Buick Lucerne

Buick Lucerne: which version to buy

The Buick Lucerne that is actually in this catalogue is one sedan generation, 2005–2011, with a restyling from 2009. Four named versions sit in that span: 3.8 AT and 4.6 AT (275 hp) for 2005–2008, then 3.9 AT and 4.6 AT (296 hp) for 2009–2011.

The Buick Lucerne that is actually in this catalogue is one sedan generation, 2005–2011, with a restyling from 2009. Four named versions sit in that span: 3.8 AT and 4.6 AT (275 hp) for 2005–2008, then 3.9 AT and 4.6 AT (296 hp) for 2009–2011. Every one is Gasoline, Automatic, 4 gears, FWD, front transverse, multi-point injection, no boost, independent spring suspension, disc brakes, a 70-litre tank, and 140 mm ground clearance. The buying question is therefore not “which layout,” but which engine and which year band: V-shaped 6 versus V-shaped 8, and pre-restyling versus restyling.

Buick Lucerne specs by version (what actually differs)

Fuel consumption city / highway / mixed is not measured on any of these four. CO2 and eco class are not measured. Wheel sizes are not measured. Compression ratio and bore × stroke are measured only on 3.8 AT (9.4; 96.5 × 86.4) and both 4.6 AT rows (10; 93 × 84); they are not measured on 3.9 AT. Fuel grade on all four is 95.

Buick Lucerne engine options: six-cylinder versus V8

There are two six-cylinder cars and two eight-cylinder cars. The sixes are 3.8 AT (3791 cc, 197 hp) and 3.9 AT (3880 cc, 227 hp). The eights are both named 4.6 AT at 4565 cc; they must be split by power: 275 hp before restyling, 296 hp after.

Specific output (hp per litre of displacement):

• 3.8 AT: 197 / 3.791 ≈ 52.0 hp/l
• 3.9 AT: 227 / 3.880 ≈ 58.5 hp/l
• 4.6 AT (275 hp): 275 / 4.565 ≈ 60.2 hp/l
• 4.6 AT (296 hp): 296 / 4.565 ≈ 64.8 hp/l

The restyled six already extracts more power per litre than the original six (+6.5 hp/l). The restyled eight is the densest of the four. That density is not free in the data: the 296 hp peak arrives at 6300 rpm versus 5600 rpm on the 275 hp eight, so the later 4.6 AT asks more revs for its extra 21 hp.

Torque tells a different story than horsepower. 3.8 AT has 305 Nm at 4000 rpm; 3.9 AT has only 237 Nm at 3200 rpm — 68 Nm less despite +30 hp and +89 cc. The later six is the peak-power six; the earlier six is the torque six. On the eights, restyling cuts peak torque from 400 Nm @ 4400 rpm to 390 Nm @ 4500 rpm (−10 Nm, +100 rpm) while adding 21 hp. If the use case is low-rev pull, 3.8 AT and 4.6 AT (275 hp) are the stronger of their cylinder counts. If the use case is peak horsepower, 3.9 AT and 4.6 AT (296 hp) win inside the same cylinder count.

Valve count is locked to cylinder count here: both sixes have 2 valves per cylinder; both eights have 4. Boost is No on all four. Engine placement is Front, transverse on all four. Feeding is Distributed injection (multi-point) on all four.

Buick Lucerne horsepower and weight: kg per hp

Kerb weight per horsepower:

• 3.8 AT: 1745 / 197 ≈ 8.86 kg/hp
• 3.9 AT: 1707 / 227 ≈ 7.52 kg/hp
• 4.6 AT (275 hp): 1855 / 275 ≈ 6.75 kg/hp
• 4.6 AT (296 hp): 1820 / 296 ≈ 6.15 kg/hp

Restyling lightened both sides of the range: the six dropped 38 kg (1745 → 1707) while gaining 30 hp; the eight dropped 35 kg (1855 → 1820) while gaining 21 hp. The lightest kerb in the catalogue is 3.9 AT at 1707 kg. The heaviest kerb is the early 4.6 AT at 1855 kg — 148 kg more than the lightest six.

Gross weight does not follow the same path. 3.8 AT is 2240 kg gross. 3.9 AT and the early 4.6 AT share 2270 kg gross. The restyled 4.6 AT jumps to 2440 kg gross — 170 kg more than the early eight’s 2270 kg, even though kerb fell 35 kg. Payload implied by gross minus kerb:

• 3.8 AT: 2240 − 1745 = 495 kg
• 4.6 AT (275 hp): 2270 − 1855 = 415 kg
• 3.9 AT: 2270 − 1707 = 563 kg
• 4.6 AT (296 hp): 2440 − 1820 = 620 kg

If the Lucerne is bought as a five-seat sedan that should still carry people and luggage, the restyled cars — especially 4.6 AT (296 hp) — have the larger allowance in these numbers. The early eight has the smallest.

Ground clearance does not help pick a version: 140 mm on all four. Tank volume does not help either: 70 litres on all four.

Performance: 0–100 and top speed (mpg is not measured)

0–100 km/h, fastest to slowest:

1. 4.6 AT (275 hp): 7.5 s 2. 4.6 AT (296 hp): 7.8 s 3. 3.9 AT: 8.6 s 4. 3.8 AT: 9 s

The early eight is 0.3 s quicker to 100 km/h than the later, more powerful eight. That is consistent with its higher peak torque (400 vs 390 Nm) and with peak power arriving 700 rpm earlier (5600 vs 6300). The restyled six is 0.4 s quicker than the original six (8.6 vs 9.0) despite 68 Nm less torque; peak power and a 38 kg lighter kerb are the arithmetic that remains.

Top speed:

• 4.6 AT (275 hp): 200 km/h
• 4.6 AT (296 hp): 199 km/h
• 3.9 AT: 195 km/h
• 3.8 AT: 180 km/h

The early eight is the fastest in this data. The restyled six closes almost all of the old six-versus-eight gap on top speed (195 vs 199–200) while the original 3.8 AT sits 15 km/h below 3.9 AT and 20 km/h below the early eight.

Fuel consumption is not measured for city, highway, or mixed on any version. An economy ranking cannot be built from these records; saying otherwise would invent a number.

Buick Lucerne dimensions and weight (what is measured)

Length, width, height, wheelbase, and wheel sizes are not measured in this dataset. What is measured, and what a buyer can actually compare, is mass and clearance:

• Kerb: 1707 kg (3.9 AT) … 1745 kg (3.8 AT) … 1820 kg (4.6 AT 296 hp) … 1855 kg (4.6 AT 275 hp). Spread: 148 kg.
• Gross: 2240 kg (3.8 AT) … 2270 kg (3.9 AT and 4.6 AT 275 hp) … 2440 kg (4.6 AT 296 hp). Spread: 200 kg.
• Clearance: 140 mm, all versions.
• Tank: 70 litres, all versions.

A “Lucerne size” search that expects millimetres of length will not be answered here; those millimetres are not in the source.

2005–2008 versus 2009–2011: what restyling changed in the numbers

Treat 2005–2008 as one band and 2009–2011 as the restyling of the same generation, not a second generation.

On the six-cylinder side, 3.8 AT is replaced by 3.9 AT: +89 cc, +30 hp, +22 kW, −68 Nm, 0–100 improved by 0.4 s, top speed +15 km/h, kerb −38 kg, gross +30 kg, payload +68 kg. Compression and bore × stroke drop from measured (9.4; 96.5 × 86.4) to not measured. Valve count stays 2; cylinders stay 6, V-shaped.

On the eight-cylinder side, 4.6 AT keeps 4565 cc, 8 cylinders V-shaped, 4 valves, compression 10, and 93 × 84. Power rises 21 hp and 13 kW; torque falls 10 Nm; 0–100 slows by 0.3 s; top speed falls 1 km/h; kerb falls 35 kg; gross rises 170 kg. Peak power rpm moves from 5600 to 6300.

Same across the restyling: Automatic 4, FWD, Gasoline, 95, 70-litre tank, 140 mm clearance, disc / disc, independent spring / independent spring, no boost, front transverse, multi-point injection. The restyling in this catalogue is an engine-and-mass change, not a drivetrain change.

Which Buick Lucerne version to choose

Choose 3.8 AT (2005–2008) if the priority is six-cylinder torque without the eight’s extra displacement. It is the torque leader of the sixes (305 Nm vs 237 Nm on 3.9 AT), the lightest-gross car (2240 kg), and the only six with a measured compression ratio and bore × stroke. It is also the slowest: 9 s to 100 km/h, 180 km/h top speed, 8.86 kg/hp. It is the “pull, not peak power” six.

Choose 3.9 AT (2009–2011) if the priority is the lightest Lucerne with a six that actually makes more horsepower. It is the lightest kerb (1707 kg), 7.52 kg/hp, 227 hp, 8.6 s, 195 km/h — 15 km/h and 0.4 s better than 3.8 AT, and only 4–5 km/h and 0.8–1.1 s behind the eights on speed. The cost in the numbers is torque: 237 Nm is the lowest of the four, 163 Nm behind the early eight. Compression and bore × stroke are not measured on this version.

Choose 4.6 AT (275 hp, 2005–2008) if the priority is the strongest sprint and the strongest torque in the catalogue. 7.5 s, 200 km/h, 400 Nm, 60.2 hp/l. It is also the heaviest kerb (1855 kg) and the smallest payload of the four (415 kg). Peak power comes earlier than on the later eight (5600 vs 6300 rpm). For a buyer who wants V8 character as these numbers define it — displacement 4565 cc, 8 cylinders V-shaped, 4 valves, 400 Nm — this is the version that maximises torque and 0–100.

Choose 4.6 AT (296 hp, 2009–2011) if the priority is peak horsepower, best kg/hp, and the largest payload. 296 hp, 64.8 hp/l, 6.15 kg/hp, 620 kg implied payload, 1820 kg kerb. It is 0.3 s slower to 100 km/h and 1 km/h slower on top speed than the 275 hp eight, and it has 10 Nm less torque. Gross weight is the outlier at 2440 kg. Same 4565 cc, same 8 / V-shaped / 4 valves, same 93 × 84 and compression 10 as the earlier eight — the later car is not a different engine size, it is a different power, torque, mass, and payload point on the same displacement.

A short rule from the arithmetic only: six-cylinder torque → 3.8 AT; six-cylinder lightest and more hp → 3.9 AT; eight-cylinder fastest 0–100 and most Nm → 4.6 AT (275 hp); eight-cylinder most hp and most payload → 4.6 AT (296 hp). Fuel use cannot break the tie: mpg is not measured. Wheel size cannot break the tie: it is not measured. Length cannot break the tie: it is not measured. The gearbox, drive, tank, and clearance are identical, so they do not break the tie either.