Ok the little Smart suprex engine is very well built but its abilities are under estimated and it is often neglected, to put it in perspective lets look at some facts and figures as an examples, Smarts are often driven flat out everywhere and the spend alot of time at FULL throttle and the 83mph limiter!
The 599cc car at 55bhp makes 91 bhp per litre so if it was 2 litres it would be 182 bhp the same as a Renault clio Cup Sport 182
The 599cc car at 61 bhp makes 101.8 bhp per litre so if it was 2 litres it would be 203 bhp the same as the legendry Ford Sierra Cosworth
The 698cc car at 61 bhp makes 87.8 bhp per litre so if it was 2 litres it would be 174bhp bhp slightly more than the first Clio 172
The 698cc car at 82 bhp makes 117 bhp per litre so if it was 2 litres it would be 234 bhp some 7bhp more than 2002 Subaru Impeza Wrx
These figures are for a 3 cylinder engine with a single chain driven overhead cam and two valves per cylinder!
The little turbo spins at almost 2000 (yes two thousand) time a second at max boost (120,000 times a minute) and reaches temps near 1000+ degrees
The 599cc car only has 2.7 litres of oil to cool and lubricate it
The 698 cc car only has 3.2/3.3 litres of oil to cool and lubricate it
What does all this mean to you?
Only Mobil 1 oil to be used, they just dont like the other oils as well and tend to burn them and create deposits.
Regular services as per the service schedules are required and the smart has 6 spark plugs not 3, its two per cylinder. The 599cc cars are about 9000 miles (15000k km) and the latter 698cc car (2003 onwards) show you when they are due a service on the display on start up in either miles or days depending on how long since the last service. They need plugs really every other year or they can run the risk of the electrodes dropping into the cylinder bores or pushing the ignition timing closer to detonation and the engine closer to poor fueling and bore wash as it copes with burnt valves and worn rings.
Premium fuel every 4th tank full or on any tuned cars every tankful, on turbocharged cars like the smart it puts different demands on fuel, it's used to cool piston crowns, maximise ignition timing and with Shell V power helps clean the combustion chambers and keep emissions and deposits down
Some regular maintainance will help prolong the life of these great little engines