Z4 vs SL
Different logos, same mission. The Z4 and the SL both want to be your next car. The Z4 is up against it here: the SL wins 3 of the 4 areas on our scorecard, with engine & performance as its standout.
At a glance
- Engine & Performance SL wins
- Fuel Economy & Range Z4 wins
- Space & Practicality SL wins
- Off-road & Towing SL wins
- Engine & Performance2.1
- Fuel Economy & Range6.0
- Engine & Performance4.7
- Fuel Economy & Range2.9
Spec scores (0 to 10) are calculated from manufacturer specs against other models in the same class. See how the formula works. They are not reviews or user ratings.
Key Differences
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The SL has 161 hp more power
This is one of the widest gaps in the whole comparison: 416 hp for the SL versus 255 hp for the Z4. Power is only part of the story; weight, gearing and torque delivery shape how quick a car feels.
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The SL has room for 4 seats
The Z4 lists 2 seats; the SL comes in at 4 seats. That’s not a rounding error. Extra seats mean you can take more people along without taking a second car.
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The Z4 has better fuel economy
At 28 mpg versus 22 mpg, this is a decisive lead for the Z4, the kind of difference you notice without looking for it. Official figures rarely match real-world driving exactly, but the ranking between two cars tends to hold.
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The SL has 74 lb-ft more torque
If torque is one of your priorities, this settles it: the SL leads clearly with 369 lb-ft to the Z4’s 295 lb-ft. The SL’s extra torque makes it more relaxed when fully loaded or towing.
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The Z4 has better city fuel economy
The numbers aren’t close. The Z4 lists 25 mpg for fuel economy (city), while the SL lists 19 mpg. In town, driving style has a big effect, but the Z4 starts from a better baseline.
Design & Size
Engine & Performance
SL leads
The engine & performance numbers point firmly in one direction: toward the SL. On its side, the SL has 161 hp more power. More power helps with merging, overtaking and climbing hills, especially with passengers and luggage on board. If this section decides it for you, choose the SL.
Total system output
Z4: 255 hp SL: 416 hp The SL’s extra output gives it more in reserve when you need to get up to speed.
Torque
Z4: 295 lb-ft SL: 369 lb-ft More torque means stronger pulling from low speeds, which you feel when accelerating from a stop or climbing grades.
Fuel Economy & Range
Z4 leads
The Z4 dominates the fuel economy & range section, and the gaps are large enough to matter in daily use. The Z4 wins here with better fuel economy. Better combined fuel economy lowers your running costs every week, and the savings add up over years of ownership. The fuel economy & range verdict goes to the Z4.
Fuel economy (combined)
Z4: 28 mpg SL: 22 mpg The Z4 uses less fuel on the standard combined cycle, which matters most if you drive a lot.
Fuel economy (city)
Z4: 25 mpg SL: 19 mpg Hybrids often shine in the city, and the Z4 has the better rating here.
Space & Practicality
SL leads
This section belongs to the SL. In space & practicality, it leads the Z4 by a margin that’s hard to ignore. The SL stands out with room for 4 seats. Third-row seats are often best for kids, so check legroom figures if adults will sit there. For space & practicality, the SL is the one to beat.
Seats
Z4: 2 seats SL: 4 seats The SL has room for more passengers, useful for growing families and carpools.
Off-road & Towing
SL leads
The SL does a little better in the off-road & towing section, though nothing here is a deal-breaker for the Z4. The SL makes its case with available all-wheel drive. All-wheel drive helps you get going on slippery roads, but good tires matter just as much for stopping and turning. That makes the SL the natural choice for buyers focused on off-road & towing.
AWD / 4WD available
Z4: no SL: yes Available all-wheel drive improves traction in rain, snow and on loose surfaces.
Safety & Tech
The safety & tech entries below are descriptive rather than numeric. Read them side by side to see where the Z4 and the SL part ways.
Full Specifications
Engine & Performance
| Spec | Z4 | SL |
|---|---|---|
| Powertrain | Gas | Gas (48V mild hybrid) |
| Engine | 2.0L turbo I4 | 2.0L turbo I4 |
| Total system output | 255 hp | 416 hp (winner) |
| Torque | 295 lb-ft | 369 lb-ft (winner) |
| Transmission | 8-speed automatic | 9-speed automatic (AMG MCT) |
| Drivetrain | RWD | RWD (4MATIC+ AWD on V8 models) |
Fuel Economy & Range
| Spec | Z4 | SL |
|---|---|---|
| Fuel economy (combined)EPA estimate where available | 28 mpg (winner) | 22 mpg |
| Fuel economy (city) | 25 mpg (winner) | 19 mpg |
| Fuel economy (highway) | 33 mpg (winner) | 27 mpg |
Space & Practicality
| Spec | Z4 | SL |
|---|---|---|
| Seats | 2 seats | 4 seats (winner) |
Off-road & Towing
| Spec | Z4 | SL |
|---|---|---|
| AWD / 4WD available | No | Yes (winner) |
Safety & Tech
| Spec | Z4 | SL |
|---|---|---|
| Basic warranty | 4 yr / 50,000 mi | 4 yr / 50,000 mi |
“N/A” means the manufacturer does not specify the value or we could not confirm it. Figures marked “manufacturer rating” are the maker’s own claims, not our measurements.
Which One Should You Buy?
Choose the Z4 if…
- you want better combined fuel economy (28 mpg vs 22 mpg)
- you mostly drive in town (25 mpg vs 19 mpg in the city)
- you cover long highway distances (33 mpg vs 27 mpg on the highway)
Choose the SL if…
- you want more power (416 hp vs 255 hp)
- you need more seats (4 seats vs 2 seats)
- you want more pulling power from low speeds (369 lb-ft vs 295 lb-ft of torque)
- you face snow, ice or slippery back roads
Also Compared
Frequently Asked Questions
Which is better for most people, the Z4 or the SL?
The SL makes more sense overall. Consider the alternative only if you know that better fuel economy would make a real difference in your routine.
Executive Summary
Let’s set the logos aside for a minute. The Z4 and the SL are close competitors, and their spec sheets tell an interesting story. Practically speaking, the SL’s biggest advantage is 161 hp more power. Secondary, but worth mentioning: the SL has room for 4 seats. To be fair, the Z4 has better fuel economy, and that’s not nothing.
A quick self-test: do you care more about fuel economy & range or engine & performance? The first answer means the Z4, the second means the SL.
My pick: the SL for most people, with the Z4 as the smarter choice if you’d rather have better fuel economy on the Z4.
Personal opinion based on the data above. Your priorities may differ.