Engine and chassis guys often don't want to hear it, but in many ways the tire specialist is right when he says that those four black rubber doughnuts are the most important things on any race car. It's true because the tires are the only things connecting your race car to the track, and their ability to maintain traction when accelerating, braking, and turning determines how quickly you can make a lap. So finding ways to get better traction from your tires helps efficiently translate power into speed.

Qualifying up front is very important for several reasons. The foremost is to avoid early trouble as the cars farther back make their moves to the front. Overaggressive driving is usually observed very early in the race, and you don't want to be in the middle of, or behind, that process.

If the engine in your race car gets too hot, it shuts down. Your body is no different. If you get too hot, you're going to shut down; that's something you don't want, especially if you're taking the white flag en route to your first feature win.

In this age of improved engine systems that help us gain more horsepower and torque, what remains as one of the greatest challenges in circle track racing is the issue of handling. It is a generally accepted truth that speed gained in the turns is much more significant than any small legal gain in engine power.

In real estate, it's all about location. In racing, it's all about communication. Probably the key ingredient in building a winning team is to have quality communication, and the flow of information between driver and crew is where it all begins.

If you cannot express what you know in numbers, your knowledge is of a meager and unsatisfactory kind. -Lord Kelvin

You won't find anything like it on a street car, but the qualities that make a Bert transmission unique also make it nearly perfect for dirt racing. Simplicity is the name of the game here. Bert Transmission's two-speed trannies are all about cutting down on the number of parts involved and reducing rotating weight. Most significantly, the clutch is actually inside the transmission housing, eliminating the typical clutch and throwout bearing assemblies. There are also only two forward gears and a reverse, and the gears themselves are physically a lot smaller than what you might be used to seeing in a typical four-speed. The net result is a lot less rotating weight burdening your engine as you power out of the corner.

Most stock car drivers use a one-piece sway bar and find it more thanadequate for normal setups on average racetracks. There can be somedisadvantages to the one-piece bar, and there is an alternative. Acurrent trend among asphalt teams is to run setups that use a biggerdiameter sway bar in combination with softer springs. It has beendiscovered, along with this development, that certain components andsettings on the cars need to evolve along with the radical change in thesetup.

Wrecks and bent chassis are part of racing here's how to use a jig toget it all straightened out.

Compared to some forms of racing, caster and camber settings are evaluated a little differently for circle track racing. Because we usually only turn left (as opposed to street driving or road racing), our front-end design is much different and asymmetrical (differing from side to side). The knowledge of what constitutes the optimum design and what the car needs has increased over the past few years.

The pieces are starting to come together for the Reality Racer Project Modified. The base engine was on hand, but there are still other engine components being ordered. It doesn't mean we have to stop and wait, because there's plenty of work to be done. Luckily, we're not on a deadline since we're not chasing points.

If you’re a racer, you know that the clutch is the vital linkage between the engine and the transmission. If you don’t have it installed or adjusted correctly, you can lose horsepower and wear out the clutch prematurely. To help you get it right, Circle Track magazine installed a clutch in a racing car to show you how it’s done. With some help from Quarter Master Industries, let’s get to it.

The first step in installing our clutch is to attach the 7-¼-inch button flywheel to the flexplate on the back of the crankshaft and torque it into place.

Next, the clutch assembly is put together. This particular clutch assembly is a 7-¼-inch, three-disc pac Pro Series set from Quarter Master. The inside contains three separate clutch discs and their attendant floater discs that are sandwiched together inside the housing and a clutch cover (same as a pressure plate) that is on the front. The three clutch discs are designed with two end discs that go on each side of the assembly with a center disc in the middle. The end discs need to be installed so the splined center extends outward from the middle. The center disc can face either direction.

The assembled clutch is then placed onto the bolts extending from the button flywheel. Before the assembly is bolted in place, the starter ring is also slipped onto the studs.

The end of an input shaft from an old transmission can be cut off and used as an alignment tool. We insert this alignment tool through the clutch assembly into the pilot bearing on the end of the crankshaft and hold it centered while the bolts holding the clutch assembly are torqued down.

With the clutch assembly in place the clearance between the throw-out bearing and the front of the transmission needs to be checked. If there isn’t enough clearance when the bellhousing is bolted on, it will push on the clutch cover and partially release the clutch. To check this clearance, the bellhousing first needs to be bolted in place.

Next, we take a measurement from the outside edge of the bellhousing to the throw-out bearing. In order to get an accurate measurement, the throw-out bearing needs to be held in the normal operating position against the clutch cover. Second, a measurement from the front surface of the transmission housing to the outside (front) of the bearing retainer is taken. The bellhousing-to-throw-out-bearing measurement needs to be greater than the retainer on the front of the transmission. If it isn’t, then the retainer will push on the throw-out bearing, partially releasing the clutch and creating slippage. This results in a horsepower loss.

In our case, the clearance is off by an eighth of an inch. The clearance should be between .063 and .125 inches.

In Part 1 we covered building the basic frame of a budget race car trailer. It was fitted with 6,000-pound mobile home axles. They are plentiful throughout most of the country, some to the point of being free if you want to crawl under a mobile home to get them. Our trailer has runners rather than a solid floor, which makes changing oil on the car easy. The target was $300 for the basics. I went $6 over budget on the steel, and I was given the mobile home axles. This month I’ll finish the details and add some nice touches such as a winch. So let’s finish it up.

Building the Fenders

Before rolling down the road, your trailer needs fenders. Arguing with the gorilla in the car behind you about a rock mark in his windshield is seldom any fun. You can buy a pair of fenders for about $75 to $100. However, I made mine from a section of leftover purling. My fenders cover behind and over the tires but not in front. The front is the part of the fender that always seems to bend back into the tire anyway.

Cut the blanks 74 inches long. Notch out 5-½ inches by the width of the flange in each side flange. This allows a smooth bend. Center these notches 16 inches from the rear of the blank. After bending, trim a piece of scrap to fit the curve and weld in place. The Millermatic 185 wire-feed machine welds the thin parts just like it does the thicker ones—easily. Use a piece of 1-½-inch angle to cap off the front. Double this and you have a nice pair of fenders. It only cost a little work. One-inch square tubing is used for mounting. This spaces the fender out properly from the frame.

The Tire Rack

Tire racks vary according to need. On this trailer, the side frames are built from 11-gauge 1-½-inch square tubing. It was going to be made from one-inch material but the steel company shipped more 1-½-inch and less of the one-inch. The crossbars are one-inch square. The larger size for the sides makes it more stable for only a slight cost difference, and I recommend this configuration. The height of the side frames is 72 inches off the trailer surface. The front side tube is vertical. The rear downtube is angled back. The width at the top is 18 inches while at the bottom the spacing is 32 inches. Bars across the top provide a base for a deck. A length of purling was added across this area for the seat. This is a good place to watch the races.

The taper of the sides lets you cut side covers from a single sheet of 4x8-foot material. I have used Coroplast material for this purpose before. This is a plastic that appears not unlike corrugated cardboard when viewed from the edge. It is light, strong and cheap. It trims to shape with a knife. Best of all, a four- by eight-foot sheet is less than $10 at plastic and sign supply shops. Attach it with self-drilling, self-tapping screws. Be sure to use washers. This panel makes a good place to display sponsor names and car numbers. The crossbars for holding the tires are 28 inches below the top crossbars. This should let you put in any size you might ever need—except some Sprint car tires—so check your tires for fit. The mounts for holding the holding rod are welded in to match the tire sizes used. It is best to put a tire in the rack and check for position before welding it.

Everybody knows that brakes can be the most important aspect of your car’s makeup. After all, what good is going fast if you can’t stop the car? You need brakes to race. It’s that simple. Otherwise, the only stopping you’re likely to be doing involves a concrete retaining wall, lots of noise and the potential for serious injury.

When it comes time to put new brakes on your racer, don’t scrimp on parts or installation. Your brakes are sometimes the only things between you and a sudden stop against something hard and painful.If you have any doubts about your welding and fabrication ability, it is best to have a professional install the brake system.

For the purposes of this story, we have decided to install a set of new brakes on a race car from stem to stern. For this, we went with a four-piston Wilwood system and a Dan Press Industries recirculating kit. For the test car, we chose the NASCAR Goody’s Dash machine fielded by Crenshaw Motorsports. Crew chief Bruce Jones did the installation, so follow along and see how it’s done.

Jones started with the Wilwood master cylinders in the front of the car and worked his way to the rear. There are three master cylinders: a one-inch bore for the front brakes, a 17/8-inch bore for the rear brakes and a three-quarter-inch bore for the clutch. Normally you would have to drill holes for both the master cylinder body and mounting bolts, but since this car had a brake system in it before it was refurbished, the holes were already in place.

Jones simply attached the master cylinders and bolted them down. Because a DPI Sure Stop 2 Master Cylinder Equalizer and Brake Fluid Recirculator kit were installed, a little work needed to be performed prior to the installation of the brake reservoir tanks. A hole was drilled into the front of each reservoir, fittings were screwed in and a plastic tube was attached to connect the two reservoirs together. As the brakes are applied, the DPI recirculator moves the brake fluid around the entire system to prevent it from overheating. When the pedal is released, the fluid is returned to the reservoir, but with the DPI kit installed the majority of the fluid goes into one reservoir. This balancing tube lets the fluid drain from reservoir to reservoir preventing either side from going empty.

With the master cylinders in place on the firewall, Jones attached the DPI kit. This kit is designed to screw onto the front of each master cylinder where the normal brake line would exit. From these blocks, the brake lines are connected and run to the calipers. A second set of brake lines is used as return lines in the front of the race car. This set of lines is attached to the caliper via the bleed hole.

Sometimes we bucks-down racers spend all our money on the race car and then have to borrow a trailer to get it to the track. This is an all-too-familiar scenario, so I sat down to devise a simple open trailer that will safely transport my beloved car at an economical cost. In this first article, we’ll cover the basic construction of the frame and running gear.

Getting Started

The needed parameters called for a 16-foot long bed with a dovetail rear to lessen the need for long or steep ramps. The objective was an open bed with runners on each side because often I don’t unload the car to change the oil and check for loose bolts. With this setup, you can also lie under the trailer and scan the bottom side of the car for damage.

It is my belief that a trailer needs springs, two axles and brakes, although many are built without them. Keeping cost in mind, mobile-home axles work very well. In many parts of the country they are abundant, but you should check with local agencies to make sure they are legal to use in other applications. Several states have laws to the effect that a mobile-home axle can be used only for its intended purpose on a mobile home. Most often, mobile-home axles are left intact by the installers.

The axles on this trailer were obtained by crawling under a friend’s mobile home and cutting them out ... with his permission, of course. All the mobile-home axles I’ve encountered have a capacity of 6,000 pounds or greater and have matching springs. That’s 12,000 pounds of capacity for two axles, more than enough for a 3,000-pound car on an 1,100-pound trailer. In choosing mobile home axles, you will find some with brakes. Get at least one of these if possible. You’ll be glad you did if you find yourself in a tight spot.

Next, find five 14-½-inch mobile home tires and wheels (one for a spare). The tires are bias-ply nylon tires made for trailers. Their load capacity is greater than 15-inch steel-belted radials, and they tow better, according to those who know. If your budget allows and you feel you must have 15-inch wheels, tandem-axle assemblies with springs and brakes are available from several sources. There should be at least one trailer-axle dealer in your area. Be prepared to spend $350-plus for a pair of 2,500-pound axles, (more for heavier ones) and then put on some good used tires.

In many cases, the mobile-home trailer tongues are also underneath. If you don’t mind using a 2-5/16-inch ball, one of these can be made to work. That will save a few more bucks.

I like high, forward-mounted brake and taillights. The lights on this trailer are up high on the tire rack. They are very visible from any angle and don’t get knocked off, a constant problem when mounted low and at the rear. It’s a good idea to use reflective tape on the rear of the trailer. In Texas, where this buildup was done, there has never been a problem with this arrangement. If the gendarmes in your area are more critical, add some lights at the rear, protecting them as best you can.

Dirt racing is increasingly becoming a buy-it-and-bolt-it-on sport. One of the few ways to get an advantage over the next guy when it comes to the race car is good suspension tuning. To get the lowdown on getting a Dirt Late Model hooked up with proper shock and spring selection, we went to Jeff Smith of J&J Racecars. In addition to being a darn good racer, Smith sells GRT and Warrior race cars from his shop in Gastonia, N.C. and spends a great deal of time helping racers find the perfect combination for their driving styles.

Circle Track: When tuning for a specific track, what areas of the car are the biggest factors.

Jeff Smith: It depends on how close we are on the setup when we get there. We generally have three areas we go to to tune. We go to the right-front spring, the Panhard bar or the top bar on the left rear (Smith runs a four-link rear suspension). We’ll change the length of the bar or it’s mounting height to change the way the birdcage indexes. After that we’ll get into shock valves. We’ll run the same on the left front and the two rears. We’ll run the same springs there probably 90 percent of the time. What we change a lot is the right-front spring to affect the car getting in and off the corner. That’s basically how we tune the GRT cars. I think most other cars are probably the same way.

CT: Like most Dirt Late Model racers these days, you run a four-link rear suspension. Please explain the importance of running the shock behind the axle versus in front on the left rear.

Smith: Putting the shock behind the axle on the left rear gives the car more drive off the corner. It also makes it tighter. It does it because of the way the birdcage indexes, or moves, as the car rolls into the turn. As the car turns, it rolls over on its right side, picking up the left side. As the top bar on the left side moves down, it spins the birdcage around the axle. If the axle is mounted on the birdcage behind the axle it actually loads the spring, helping it push the left-side tire down to keep it in good contact with the track. The more pressure you put on that spring the harder it pushes the tire into the ground.

It’s the opposite if you have the shock and spring in front of the axle. As the left side rolls up and the top bar pulls the birdcage, it’s actually unloading the spring. So if we are at a racetrack that’s taking rubber and really getting hooked up, and you are able to be on the throttle all the time, the car will start rearing up with the shock behind and get too hard to drive. Then we’ll go to the shock and spring in front of the rear end to calm the car back down.

The rule of thumb is you go in front of the axle tube on the left rear when the traction is there already. Also, putting the shock on the front of the axle will free the car up and keep it from rearing up so much. It’s just reducing the traction available to the rear wheels.

Here’s the scenario: It’s early Monday evening. You are home from work and have finally decided it’s time to get back to work on the car. Saturday night was the race you had been dreading but knew was inevitable—the big wreck (insert your situation here). Now you are faced with some rumpled sheetmetal, a busted spindle and who knows what else in addition to a stiff neck. As you work your way through the flotsam and jetsam of broken race car parts you give the headers a quick once-over. No cracks or obvious breaks, so they must be good.

Unfortunately, racing headers are a lot more susceptible to damage than many people think, and it’s often a lot more difficult to detect than a crack or broken weld. That’s the bad news. The good news is stainless- and mild-steel headers can often be repaired to like-new status for a significant cost savings over replacing them.

“The headers can get extremely hot during a race,” explains Steve Sousley, owner of Pro Fabrication, a custom header shop. “That heat makes the tubing of the headers a lot easier to bend. If a race car gets into a wreck, a knock all the way down at the merge collector can bend the tubing up near the exhaust flange.” Sousley should know: In the seven years Pro Fabrication has been building custom headers for Winston Cup teams, he’s seen—and built—it all.

Header tubes are selected for one reason: performance. A circle contains the largest interior area for a given surface area of any shape. Want to evacuate exhaust gases from the combustion chamber as cleanly and efficiently as possible? Use a round tube with as few bends as possible. If for any reason the tubing becomes kinked, warped, squashed or anything other than perfectly round, the interior area of the pipe is reduced and so is its ability to flow exhaust gasses from the engine. Now we are talking backpressure. Also, to work effectively, header pipes must bolt to the head on a plane perpendicular to the face of the exhaust port. If pipes are bent so the header pipe mates with the exhaust port on an angle, performance will be affected. While small dings and even small flat spots aren’t a big deal for the Saturday-night racer, kinked or bent pipe is and should be repaired.

Detecting header pipe that has been knocked out of round is more difficult than checking for cracks. The best way to do it is wait until the headers are cool and use your hand to feel each pipe. Don’t always trust your eyes; they can deceive you. If you find damage, most problems are easily repaired if you can find a qualified header fabricator. Be careful using your local muffler shop for repairs. Making the proper bends for header tubing requires a mandrel bender. Good ones go for $50,000, and it’s unlikely you are going to find one anywhere except a specialized racing fabricator.

“Header repair is fairly straightforward and often preferable over going out and buying a new set,” Sousley says. “The headers I build are mostly for Winston Cup and Busch Series teams. They are custom to the engine builder’s requests and run about $2,500 for a set. Generally, I can repair a stainless-steel set of headers for $250 to $400 per side. Mild steel headers are even less: $150 to 250. So you can see there’s a pretty big cost savings, even over buying a prefab set out of a catalog. Merge collectors are pretty expensive, so even if that’s all you can salvage you still will come out ahead.”

The average racer these days desperately needs a shock absorberdynamometer. Why, you ask? Because what you buy might not be what youneed. Due to many factors, design, production methods, etc., a shockabsorber may not have the rate of compression and rebound the labelsays. Trouble is, you will never know unless the shock is run on a shockdynamometer. There are several shock dynos on the market that can cyclea shock at various speeds, control temperatures and give a computerizedreadout. The readout provides much useful information.

Roehrigmakes one of the best commercial shock dynos, but the problem for manyof us is its $22,000 price tag. ND Tech has a very good air-powered dyno, which provides a lot ofinformation and sells for about $11,000. Powerhouse Products makes agood air-powered dyno, too. Winston Cup teams typically have one ofthese types of dyno in the shop and another in the transporter. If youare a Saturday-night racer with that kind of budget, purchase one now.It will tell you a lot about your shocks. The problem is, most of usdon't have that kind of money in our race cars, let alone thediagnostic equipment to tune it. Some shock manufacturers will dyno ashock for you and give you a printout for less than $10 per shock.

Why dyno-test shocks Some shocks, particularly those on the lessexpensive side, do not always conform to the labeled rate. This isusually because of production tolerances. A .001-inch difference in ahole or plate can mean big changes in shock control. Racers often say,"Well, I changed a shock and it didn't make anydifference." It could be, his No. 5 shock might have thecharacteristics of a No. 4 or a No. 6 valve could be closer to a No. 5valve. This could lead to a situation where you think you are putting ona lighter/ heavier shock when in fact you didn't make a change atall. Worse yet, you might be going the wrong way. But all is not lost aslong as you know what your shock is doing.

Some of yourolder or less-expensive shocks might be quite good. They can do theirjob and last a long time. But for proper handling, the shocks need to bechecked for specific compression and rebound values. Only then can theybe used on a car with confidence. One other thing to think about is theneed to check shocks occasionally. Even expensive shocks can lose gaspressure, wear or be internally damaged. Also, if you have rebuildableshocks, such as QA1, a dyno can confirm your changes and adjustments.

How the dyno operates This racer's dyno does notconnect to a computer and it doesn't cycle a shock at varyingspeeds while controlling the temperature. It is not the equal of theexpensive, purpose-built units, but it will give you a repeatableindication of the valve ratings of your shocks at an affordable price.This dyno can do that for about $100.

Editor's Note: Andy Petree has been a NASCAR team owner since 1996, and prior to that he was a chief mechanic and driver. He knows that of which he speaks, and as a member of the Circle Track Magazine Technical Council, he's sharing that knowledge with our readers. As a team owner, his cars have won more than $12 million in prize money, and Bobby Hamilton earned Andy Petree Racing's first NASCAR Winston Cup victory last season at the 2.66-mile Talladega (Ala.) Superspeedway.

We all know the engine supplies power to the race car, but what supplies power to the engine? Fuel is where the engine’s power comes from and getting it to the engine is one of the most important systems in the race car. To help understand what is involved with installing a fuel system in your race car, we talked with representatives from Holley Carburetors, ATL Fuel Cells and Earl’s Performance and visited Hooters Cup driver Mario Gosselin’s shop for some guidance.

In today’s ultra-competitive racing environment, every component in an engine is expected to play its part in increasing power output. Gains can come from some unlikely sources—including the humble piston ring. In this article, we talk to four experts in ring technology—Bob Koch of Race Engineering; Jim Walther, former automotive sales manager of Wiseco Pistons; Dave Calvert of CP Pistons; and Tony Alteri of T/A Engines—about new developments in ring design and the latest products available to racers.

Engine builders have long sought to increase power by reducing friction, thus enabling an engine to accelerate faster. However, you can only make parts so light without getting into exotic materials, so thinner ring packages have become an area of interest. Borrowing from proven motorcycle technology, new smaller top and second rings, measuring 1.2mm or .047-inch thick, have been developed.

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Are you building a new race car or is it time to freshen up the dash panel in the car you have? An easy-to-read gauge for monitoring the engine’s functions can be the deciding point on whether you win or lose a race. Bruce Jones, crew chief for Crenshaw Racing, was in the process of building a Goody’s Dash machine and was ready to install a dash panel. Circle Track magazine decided to jump in and go along for the installation ride to show you how to assemble the dash panel for your race car.

Jones started with a sheet of .024-inch-thick sheetmetal and a ruler. He carefully measured the inside of the race car and cut the sheetmetal to size. During the measuring, Jones added in width to accommodate for the front panel and for the metal to be folded under for added strength.

With a new piece of sheetmetal, Jones started by placing marks where the gauges and switches would go. Jones likes all the gauges to be on the left side of the dash. This keeps the weight on the left side of the car, and when the car makes left turns, this will also make it simpler for the driver to see at a glance.

Which gauges should you use? It depends on the type of races you compete in, as well as driver/crew chief preference. A typical race car would use a tachometer, oil-pressure, oil-temperature, water-temperature, fuel-pressure and voltage-meter gauges. Because this race car will only run short-length races, Jones installed an Auto Meter tachometer and oil-pressure, oil-temperature and water-temperature gauges.

Once Jones carefully measured where the gauges would go, he used a hole saw to cut the holes through the sheetmetal. Higher-end shops may have a rotary punch to handle this type of job, but a hole saw works fine for the on-a-budget-type shop. Before drilling the second hole, Jones clamped two pieces of flat stock close to the area. A small amount of metal between the hole helps prevent the metal from twisting or bending.

With all the holes set, Jones made bends in the metal to shape it into a dash. The bottom ¼-inch edge was bent over to add strength and a smooth edge. Next, the panel was sent through a bead roller. This also adds strength, especially to large, flat areas. The dash panel was given a quick coat of flat black paint to help keep any glare to a minimum. The freshly painted dash was then ready for the gauges to be permanently mounted. Jones inserted each gauge with the normal reading pointing straight up. This makes it easier for the driver. If the needles aren’t pointing up at quick glance, the driver can tell there’s a problem.