Going Turbo

With increasing petrol prices, environmental concerns and calls for better engine effiency, we have started to see the disappearance of the naturally aspirated engine in favour of forced induction alternatives. In the past, the turbo was a sure way to gain extra power. Some manufacturers installed turbos on cars which did not have enough space to fit a bigger engine, others, to make fast machines. The trouble was however, that such forced induction had many flaws, such as turbo-lag meaning that the required torque and power did not arrive immediately meaning a less than sharp response.

Turbo vs. Naturally Aspirated

Most car manufacturers found that it was better to improve and upgrade technology on naturally aspirated engines; with Honda introducing its variable cam profile VTEC to improve engine response at higher revs; BMW developing its Valvetronic variable valve timing technology as well as some manufacturers simply using larger naturally aspirated engines. Direct fuel injection has also been a major leap forward, replacing the now archaic carburettor.

No more lag

Advances in turbo engines meant that lag was becoming a thing of the past. Mitsubishi’s inlet bypass method, igniting petrol down the exhaust manifold to keep the turbo running (when the throttle was closed) was one of the first systems. This was however only used in rally cars as it was extremely polluting and would not be acceptable on the road. Aside from this many turbo systems remained the preserve of the enthusiast.

Newer systems include multi turbos; a small and larger turbo configured to one engine, the small turbo to run at low revs and large to boost to high revs. The same configuration can be achieved with a supercharger and turbo charger. Now however the emphasis has been placed upon variable geometry turbo chargers. These have vanes which change angle according to the boost in order to deliver instant torque across a set of revs.

Fuel economy

New advances in turbo technology have meant that this has become the obvious choice for car manufacturers who wish to produce more fuel efficient, smaller engines but with the same torque and power as their non-turbo bigger brothers. All the recent advances in naturally aspirated engines have transferred to turbo engines, which means that you get the best of both. You won’t hear yourself though as turbos muffle exhausts considerably. Manufacturers have attempted to rectify this however, with synthetic exhaust notes being passed through the speakers.. nice.

Say goodbye to cylinders

The BMW M5 engine has dropped from a naturally aspirated v10 to a twin turbo v8. America’s favourite pickup truck, the Ford F150 has had its v8 replaced with a v6 turbo. Ford’s inline 4 engines are being replaced with three cylinder turbo charged variants. The new Renault Clio base model now has a tiny 0.9 litre triple. Car manufacturers are looking to create smaller and more efficient engines in any way possible.

The bottom line is, turbos give us more performance and better economy, meaning that naturally aspirated engines may well have had their day. You can expect with a small turbo, to see your road tax, fuel costs and car insurance costs to be reduced substantially.

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