Exhaust Upgrades

Below we cover performance upgrades, turbochargers and superchargers.

Performance Upgrades

Today manufacturers need to satisfy the conflicting criteria of low noise, lightweight, low emissions and low cost, the result is usually a very quiet and restrictive exhaust.

Low emissions require the use of small and restrictive catalytic converters placed near the engine, and low cost means press bent pipes are used and other corners are cut. Because of this, the fitting of aftermarket exhausts is one of the most common and cost-effective power upgrade made to cars

Exhaust upgrades can include an increase in the pipe size, mandrel bends, high flow mufflers, high flow catalytic converters (or the removal of the converters altogether), and the fitment of high flow headers or extractors to replace the stock exhaust manifold. All this increases the flow of the exhaust gas and increases engine performance, economy and responsiveness.

Turbochargers & Superchargers

Both turbochargers and superchargers force air into the intake manifold and pressurise it when the intake valve opens air is forced from the intake manifold into the cylinder and the cylinder fills up more efficiently than it would without being charged.

A non-turbocharged or non-supercharged engine is termed a naturally aspirated engine. In a naturally aspirated engine, the vacuum created by the pistons moving down the cylinders draws in air to the cylinders. With naturally aspirated engines the cylinder is not fully utilised or filled up at high engine rpm because everything is happening so fast; the valves are only open for a split second meaning there is not enough time for air to fill them up.

The benefit of charging an engine is that by having more air in the engine you can put in more fuel resulting in more power output from the same sized engine

Operation

a turbocharger uses the flow of exhaust gases to spin a turbine; the turbine is mounted on the same shaft as a compressor, which in turn forces air into the engine. The more exhaust gas the engine produces the faster the turbo spins, forcing even more air into the engine.

Older turbochargers are renowned for having ‘lag’ meaning there is a delay between putting your foot down and the power coming on. This is due to the turbo taking time to ‘spool up’ or spin faster due to being driven by exhaust gases.

Modern turbochargers have greatly reduced this problem by better design and by lighter materials being used. Rally cars also use ‘anti-lag’ kits that keep the turbo spooled up at all times. On the other hand, a supercharger is belt driven directly from the engine crankshaft. It is an engine-driven air pump that forces air into the engine’s intake. Superchargers have no lag and instant power at low rpm, however, power tends to drop off at higher rpms.