Opel Diplomat (1964–1978): generations, specs, engine, dimensions
The Opel Diplomat is a rear-wheel-drive Opel with 2 generations in the catalogue, produced from 1964 through 1978. Body types in the data are Coupe (1 generation, 1964–1968) and Sedan (2 generation, 1969–1978). Across both generations the catalogue lists 8 named versions (5 in generation 1, 3 in generation 2). Every version is Gasoline, RWD, with a Front, longitudinal engine.
The Opel Diplomat is a rear-wheel-drive Opel with 2 generations in the catalogue, produced from 1964 through 1978. Body types in the data are Coupe (1 generation, 1964–1968) and Sedan (2 generation, 1969–1978). Across both generations the catalogue lists 8 named versions (5 in generation 1, 3 in generation 2). Every version is Gasoline, RWD, with a Front, longitudinal engine. Power in the data runs from 100 hp (2.6 AT, 1 generation) to 230 hp (5.4 AT in both generations). Cylinder counts are 6 (Inline) or 8 (V-shaped). Displacements in the data are 2600, 2784, 2800, 4600, 5354 and 5400. Fuel consumption, tank size, CO2, eco class, wheels and many first-generation performance figures are not measured.
People looking up Opel Diplomat specs, Opel Diplomat V8, Opel Diplomat Coupe, Opel Diplomat B, Opel Diplomat 5.4 V8 specs, Opel Diplomat engine and Opel Diplomat dimensions will find those topics in the sections below. Figures that the source does not give are written as not measured, not omitted.
Generations
1 generation (1964–1968) — Coupe
1 generation of the Opel Diplomat ran from 1964-01-01 to 1968-12-31. Body type: Coupe. The catalogue lists 5 versions, all Gasoline, Automatic, 2 speeds, RWD, engine Front, longitudinal, 2 valves per cylinder, front suspension Independent, spring, front brakes Disc. Rear suspension, rear brakes, boost, fuel system, compression, bore × stroke, torque, 0–100, top speed, kerb/gross weight, ground clearance, tank, wheels, fuel consumption, CO2 and eco class are not measured on these five versions.
The five versions are:
- 5.4 AT — 230 hp (169 kW), displacement 5400, 8 cylinders, V-shaped. Two catalogue rows share this exact name and the same 230 hp / 169 kW; both are Automatic with 2 gears. Power rpm, torque and torque rpm are not measured on either row.
- 2.6 AT — 100 hp (74 kW), displacement 2600, 6 cylinders, Inline.
- 2.8 AT — 125 hp (92 kW), displacement 2800, 6 cylinders, Inline.
- 4.6 AT — 190 hp (140 kW), displacement 4600, 8 cylinders, V-shaped.
On 1 generation, 5.4 AT (230 hp) is 130 hp above 2.6 AT (100 hp), 105 hp above 2.8 AT (125 hp) and 40 hp above 4.6 AT (190 hp). Displacement of 5.4 AT (5400) is 2800 larger than 2.6 AT (2600), 2600 larger than 2.8 AT (2800) and 800 larger than 4.6 AT (4600).
2 generation (1969–1978) — Sedan
2 generation ran from 1969-01-01 to 1978-12-31. Body type: Sedan. The catalogue lists 3 versions. All three are Gasoline, RWD, engine Front, longitudinal, 2 valves per cylinder, boost No, ground clearance 150, front and rear suspension Independent, spring, front and rear brakes Disc. Fuel, tank, city/highway/combined consumption, CO2, eco class and wheels are not measured on all three.
The three versions are:
- 2.8 MT — 165 hp (121 kW) at 5600, 229 Nm at 4100–4600, displacement 2784, 6 cylinders, Inline, fuel system Distributed injection (multi-point), compression 9.5, bore × stroke 92 × 69.8, Manual with 4 gears, 0–100 10.5, top speed 190, kerb weight 1530, gross weight 2030, ground clearance 150.
- 2.8 AT — same engine figures as 2.8 MT: 165 hp (121 kW) at 5600, 229 Nm at 4100–4600, 2784, 6 Inline, Distributed injection (multi-point), compression 9.5, 92 × 69.8, boost No. Gearbox is Automatic with 3 gears. 0–100, top speed, kerb weight and gross weight are not measured. Ground clearance 150.
- 5.4 AT — 230 hp (169 kW) at 4700, 427 Nm at 3000–3200, displacement 5354, 8 cylinders, V-shaped, fuel system Carburetor, compression 10.5, bore × stroke 101.6 × 82.55, Automatic with 3 gears, 0–100 8.5, top speed 205, kerb weight 1690, gross weight 2200, ground clearance 150.
On 2 generation, 5.4 AT has 65 hp more than 2.8 MT and 2.8 AT (230 − 165). Torque is 198 Nm higher (427 − 229). Displacement is 2570 larger than 2784. 0–100 on 5.4 AT is 2.0 seconds quicker than 2.8 MT (10.5 − 8.5). Top speed on 5.4 AT is 15 higher than 2.8 MT (205 − 190). Kerb weight of 5.4 AT is 160 above 2.8 MT (1690 − 1530); gross weight is 170 above (2200 − 2030). Ground clearance is the same 150 on all three 2-generation versions.
2.8 MT and 2.8 AT share engine output; the measured difference is the gearbox: Manual 4 versus Automatic 3. Acceleration and top speed are measured only for 2.8 MT, not for 2.8 AT.
Opel Diplomat specs: engines and versions
Dictionary labels below are taken from the English fields in the data (Gasoline, Inline, V-shaped, Manual, Automatic, RWD, No, Distributed injection (multi-point), Carburetor, Front, longitudinal).
| Generation | Years | Body | Version | hp | kW | rpm (power) | Nm | rpm (torque) | Displacement | Fuel | Cylinders | Layout | Boost | Gearbox | Gears | Drive |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 generation | 1964–1968 | Coupe | 5.4 AT (230 hp) | 230 | 169 | not measured | not measured | not measured | 5400 | Gasoline | 8 | V-shaped | not measured | Automatic | 2 | RWD |
| 1 generation | 1964–1968 | Coupe | 5.4 AT (230 hp), second row | 230 | 169 | not measured | not measured | not measured | 5400 | Gasoline | 8 | V-shaped | not measured | Automatic | 2 | RWD |
| 1 generation | 1964–1968 | Coupe | 2.6 AT | 100 | 74 | not measured | not measured | not measured | 2600 | Gasoline | 6 | Inline | not measured | Automatic | 2 | RWD |
| 1 generation | 1964–1968 | Coupe | 2.8 AT | 125 | 92 | not measured | not measured | not measured | 2800 | Gasoline | 6 | Inline | not measured | Automatic | 2 | RWD |
| 1 generation | 1964–1968 | Coupe | 4.6 AT | 190 | 140 | not measured | not measured | not measured | 4600 | Gasoline | 8 | V-shaped | not measured | Automatic | 2 | RWD |
| 2 generation | 1969–1978 | Sedan | 2.8 MT | 165 | 121 | 5600 | 229 | 4100–4600 | 2784 | Gasoline | 6 | Inline | No | Manual | 4 | RWD |
| 2 generation | 1969–1978 | Sedan | 2.8 AT | 165 | 121 | 5600 | 229 | 4100–4600 | 2784 | Gasoline | 6 | Inline | No | Automatic | 3 | RWD |
| 2 generation | 1969–1978 | Sedan | 5.4 AT | 230 | 169 | 4700 | 427 | 3000–3200 | 5354 | Gasoline | 8 | V-shaped | No | Automatic | 3 | RWD |
Opel Diplomat engine notes
Opel Diplomat engine layouts in the data are only Inline 6 and V-shaped 8. There is no other cylinder count.
On 1 generation, 2.6 AT (100 hp, 2600, 6 Inline) is the lowest-output engine. 2.8 AT (125 hp, 2800, 6 Inline) is 25 hp above 2.6 AT and 200 larger in displacement. 4.6 AT (190 hp, 4600, 8 V-shaped) is 65 hp above 2.8 AT and 90 hp above 2.6 AT. Both 5.4 AT rows (230 hp, 5400, 8 V-shaped) sit 40 hp above 4.6 AT. Fuel system, boost, compression and bore × stroke on 1 generation are not measured.
On 2 generation, the 2.8 MT and 2.8 AT engine is 2784, 6 Inline, Distributed injection (multi-point), compression 9.5, 92 × 69.8, boost No, 165 hp at 5600, 229 Nm at 4100–4600. The 5.4 AT engine is 5354, 8 V-shaped, Carburetor, compression 10.5, 101.6 × 82.55, boost No, 230 hp at 4700, 427 Nm at 3000–3200. Compression on 5.4 AT is 1.0 higher than on the 2.8 versions (10.5 − 9.5). Peak power rpm on 5.4 AT is 900 lower than on the 2.8 versions (5600 − 4700). Peak torque rpm band on 5.4 AT (3000–3200) sits below the 2.8 band (4100–4600).
5.4 AT in 1 generation is listed at displacement 5400; 5.4 AT in 2 generation is listed at 5354 — 46 smaller in the later generation. Power is the same 230 hp / 169 kW in both generations for 5.4 AT. Gear count on 5.4 AT is 2 in 1 generation and 3 in 2 generation.
2.8 AT in 1 generation is 125 hp and displacement 2800; 2.8 AT in 2 generation is 165 hp and 2784. That is 40 hp more on the later 2.8 AT, with displacement 16 smaller (2800 − 2784). Gear count is 2 on 1-generation 2.8 AT and 3 on 2-generation 2.8 AT.
Performance and economy (0–100, top speed, mpg)
Measured 0–100 and top speed exist only for two 2-generation versions:
- 2.8 MT (2 generation, Sedan): 0–100 10.5, top speed 190.
- 5.4 AT (2 generation, Sedan): 0–100 8.5, top speed 205.
2.8 AT (2 generation): 0–100 not measured, top speed not measured.
All five 1-generation Coupe versions (5.4 AT 230 hp, 5.4 AT 230 hp second row, 2.6 AT, 2.8 AT, 4.6 AT): 0–100 not measured, top speed not measured.
City consumption: not measured on every version. Highway consumption: not measured on every version. Combined consumption: not measured on every version. CO2: not measured. Eco class: not measured. There is therefore no mpg figure in this catalogue for Opel Diplomat.
Dimensions and weight
Length, width, height and wheelbase are not measured in the supplied data, so Opel Diplomat dimensions in this article are limited to weight, clearance, tank and wheels.
Ground clearance: 150 on 2.8 MT, 2.8 AT and 5.4 AT of 2 generation. On all 1-generation versions, ground clearance is not measured.
Kerb weight: 1530 on 2.8 MT (2 generation); 1690 on 5.4 AT (2 generation); not measured on 2.8 AT (2 generation) and on every 1-generation version.
Gross weight: 2030 on 2.8 MT (2 generation); 2200 on 5.4 AT (2 generation); not measured on 2.8 AT (2 generation) and on every 1-generation version.
Payload from the two measured pairs: 2.8 MT 2030 − 1530 = 500; 5.4 AT 2200 − 1690 = 510.
Tank: not measured on every version. Wheels: not measured on every version.
Brakes (2 generation): front Disc, rear Disc on 2.8 MT, 2.8 AT and 5.4 AT. Brakes (1 generation): front Disc; rear not measured.
Suspension (2 generation): front Independent, spring, rear Independent, spring. Suspension (1 generation): front Independent, spring; rear not measured.
Which version to choose
Choice here is only a comparison of the numbers in the data.
Coupe versus Sedan. If the body must be Coupe, the catalogue only has 1 generation (1964–1968). If the body must be Sedan, only 2 generation (1969–1978). There is no Coupe in 2 generation and no Sedan in 1 generation in this dataset.
Lowest output. 2.6 AT (1 generation, Coupe): 100 hp, 74 kW, 2600, 6 Inline, Automatic 2, RWD. Torque, 0–100, top speed and weights are not measured.
Mid six-cylinder, first generation. 2.8 AT (1 generation): 125 hp, 2800, 6 Inline, Automatic 2. 25 hp above 2.6 AT.
Mid eight-cylinder, first generation. 4.6 AT (1 generation): 190 hp, 4600, 8 V-shaped, Automatic 2. 90 hp above 2.6 AT, 65 hp above 1-generation 2.8 AT, 40 hp below both 5.4 AT rows.
Highest output, first generation. 5.4 AT (230 hp) — two identical catalogue rows: 230 hp, 169 kW, 5400, 8 V-shaped, Automatic 2, RWD. Torque, 0–100, top speed and weights not measured. This is the only 1-generation name that matches common “Opel Diplomat V8” / “Opel Diplomat Coupe” searches in this dataset (along with 4.6 AT, which is also 8 V-shaped).
Six-cylinder sedan with a measured sprint. 2.8 MT (2 generation): 165 hp, 229 Nm, 2784, Manual 4, 0–100 10.5, top speed 190, kerb 1530, gross 2030, clearance 150. It is the only Manual version in the whole Diplomat catalogue here, and the only 2.8 with measured 0–100 and top speed.
Six-cylinder sedan automatic. 2.8 AT (2 generation): same 165 hp / 229 Nm / 2784 as 2.8 MT, but Automatic 3. 0–100, top speed and weights not measured. Versus 1-generation 2.8 AT, it has 40 hp more (165 − 125) and 1 extra gear (3 versus 2).
Eight-cylinder sedan with measured performance. 5.4 AT (2 generation): 230 hp, 427 Nm, 5354, Carburetor, Automatic 3, 0–100 8.5, top speed 205, kerb 1690, gross 2200, clearance 150. Versus 2.8 MT it is 65 hp stronger, 198 Nm stronger, 2.0 seconds quicker to 100, 15 higher in top speed, and 160 heavier at kerb. Versus 1-generation 5.4 AT it keeps 230 hp but lists displacement 5354 instead of 5400, 3 gears instead of 2, and is the only 5.4 AT with measured torque, 0–100, top speed and weights.
Opel Diplomat vs Mercedes and Opel Admiral vs Diplomat are common search phrases. This catalogue has no Mercedes figures and no Admiral figures, so no comparison numbers exist here.
Problems and reliability are not measured in the source data.
Fuel and economy reminder: tank, city/highway/combined consumption, CO2 and eco class are not measured for every Opel Diplomat version in this dataset. Any mpg or range claim would be outside the data.