Sales promotion consists of promotional activities that stimulate purchases, other than advertising, personal selling, and publicity. It normally involves a direct inducement (such as money, prizes, free trials, extra products, gifts, or specialized information) that provides extra incentives to buy now or buy more, visit a store, request literature, display a product, or take some other action. Promotions are also designed to motivate impulse purchase (through the implementation of in-store displays), increase the quantity purchase (via pricing discounts), or shift the burden of inventory from the manufacturer to distributors or retailers (by providing volume discounts or other incentives). Sales promotion activities occur simultaneously with, and leverage advertising and publicity. Examples of Sales Promotion Displays Fashion shows Coupons Exhibits Free samples Novelty items Trade shows Demonstrations The Positive Effect of Sales Promotion on Brand Volume Sales promotion adds immediate and tangible value to the brand by maximizing sales volume. Advertising helps to develop and reinforce quality, differentiate brand reputation, and build long-term market value. A short-term price cut or rebate may be very effective at boosting sales. When all brands appear equal, sales promotion can be more effective than advertising in motivating customers to try a new brand or to select one brand over another. A strong sales promotions should be focused, creative, hard to imitate, and should well timed. The Negative Effect of Sales Promotion on Brand Volume Excessive sales promotion at the expense of advertising hurts profits. Some marketers believe the proper expenditure balance is approximately 60% for trade and consumer promotion and 40% for advertising. High levels of trade promotions relative to advertising and consumer promotions, have a positive effect on short-term market share, but may have a negative effective on brand attitudes and long-term market share. Many consumer promotions can undercut a brand's image, especially those that offer discounted pricing. Customers may not develop brand loyalty and promotions may erode brand perception. Sales promotion has a high cost relative to gains generated. Overly aggressive sales promotion can draw competitors into a price war, which reduces sales and profits for everyone.

Gasoline Engines

Gasoline engines have the advantage over diesel in being lighter and able to work at higher rotational speeds and they are the usual choice for fitting in high-performance sports cars. Continuous development of gasoline engines for over a hundred years has produced improvements in efficiency and reduced pollution. The carburetor was used on nearly all road car engines until the 1980s but it was long realized better control of the fuel/air mixture could be achieved with fuel injection. Indirect fuel injection was first used in aircraft engines from 1909, in racing car engines from the 1930s, and road cars from the late 1950s.

Gasoline Direct Injection (GDI) is now starting to appear in production vehicles such as the 2007 BMW MINI. Exhaust gases are also cleaned up by fitting a catalytic converter into the exhaust system. Clean air legislation in many of the car industries most important markets has made both catalysts and fuel injection virtually universal fittings. Most modern gasoline engines are also capable of running with up to 15% ethanol mixed into the gasoline - older vehicles may have seals and hoses that can be harmed by ethanol. With a small amount of redesign, gasoline-powered vehicles can run on ethanol concentrations as high as 85%. 100% ethanol is used in some parts of the world (such as Brazil), but vehicles must be started on pure gasoline and switched over to ethanol once the engine is running. Most gasoline engines cars can also run on LPG with the addition of an LPG tank for fuel storage and carburetion modifications to add an LPG mixer. LPG produces fewer toxic emissions and is a popular fuel for fork lift trucks that have to operate inside buildings.