrail, or track fixture.
Another action that could lead to disqualification is failing to stage properly, or failing a post-run inspection. Some sanctioning bodies weigh each car and check their fuel after each run. They also do a complete engine teardown after a victory. Both NHRA and IHRA use a handicap starting system to equalize competition in certain categories. This system enables vehicles of varying performance levels to compete against each other on an equal basis. The estimated elapsed times for each vehicle are compared, and the slower car is given a handicap head start. By using this system, virtually any two vehicles can be paired in a competitive drag race.
Here’s how it works. If car A chooses a dial of 16.00 and car B chooses a dial of 14.50, car A gets a 1.5-second head start. If both vehicles cover the 1/4 mile in exactly the predetermined elapsed time, the win goes to the driver with the best reaction time, or whoever reacts quickest to the green “go” signal on the Christmas Tree. If a driver runs quicker than his or her dial, he or she is said to break out and is disqualified. If both drivers run quicker than their dials, the win goes to the driver who breaks out by the least. A foul start, or red light, takes precedence over a breakout, so a driver who red-lights is automatically disqualified even if his or her opponent breaks out. If both vehicles cover the 1/4 mile in exactly the predetermined elapsed time, the win goes to the driver who reacts quickest to the starting signal. Reaction to the starting signal is called “reaction time.” Both lanes are timed independently of one another, and the clock does not start until the vehicle actually moves. Because of this, a vehicle may sometimes appear to have a mathematical advantage in comparative elapsed times but can actually lose the race. This fact makes starting line reflexes extremely important in drag racing. The drag-racing fraternity has increased tremendously in recent years, with more and more people converting their everyday street cars into 1/4-mile rockets. Modifications to a Corvette can be anything from just changing the intake and exhaust to a full, twin-turbo conversion. This could include turbos, nitrous oxide, bigger engine capacity, or replacing standard body panels with aftermarket lightweight products. For many, drag racing is just a hobby, but others, like Lingenfelter, have turned their hobby into a successful business.
As we have said before, drag races are conducted in heats over a distance of 1/4 or 1/8 mile. The driver with the best time wins and goes on to the next heat. This continues until a final winner is achieved in the class. Cash prizes and trophies are awarded to the winners, but most compete for the fame achieved and the pure thrill of going at such high speeds. A welltuned Corvette street car can run a 12-second ET and reach a speed of 115 mph on a 1/4-mile track. The times you achieve are also based on the height above sea level of the racing track. Drag Racing has become a way of life for many competitors. People still like to race illegally on the street rather than on a drag strip. Some feel the danger makes it more thrilling. I think you not only endanger yourself by doing this, you also endanger innocent people. There are some things to remember the first time you attempt to race your car at the drags. The race winner is determined when the elapsed time is scored by two lights. The first is when the light turns green at the start, and the second is when the front end passes through the traps at end (far end) of the track. In practice, it is necessary for the driver to “jump the gun” by a fraction of a second, starting the car during the split-second interval between when the yellow light goes out and the green light goes on. However, if the car crosses the electric eye (beam) in front of it before the green light comes on, the driver has red-lighted and is disqualified. (If both cars red-light, only the first car to cross is disqualified.) A driver who gets a substantial lead at the start is said to have gotten a holeshot. The driver’s reaction time (like Paul Jr.’s 1.373, 60-foot time) is crucial to winning a drag race. Timing lights also record the car’s top speed, in addition to the ET that is shown on the timeslip. The car that crosses the finish line first wins. A car can actually blow an engine part way down the strip and coast to the end of the track at a (relatively) lower top speed than the competitor, and still win with a lower elapsed time. This is called “heads-up racing,” and is used in all professional classes.
In the common Eliminator racing format, the losing car and driver are removed from the contest, while the winner goes on to race other winners, until only one is left. In some instances, there are three cars remaining. In that case, one car—either chosen at random or the car with the fastest elapsed time at that point—gets a “bye run,” where his or her car goes down the track by itself (in order to at least partially eliminate the advantage that otherwise comes from the engine having one less run on it) and then awaits the winner of the other two for the title. However, in most Eliminator formats, the bye runs take place only in the first round. Drivers are equally divided between making an easy pass on the bye run so as not to stress the car unduly, or making a real effort for the benefit of the spectators.
As I mentioned before, the NHRA oversees the majority of drag 1/4-mile racing events in North America. The next largest organization, the IHRA, is about one-third the size of the NHRA and conducts a majority of 1/8-mile events in North America. Nearly all drag strips associate and select one or the other of these sanctioning bodies. The NHRA is more popular because of its large, 1/4-mile, nationally recognized tracks, while the IHRA is a favorite of smaller, 1/8- mile, local tracks. One reason for this (among others) is that the IHRA is less restrictive in its rules and less expensive to be associated with.
There are literally hundreds of different classes in drag racing, each with different requirements and restrictions on things such as weight, engine size, body style, modifications, and many others. The NHRA and IHRA share some of these classes, but many classes are only used by one sanctioning body or the other. The NHRA boasts over 200 classes, while the IHRA has fewer. Both organizations even have a class for aspiring youngsters— Junior Dragster. During a race, vehicles are classified based on the extent of modifications that have been made to a car. Classifications take into account engine capacity, number of cylinders, and if it is turbocharged or supercharged or has nitrous oxide installed. These classifications are in place to ensure that all of the cars are evenly matched. To allow different horsepower cars to compete against each other, some competitions use a handicap system. This system delays faster cars on the starting line long enough to even things up with a slower car. This may be based on rule differences between the cars in Stock, Super Stock, and Modified classes, or on a competitor’s chosen dial-in in bracket racing.
The victory goes to the driver who is able to precisely predict elapsed time, whether it is fast or slow. This, in turn, makes victory much less dependent on large infusions of money, and more dependent on skill. Therefore, bracket racing is popular with casual weekend racers. Many of these recreational racers drive their vehicles to the track, race them, and then simply drive them home. Most tracks do not host national events every weekend, so they host events for weekend racers. Organizationally, however, the tracks are run according to the rules of either the NHRA or the IHRA (for the most part). Even street vehicles must pass a safety inspection prior to being allowed to race.
Blown-alcohol and nitrousoxide- injected Pro Modifieds with 2,000 horsepower engines are capable of running in the low 6-second range at over 230 mph. The IHRA Pro Stocks are just behind, running in the 6.3-second range at over 210 miles per hour, while the NHRA Pro Stocks run in the high sixes at over 200 miles per hour. Top Sportsman and Dragsters, the two fastest sportsman classes, run a bracketstyle race and can range from the 6.4-second range at 210 mph to the high sevens at over 170 miles per hour. Cars in Super Comp/Quick Rod are either dragsters or doorcars, but run with a throttle stop. Some of these cars can run as low as a 7.50 at around 180 mph without a throttle stop. Recent NHRA rule changes have been making Pro Stock cars smaller. Engines have been changed from 500 cubic inches (8.2-liter V-8s) to factorymodified 4- and 6-cylinder double overhead camshaft engines. Competitors are allowed to convert a Pro Stock car to a Sport Compact Pro Rear Wheel Drive car. Corvette tuner John Lingenfelter, driving a Chevrolet Cavalier, lost his life driving one of these compacts.
When approaching the starting line (also known as the staging area), most racers apply water (formerly bleach) to the rear tires, either by backing into a small puddle (the water box) or having it sprayed on. The car then exits the water and does a burnout to heat the tires, making them even stickier. Some cars have a mandatory line-lock that prevents the rear brakes from engaging when the brake pedal is depressed (which can be toggled on and off). This allows the car to remain stationary (with the brakes applied) without burning up the rear brake pads while doing a burnout. Cars in street classes (must be street legal) are the only exception to this pre-race ritual, as the grooved tires tend to retain some of the water.
After the burnout comes the staging phase, where the cars pull up to the starting line. Each lane has its own string of lights on the Christmas Tree, with two small orange lights on top. These are the pre-staged and staged lights. The two cars slowly creep forward until the first (pre-staged) orange light is lit. This means they are very close to the actual starting line (a mere 7 inches). Then the cars nudge forward until the second (staged) light is lit. This indicates they are at the starting line. When both cars have lit both bulbs, the starter begins the Christmas Tree.
The Nitrous Purge
Only cars running nitrous oxide can do this. The driver pushes a button that activates a solenoid called a purge valve, which clears the gaseous nitrous oxide in the line out into the atmosphere without entering the motor. This brings the liquid nitrous oxide towards the motor, ensuring a correct mixture of nitrous oxide and fuel when the system is activated. Motors that utilize nitrous oxide are generally built with stronger internals to facilitate the increased combustion temperatures and pressures seen in a nitrous-injected (sprayed) powerplant.
Several things are important on the way down the track in drag racing. First,do not cross into your opponent’s lane, as this results in disqualification. In the case of a double disqualification in which one driver commits a foul start and the second driver crosses into his opponent’s lane, the driver who committed the foul start wins. Another important consideration is when to shift gears. Most drag cars are shifted manually by the driver, and there are optimum times for shifting that vary with each car. Typically, power increases as the engine RPMs increase, but only up to a point before power begins to taper off. The ideal time to shift is at the peak power point. Most drag racers use a tachometer to judge shift points. In Fuel classes especially, pedalling the car (adjusting the throttle) to prevent loss of traction is often important and is one measure of how good a driver he or she is. Strategies for crossing the finish line usually only involve bracket racing. If one car has a huge lead, it may slow down before crossing the finish line to prevent a breakout. Especially in bracket racing, it is not uncommon to see the leading vehicle’s brake lights come on briefly before the finish line. If both cars break out, the car closer to their dial-in wins.
While the professional and other faster classes get all the attention on television and in the press, there are far more casual and weekend racers, like Corvette owners, to whom it’s just an enjoyable hobby. Many potential first-time amateur drag racers are put off by their lack of knowledge as to what to do. Even if you have a 13.0-second or slower car, it is relatively easy to have an enjoyable weekend at the track. Other cars run at the sportsman level and are usually not street driven. They are Super Comp/Quick Rod cars, Top Dragster vehicles, Top Sportsman cars, cars that run in Super Gas/Super Rod and Super Street/Hot Rod, and vehicles built specifically for bracket racing. Each track usually has three car categories and a Super Pro Bike category. The car categories are Super Pro (any electronic devices are allowed, from 7.00 to 12.99 or depending on the track), Pro (doorcars with no electronics except for a transbrake, 9.00 to 14.99), and Street (no electronics allowed, full street equipment, must be street legal, 12.00 to 17.99).
When You Arrive
If you are racing, most of the time you need to have your Corvette tech’ed, which means inspected. Gate attendants (where you enter and pay) are used to this question, and know whether a street car needs to be tech’ed or not. Two things can happen here. First, you need to have the car tech’ed and should go to this area. Second, street classes have no tech requirement (mostly IHRA tracks), so you simply head for the pit area. In the case of a tech requirement, you need an official to look over the car and be sure there are things such as seat belts, a correct helmet (if required), street-legal tires, a correct exhaust, and other street-legal items. The tech official (assuming the vehicle passes) then uses his white shoe-polish to paint an identifying number on your upper-passenger windshield, and possibly on a side window as well. The official then gives you a slip verifying you have been tech’ed, and you may then proceed to the pit area. In the case of no tech requirements, be sure to save the stub you got at the gate, since you need it before being allowed to race.
Unlike NASCAR, the pit area in amateur drag racing is a huge parking lot. If your car didn’t need to be tech’ed, you need a number on your windshield. Although most tracks have an official who supplies the number, not all do. Use the shoe polish up high on the passenger side, then draw a line under it. The pit area is where everyone in amateur drag racing walks around and enjoys talking to other people, seeing similar cars, and generally just talking trash with others over performance.
Arriving early, as mentioned, means you can get in line to do a few practice runs down the track. During these runs, it’s only practice, so you could conceivably be paired up with a much faster car. The object here is not to win, but to simply get a feel for how your car performs. All tracks have a place back around the pits where you can get a timeslip after a run.
Years ago, timeslips were written out by hand, but now they are computerized. A quarter mile is a fair amount of distance, and after slowing down the car needs to turn around (not on the track—there are roads leading back to the pit area, called return roads). A small building or other place is where you get a slip of paper with your number at the top (and the one you raced against as well).
Aside from winning or losing, practice runs are the same as the real thing. You get your ET, your average speed through the final 66 feet of the track (MPH at finish, or trap speed), and your reaction time. Most tracks also include your time at various intervals on the way down the track. One of the most common is the 60-foot time. The 60-foot time is a good indication of how quickly you got off line.
Before actual racing begins, drag racers need to dial in, or put their estimated time on their windshield underneath the ID number. The time is to the hundredth, as in “14.55.” After a couple of practice runs, most racers have an idea of how his or her vehicle is going to perform. It is worth noting that the time you post is an estimate of your car’s quickest time, since going faster than your dial-in results in disqualification, called a breakout. You are allowed to change this number as many times as you like, right up until you actually stage for the race. Shoe polish is easily removed with Windex and a few paper towels. A common ego trip for many weekend racers is to paint a ridiculous dial-in (say, 8.45) on a car that can barely do 17s and watch as people walk by and wonder what you have under the hood.
Smart racers dial in closer to their real times. For example, a Super Comp/Quick Rod Corvette in Super Pro ran two practice runs of 8.18 and 8.16, so the driver believes an 8.17 dial-in is good. His opponent in a 1967 Mustang ran times of 11.13 and 11.16, so he believes that an 11.14 is a good dial-in. The driver in the Mustang leaves three seconds before the Corvette. So there you have it, probably more than you ever wanted to know about drag racing. But trust me, it takes a lot more skill to be a 1/4-mile winner than most people think and, as in any other sport, winning is sweet glory.
Written by Walt Thurn and Posted with Permission of CarTechBooks