Breaking In

By Staff Writer
Mar 26, 2012 | Honda | Posted in Drivetrain | From the June 2004 issue | Never miss an article

Story By Per Schroeder

There’s a large step between building a race car in your own garage and that wonderfully devil-may-care feeling of chucking that fresh, new machine into a series of high-speed kinks at terminal velocity. After all, the car may be new, but are all the bolts tight?

It takes trust in the quality of materials and assembly to push a newly built race car to the limit. Based on many people’s wrenching skills, it’s a leap of faith to drive some cars to the store for milk, let alone going under the bridge at Road Atlanta without lifting.

No matter who built the car—a hired professional shop or any one of us—it’s just not reasonable or prudent to take a new race car into competition only hours after that last bolt was tightened. Some period of sorting and evaluating is necessary for a safe maiden voyage. If you weigh the alternatives, like having an important part fail or fall off at the wrong time at speed, you’ll see that taking a deep breath and planning a sorting session is the wisest move.

Professional car builders recommend and often require shakedown and sorting sessions before a wheel is turned in anger. The question is, what exactly does this entail on a newly built race car?

Meet Our Subjects

OPM Autosports’s Tom Fowler Jr. has built a lot of race cars through the years, with several of his Hondas, Mazdas and Volkswagens taking the top spots at the SCCA’s American Road Race of Champions. In fact, Tom himself took the Improved Touring A crown this past fall behind the wheel of a Honda CRX Si. Tom’s good at building a car, but even he knows that a new machine needs some attention before heading off into battle.

Sage Marie, the Southeast regional public relations manager for American Honda, recently decided to make the jump from track events to road racing. So he sold his track car and ordered an ITA-class Honda CRX Si from OPM Autosports. Showing his true colors, Sage had the CRX painted Sunset Orange Pearl, a hue available on Honda’s new Element.

The sorting procedure took place at Michelin’s Laurens Proving Ground near Greenville, S.C., and we were there to document the process. What we did could have easily been done at a larger autocross site.

Before You Leave the Garage

The sorting process actually starts in the garage, before the car even gets to the track. You must budget time for this phase, as doing it at the track is a waste of both time and money.

First things first: Check every nut and bolt on the car. The phrase “nut and bolt” is often tossed around, and the meaning is simple: torque every fastener to the correct specification. We’re not saying every bolt should be tightened to the point of failure, however, a fastener that is too tight or too loose is not a good thing. If in doubt, loosen the fastener and properly retorque it with a calibrated torque wrench.

On a new car, this process should be repeated between the initial track sessions. It should also become part of your prerace procedure.

Lug nuts and bolts are often the source of problems on a new race car, and they, too, need some attention. Despite proper tightening with a torque wrench, lug nuts can loosen up—and worse, fall off—with little warning. Mostly this is due to the use of new wheels, as the lug seats are often powder coated along with the rest of the rim at the factory.

Until it is worn off, this coating can prevent the lugs from tightening properly. There is a reason why many wheel manufacturers affix warning stickers to new wheels warning that lugs should be retorqued after a certain amount of miles.

Whether the car is new or not, torquing the lug nuts before every session should become routine. Losing a wheel due to loose lug nuts is not only dangerous, it’s embarrassing.

When selecting lug nuts for your new wheels, make sure everything is compatible. If the taper of the lug nuts doesn’t match the taper of the wheels’ seats, big problems could be in store.

After the nut and bolt procedure, start concentrating on getting the car going. On a fresh engine, you should remove the coil wire and spin over the engine with the starter until the oil pressure warning light goes out. This pre-oiling helps minimize startup wear on a dry engine.

Next, start the engine and allow it to completely warm up. Watch everything for leaks. It’s normal to have unusual smells come from a new, warm engine as various oils are burned off the hot parts. Frequently check your fluid levels to make sure nothing is leaking or burning off.

After the engine has cooled down, check every fastener in the engine compartment to make sure it’s snug. Then repeat the warming-up and cooling-down process as much as possible before the car is wheeled out of the garage. The cycling helps gently break in the bearings and piston rings while also pointing out any suspect clamps or fasteners.

Next, check the operation of everything while the car is sitting still. Does the clutch pedal completely actuate the pressure plate? When the gas pedal is fully depressed, does the throttle open completely? Does the transmission shift smoothly through all of the gears? Can you see the mirrors and release the fire system?

Car setup should follow a pretty mild baseline. Ignition timing should be set at a factory setting, shock absorbers and anti-roll bars should be as soft as possible, and even tire pressures should be relatively mild. You want the car to be easy to drive, forgiving and unstressed as you make sure everything is in working order.

If you have your own scales, cornerweight the car before it hits the track. Cornerweighting the car will sometimes pinpoint issues with anti-roll bars that are preloaded and need to be adjusted. It’s better to discover these things while the car is stationary. Next, align the car, making sure to check for chassis squareness: Is the wheelbase equal from side to side?

It’s easy to get wrapped up in bench racing and discovering what the fast drivers are doing when you’re building your new race car, but resist the temptation to dial in the ARRC-winning alignment settings when you’re new to the car.

These “fast” settings are often very oversteer-prone and difficult for a new racer to handle. Sorting a new race car at speed can be a tough task, even for an expert, so there’s often no need to have the rear end constantly trying to pass the front. Take a deep breath and make the car easy to drive, and you’ll learn a lot more about it without scaring the crap out of yourself or potentially harming your new baby.

After you’ve rechecked all of your fluid levels—are you sure you still have enough oil in the crankcase?—put the car on the trailer and head off to your test area.

Where Not to Sort a Car

More often than not, the place that a new race car is sorted is at the owner’s first driving school. This is probably the worst place to do it. There’s enough going on at a driving school without having to worry about any funny noises coming from the car.

Despite conventional wisdom, it’s still not unusual to see budding drivers in full race garb crawling under a new car to fix something that has failed—at the time they should be on the track or working with an instructor. It’s also not a great way to break in your shiny new driver’s suit.

Another no-no is driving a newly built racer on a public street. Johnny Law usually doesn’t have much tolerance for an unmuffled, unregistered and uninsured race car cruising the streets of his town—not to mention the liability concerns if something happens to fail and you hurt someone. It’s just not worth it.

Where to Test

The two best bets for a nice, relaxed shakedown are a local autocross “practice day” or a track day, such as those organized by CarGuys, BMW CCA, SpeedTrialUSA, NASA and so on.

Many SCCA regions and autocross clubs have practice days that provide a lot of runs, all surrounded by a more relaxed atmosphere than experienced at a normal series points event. While the speeds are lower than those seen on a race track, an autocross can still push a car to the limit, giving the suspension, brakes, steering, engine and other components a good workout.

There’s also a lot more cycling through warming and cooling to shake loose the nuts and bugs. Idling in line at grid will exacerbate any cooling issues as well. Fix them now before you cook an engine.

Noncompetitive track days are also great places to shake down a new race car. The atmosphere tends to be low-key, and if a session is missed, who cares? With no trophies or points on the line, there’s no harm in missing a session or two.

Low and Slow

Once at the test day, begin slowly. After the car has been unloaded and all of the fluids have been checked, perform a series of loops and turns, shifting up and down as you go through the motions.

Listen to the car for any strange noises, smells or vibrations. After several of these maneuvers, going from full steering lock in one direction to full lock in the other direction, stop the car and allow things to cool down. Jack up the car and check the suspension and wheels for any problems, including signs of rubbing.

On Sage’s car, we found that a stainless braided brake line was rubbing against the inside edge of one of his Team Dynamics wheels. That’s a situation that can quickly get ugly: If the brake line snags and breaks, the car would quickly lose hydraulic pressure. The cure was to zip-tie the brake hose away from the wheel.

Keeping the Rs Low

Like most experts, Tom recommends rpm limits for each session when breaking in a new engine. For example, on this CRX engine, Tom suggested that engine speeds be kept below 5000 rpm during the first hour and 6000 rpm during the second one. After that break-in procedure, and assuming everything passed with flying colors, trips to the redline could then be made.

With most track events yielding about an hour of track time per day, this equates to each day having its own rpm limit. It’s easy to remember this advice that way.

Bedding Your Friction

New friction materials, like the brake and clutch linings, need to be bedded in before they work optimally. Properly break in these linings, and they’ll deliver increased performance along with a longer service life.

Bedding in a new set of brake pads burns off some of the organic binders while transferring a coating of the friction material to the rotor. Each pad manufacturer may have their own recommended procedure, but basically you’ll perform a series of threshold braking stops, slowing the car from about 60 mph to walking speed. When the pads start to stink—generally after a dozen or so stops—the bedding procedure is considered complete.

When bedding in brake pads, don’t completely stop the car. Doing so can allow the rotor to cool unevenly, causing warp. Also, don’t forget to bed in brakes in a safe environment, as in one with plenty of run-off room.

Clutch linings should also be bedded in. In this case, treating the clutch gently for the first few sessions is often enough preparation. You can’t speed shift away from the paddock and expect a newly minted clutch disc to hold on.

Tire Break-In

Tires can be one of the biggest expenses for the racer, and what to run during the shakedown session can be open to debate. In addition to the various makes and models, do you go with new or used tires?

Some say it’s silly to start the shakedown process with brand-new tires, as it’s hard to justify expensive rubber when you’re just scrubbing around on track. A brake-bias problem could quickly lead to a flat spot on new tires, while a novice’s heavy foot could flatspot a new Hoosier in no time flat.

On the other hand, it’s frustrating to chase handling ills that are caused by worn-out and heat-cycled tires. If the car is handling strangely, is the culprit the tires or a bad shock absorber?

Our recommendation is to start out with nearly new “beginner-resistant” tires such as the Toyo Proxes RA-1 or the Hankook Ventus Z211. These will deliver many heat cycles, offer good track traction, wear well and are less prone to flat-spotting under braking than other R-compound tires. Take-offs from the local hotshoes may be the answer.

For Sage’s CRX, Tom found a set of well-worn A3S03-spec Hoosiers that were put out to pasture by a local autocrosser. They had been run past their prime, but still had enough rubber for our shakedown work.

However, these tires weren’t perfect, as Sage mentioned that the car started pushing after about 25 runs. After all of the action these tires had experienced during their lifetime, we weren’t surprised.

Starting the Tuning Process

Once you become truly confident in the car’s construction and design, you can start to explore its handling attributes. On a set of fresh—or fresher—tires, evaluate how the car is behaving. While some handling problems are driver related—such as corner exit understeer—you can get a general sense of how a car is behaving within a few laps.

Our recommendation is to not touch any of your adjustments until after the second full track session. This will give you enough time to learn for yourself if the car’s behavior is related to a suspension setting or the inputs given through the steering wheel.

From there, adjust one thing at a time in incremental steps. If the car is understeering on transition, stiffen the rear shock absorbers about one half of their usable range. Head back onto the track and see how that affects handling. Remember that a car will handle differently on cold tires than on warm ones. Wait until the rubber is good and warm before forming your opinion of how the car responded to the change.

Does Sorting Ever End?

New cars don’t stay new for long. New parts and modifications will start to work their way onto your race car within a few races, if not sooner. Make sure that you take the same care and patience when bolting on a new part as you did when you put the car together. You should double-check newly installed fasteners before and after the first few sessions.

It also makes darn good sense to play it cool for the first few laps of any session. It doesn’t matter if it has new parts or even new tires, sometimes cars just behave differently due to weather conditions. Don’t take your first lap off the trailer at warp speed. Build up your speed and build up your confidence before you go crazy.

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