Tests: Bad Aftermarket Exhausts Markedly Increase Pollution

Shocking results from one of Europe’s foremost vehicle emissions testing labs have revealed shortcomings in some (legal) replacement exhaust systems. The results show 20 times the level of harmful Nitrogen Dioxide and 50 per cent higher levels of damaging Hydrocarbons being emitted by non Type-approved exhausts, leading to calls from manufacturers such as Klarius for type approval to become mandatory in the UK, as it already is in Europe.

Extensive testing by Longbridge-based Emission Test Facility UK has called the quality of construction, design and materials used in exhaust pipe make-up into question. Emission Test Facility UK’s directors and testers, Tim Colgan and Graham Downing, tested a selection of non Type-approved exhaust systems against an original manufacturers unit and a fully Type-approved replacement model.

The news comes after a report last year cited the UK as having the worst road pollution in Europe. According to the government findings 95 per cent of UK cities exceeded the European Union limits for nitrogen dioxide (NO2). This figure is almost double that of the next worst polluter, Germany, where 52 per cent of cities exceed the limit, followed by Italy with 42 per cent, France 21 per cent and Spain 14 per cent. The report, by the Department for Environment, Food and Rural Affairs (DEFRA), warns that the UK will face large fines for breaching the EU limit unless radical measures are taken.

The effect of potentially millions of vehicles with poor quality replacement exhausts systems, (industry figures estimate over 8 million vehicles on UK roads have an aftermarket exhaust fitted, some of which may be Type-approved), driving around kicking out thousands of tonnes more Nitrogen dioxide and hydrocarbons than the manufacturers intended not only represents a serious health risk, and a huge environmental issue, it could mean that government and industry quoted figures for road car pollution would be extremely wide of the mark.

Klarius reports that the figures have been sent to the Department for Transport, and although interest has been expressed in the results, there is no clear intention being expressed by the department to make changes to the law in order to protect the public from this severe pollution issue.

Following repeated industry calls for the protection afforded the consumer by new legislation by UK and EU manufacturers of Type-approved exhaust systems, there’s little support from government for law changes: “The UK government has changed the law to ensure that replacement catalysts are type-approved, in order to improve pollution levels, but refuses to apply the same controls on exhaust systems, although the rest of Europe already complies.” Colgan commented.

So why are non-type approved exhausts showing such a poor results? “The quality of the material and the design of the internals used in the exhaust pipe and silencer boxes will affect the way gases build up in the catalyst, and if that gets too hot the catalyst won’t work properly. And while non type-approved exhaust systems might be cheaper to buy they can have more drastic effects,” said Colgan.

So what is the legacy of that poor-quality pipework? Graham Downing explains: “People will buy a cheaper replacement or a performance exhaust because it saves them money or is claimed to increase performance. That’s usually not the case, especially with a cheap performance system, which might look good but does nothing other than make the car much noisier.”

And because of their poor quality, cheaper standard systems often either don’t create enough back pressure or create far too much back pressure for the engine to work properly. The result is more emissions because the engine is working inefficiently, says Colgan: “When the original exhaust fails it should be replaced with a good-quality one in order to protect the car and it seems now our environment.”

According to a Klarius-issued statement publicising the results, type-approved systems will not only raise the quality bar while reducing harmful emissions and increasing miles per gallon, their introduction will also help to level the playing field between independent workshops and national fitting centres, making sure both channels to market deliver a quality product that does not pollute unnecessarily.

Another particularly salient point Klarius made is that ever-tightening legislation puts the onus on vehicle manufacturers to clean up their cars’ emissions “only for a non-type approved aftermarket item to potentially nullify all those efforts.”

“Ultimately I think that within the next five years all aftermarket components will be Type-approved,” Downing concluded.