Monday 4 March 2024

A guide to car upgrades: improve performance, handling and looks

If you’ve got a performance vehicle or regular sleeper begging for a few upgrades, then definitely consider aftermarket parts in achieving your goals. These will be in line with providing better acceleration, more control in turns, and faster braking. Tuning is not just about increasing available power. You need that power delivered in a controlled way while not overwhelming the chassis and enough bite in brakes to bring your modified car to a safe stop.

Wringing the last horses out of the engine, and adding a few more needs to be followed through with changes to handling and aerodynamics. Upgrades are done with subtlety, and getting the right balance is key. Pairing parts that don’t go together can have the opposite effect of what you initially intended. And this is a recipe for hastened parts wear which can ultimately lead to engine failure.

The above is just a precaution, but you know what you’re getting into. There are hundreds of tuning specialists across the UK offering their unique take on tuning. They’ll offer sound advice as to which aftermarket car parts you’ll want in increasing performance figures, getting more grip down to the wheels, improving feel in turns and bends and adding a little more style in the process.

Performance upgrades

The first steps you take in tuning will include parts that can be used on their own. This sets the foundations for upgrades further down the road where pairing becomes more of an issue. For stage 1 upgrades, you can look to modifications done to intake and exhaust systems, fuelling and timing, and some tuners may consider forced induction. The goal here is to get better combustion, with improved air and fuel mixtures delivered at optimal intervals.

Aftermarket exhausts are where most upgrades begin. Here wider tubing than the stock exhaust, and additional parts like downpipes and modified headers and manifolds are for freer airflow along the length of the exhaust, effectively reducing potential back-pressure making its way back into the cylinders.

In short, a modified exhaust goes a long way in reducing pressure and temperature buildup that stresses engine parts and increases wear. Buyers have a range of choices, from simple axle-back systems to full-on header or turbo-back exhausts with included oxygen sensors and piping deletes with wider tubing. Modified catalytic converters, the inclusion of resonators and varying muffler combos will also affect emissions and the exhaust note. Best performance gains are naturally in turbo-back exhausts, with rough estimates of a 5 per cent increase in overall power.

Modified exhausts are best paired with changes to air intakes. These are tasked to push more clean (and cooled) air into the cylinders for combustion. Carefully engineered systems make use of tough materials, like oil-free synthetic filters, aluminium inlet pipes, carbon-fibre hoses and air boxes, and heat shields to minimise the effects of engine heat. Intakes like these reduce overall weight and also look the part with the bonnet up.

Changes to camshafts and inlet valves and springs can be done earlier on, though this generally marks the onset of stage 2 tuning. With airflow optimised, you’ll need to get the timing right. Advancing camshaft timing means intake valves open and close sooner, so there’s an increase in low-down pull. Adversely, retarding the cams and valves changes the power-band towards the top end for more horsepower at higher revs. Bigger displacement engines will definitely benefit from cam retarding, while 4-pot turbos with higher redlines can use some low rev torque. It all depends on the engine.

Here there are also mods done to the fuelling. This can be moderate ECU remapping, to correlate air intake with the needed fuel ratios. It can also mean changing out fuel pumps, fuel lines, regulator valves, return pipes and injectors for increased fuel pressure. The last link in the combustion process is ignition. Uprating spark plugs that have higher heat ratings, means the better handling of bigger bangs. This, like the fuelling, needs precise timing and is controlled by the ECU.

Before delving deep into the internals, tuners also do a little wizardry with the turbo. Naturally aspirated. big displacement engines see significant power and performance gains by strapping on a turbo. This also requires changes to the fuelling and timing, with uprated cams, valves and pressure regulators the first items on the shopping list. Cars already with forced induction can be modified with the addition of boost controllers and upgraded wastegates or actuators to broaden the power range, and change when the turbine kicks in and how long it holds its puff. If considering installing a bigger and faster-spooling turbo, make sure the engine can handle it. Adversely, you’ll do more harm than good.

Stage three tuning is where things get costly, and this is reserved for tuners with serious intent. Here, pistons connecting rods and crankshafts are swapped out for variants that are lighter, take the beating of increased combustion pressure and temperatures better, and spin that much faster.

Materials range from the mundane (aluminium and steel alloys) to more coveted titanium or nickel chromoly alloys with high degrees of flex as revs go up. Production processes make way for forged and billet parts that are stronger in every respect, and well sorted in a performance engine. Additional heat-treating allows for improved hardness, ductility and wear resistance and reduced fatigue levels. Cranks benefit the most, and a heat-treated (nitride-coated) billet crank in hard-wearing chromoly can get more power down to the wheels. Depending on the engine and the level of engineering involved, these are some of the more pricey mods that you can do, but the results are definitely there.

Handling tweaks and upgrades

Handling improvements might not be as glamorous as a full 3-course performance tune, but this is another way of getting more speed without even lifting the bonnet. What you miss out in pure bhp numbers you more than make up with the over-the-roof fun factor. Aftermarket car parts aimed at better handling improve ride quality, sharpen the steering, get more traction in the wheels and give you a vehicle that you can easily throw around and which still stays planted on the road.  Safety is also better, as there’s more feedback through the steering. Other benefits include better fuel economy, and with basic wheel, tyre and steering alignments reduced tyre wear.

The ultimate in better handling is done with a performance suspension kit. With stiffer struts and shocks, coilovers set the car lower meaning a lower centre of gravity and more stability in the bends, you can keep more speed in the wheels without over or understeer pushed along by physics and the weight of the vehicle. Here anti-roll bars placed at the front, rear or both axles mean cornering hard and fast is possible without going overboard. To reduce flex, chassis are stiffened with the addition of struts and braces in mild changes, or complete roll cages in track-spec vehicles. The latter mean you might need to get rid of some of the interior, but the benefits in driving pleasure, as well as safety in the event of a crash more than pay off. Lastly, for a firmer ride consider polyurethane suspension bushes, which outlast stock rubber bushes while also bettering handling.

Styling and aerodynamics

You can add more bling and performance with stylish accessories, that are often one and the same part. This can include a full body kit that improves airflow over, under and to the sides of the car, virtually sticking the vehicle to the road. High pressure, slow flowing air is boosted with front and rear spoilers, creating downforce, while diffusers and splitters in the front and rear bumpers disperse remaining air at higher speeds under the car and in lower pressure. Kits and parts differ in weight and materials, but the higher up the price scale you go, the stiffer and lighter parts get. Carbon fibre body additions are the pick of the bunch, with the best strength, while also lowering weight.

And finally, let’s not forget rubber and alloys. Bigger wheels sourced in lightweight and reinforced alloys help in stability and handling, though the bigger the wheels the more you’ll feel road imperfections. Choose a design from respected brands to suit the car.  Low-profile, grippy tyres keep you planted and offer better traction on different surfaces and in varying weather conditions.

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