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Singer Vehicle Design Porsche 911. (Singer Vehicle Design)
Singer Vehicle Design Porsche 911. (Singer Vehicle Design)

Road Rush

How to modify your car the right way Add to ...

If you read my column last week (An Idiot’s Guide to Automotive Un-Improvement), you may be surprised to learn that I am planning some modifications to my car. (And in case you were wondering, they do not involve a V-8 engine swap, chrome spinners or cutting off the roof.)

I do believe that most cars can be improved. But as I wrote last week, many car modifications actually make a vehicle worse. My own early modification efforts were a litany of blown motors, too-stiff suspensions and oversized carburetors that refused to let my car idle below 2,000 rpm.

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I realized the error of my ways after apprenticing with a group of mechanics who taught me the value of moderation and strategic change. Instead of boring and stroking a 1.5-litre motor out to 2.2 litres for example, I learned to limit myself to 1.7 and focus on perfect mechanical balance. (As I learned, the 2.2 was the automotive equivalent of the 12-inch stiletto heel.)

Making a car better isn’t easy. So, as I ponder modifications to my 2012 Lotus Evora S, I have some ironclad rules that were learned through costly personal experience. Here they are:

Rule One: Don’t make changes that you can’t undo. So I won’t be flaring the fenders or hacking up my Lotus to jam in a V-8.

Rule Two: Let the factory do as much of the work as possible. Instead of spending thousands of dollars to turn a 3-Series BMW into an M3, you should just buy an M3 in the first place.

Rule Three: Respect the wisdom of the factory engineers. In the case of my Lotus, the engineers produced a car with a near-perfect balance of power and agility. This called for thousands of hours of analysis and experimentation – only a fool would start making major changes to such a well-developed package. This is a car with parts that work extremely well together, so the goal is not to mess it up.

Even so, I want to try a couple of things. For starters, I want to shorten my Lotus’s shift lever a bit and make the action crisper by installing stiffener gussets in the steel tunnel that the shifter mounts in. A set of Ultradisc brake rotors will lower the weight of the wheel and brake package at each corner (and if I don’t like them, I can pull them off and bolt the original discs back on).

Next, I will turn to the suspension – I have my eye on a set of Ohlins coil-over shocks with threaded spring perches that will let me lower my Lotus when I’m on the racetrack, where a low roll centre takes precedence over ground clearance.

I’m attracted to the Ohlins because they’re part of a Lotus factory package. The chassis engineers in England have spent a lot of hours figuring out spring and shock specifications, matching components for optimum performance. As I learned the hard way back in the day, bolting on a set of racing shocks can actually destroy your car’s handling (when I was 20, I assumed that the stiffest shock would be the best. Wrong).

Swapping major components can open a mechanical Pandora’s box. Big changes call for experience, engineering skill and superior judgment. For an example of how it should be done, take a look at a California company called Singer Vehicle Design. I got interested in it a few years ago, because it specializes in restoring and modifying air-cooled Porsche 911s like the ones I used to work on back in the 1970s.

Singer turns vintage 911s into something truly spectacular. The original steel hood, trunk lid and fenders are replaced with carbon-fibre versions. (The fenders are wildly flared to allow massive tires, but are so beautifully shaped that they don’t look like add-ons.) Singer’s technicians tear out the old 911’s antiquated torsion bar suspension and replace it with modern coil-over shocks that are sized and calibrated for the revised car. The feeble incandescent headlights are switched for powerful HID models, and the plumbing is replaced with aerospace-grade hoses and fittings. The leather interior looks like one from an old 911, but it’s all new and subtly improved.

Singer swaps the old 911’s engine, but the upgrade is the perfect choice – a 3.8-litre motor from a later-model 911. Each motor is hand-built and balanced in England by the legendary Cosworth company. The more powerful engine calls for a revised transmission, different motor mounts and improved cooling. All are attended to.

By the time it’s done, a Singer Porsche is a masterpiece of artful modification. And it should be – the car starts at $255,000, and options can drive the price much higher. If you can come up with the money, and you really want a highly modified air-cooled Porsche, the Singer is worth it. Who knows how many years and how many thousands you might spend on your own, only to end up with a car that’s worse than when you started?

Money spent on car modifications is one of the worst investments of all time. (As one of my favourite car buddies recently noted, every dollar spent on altering a car lowers its value by approximately $100.) With this in mind, I’ve put together a short list of car modifications that will actually improve your vehicle and maintain its resale value (as long as you observe the cardinal rule of not making changes that can’t be undone.) Feel free to add your own.

Top-of-the-line tires: The difference between standard passenger-car tires and R-compound models like the Pirelli P-Zero Corsas on my Lotus is vast. High-performance tires accelerate and stop far better. The downside is higher cost and shorter tread life, but they are the crack cocaine of driving.

Lighter, properly sized wheels: Every gram you remove from the wheel and tire package reduces what’s known as unsprung weight. This improves suspension performance. And lighter wheels reduce rotating mass, which improves acceleration, braking and steering. But don’t assume that an alloy wheel will be an improvement – not all alloy wheels are created equal, and some are heavy and brittle. For real performance, you need forged wheels. Choosing the correct size is critical, and bigger is not always better. Generally speaking, wider wheels with lower-aspect ratio tires will improve traction and cornering performance. But going too far is counter-productive ,since wheel mass increases with size. Too-wide rims can lead to steering issues (like tramlining, where the car tries to follow surface variations in the road).

Cold-air induction: You may get a modest power increase by installing a snorkel-type intake that draws air from outside the engine compartment. (Cooler air is denser.) There can be problems, though, including increased noise, and the chance of sucking water into the motor.

Motor blueprinting: Blueprinting means assembling a motor to ideal specifications. If you need an engine rebuild, you can improve performance and smoothness by balancing and equalizing the mass of all rotating and reciprocating parts (like the crankshaft, pistons and connecting rods). Pistons, for example, are weighed on laboratory scales, then equalized by removing small amounts of metal from the heaviest ones. The volume of each combustion chamber must also be made exactly the same. (You do it by filling them with measured amounts of liquid, then removing material from the walls of the chambers that are undersized.)

Suspension upgrades: Replacing your shocks, springs and sway bars with a properly engineered performance package will improve your car’s handling. Matching components calls for specialized knowledge and thorough testing. (If your car’s manufacturer offers an upgrade package, that’s usually the safest choice.)

For more from Peter Cheney, go tofacebook.com/cheneydrive(No login required!)

Twitter:Peter Cheney@cheneydrive

E-mail:pcheney@globeandmail.com

Globe and Mail Road Rush archive:http://www.theglobeandmail.com/globe-drive/car-life/cheney/

Follow on Twitter: @cheneydrive

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