From air filters to stressbars, there are all sorts of things you can bolt on to your car to improve its performance. James Ruppert looks at the options

Some drivers are never satisfied. They reckon the manufacturers could have done much better and believe that bolting bits on to make a car go faster, stop quicker and handle better is a great idea. It's called tuning, and has been around for as long as there have been cars. It is often regarded as a baffling black art, but the principles are simple.

There are two distinct ends of the tuning spectrum. Younger motorists will resort to all sorts of tricks to make their cheap-and-cheerful motors really get a move on. Then there are owners of vehicles that, on the face of it, wouldn't seem to need much improvement. For 40 years, German company Alpina has been making BMWs go faster. Brabus has been doing the same for Mercedes. These tweaks do not come cheap.

Enthusiasts, though, can spend fortunes on more "ordinary cars". I met up with Adam Moran, 21, who has spent over £22K making his new Ford Focus much faster. "The original plan was to wait three years and then drop a Cossie [Ford Cosworth] engine under the bonnet, but then I thought, sod it, this has to be done right now ... what I really wanted was some serious power, over 300bhp."

A standard 1.8 Focus produces a modest 115bhp, so Adam had to take his car to specialists Power Engineering in West London. They had to get rid of the original engine and get a larger Ford unit to work their magic on. I won't bore you with the technical details, but they rebuilt the engine to racing car tolerances. Is Adam happy? "I have targeted the bhp figure at 410, which would be incredible for a Zetec with some help from some Nitrous injection, and getting all that power down will be a four-wheel-drive system."

To translate then: Adam has plans to fit a Nitrous Oxide injection system (to a Ford Zetec engine), which injects this gas along with oxygen direct into the engine for short bursts of substantial power. A four-wheel-drive system means that the transmission will need to be modified to drive the rear as well as the front wheels. That is complicated and expensive, but there are plenty of companies that will help, such as Power Engineering and DMS Automotive.

The rest of us, with real-world budgets, could pop down to Halfords and look at their Ripspeed range of goods or just sit down with a copy of the Demon Tweeks catalogue and pick the bits that might just help. So what should we be looking for?

Anchors away

An essential pre-requisite to an engine tune. Fitting ventilated disc brakes with matched high-performance pads is the usual route. Sometimes larger diameter discs can also be installed. You will definitely stop quicker.

Airy fairy

A free-flow air filter that will help the engine breath better while keeping harmful dirt out. This is probably the cheapest and simplest way of giving an engine a couple of extra bhps.

Head case

Extra power mostly comes from the cylinder head and, without getting too technical, the head can be modified to improve airflow by removing manufacturing imperfections such as casting lines and machined edges. In addition, the head can be gas flowed. The result is more efficient running and higher power output. Also, as valve timing becomes more critical with regard to output, emissions and power-throttling devices like catalytic converters, a sports camshaft can be slotted into the cylinder head.

Chips with everything

Modern cars have lots of computer technology. The Electronic Control Unit is controlled by chips. A reprogrammed chip can optimise a standard engine's performance with increased horsepower, although the real gain is driveability, with smoother acceleration. Improvements are even more dramatic with tough diesel and high performance engines. Don't be tempted to buy a chip and install it yourself - get an expert to set the engine up properly.

Wheely good

A set of low-profile tyres surrounding an alloy wheel will improve the looks of your car. The dynamic payoff is improved handling and grip. A larger wheel may even expose the brakes, improving airflow and efficiency, meaning better brakes. Expert help is essential to fit the right combination for your car.

Suspended animation

Ride and handling is always a compromise. You don't want to roll around corners or bungee jump along a bumpy road. But set the suspension too hard and it all becomes jittery and uncomfortable. There are lots of springs and damper sets on the market, some of which are adjustable to suit the conditions. Other improvements include the replacement of rubber suspension bushes with polyurethane ones to cut down road noise and locate the suspension more accurately.

Brace Yourself

For the seriously enthusiastic driver, stressbars are the answer to the flexing that occurs when the car is driven hard. Modern one-piece bodyshells, especially hatchbacks, are less rigid than saloons and can benefit from a strut, brace, or bar fitted to the tops of the suspension towers or underneath, attached to the suspension wishbones. The result is more positive steering, and assured behaviour when cornering.

Exhausting Work

Getting gases out of the engine is crucial to getting the most power out of an engine. That is why a good manifold (bolted to the engine) attached to a free-flow sports exhaust is the answer. It also teases a few extra bhp out of the engine.

Transplant Surgery

The most expensive tuning option is enlarging the engine by boring out the block to increase its size. Ultimately, you could fit a turbocharger, but simplest would be to fit a bigger engine.

At Your Service

Finally, you could just take your car to a dealer or specialist and get it tuned as the factory intended. It's amazing how well a standard car runs.

Demon Tweeks (0845 330 6245), Brabus (070712 44166), DMS Automotive (01264 729016),,


Vauxhall Nova GTE

Fit a Scorpion Air Filter £26, a Motech suspension kit £200, put on a Janspeed exhaust £125, and get a 10 per cent power increase from a superchip £200. Expect 15bhp more engine power for £500.

Volkswagen Golf GTI Mark 2

K&N air filter £45, Tarox Brake Pads £30, V-Spec Sports Exhaust £160, Grooved front brake discs £116, 40mm lowered Bilstein Suspension £340. £500 buys around 5bhp worth of extra power.

Renault 5GT Turbo

Jetex cone filter kit £70, Powerflex suspension bushes £14, Scorpion Stainless Steel exhaust system £200. £500 spent purely on engine mods can translate into a useful 30bhp, up from 120bhp to 150bhp.

Mini 1.3

K&N air filters £40, Mini Sport Superflow exhaust £60, Stage 3 cylinder head £320, 5 speed gearbox (no it hasn't got one) £1,500. £500 can boost output by up to 20bhp, from 62bhp to 82bhp, scarier than it seems.

Ford Escort RS Turbo

K&N Air filter £40, Koni adjustable dampers £86 each, G-Force vented front discs £107. For £500 you ought to be able to up the bhp by an impressive 40bhp, going from 132bhp to 172bhp. Wow.

Peugeot 205 GTI

Install a performance camshaft £210, a reflowed cylinder head £390, and a new inlet manifold £115. For about £500 expect a modest 7bhp increase - that's 121bhp, up from 115bhp

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