VEHICLE MODS & SAFETY: PEACEFUL COEXISTENCE

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Mildred Megan Lawson
5 years ago
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1 38 January 2013

2 Photoillustration: Harold A. Perry; images: Wieck Media & Thinkstock VEHICLE MODS & SAFETY: PEACEFUL COEXISTENCE BY PAUL WEISSLER How might performance parts your shop installs affect the operation of a vehicle s electronic stability control system? If the manufacturer can t tell you, even an ESCape clause probably won t get you off the hook. You ve seen them on the road; you may even have seen them in your shop. In fact, you may have done the installation work in your service bays. The outward signs of what we re talking about are those really stylish wheels, intense body graphics, brightcolored calipers and external trim pieces obvious giveaways to the installation of lift and lowering kits. If we add in all the parts that are beyond the visibly obvious, there s a market of tens of billions of dollars in aftermarket parts. And many independent shops find installing them very profitable because the work is less pricesensitive than so-called commodity repair and maintenance jobs. But a safety system that became a legal requirement toward the end of 2011 on 2012 model year passenger vehicles has created a compliance challenge for the companies that make popular aftermarket parts and perhaps even for the shops that install them. We re talking about Federal Motor Vehicle Safety Standard (FMVSS) No. 126, the regulation that mandated January

3 VEHICLE MODS & SAFETY: PEACEFUL COEXISTENCE electronic stability control systems. Yes, we ve had such systems in growing numbers for ten years, since they appeared on 10% of motor vehicle production in However, they became legally required by September 2011, and many aftermarket parts are now covered by a have no harmful effect requirement. During vehicle cornering, electronic stability control (ESC) continuously receives signals of the driver s steering wheel action (steering angle sensor input) and the vehicle s direction (from the lateral acceleration sensor). In addition, ABS wheel speed sensors and a yaw rate sensor may be used to help measure how much and how fast the vehicle is turning on its axis. Some systems also have longitudinal acceleration and roll sensors, which provide some additional detail to the stability controller, but there also may be just a single multifunction sensor with a complex software algorithm to do the job. In this photo, a Ford F-150 pickup undergoes a simulation test of its performance parts in this case a 6-in. lift kit, wheels and tires. Whatever the sensor inputs and the software, it comes down to this: If the vehicle is traveling forward, in excess of 9.3 mph, but isn t going where the driver intends that is, if it s in the very beginning of a skid the stability controller goes to work. It operates the antilock brake hydraulic module to apply the brakes to specific wheels to create a countering torque against the skid, so the vehicle is guided in the intended direction. The objective of the standard, promulgated by the National Highway Traffic Safety Administration, is to reduce single-car accidents due to steering errors, primarily run-off-road with rollover. NHTSA estimated that rollovers account for 42% of single-car accidents with fatalities. FMVSS 126 describes a physical test procedure that requires outfitting trucks, multipurpose vehicles (cross - overs) and buses with outriggers. It consists of a series of lane change-type Photos: Paul Weissler maneuvers at speeds up to 50 mph, with the stability system returning the vehicle to the position dictated by the steering input. The test is performed on a track with a road surface that has a specific coefficient of friction, with robotic control of the vehicle steering, after the tires and brakes have been preconditioned with a series of maneuvers. Passing the test is required for all variations of all light-duty vehicles (cars, light-duty trucks and SUVs and crossovers with a gross vehicle weight rating of 10,000 lbs. or under). The standard was legally in force as of Sept. 1, However, final stage manufacturers and alterers (that includes anyone producing aftermarket parts) were permitted an additional year for compliance, until Sept. 1, So any replacement part that you install on a vehicle must not adversely affect the operation of the stability control system under any of the test conditions listed in the safety standard. In practical terms, OE parts or any of the standard replacement parts of reputable manufacturers that are used in routine repair jobs require only that you do the installation properly. Replacement parts are engineered to replicate the performance of the parts with which the car was built, although perhaps made more robust for longer life, or designed to fit several applications that require different OE part numbers. What parts might affect the operation of a vehicle s stability system? Well, tires and wheels, suspension and steering parts are pretty obvious candidates, and that includes even rubber or elastomeric bushings. But the system uses the brakes, so anything that changes the brake system characteristics also could affect stability system operation, including high-performance brake shoes, for example. The stability control system also relies on a predictable powertrain; therefore, modifications that increase engine output just might affect any stability control strategy that reduces torque. Even a high-current-draw accessory 40 January 2013

The fact that a part meets some SAE standard is no might have some effect. Oversize wheel/tire assemblies that create a tight fit in the wheel wells raise separate safety questions, of course.

4 might have an effect. Unless there s a satisfactory test result to which you can refer, you really don t know. An important thing to remember is that there are many aftermarket performance parts that, even if of perfectly good quality, could have an adverse effect on an ESC system. The fact that a part meets some SAE standard is no might have some effect. Oversize wheel/tire assemblies that create a tight fit in the wheel wells raise separate safety questions, of course. You might think that it s strictly the parts manufacturer s responsibility to ensure that his product doesn t affect the stability system, and it likely is. But in our litigious society, failure of a repair program to enable its members to certify its parts. The real-world situation is this: That robotic test, performed at a proving ground, is time-consuming and expensive, and these comparatively small aftermarket performance parts makers face a real problem. The carmakers, who also sell performance parts, can If you looked at the underbody of this 2012 Ford Focus, you d see Eibach aftermarket performance parts. The photo on the left shows the front struts with coil spring rubber separators (the sway bar is not visible in photo). The photo above shows the Eibach sway bar, which is at the rear of the car. assurance that it can t or won t create an issue with the stability system. An example is a group of SAE standards that cover wheels. The testing in these standards is primarily for resistance to fatigue cracking, and it includes many required identification labels. A wheel should meet the appropriate standard, but meeting it really has nothing to do with whether or not it might adversely affect the stability control system. As a practical matter, although tires have a major effect on stability system response, the wheels have far less, although the weight of a wheel, if outside normal parameters, shop to take reasonable precautions in this area might draw the shop s name on a lawsuit as well. Even if the possibility is remote, you certainly don t want to make any changes that could create a problem in any situation where the stability system could have saved the day. The pre-2012 aftermarket parts that are sitting in warehouses aren t covered by FMVSS 126. But the leading aftermarket performance parts companies are well aware of the situation, because the Specialty Equipment Market Association (SEMA) has been very active in bringing its membership up to speed. SEMA also has an aggressive afford to do some testing, but even they can t do an actual test on every variation of every parts package they offer their dealers. What s the answer? The fact is that FMVSS 126 permits self-certification that is, the manufacturer is in compliance if he says he is. There are no forms to fill out and file with NHTSA or any other agency. But if an issue ever arises and that maker s product is involved somehow, it had better have some documentation to back up the claim. If an engineering analysis of a part clearly indicates that it can t throw the vehicle out of compliance, that s enough, if, of January

We have to be able to tell our insurance company and show that we performed due diligence on compliance with FMVSS 126, is the way it was viewed by Mark Hellwig, president of Hellwig Products, a

5 VEHICLE MODS & SAFETY: PEACEFUL COEXISTENCE course, the analysis passes scrutiny in any investigation. But because the manufacturer could go much further to be sure of compliance, it has to consider something more that it might do. We have to be able to tell our insurance company and show that we performed due diligence on compliance with FMVSS 126, is the way it was viewed by Mark Hellwig, president of Hellwig Products, a manufacturer of suspension parts. Companies that rank as big names in the performance aftermarket still are small when compared with the major brands of repair parts. They re typically too small to self-insure. They also can t track-test every variation of their products, and The monitor shows a Ford F-150 truck running FMVSS 126 in simulation, on a dspace Simulator. This simulator with CarSim program tests the stability system operation of a Ford Focus that s equipped with Eibach suspension parts and Falken tires. certainly not in every possible combination with other parts that might be installed simultaneously. Fact is, neither can the OE makers. The answer is simulation, which is a program that takes all the operating characteristics of performance aftermarket parts and virtually replicates the operation of the stability system of the vehicle in which the parts will be installed. Sounds almost simple, but even simulation takes time and money, so the carmakers and parts manufacturers use it in combination with engineering analyses. That means that if one package is so close to another in performance characteristics, the engineering comparison may be enough assurance if sufficient margin is displayed in the test track and/or simulation testing. Simulation itself does pose an obvious problem for an aftermarket company. The stability controller is a black box, and its software is a trade secret. So a simulator is plugged into the actual controller on the vehicle for which the aftermarket parts are specified, a procedure called hardware in the loop. In the SEMA program, a dspace simulator and CarSim software, a program by Mechanical Simulation, is the combination, and the testing is being done at the Clemson University International Center for Automotive Research and Link Engineering of Dearborn, MI. The CarSim software analysis, which uses output data from the vehicle s stability controller and ABS module, has been validated against physical testing. And it s being widely used, even by car manufacturers who have a simpler task, because they have vehicle baseline data and know the software in the stability controller. Ford has been especially cooperative with the SEMA initiative, furnishing baseline data so an aftermarket company with products intended for use on Ford vehicles saves the time and expense of testing to develop similar data. One test program that was run on a Ford F-150 permitted three companies Superlift Suspension Systems 42 January 2013

(6-in. lift kit), ProComp/Smittybilt (Extreme AT tires) and American Outlaw (20-in. wheel) to validate their parts. Here s a logical question: What if another combination of parts were used?

6 (6-in. lift kit), ProComp/Smittybilt (Extreme AT tires) and American Outlaw (20-in. wheel) to validate their parts. Here s a logical question: What if another combination of parts were used? In the case of the Ford F-150, the wheels and tires were recommended for the test by Superlift, and it would be logical to expect that leading performance parts makers would list recommended combinations they ve already validated. Another F-150 test program underway is evaluating Hellwig and Rancho Suspension parts. These two companies are cooperating on both an F-150 and an F-250. They re testing separately but sharing some data. Two other performance suspension companies, Eibach Springs of North America (the U.S. arm of the German company) and Falken Tires are running a simulation on a 2012 Ford Focus. In addition, the carmakers are releasing approved kits combinations of wheels and tires, brakes and some engine performance packages. Installing these would be one approach for an independent shop. But these factory kits really are being promoted to car dealers as competitive offerings vs. what the independent shops are installing. So from a competitive standpoint, the aftermarket performance names are what you might prefer to promote. Furthermore, many motorists will prefer them, believing (typically, rightly so) that the aftermarket companies push the envelope further. However, these companies know that even if their parts pass testing solo, there could be problems with some combinations of parts that individually were not an issue. So as time goes on, you should find that the aftermarket companies will have more data on combinations, and you can be sure they ll be passing them along to independent shops. If a customer is interested in a combination of upgrades say, for example, wheels, tires and brakes an independent shop should check with the technical support group at each manufacturer for guidance if what the buyer wants isn t listed. It would be nice if whatever the Circle #22 Circle #24 customer wants were all you had to worry about. But that s not the case anymore. Just as many manufacturers are taking the extra steps to show their insurance companies how careful they are, so must you. Circle #23 Circle #21 This article can be found online at January

BY BOB PATTENGALE. Photoillustration: Harold Perry; photos: Jupiter Images & Wieck Media

BY BOB PATTENGALE. Photoillustration: Harold Perry; photos: Jupiter Images & Wieck Media 42 June 2008 ESCAPE ROUTE BY BOB PATTENGALE Photoillustration: Harold Perry; photos: Jupiter Images & Wieck Media Electronic stability control will be a mandatory safety system on 2012 passenger vehicles,