When Going Faster Becomes a Passion: Competition Upgrades for Your MINI (Part III)

Competition Upgrades for Your MINI

Snappier Response

  If you’re really getting into doing track days or autocrossing, and haven’t considered replacing the clutch and flywheel with a quick-reaction clutch and lightened flywheel as we discussed in the preceding section of the book, now is the time to consider doing that upgrade. If you can make your downshifts into corners quickly, losing as little time as possible coasting between gear changes, your lap times will improve.

  A performance clutch and lightened flywheel is key to this aspect of your driving. For the same reason—improving your performance through the gears—a close-ratio gear kit can help reduce your lap times.

Tilton High-performance Flywheel and Clutch

  If you haven’t yet made the change, and are serious about finding every tenth of second that you can, you may wish to consider doing what the pros do and replacing your MINI clutch and flywheel with a Tilton high-performance clutch and flywheel.

  This substitution offers several advantages over stock components and less-expensive upgrades. Going from front to back, the system starts with a light, balanced flywheel weighing only 11 pounds, which means the minimum amount of inertia and quicker response. Behind the flywheel is a smaller-diameter lightweight clutch, which means less weight in the car and a reduction in rotational inertia as with the flywheel.

  The clutch disc itself has a cera-metallic surface, which means quick pick-up with no clutch fade over a long race. Finally, manufactured to racing standards by a well-respected racing supplier, this whole system is guaranteed to stand up to racing demand and provide long-lasting performance.

  The only drawback to the competition clutch is that it does away with the vibration-damping springs with which the stock flywheel is equipped. As a result, your Tilton-equipped MINI will be louder at idle than a stock MINI. But then quiet idling isn't the point, is it?

  As you might expect, the Tilton materials and manufacturing quality are going to cost a little more than typical clutch and flywheel upgrades, but the performance and especially the durability make it the best choice when you’re seeking to be the very best. The full kit, including flywheel, clutch disc, pressure plate, throwout bearing adapter and installation hardware costs about $1500.

Straight-Cut Close-Ratio Gear Kit

  When the engineers are selecting gear ratios for a manual gear box, they’re generally going for the best gas mileage possible. That means that gears are selected to produce reasonable torque at the lowest possible engine speed, which may not be what you’re looking for in a track car. They’re also assuming that the average driver may not be all that precise in shifting, so they’ll use bevel-cut gears to reduce the possibility of grinding gears when shifting.

  In racing, you’ll sometimes hear drivers bragging about their “close-ratio” gearbox. They’ll also talk about using “straight-cut” gears in the gear box.

  The first term—close-ratio gears—describes a gear set that has different ratios than the standard gears that are installed in stock MINIs. The purpose of installing a close-ratio gear set is to keep the engine well up in the power band (which as you may remember really starts about 3500 RPM) at the range of speeds common on a road track. It is especially important to making sure that you have all the torque possible for those all-important part of the turn where you are accelerating, because the car that accelerates faster out of the corner will be the one that’s ahead at the end of the next straightaway.

  For comparison, the following table shows the ratios of the standard five-speed gear box and those in an aftermarket gear kit available in the aftermarket. To understand this table, remember that the lower the ratio, the slower the engine is turning relative to the driveshaft at the differential. So, for example, in first gear, the engine is turning 3.42 times as fast as the shaft on the end of the transmission. You’ll note there’s little difference between the gearing on the standard gearset and the close-ratio set, since first gear is only used to get out of the pits.

  However, the differences become more obvious as you move up through the gears. There is a significant gap between first and second gears on the stock gear box, going from 3.42:1 to 1.95:1. However, on the close-ratio set, the ratio only changes to 2.333:1. From this, you can tell that the engine speed will be much closer between first and second gear on the competition box than on the stock box, which of course is why this is referred to as a close-ratio box.

  You can also see that the engine is going to be turning over about 15 percent faster in second gear with the competition box than with the standard box, so when the stock engine is turning at about 3000 RPM in second gear, the engine in the close-ratio equipped MINI will be turning at about 3450 RPM at the same speed, or right at the point where torque really starts to increase.

  The difference is very marked in fifth gear. On the stock box, the engine is actually turning slower than the final drive, the ratio that is called “overdrive.” This overdrive ratio is excellent for highway driving where you don’t need any real torque because you’re cruising at a constant speed, but you want the best gas mileage. However, it would be totally unsuitable for the track. In contrast, the close-ratio box has a gearing that about 40 percent higher. So when the stock engine is loafing at 2500 RPM in fifth—perfect for highway driving—the competition engine will be running at 3550 RPM to produce the same speed, right at the beginning of the power band.

  With this gear box, the engine easily can be kept in the power band at normal racing speeds in all types of corners. To stay equal in acceleration out of corners, the stock MINI would have to be able to put another 100 horsepower to the wheels.

                      Standard         Close-Ratio

First                 3.42:1              3.417:1

Second            1.95:1              2.333:1

Third               1.33:1              1.788:1

Fourth             1.05:1              1.429:1

Fifth                0.85:1              1.208:1

  The second feature of this competition gear kit is the design of the gears. In a standard box, the gear teeth are cut at an angle to the gear shaft  so that two gear teeth are engaged at any one time. These are called “helical gears.” By contrast, “straight-cut” gears have teeth edges that are parallel to the gear shaft  The helical gears significantly reduce the chance of the driver grinding gears when shifting and they are also noticeably quieter in operation than if the gear teeth were parallel to the shaft.

  However, in racing the helical gear is slower to engage than the straight-cut gear. Also, it doesn't transmit power as effectively as a straight-cut gear. Since a race driver should be able to shift more precisely, and gear noise is not an issue, for competition the straight-cut design is preferred.

  Most MINI owners who use their cars on the street as well as for competition probably wouldn't enjoy the straight-cut gears in daily use. They also require higher rev levels for given speeds because of their ratios, so the competition box would deliver much lower mileage and greater engine wear. However, for MINIs that are being built up primarily for track use, they are worth serious consideration because of the competitive edge they provide.

  The gear kit with the ratios described above is available for about $3500. Since it requires removal of the gear box and replacement of the gears, installation is best left to a service shop that is experienced in MINI work.

Next Installment: More Stopping Power

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When Going Faster becomes a Passion: Competition Upgrades for Your MINI (Part II)

Competition Upgrades for Your MINI

High Performance Cylinder Heads

  The cylinder head is the portion of the engine that channels the fuel-air mixture into the cylinders and the exhaust gases out of the cylinders, and controls the flow of fuel and exhaust with the valves and valve springs that are installed in the cylinder head. The cylinder head also includes the upper portion of the cylinders where the fuel/air mixture is compressed and the explosion takes place that pushes the cylinder downward.

  The design of the cylinder head, and the quality of its manufacturing determine how easily air can enter the engine and how efficiently exhaust gases can be removed from the engine. The design also determines the pattern of the compression and explosion in the cylinders.

  For the owners who want maximum performance from their MINIs while still using them primarily as daily drivers, additional increases in horsepower and torque can be achieved through substituting a high-performance cylinder head.

  In high-performance cylinder heads, the passageways through which the air and gases flow are engineered so there is a minimum of obstruction. To further improve flow, the manufacturing process is as precise as possible, and then is finished off by hand-polishing, so that the surfaces of the air and exhaust passages are very smooth to reduce turbulence in the flow. Finally, the shape of the upper portion of the cylinders is altered to increase the explosive power of the fuel-air mixture. One product that has proven its benefits is the Stage 1 Performance Cylinder Head, available through some aftermarket MINI suppliers. Because of the complexity of its design and intricacies of its manufacturing, this cylinder head isn’t cheap, but it has been shown to add 20 to 30 horsepower to the engine’s performance.

  The Stage 1 head sells for about $1900, and there is a $1000 core charge, which is refunded if the original head is returned to the supplier within 30 days.

  Installation also requires a head gasket kit and new headbolts, which will add about $200 to the costs. Professional installation is required so the total cost will be around $2500.

Exhaust Header

  Breathing is still the means to the biggest improvements in horsepower and torque. Air has to get into the engine, and the exhaust has to get out. Because of environmental protection requirements in many states, we've left until last one of the critical links in that path: the exhaust header.

  The exhaust header is that set of curly pipes that connects the exhaust side of the cylinder head to the exhaust pipes and muffler. Four pipes coming off the exhaust side of the head, one for each cylinder, channel the exhaust gases from the cylinders into common pipes that flow into a single pipe and into the exhaust system. On the MINI, the engineers have attached the catalytic converter directly to the bottom of the exhaust header. The cat then attaches to the “cat-back” portion of the system. (In many other cars, the cat may be further back in the system). The design of the exhaust header can make a big difference in how smoothly exhaust gases flow out of the cylinders. Any constraints on this flow and the pistons have to do more work as they push upward in the exhaust cycle, which means a drag on horsepower and torque.

  As with many other parts of the engine, manufacturing costs and engineering constraints have prevented MINI engineers from designing the high-quality system that would fully optimize exhaust flow. Fortunately, aftermarket manufacturers have jumped into that gap, making a stainless steel exhaust header that includes a catalytic converter which is a bolt-in replacement for the factory part.

  Tests on one of the better versions of this performance component show that replacing the exhaust header can produce a significant increase in torque, especially in the mid-RPM range. In practical terms, that can mean better acceleration out of corners and higher speeds on entrance into the straights, which means lower lap times. Because the catalytic converter is an integral part of the emissions control system on modern cars, in most states it is illegal to remove that portion of the system or replace it with a non-factory substitute. As a result, it isn't legal to replace the exhaust header on MINIs that are going to be used on the street.

  However, if you’re building a car that is designed primarily for competitive events and isn’t used on the street, putting on a high-flow exhaust header is a sensible and relatively inexpensive performance enhancer. If you only use the car occasionally for competition and don’t mind doing a little wrench work before the big weekend, the bolt-in design of this system means that it can easily be swapped in for competition and then removed for street use. Since many of the MINI aftermarket headers include a catalyst, you don’t even have to fret about increased emissions. The aftermarket header won’t produce any greater emissions out the tailpipe than the stock header. With a catalytic converter attached, a high-performance exhaust header is available for about $750, and you can install it in your garage with standard tools. A new gasket, costing less than $10, will be needed when you make the exchange.

Next Installment: Competition Upgrades for Your MINI (Part III) - Snappier Response

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When Going Faster becomes a Passion: Competition Upgrades for Your MINI (Part I)

Competition Upgrades for Your MINI

When you get to the point that you want to take your MINI driving to the next level and get seriously involved in auto-crossing and track events, you’ll need to add some safety gear to the car to meet most organizations’ requirements. Also, as you reach a point in your driving ability where you’re starting to reach your MINI’s limits of acceleration, handling, or braking, you may also want to make some mechanical upgrades to improve the car’s performance.

Either way, the aftermarket suppliers have just what you need. In this chapter, we’ll discuss means of further increasing your horsepower and response, gaining stopping power and improving the MINI’s handling. We will also discuss how you can meet the safety requirements of your racing organization if you have decided you want to take your MINI out onto the track for some serious competitive motoring.

Finding Even More Horsepower

By now, in your desire for more power, you have changed out the air intake, remapped the ECU, replaced the Cat-Back exhaust system, and replaced the supercharger pulley if those changes are permitted by the group that organizes the events in which you participate. In addition, you may have replaced the spark plug wires, added a spark booster, and installed a water-to-air inter-cooler to increase your net horsepower for enthusiastic driving. 

Be assured, there are still more parts on the shelf that will help you get the maximum available horsepower out of that sturdy four-cylinder engine under your hood. You can substitute a high-performance camshaft and if you’re really serious, replace the cylinder head to improve the engine’s ability to breathe. If your car is going to be used just for track or autocross competition or you’re willing to do a little work before big weekends, a high-flow exhaust header and catalyst can give you a solid boost in performance.

High-Performance Camshaft

The MINI engine has what is called a “single overhead camshaft” (abbreviated SOHC). The camshaft is the component on the engine that is connected to the drive shaft by a roller timing chain (it looks like a bicycle chain) and rotates with the crankshaft to cause each of the intake and exhaust valves to open and close at the right times. The MINI uses a single camshaft to control both intake and exhaust valves on all the cylinders, and it is mounted in the top of the engine, so it is called a single overhead camshaft.

The actual camshaft consists of a shaft that runs from the front to the rear of the engine. On this shaft are mounted twelve cams, three for each cylinder. As these eccentrically shaped cams rotate on the shaft, they push on two rocker arms for the two intake valves and a dual rocker arm for the two exhaust valves on each cylinder, causing the intake and exhaust valves to open and close. A high spot on the cam pushes the valve open, and then as the cam continues to rotate, the lower spot allows the spring on that valve to push the valve closed.

As the intake valves open, they allow the air/fuel mixture to enter that cylinder. As the intake valves close, the exhaust valves open, allowing the combustion gases left after the explosion to escape from the cylinder.

By changing the size and shape of the cams, it is possible to change the points at which the valves open and close, and the time during which they are open. Consequently, changing the camshaft is a standard way of upgrading the performance of an engine. A camshaft that causes the valves to stay open longer is said to be “hotter”—producing more power—than one that does not allow as much time for the fuel/air mixture to enter the cylinder, or the exhaust gases to escape.

The trade-off here is that additional horsepower can only be gained by negatively affecting the smoothness of the engine operation, especially when idling, so a hot cam is often said to be “lumpy.” To some extent, the design of the camshaft also has a negative effect on gas mileage, since more fuel is allowed to enter with each rotation of the engine.

As one might expect, there are several different variations of cams available, with the hottest being very good on the race track, but totally unsuitable for street use. However, there is a middle ground with several aftermarket camshafts that have been engineered to provide better engine performance without noticeable negative effects on the smoothness of the engine. These camshafts are ideal for the MINI that is used primarily for street use by an owner who would also like improved performance for occasional track days and autocross events. 

To select the one that’s right for you, rely on the advice of an established supplier and tell them what your objectives are in replacing the camshaft, as well as what else you have already done to the car. It’s possible they may be able to recommend other changes that you can make to increase performance and horsepower before going to the expense of buying and installing a new camshaft. If they think a higher-performance camshaft is the right answer, they should be able to recommend one that will meet your goals.

Replacing the stock camshaft with a high-performance camshaft is an effective way of improving engine performance while still using stock valves and valve springs. This way, engine performance can be improved without the expense of disassembling the motor and changing the cylinder head.

A high-performance camshaft typically is available for the Cooper S for about $500 and for the Cooper for less than $600. In both cases, there is generally a core charge of about $100 which is refunded when the original camshaft is returned to the supplier. Installation should only be undertaken by an experienced professional shop.

Next Installment: Competition Upgrades for Your MINI (Part II) - High Performance Cylinder Heads

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When Going Faster becomes a Passion: Sports Car Club of America Club Racing

Sports Car Club of America Club Racing

  The Sports Car Club of America (SCCA) is the largest and oldest racing organization in the country with an amateur club racing program. It offers competition at major tracks in all parts of the United States in the same way as the BMWCCA does, but with cars of all manufacturers eligible to participate.

  In the same manner as in BMWCCA club racing, cars are classed by their level of preparation and performance capability, so it is possible to compete at SCCA events in a car that is very close to showroom stock condition. SCCA racing classes and preparation rules are very similar to SCCA autocross classes. These classes, and preparation rules, are documented in the SCCA’s General Competition Rules, known as the GCRs

  Though many SCCA club racing competitors compete in purpose-built cars at a near-professional financial level, the entry-level Stock Class is designed to allow new racers to participate without making much more than safety changes to their car. It is certainly possible for you to compete in wheel-to-wheel races through the SCCA on a budget that doesn’t require bottomless pockets or a wealthy sponsor.

  Just as with the BMWCCA program, you have to go through a training and qualification program before you can venture out on the track for wheel-to-wheel competition. SCCA requires proof of good physical condition with a medical exam, and satisfactory completion of two school sessions in order to earn a provisional novice license that allows you to take part in your first race.

  You’ll be classified as a novice until you have safely and satisfactorily completed two races. Complete those requirements and you earn your regional racing driver’s license that qualifies you to continue racing in regional SCCA races.

  One difference between the SCCA program and the BMWCCA program is that you must have a race-prepared car to participate in an SCCA driving school. That means installing a roll cage, safety harness, and basic safety gear in your car, as well as buying full driver’s safety gear before you can begin racing.

  Consequently, you’ll certainly want to find other means to decide whether wheel-to-wheel racing is for you before making this investment. You can do this by taking part in a BMWCCA driving school or one of the commercial race driving schools , or you may be able to arrange to rent a race car to take the SCCA school, before making the investment to turn your street MINI into a race-capable car.

More information on the SCCA programs is available at www.SCCA.com/club/.

Next Installment: Competition Upgrades for Your MINI (Part I)

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When Going Faster becomes a Passion: BMWCCA Club Racing

BMWCCA Club Racing

  The BMW Car Club of America runs an excellent club racing program that includes specific classes for the MINI Cooper and MINI Cooper S. This program offers competitive wheel-to-wheel racing with cars grouped generally by their performance capabilities so it can be a great way to experience real track racing.

To make it as easy as possible to get your feet wet, BMWCCA runs organized race driving schools all over the country. All you need to participate in one of the schools is a driver’s helmet and a safe street MINI (or other BMW).

  In the Club Racing program, The BMWCCA has established Spec Classes for both MINI Cooper and MINI Cooper S models. These classes allow MINI owners to race against other MINIs in an active racing schedule at race tracks in all regions of North America.

  In the MINI Spec Classes, relatively few items must be, or in fact can be, changed from the car as it came from the showroom, so racing preparation can be done for much less than most owners spend to modify their cars for the street.

  Safety preparations are mandatory. The car must be equipped with a bolt-in roll cage, five-point safety harness, headlamp covers and window net. Though gauges can be added, nothing in the interior can be removed, including the rear seat and carpeting. As a result, there’s no reason why a car can’t be used for street transportation and racing.

  Drivers are also required to have full safety clothing to race, including a Snell-approved auto racing helmet, and fireproof racing suit, gloves, and shoes.

  Tires, wheels, shocks, springs, rear sway bar, and rear adjustable control arms must be changed to race-grade products, and the brands, types, and sources for these modification components are specified in the rules.

  The car can be mechanically upgraded to improve performance, but only with the addition or substitution of specific components. These allowed (but not required) modifications include drilled brake rotors, cold air intake, cat-back exhaust system, and power steering punp heat shield. Replacement of the stock front seats with racing seats is also permitted.

  Owners are permitted to overhaul the engine, but boring and machining can only be done within specified tolerances. To insure that racing advantage comes from driving skills, rather than from the size of the owner’s check book, no other changes can be made to the car. The supercharger pulley can not be changed, nor can the ECU be remapped, and exhaust headers can not be replaced.

  As a result of these strict limitations, it is quite possible to put a MINI on the track for BMW CCA Club Racing for less than $5,000 in modifications. For that you get all the fun, excitement, and Monday morning bragging rights of taking your car on the track for wheel-to-wheel competition. and you’ll still be able to drive it on a daily basis (with or without your competition numbers on the doors).

*************************************

BOX:

MINI Spec Classes for BMWCCA

Required and optional items and approximate costs

Required Safety Modifications

Bolt-in Rollcage $850

Driver’s Safety Harness $200

Headlight covers $50

Window net $60

Driver’s Safety Wear $800

Approximate cost of safety modifications $2000

Required Performance Modifications

Shocks and springs $875

Tires and wheels $1100

Rear control arms $500

Rear sway bar $250

Approximate cost of required performance modifications $2750

Total cost of required modifications $4750

Permitted Performance Modifications

Cold Air intake $200

Cat-back exhaust $700

Drilled Brake Rotors $450

Driver’s Race Seat $500

Hood pins $50

Power Steering pump heat shield $50

Approximate cost of permitted performance modifications $2000

  If you find that you enjoy racing and want to devote more resources to the hobby, BMWCCA stock, prepared, and modified classes allow you to upgrade the performance of your MINI and compete in faster and more challenging classes as your driving skills improve.

  If this sounds like it may be your cup of tea, the best way to find out is to enroll in one of the many excellent BMWCCA Club Racing drivers’ schools that are offered at tracks all over the United States and Canada. Completion of a BMWCCA racing school is the first prerequisite to racing with the BMW car club, so it’s where everyone starts.

  Once you’ve completed the school you can decide if you want to invest the money to upgrade your MINI to the club’s standards for MINI spec racing or stock classes. More information on the BMWCCA club racing programs is at www.bwmccaclubracing.com.

When Going Faster Becomes a Passion: Club Racing - Almost the Real Thing

Club Racing—Almost the Real Thing

  When you’re ready to get really serious and want to find out what it’s like to cope with the added variable of other cars on the track at the same time you are, trying to hit the same apex that you want, you’ll be ready for wheel-to-wheel racing. MINIs are regularly raced in Sports Car Club of America, and BWM Car Club of America Club Racing. MINIs are even professionally raced in the Grand Am Cup Series.

  Each of these organizations has defined classes that allow you to race with a MINI that is close to its original showroom specifications, or modify your MINI to run in relatively more unlimited classes. The Spec Classes are a great place to start racing without finding a deep-pockets sponsor or breaking your own bank. In the words of the BMWCCA rules, spec racing places “the emphasis on driving skills while offering a finite capital expenditure’ by racing cars that are still street-legal.

When Going Faster Becomes a Passion: Organized Track Day Programs

Organized Track Day Programs

  Track days can be a fun and relatively safe way to enjoy your car’s speed and handling capabilities. Driving around a race track, at speeds sometimes in excess of legal road limits, is a pretty cool thing to do.

  However, if you continue to do it with no real goals in mind, and no help in meeting those goals, it’s as if you were out by yourself, simply whacking a ball around a golf course without worrying about whether it got into the holes, much less how many strokes you took each round. You’d never do that if you wanted to master the game of golf. You’d get a pro to give you lessons, critique your swing, and help you learn which club to use.

  So why would you think that you could become a better driver, much less a race driver, without any more help than following other people around a race course. You wouldn't  But there is help available, even after you’ve completed an advanced driving skills course.

  At least one organization, the National Auto Sports Association (NASA), offers an excellent program called the High Performance Driving Events (HPDE) at tracks in northern and southern California, Arizona, and Nevada. These programs offer opportunities for novice drivers to work with experienced racers to improve their driving skills on the track.

  The HPDE program divides drivers into four classes, ranging from first-timers through experienced track drivers, with the instructors deciding when you’re ready to move up to the next class.

  In the first level, you have an instructor riding with you, or you are following an instructor, during every session, with lots of off-track time for tips on finding the fast line, getting through corners, shifting and braking. Passing is very limited.

  At the second level, you drive without direct supervision, but are still given critiques on your technique, and passing is permitted in specified areas of the track. At the third level, speeds increase, the number of cars on the track increases, and passing is permitted in most areas.

  By the time you are judged to be capable of driving in the top level, your skills are at nearly at the point of racing. Passing is permitted everywhere on the track, but under the standard practices of any amateur racing group. The only difference between level 4 driving and actual racing is that you aren't trying to beat anyone over a specified number of laps, so there are no grouped starts, or sprints for the finish line.

  Progress from group 1 to group 4 typically occurs over a number of track events, so each driver can move ahead at their own pace as they acquire more experience and skill. NASA also sponsors the International Touring Car Series, and is currently working with BMWCCA on racing events with classes that includes the MINI Cooper S, so graduates of the HPDE activities can move up to wheel-to-wheel racing within NASA if they wish.

  For more information about NASA HPDE, check the NASA website: www.NASAProRacing.com. Also, check with race tracks in your region to find out if similar programs are offered at their tracks by other organizations.