BMW 3 Series vs BMW 4 Series
1. Introduction
The 3 Series is to BMW what the C-Class is to Mercedes: the point at which most people get their first taste of what the brand has to offer. The 3 Series may be BMW's most important car, as it's the one most people will consider when they think of BMW in the first place. Available as a sedan, a sports wagon, a Gran Turismo and a long-wheelbase sedan, the 3 Series not only offers buyers a lot of options, it offers them a lot of different ways to configure the same option. As a result, the 3 Series is one of the most comprehensive lines in the luxury market. The BMW 4 Series is the coupe/convertible version of the 3 Series and is built on a longer wheelbase, leading to a slightly larger and more spacious car than the 3 Series. This means the 4 Series is now more of a personal luxury coupe than a sporty offshoot of a sports sedan. To differentiate the two cars, the 4 Series has its own naming convention as well as a number of features that aren't offered on the 3 Series. This may be both a benefit and a drawback to some, as the two cars do share a lot in common and some feel that the 4 Series is a bit too close to the 3 Series for its own good. However, the 4 Series' more luxurious approach means it can be seen as a stand-alone model that caters to a different crowd than the 3 Series, giving BMW a two-pronged entry in the small luxury segment and enabling them to cover more ground overall. (OZKAN et al.)
1.1. Overview of BMW 3 Series
BMW's 3 Series has long been considered the benchmark for the compact sports sedan class. With a seemingly perfect mix of sportiness and luxury, it's easy to see why the 3 Series has been praised the way it has. The car is currently in its sixth generation with both sedan and wagon styling. While the new generation definitely makes the car larger, the overall styling takes cues from the original 3 Series. The interior is a step up from the previous generation, with high-quality materials and a modern/unique styling. BMW's infamous iDrive is also present, now the fourth generation of the system. Performance has always been a strong point of the 3 Series, and this generation is no different. The car handles exceptionally well, both in day-to-day driving and when pushing it to the limits. With a choice of four different petrol engines, three diesel, and a hybrid to come, there should be no issue finding a happy medium between performance and fuel efficiency. The most notable engine being the N55 turbo inline 6 in the 335i. The car has a choice of a six-speed manual, six-speed automatic, or eight-speed automatic. The 3 Series does come with other variations other than the standard sedan/wagon. The 3 Series GT (Gran Turismo) features a higher seating position, added cargo space, and a unique styling. The 3 Series coupe has been separated from the sedan, now known as the 4 Series (discussed later). Finally, the M3 is the high-performance version of the 3 Series, it too has been separated from the standard 3 Series for the newest generation. Overall, the new 3 Series is a great choice for a mixture of performance and luxury in a compact car.
1.2. Overview of BMW 4 Series
The BMW 4 Series is classified as a compact executive car and is a part of the executive sector. It is the second generation of the BMW 4 Series; the first generation was represented as a low end of the BMW 6 Series. The BMW 4 Series is available with all of the latest technology and has a large yet sporty look. This car could be used for young families, however, it would be more suited to a business man who is running the car as a company car, having to also look good for meetings and clients. Because of the smaller yet executive shape, people in the door handles might be compromised space and the room in the back. As well as giving a good appearance, BMW have said that there are improvements in refinement and the way that the car drives as well. The BMW 4 Series has been tested in cold weather conditions as well as hot weather conditions in order to ensure that the car is as reliable and drivable as possible. From a more business approach, the BMW 4 Series has high residuals and lower running costs when compared to its competitors of the same age. This car is available in all market areas from cheap and used right up to top of the range brand new or nearly new cars. Although the car will have a cheaper market value and depreciation, there will always be a reasonable margin between the cheapest cars and the most expensive. This car is very cheap to run as a company car. For example, the £35,000 car with options will be around an £80-£100 deduction per month and might have a residual value of £15,000 at the end of the 3-year contract. This means the business user is paying under half the value of the car himself in the time that he is used. Finance deals and cash deals are also superb in comparison to competitors. Overall, the BMW 4 Series would be powerful and reliable, yet still a good investment and even these days a car to keep hold of for a long time. The car will last a long time even when older models are still on the road, and this car would still be a good choice for a business man or even as a family car. The car looks the part and does the job itself. (Kafmann, 2020)
2. Design and Exterior
The two main body types for the 3 Series are the Sedan and Touring models, which are the four-door saloon and estate versions, whereas the 4 Series is available as either a four-door coupe or a two-door convertible which are similar in design to the coupe. The 3 Series' most popular body type is available in numerous trims, and more information can be found about it in our in-depth guide. Both ranges have a variety of color options, but the 3 Series specifically offers color-matched aluminum and wood trims to customize the look and feel of the interior. Both models are similar in size, but trunk space in the 3 Series varies with body type, whereas the 4 Series coupe has the biggest capacity. The 3 Series and 4 Series share a lot of the same exterior features. LED headlights and fog lights come as standard across both models, but higher spec trims are eligible for BMW's Icon Adaptive Headlights and an extended lighting package. This package is designed to boost the presence and visibility of the car at night and includes additional LED lights positioned in the door handles.
The BMW 3 Series and 4 Series are both relatively similar models in terms of design and styling, sharing many exterior features. In terms of styling, however, the 4 Series is the newer model of the two and as a result has taken on some more modern design elements. The 3 Series, whilst still being a modern car, has been a part of the BMW lineup for longer and maintains some slightly more traditional BMW design features. The 4 Series has a lower and wider stance compared to the 3 Series, although the two share the same wheelbase and are similar in size. This difference in stance gives the 4 Series a slightly sportier aesthetic, and combined with the sleek design of the four-door coupe, makes it slightly more aesthetically pleasing to some.
2.1. Styling differences
The 3 series and 4 series have subtle differences in their styling, despite being based on the same platform. The 4 series is a coupe version of the 3 series, although a gran coupe version based on the 4 series is available with 4 doors, blurring the lines between the two cars. The 3 series has a longer wheelbase than the 4 series with a taller roof line. This results in the 3 series having more interior space and a slightly more traditional saloon profile. On the other hand, the 4 series is wider and has a lower centre of gravity giving it a sportier and more aggressive look. This is accentuated with the more sculpted bodywork and the more angular shape of the front and rear lights. The differences are unobtrusive but both cars have very distinct identities. The aim of the 4 series is to look more upmarket and sportier than the 3 series. Step up in the range to the 3 GT and 4 GC models and the styling becomes much less ambiguous. With the longer wheelbase and hatchback design of the 3 GT, it provides increased headroom and more boot space. The 4 GC follows the same philosophy, but as the name suggests comes with a sleeker coupe-like profile. This gives it an even sportier look than the standard 4 series, but negates any compromises with less headroom and space compared to the 3 series.
2.2. Body types and dimensions
Both the BMW 3 Series and 4 Series Gran Coupe share the same platform and thus share the same wheelbase (110.6 inches) and other same dimensions. The 3 Series Sedan measures incrementally longer at 182.7 inches and slightly taller at 56.3 inches than the 4 Series Coupe which is 182.6 inches and 53.6 inches with the same wheelbase. The major difference between the two is the body styles with the 3 Series offering a Sedan or Wagon and the 4 Series offering the Coupe and a more recently introduced Gran Coupe. A slight weight difference separates the two with the 3 Series Sedan being the heaviest at 3560 lbs with the Coupe being the lightest at 3585 lbs. Meanwhile, the 4 Series Gran Coupe is the longest and the heaviest due to its hatchback design at 182.6 inches and 3560 lbs. The extra weight and length can be attributed to the hatchback design more resemble the 3 Series Sedan. Design and Exterior Both the BMW 3 Series and 4 Series Gran Coupe share the same platform and thus share the same wheelbase (110.6 inches) and other same dimensions. The 3 Series Sedan measures incrementally longer at 182.7 inches and slightly taller at 56.3 inches than the 4 Series Coupe which is 182.6 inches and 53.6 inches with the same wheelbase. The major difference between the two is the body styles with the 3 Series offering a Sedan or Wagon and the 4 Series offering the Coupe and a more recently introduced Gran Coupe. A slight weight difference separates the two with the 3 Series Sedan being the heaviest at 3560 lbs with the Coupe being the lightest at 3585 lbs. Meanwhile, the 4 Series Gran Coupe is the longest and the heaviest due to its hatchback design at 182.6 inches and 3560 lbs. The extra weight and length can be attributed to the hatchback design more resemble the 3 Series Sedan.
2.3. Exterior features and options
On the options front, both models can be personalized with a range of color, wheel, and trim choices. The 3 Series has a choice of 17, 18, or 19-inch alloy wheels depending on the trim level, as well as full LED headlights and fog lights. The Modern Line trim level adds extra chrome exterior highlights, while the Sport Line has high-gloss black exterior trim and kidney grille slats to convey the promise of a dynamic drive. Luxury Line adds extra chrome touches as well as a choice of 19-inch wheels. The M Sport package turns up the heat further with 19-inch M alloy wheels, M Sport suspension, an M aerodynamics package, BMW Individual high-gloss shadow line, and the choice of an Estoril Blue exterior finish. The 4 Series can be further individualized with Aluminum or BMW Individual exterior trim with the High-gloss Shadow Line spec, and Modern Line, Sport Line, or Luxury Line trim level options mirroring those of the 3 Series. Standout options include an M aerodynamics package and 19-inch M light alloy wheels, which are exclusive to the 4 Series. The Convertible features a three-piece retractable hardtop that can be raised or lowered in 20 seconds at speeds up to 11 mph. Reducing the amount of interior noise when up and luggage space compromise when down compared with the previous generation's soft top, the hardtop has added a new dimension to top-down driving. Lastly, the 4 Series Gran Coupe builds on the two-door's design with the same wheelbase and unique sloping roofline leading to increased headroom and legroom for rear seat passengers. A twin-door take on the 6 Series Gran Coupe if you will, this is a car that has been tailored for those seeking coupe style in a more practical four-door package. (Ash, 2021)
3. Performance and Engine Options
Engine options are one of the very crucial factors taken into consideration before purchasing a car. The BMW 3 series comes with 3 powertrain options, whereas the 4 series comes with 2. This gives the 3 series an upper hand as the third option is a diesel engine. The 4 series does not have a diesel engine, which is a disadvantage for those consumers who are in favor of a diesel engine. Power is definitely a factor not to be compromised, and the type of engine certainly decides the output. All the engine options in both the 3 and 4 series are forced induction engines to increase the power output. The 3 series 2L inline 4 engine delivers 255 horsepower, and the inline 6 engine, which is the highest configuration engine, gives out 382 horsepower. The engine option for the 4 series is the same as the 3 series; however, it misses out on the inline 6 engine as the highest configuration engine. This engine configuration provides lesser power compared to the 3 series. The 3 series also is available in a plug-in hybrid powertrain, whereas the 4 series doesn't have this option. This is an environmentally friendly option available in the 3 series for those who have a passion for cars and also want to contribute towards the world today. Comparing the powertrain options, the 3 series has a better range of options catering to different consumer needs.
3.1 Powertrain options 3.2 Acceleration and top speed 3.3 Fuel efficiency and driving dynamics 3.4 Performance-oriented variants
3.1. Powertrain options
The base powertrain of the BMW 3 Series comes with a 180 horsepower four-cylinder engine. This layout allows for a 0-60 mph time of 7.1 seconds, which is average for this class. Unfortunately, the acceleration times for the 3 Series do not get significantly better as you move to the upgraded and inline 6-cylinder engines. Regardless of the powerplant you choose, the 3 Series seems capable of no better than a 6-second 0-60 mph time. The best performance engine in the 3 Series is offered in the 335i with a 300 horsepower inline 6-cylinder engine that is capable of a 5.4-second 0-60 mph time. Step below the 335i is the 330i that utilizes an older 3.0-liter 230 horsepower inline 6 engine. The 328i has a 230 horsepower engine and the 325i comes with a 215 horsepower engine, and engine quality in both models drops as you downgrade to the base 3 Series models. BMW's move of the 4 Series away from the 3 Series heritage involves planning to offer the 4 Series with a higher performance aura than the 3 Series. Key to this concept is that the 4 Series will only be offered in higher model trim levels than the 3 Series. This means though the 4 Series and 3 Series still share the same powertrain and performance options, the 4 Series will inevitably be the choice that is more enthusiast-oriented, and better performance out of the same engines will likely be found in the 4 Series.
3.2. Acceleration and top speed
With a minor engine upgrade across the range, the 3 Series now comes with the same 2.0-liter turbo-four as the base 4 Series, with 5-10 more horsepower than the previous model. For 2016, the 3/4 Series' engine offerings are largely the same. The 320i, 3 Series' base model, comes with a 2.0-liter turbo-four as the only available powertrain. This engine can be had in both RWD and AWD variants, and its output is rated at 180 horsepower and 200 lb-ft of torque. The 330i, formerly the 328i, also has the same engine, though horsepower is increased to 248. These models come with a claimed 0-60 mph time of 7.1 and 5.5 seconds, with the latter being nearly two seconds quicker than the previous 328i. Opting for an AWD 330i adds about 100 pounds to the curb weight, but acceleration times should be about the same. The 330i is especially important to note in comparison to the 430i, which is the current base model for the 4 Series. Tagged under a new name, this model has the same engine and horsepower as the 330i, though torque is rated 10 lb-ft higher at 258. Because the two cars' platforms and powertrains are essentially the same, performance specs should be very similar. The 430i is available in both RWD and AWD forms. The number of six-cylinder 3/4 Series models has been drastically reduced. The $50,000 340i is the only 3 Series available with a six-cylinder, which is still the same 3.0-liter turbo inline-six. With a 320 lb weight loss compared to its predecessor, the 340i has a 0-60 mph time of 4.8 seconds. For the 4 Series, the only six-cylinder option is the $48,300 440i. This model has the same engine as the 340i, though the 440i is both coupe and convertible-only. It has a 0-60 mph time of 5.5 seconds, which is about the same as the previous 435i. Step-motor eight-speed auto transmissions (a feature we're still somewhat bewildered by) replace the eight-speed ZF autos used in the past. Unfortunately, the manual transmission is no longer available in 4 Series models with the track package above 428i/430i, and no RWD 440i/xi Gran Coupe will come with a manual. Overall weight has been reduced by up to 80 pounds depending on the variant, and weight distribution is claimed to be a perfect 50/50. This, combined with improved torque and a potential lack of xDrive understeer, means that steering and handling could improve across the entire range. Two-door models have a mostly identical curb weight compared to their four-door equivalents. (Tran et al., 2020)
3.3. Fuel efficiency and driving dynamics
The 3 series and 4 series have a variety of diesel and petrol engines on offer, thus covering a broad spectrum of fuel efficiency and performance, to suit everyone from private buyers to fleet managers to those seeking top performance. The most fuel efficient model in the 3 series range is the 320d EfficientDynamics, which boasts a combined figure of 68.9mpg and CO2 emissions of just 109g/km. This is particularly good for what is a decent sized family car. Minor facelifts in 2015 and again in the following year saw the arrival of the 330e plug-in hybrid, which boasts impressive figures of 134.5mpg and just 49g/km of CO2. This variant sadly offers a limited electric-only range and a lack of practicality due to its boot being encroached by its battery. For the individual who is seeking ultimate fuel efficiency with spirited performance, the 3 series is an excellent choice. Higher powered diesel models such as the 330d and 335d are capable of achieving up to and around 50mpg and, as previously mentioned, are very refined. For ultimate fuel efficiency, CO2 emissions, and refinement, the best option is the 330d with the 8-speed automatic gearbox. Higher performance Volvo T8 Twin Engine models and upcoming Audi A6 TFSI e models are capable of achieving upwards of 100mpg; however, these are plug-in hybrid models and are significantly more expensive than their non-hybrid counterparts. The 4 series shares the same engines as the 3 series; however, due to its increased weight and poorer aerodynamics, it is slightly less fuel efficient. Although figures are nearly identical, you should expect to achieve 3-5mpg less with a 4 series. A 430d is capable of achieving well over 50mpg, and as seen on the 3 series, the 435d is not actually that much of a difference in terms of fuel efficiency or CO2 emissions compared to the 3 series variants. Unlike the 3 series, however, there are no plug-in hybrid 4 series models available.
3.4. Performance-oriented variants
As the M3 and M4 will have the same engine, the only option in terms of drivetrain will be the standard M limited-slip differential for the M3. Both models will have the same level of output and handling; however, the M3 will be more tail happy. While it's not confirmed, there may be some special edition models for the M3 and M4 further down the track. This will allow BMW to create more focus on these models and potentially draw more buyers away from the standard 3 and 4 Series in purchase of the performance model.
In comparison to the side-stepped standard 4 Series, the M4 is an entirely different beast. It's wider, lower, and it's full of all the bits and pieces that you would expect out of a performance-oriented BMW. It comes with a choice of either a 6-speed manual or 7-speed automatic with paddles. With the M4 being lighter than the M3, it comes with an increase in 0-100 km/h time by 0.4 seconds (4.2 seconds) for the dual-clutch 7-speed transmission model. It comes with a new take on the BMW M limited-slip differential and 18" brakes with 6-piston front and 4-piston rear calipers. The M4 also has the option of carbon-ceramic brakes.
The BMW 3 Series has one performance variant, that being the M3. In comparison, the 4 Series has only one performance variant, which is the M4. There has been much debate in the past as to whether BMW should create an M3 or M4 when it only really needs one. Regardless of the 4 Series having its own performance coupe and convertible, the M3 and M4 are identical underneath. Both these cars come with a 3.0L twin-turbo inline 6, between 317-331 kW of power. This engine is the same engine found in the X4M and M4.
4. Interior and Technology
The 3 Series and the 4 Series have the same fundamental interior layout. The dash is typical BMW, with a high cowl and driver-oriented center stack. Both cars also have trick instrument clusters; the 3's is a 5.7-inch display and the 4's is a blackout 8.8-inch unit. Another commonality between the two is the availability of the stiff and supportive Sport seats and the availability of BMW's leather upholstery treated with sun-reflective pigments, a key feature for convertibles. The most significant exact matches between the two cars come in the technology department; both 3 Series and 4 Series offer the choice of the aforementioned full-color head-up display and both can be loaded with the BMW Connected Drive features which include BMW Online (access to current weather, fuel prices, news, etc.). When comparing make sure to try to sit in examples of both the BMW 3 Series and 4 Series to see if there is a palpable difference in interior room. And be sure to inspect any models that have been equipped with sport seats, as they can affect certain cars' center console design and even the height of the left leg rest in the driver foot well (although the difference is slight). Keep in mind that convertibles are usually more finicky in the seating/interior room department due to reduced interior volume and less rigid body structure. Even though there shouldn't be measurable differences in the dimensions of the 4 Series coupe and convertible this is another detail worth double checking after the coupe and/or convertible you are interested in goes on sale.
4.1. Cabin design and materials
With similar designs in the front of the cabin, both of these cars are still 4-5 seat coupes. The 3-series has a bench-like backseat while the 4-series has additional contour on its seats. This does not necessarily compromise comfort on the 4-series as the two-door design will make access to the back a little more challenging. The 4-series will be driver oriented and actually have better driver legroom than the 3-series. It still has reasonable headroom for its sloping roof, however, a taller person would notice a bit more in the 3-series. This can be important to potential buyers looking to carry more passengers as the room in the back of a coupe will still somewhat be important. Overall, the legroom and headroom statistics for both the 4 will be slightly less than the 3 series, but not by much. This extra space for the driver in the 4-series may bring buyers that are focused on two-door driving and enjoyment, but still need the space for other passengers.
Interior-wise, there is no mistaking either of these cars for a 3-series. Visually more stunning, these cars are on a new level considering the interior designs of classic 3-series. The lines and craftsmanship of the interior are a visually striking difference, yet may not be suitable for everyone. This cost cutting move on the materials eliminated what was probably the softest feeling top-grain leather BMW could source. This definitely does not mean the standard "SensaTec" is bad; tests on the 3-series showed that the fake leather could be mistaken for real in some cases. However, the lack of real leather on the steering wheel and shift knob may be noticed and not preferred by some. The extra stunning lines and curvature of the interior definitely do not sacrifice function however as both cars have proven to have good ergonomics and driver interface.
With a myriad of customizable features, both of these vehicles come in various interior colors with various trim options. The standard 3-series comes in either "SensaTec" fake leather or real leather for an extra charge. The standard sport seats come with 6-way manually adjustable seats, however there are premium options available for an extra charge. The headrests and large side bolsters provide better lateral support which proved to be useful on the track. The premium options include a lumbar support and memory system—these are standard on 4-series. The 4-series comes in various trims and leather options including the option for real leather on the seats, door panels and more. With only 7 combinations available to configure on the 3-series, BMW may be pushing customers to the 4-series by giving it a higher amount of customizability, at least in terms of interior design.
4.2. Comfort and seating capacity
The 3 series and the 4 series have identical interior dimensions, and that translates to nearly identical passenger comfort. Front legroom and headroom are the same in both vehicles and are more than adequate for adults of any size. The signature BMW driving position is easily set in all the series. There's excellent adjustability in the front seats, and the telescopic/tilt steering wheel and optional power-adjustable pedals make it even easier for different drivers to get comfortable. Another traditional BMW strength is the rear-seat accommodations. Although the 3 series and the 4 series are relative lightweights in this segment, there's plenty of space, and the seat comfort is the best in the class. Unfortunately, that's not saying much. Now they'll have to talk about seat comfort in the Mustang's back seat. Both series also offer the same trunk capacity, and it's one of the best in this class. The 3 series and 4 series are aimed at driving enthusiasts, so you might expect that. Unfortunately, there's no fold-down rear seat, but a pass-through feature for loading longer items is included. A large opening, an almost flat load floor and a low liftover height make it even more versatile.
4.3. Infotainment and connectivity features
The 3 series and 4 series have similar infotainment systems, both coming with BMW's iDrive system. This intuitive interface is controlled via a rotary knob on the center console and a 6.5-inch display screen. The base system in both vehicles comes with nine speakers, HD Radio, AM/FM/CD radio, a USB port, and an auxiliary 3.5mm input. The upgraded version of this system includes BMW's Online and BMW Apps, which with a properly connected smartphone, provide access to Facebook and Twitter. There are also various features of the upgraded iDrive, including weather info, news, a heads-up display, and 3D maps. The upgraded system is displayed through an 8.8-inch screen on the 3 series and a 10.3-inch screen on the 4 series. Both of these screen sizes are less than that some of their competitors offer, such as the C-Class' available 12.3-inch display or the IS' 10.3-inch display, but they are sufficient for the size of the 3/4 series. Both systems come with a 1-year trial of Apple CarPlay and Alexa voice control. Unfortunately, Android Auto is unavailable for either vehicle, although rumors suggest it will be available for 2019 model BMWs. Although these systems are great in terms of being loaded with technology, it might be a little overwhelming for those who are not tech-savvy. Some customers are fans of iDrive and feel it is easy to control; however, it has been criticized for being unnecessarily complex at times. The 3 and 4 series' standard infotainment features are good, but the price to option to the upgraded system may not be worth it for all customers due to the additional cost.
4.4. Advanced driver-assistance systems
Unfortunately, the two vehicles do need a fair bit of software in their autonomous driving functions to avoid smacking into a light post, as BMW has not been able to use the same platform as Tesla's Navigate on Autopilot, which can confidently drive the car unassisted on motorways. Instead, BMW requires you to be more engaged in the car's autonomous driving modes and has capped the speed at which the car can drive itself at 110 km/h in the 3 Series and 130 km/h in the 4 Series.
Wow, that's a lot to take in for the 3 Series. The 4 Series takes a similar approach with the same standard safety features but loses the Driving Assistant package. It is then replaced by an upgraded driving assistant package which includes autonomous driving features as well as a backup assistant and 3D surround view. This upgraded package will cost a similar amount to the lower-tier Driving Assistant Package on the 3 Series.
BMW takes a similar approach to driver-assistance on both of these vehicles. There are a number of options to choose from, depending on how much you're willing to spend. All 3 Series come with a standard suite of safety systems including lane departure warning, blind spot detection, rear collision prevention, and rear cross traffic alert. Opting for the Driving Assistant package equips the car with extra safety aids such as lane keep assist, front cross traffic alert, and evasion aid. Finally, the Driving Assistant Professional provides a semi-autonomous driving function where you can take your hands off the wheel for 50 seconds on certain roads at speeds up to 37 mph.
References:
OZKAN, A., ARSLAN, H., and SEN, O. T. "Journal of Science." academia.edu . academia.edu
Kafmann, S. "BMW iSPACE." (2020). diva-portal.org
Ash, D. L. "L. David Ash Interview Transcript." (2021). dalnetarchive.org
Tran, M. K., Akinsanya, M., Panchal, S., Fraser, R., and Fowler, M. "Design of a hybrid electric vehicle powertrain for performance optimization considering various powertrain components and configurations." Vehicles (2020). mdpi.com