TROUBLE SHOOTING

Upgrading your car? Here are some tips DT6

If you’ve been buying vehicles for more than a few years, you’ll probably look back at your earlier experiences with rose-coloured glasses.

In the era of the early muscle cars, it was easy to walk into your dealership’s parts department (or any number of specialty shops) and plunk down your cash for a new rear-axle gear set, carburetors and intakes, exhaust headers, a performance clutch, or more. Today, you really have to hunt for quality upgrades, and automakers have made more than a few of these almost impossible to incorporate.

Here are some things to consider when looking at upgrading your vehicle:

Axle ratio upgrades: This has been a popular mod with pickup truck owners since the beginning. It’s usually done to increase towing capacity, as a higher ratio can make it easier for the engine and transmission to put more torque into the equation.

Fast forward to today’s trucks, with their multitude of computers and electronics. If you swap out a gear set for a ratio that’s different than what the truck was built with, you can run into a multitude of problems with anti-lock brakes, transmission shifts, stability control and the like. These systems rely on accurate calculations of vehicle and driveline speed; if the ratio is changed, those calculations go out the window.

Some automakers will allow various on-board computers to be reprogrammed to recognize the new ratio, but others cannot. So, if you go ahead with this expensive upgrade without asking first, you may be disappointed.

Tire size swaps: The same problems that can arise with axle gear changes may pop up when upsizing tires. However, this doesn’t just apply to trucks and SUVs, because many owners will look for different tire options for their sedans, hatchbacks, CUVs and sports cars. Some consumers do it for looks and performance, while others are looking for less expensive boots for vehicles equipped with expensive low-profile tires.

A good rule of thumb is to stay within three per cent of your ride’s original tire circumference, either larger or smaller, when searching for a new fit. By using a tire-size calculator — these are a dime a dozen online — you can easily find a website that will do the math for you. If you’re not absolutely sure of your vehicle’s original sizing, check the label on the door frame.

LED lighting systems: Even low-tech headlamps have become computerized, and adding LED lights can confuse lighting-control systems, to the point where daytime running lights may not function. Fortunately, as more and more vehicles are coming with LED as a factory option, you may be able to get your dealer to upgrade the vehicle’s software to keep things bright — but ask first.

Full exhaust swaps: For some, sound is what it’s all about, thus keeping performance-exhaust manufacturers very busy. If you do a little online searching, you’ll find most systems are advertised as “cat back,” meaning the original emission control parts of the system remain in place and working. Swapping out the entire system, without taking into account the effect on oxygen sensors and other electronics, can mean a permanent check-engine light as well as risking some hefty fines from local environment officials.