Telematics and performance racing

A. While some may see telematics implementation that way, the convergence of different technologies simply lends itself to provide more features for today’s demanding customers. Telematics certainly accomplishes that and will continue to do so. Inherently, you might say dealers have an initial advantage when it comes to telematics service, since the technology is “bred” in by the manufacturer. The best way to ensure that your shop gets its share of the telematics service pie is to stay informed on this rapidly developing technology so you can make good decisions.

Q. We run a performance tire shop where we install a lot of expensive tires and wheels. What can we do to ensure that we install tires and wheels properly on the vehicle to reduce comebacks?

A. First, make sure you’ve got a wheel balancer up to the task for today’s sensitive suspension systems. You’ll want to make sure you have the capability to match balance tires with wheels and the ability to fine balance a wheel/tire if needed. A customer with a Porsche making a big investment in wheels and tires isn’t going to be very happy with a car that shakes going down the road.

When installing wheels, not only is it important to apply the right amount of torque, but also to apply it evenly around the wheel. The techniques for accomplishing this vary somewhat according to the configuration of the wheel studs. You should do this by applying torque gradually and evenly to the wheel studs, alternating the pattern of tightening. On five-stud wheels, the most common application, this means tightening the studs in a “star” pattern. For 4- and 6-bolt wheels, use a similar procedure. Start with about 25 percent of the manufacturer’s specified torque value, and work your way up gradually from there. Do not apply full torque to just one stud before moving on to the next. You should always look up the recommended torque spec first, especially when you are installing custom or alloy wheels.

A final tip: make sure you consistently access service information for tire and wheel related information. As the spectrum of tires and specialty wheels have increased, so have problems related to their installation.  

Q. We run a performance shop and want to make sure that exhaust backpressure is OK before we release a car to a customer. What kind of equipment can we use to check this?

A. The best way to check backpressure is directly from the exhaust system. The oxygen-sensor-mounting hole offers a handy port to check backpressure. Since all sensors use 18mm threaded holes, one adapter fits all cars equipped with an oxygen sensor. With the engine off, carefully remove the sensor. Install the adapter in the hole and tighten it according to the manufacturer's torque spec. Connect your vacuum/pressure gauge to the adapter. Start the engine and let it warm up to normal operating temperature. Take one reading with the engine idling in neutral and another with the engine running at 2000 rpm. Faster engine speeds should show a higher backpressure reading. Don't use a powered exhaust venting system when backpressure testing. The system's draw could alter the readings. If necessary, do your testing outside. If you have a chassis dynamometer, run the car under road load conditions to heat up the exhaust system. Sometimes, backpressure slowly builds as the exhaust system heats up. If you don't have a chassis dynamometer, carefully route the hose so it doesn't drag or get pinched. Take the car for a ride and check backpressure under load. As a general guideline, backpressure at idle shouldn’t exceed 8.62 kPa (1.25 psi) and 20.68 kPa (3 psi) at 2000 rpm. Remember that readings may vary with each vehicle and its specific configuration. When you’re finished, remember to reset any oxygen-sensor-related codes.

Q. During an engine performance diagnosis, we found low compression in a cylinder. What kind of equipment can we use to get more details on the specifics of this compression problem?

A. As a next step, connect a cylinder leakage tester to determine where the source of the compression leak is. As a rule, most engines in good mechanical condition will show less than 20 percent leakage, though some engines can read as high as 25-30 percent and still perform okay. Generally, leakage more than 20 percent means trouble. Cylinder leakage testing really proves itself when you pinpoint the leak source:

-Air escaping out the tailpipe indicates a leaky exhaust valve.

-Air escaping into the intake manifold tells you there's a leaky intake valve.