The problem isn't the cars but the economy tests - in the old days cars were tested at 56mph and 75mph which consumers didn't like as it wasn't representative of their driving style; however, they did allow a fair comparison of cars so yes, you may never get 45mpg at 56mph but if three cars you were looking at were spread over 4mpg that spread would be typical in normal driving. Since the introduction of urban, extra urban and combined tests which are purely calculated in laboratory conditions figures have become increasingly unrealistic, an acceleration of which is the current Europe-wide taxation based upon CO2 emissions (CO2 and economy are intrinsically linked as the CO2 is a measure of gases coming out the exhaust as a result of combustion); manufacturers know that a low consumption car will have low CO2 figures and therefore taxation; the EU tests hold little relevance for modern cars as they tend to allow over-use of stop-start in the urban stats and light throttle opening which rarely get turbo's blowing which is why modern 'tiddler' downsizing engines rarely act as well as they are expected too. A guy I know works in a Renault dealer and had a Clio 1.4 16v company car, replaced with the then-new 1.2tce engine, supposedly the performance of a 1.6 and economy of a 1.4; over a number of months the 1.4 got about 38mpg, the 1.2tce 35mpg...
The problem is this leads to customer discontent as you end up with people believing 60mpg is possible from a small petrol engine; it is, technically, but if only if you use the accelerator like an unexploded bomb. Diesels are the same but people feel happier that they still get mid 50's despite the promise of 80mpg; I own one of the first 'economy' cars (a 2005 Audi A2 1.4TDi) which has 119g/km of CO2, engineered at a time where supermini's would regularly achieve 50% higher than that figure - truth is though I get 55mpg and even the hyper-milers who own A2's 'only' achieve 70mpg - according to the tests, 'extra urban' is a shade over 80mpg...
I've no doubt that in my hands a 0.9tce would get late 30's perhaps 40mpg which doing 8kpa is fine; if I wanted better economy I'd go for boat-fuel and suffer the tuneless engines return for better economy.Edited by: Frank Bullitt
