Since BMW has already released many details about the M3/M4, it now becomes a bit of a refresher. As you all know, it is a heavily reworked 3 liter turbo six that we find under hood of both models. S55 engine is based on the familiar N55 engine with 84.0 mm in bore and 89.6 millimeter stroke, but the similarity stops here. The modifications are so extensive on S55 that according to BMW engine blocks, cylinder heads, intake, exhaust, and most internal components are all new.
The two turbochargers delivers 1.3 bar and it has an intercooler placed above the engine. Weight has been saved everywhere and engine package weighs 205 pounds(93 kgs), which is ten kilos less than the V8 in previous M3. The car develops a peak power of 431 hp between 5390-7000 rpm and maximum torque of 550 Nm is available between 1800-5390 rpm. Turbo Engine torque is about 40 percent higher than the usable range as compared to the previous V8.
As we all know, turbo engines get quite thirsty when reved hard but despite the increased power, fuel consumption is about 25 percent lower, at least according to official data. According to the EU driving cycle, the consumption with
dual clutch transmission is 8.3 l/100 km and 8.8 l/100 km with manual transmission. CO2 emissions down to 194 g / km which qualifies engine as Euro 6 standard for exhaust emissions. The sprint from 0-100 km/h is down to 4.1 seconds for both the M3(Sedan) and M4(Coupe) with the seven-speed dual clutch transmission and 4.3 seconds with manual gearbox. Top speed is electronically limited to 250 km/h. BMW has introduced a new dual clutch transmission known as «M Double Clutch». It is now possible to do «Smoky Burnout» when using launch control. This feature allows a greater amount of wheel spin from standing start position.
The Propeller shaft of BMW M3 and M4 is made of carbon fiber reinforced plastic, a material that is both lightweight and strong. The roatating mass is lower which reduces the load. In comparisson with previous model, the propeller shaft of the M3/M4 is 40 percent lighter. BMW’s «Active M Differential» has been further improved and provide excellent grip and wheel locking up to 100 percent. Vehicle Stability Control and DSC (Dynamic Stability Control) helps the driver to keep the car in the right direction along with its active torque control. Anyone who wants a bit more sweeping driving style has an option of «M Dynamic Mode» where the system allows a certain amount of drifting on curves. If you feel brave you can turn off the system completely, but this is at the «individual responsibility» as BMW puts it.
Weight saving has been substantial on the new M3/M4 and the car has managed to trim away eighty kilograms. Something that benefits both performance and fuel consumption. Even four-door sedan model M3 has roof in carbon fiber, it was only on the M3 Coupe before. BMW M4 has the same active limited slip differential and seven-speed dual clutch transmission as M5 and M6. The six-speed manual transmission is retrieved from old 1 Series M Coupe, but has been modified and now weighs twelve kilograms less. Hydraulic steering has been replaced by a electro-mechanical steering which save three kilograms.
According to BMW officials, «No other M model has evolved so consistently for use on the road than the new M3 and M4. It has not been about to increase power, but to lower the weight and create a unified concept». The six cylinder S55 engine will be fitted on the production line in Steyr, not in Munich.
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