The vehicle

Dodge Diplomat and Plymouth Gran Fury

Twenty-six entries across nine Michigan tests, 1981 to 1989. The fastest sedan in three of them and the fastest scored car in a fourth, thrown out of one by a quarter of a second, and the last Chrysler police sedan in the published results for thirteen years.

Every test

The four-barrel V8 Diplomat and Gran Fury each year. The two-barrel and six-cylinder versions are in the full list below.

† Eliminated from the 1987 bid for missing the 0–80 requirement (23.25 seconds against 23.0); Michigan tested it for information. ‡ 1985: the scoring sheet prints one acceleration figure per car, headed “ACCEL”, without saying which interval; it is shown as 0–100 because the specification’s acceleration category is 0–100. Gold rows: the highest sedan top speed of that test; for 1985, of the four cars on the scoring sheet, the only document held for that year.

One car, two names

The books treat the Diplomat and the Gran Fury as one car. In 1982, the first year both are in the test on the same body, Table 1 gives them the same length, wheelbase and height, and their ergonomics totals are identical as printed: 191.36 each. The totals match again in 1983, 1984, 1986, 1987 and 1989; in 1986 and 1989 the bulletins say they scored only one car of each size, so one figure stands for both. The one exception is the 1985 scoring sheet, whose combined ergonomics and communications column gives the Diplomat 199.40 and the Gran Fury 198.40. In 1981 the Diplomat shared the same treatment with the Chrysler LeBaron 318: the same length and wheelbase, and the same ergonomics total.

The stopwatch did not always agree. In the books that print the hardware, the two carried the same 318 four-barrel, 165 horsepower in the 1981 to 1984 books and 175 in 1987, through a Chrysler automatic without overdrive and a 2.94 axle, yet the results often differ by more than a mile an hour or half a second. In 1983 the Gran Fury ran 120.0 mph and the Diplomat 118.8; in 1986 the Diplomat ran 121.5 and the Gran Fury 119.4. The books do not explain the differences.

Never far from the lead

For nine years the four-barrel cars sat in a narrow band: 115.4 to 121.5 mph, and 10.88 to 12.84 seconds to 60. That was enough to lead the sedans on top speed in three of the nine tests, lead the scored cars in a fourth and tie in a fifth.

• 1982: the Gran Fury’s 116.3 mph was the highest top speed the book publishes, ahead of the Ford LTD’s 115.8 and the Diplomat’s 115.4.
• 1983: the Gran Fury’s 120.0 was the highest sedan top speed; only the two-door Mustang, at 132.0, went faster.
• 1984: the Gran Fury had the highest total weighted score of the four cars scored, quickest to 80 and 100 and fastest at 121.4 mph. The Diplomat was fourth. A mid-size Ford LTD, not scored, ran 122.6.
• 1985: the Gran Fury was fastest of the four scored cars at 119.4, and the Diplomat had the lowest adjusted bid, $11,042.60. The two were bid at the same price; the score alone separated them.
• 1986: the Diplomat’s 121.5 was the highest sedan top speed in the test, and the best of any 1981–89 Diplomat or Gran Fury in these books.
• 1988: the Diplomat, the Gran Fury and the Crown Victoria 5.8 all recorded 117.0.

The best all-round figures are the 1984 Gran Fury’s: 10.88 seconds to 60, 34.43 to 100 and 121.4 mph, from a full test book. Only the 1986 Diplomat, in a preliminary bulletin, ran faster.

1987: a quarter of a second

In 1987 Michigan tightened its acceleration requirements, and the Diplomat became the last of the six cars the books held here name as disqualified. It needed 23.25 seconds to reach 80 mph against a limit of 23.0, and was eliminated from the bid; Michigan went on testing it for information. The Gran Fury, with the same body and engine, reached 80 in 22.09 and stayed in.

The next year the limits were eased, to 13.6, 24.3 and 43.2 seconds, and the 1988 Diplomat four-barrel cleared all of them, reaching 60 in 11.55 seconds. The 1987 car’s own times would have passed the eased limits too. The six vehicles named as eliminated in the documents held here are on the vehicles that failed.

The brakes

The same 1987 test gave the Gran Fury an average braking rate of 27.44 ft/s² and the Diplomat 27.24, a computed 141.1 and 142.2 feet from 60 mph. They are the two highest average rates on any year page from 1978 to 1989. The Diplomat had already set the previous best, 27.11, on the 1985 scoring sheet. The longest stop by a four-barrel Diplomat or Gran Fury is the 1984 Diplomat’s computed 165.8 feet.

The last one

The 1989 bulletin has the last of them: the Gran Fury at 120.2 mph and the Diplomat at 119.1, with only the fuel-injected 5.7 Caprice, at 122.0, faster among the sedans. On ergonomics both are printed at 190.20, the best of the year, ahead of the Caprice’s 189.60 and the Crown Victoria’s 168.53.

The 1990 book has no Chrysler product at all. The December 2002 federal bulletin called the Dodge Intrepid the first police-package sedan DaimlerChrysler had entered “in the MSP tests since the Dodge Diplomat in 1989”; a prototype Intrepid had been tested in the 2001 test, but its results were not published. The Dodge page follows the make from there to the Charger.

Engines, codes and the speedometer

What the books, and The Golden Age, show about which Diplomat or Gran Fury you are looking at:

• The engine. Every car in the main table has the 318 (5.2-litre) V8 with a four-barrel carburettor. Michigan also tested a two-barrel 318 Gran Fury from 1984 and two-barrel Diplomats in 1988 and 1989. They ran 106.2 to 113.6 mph and have no braking or lap figures.
• The six. A Gran Fury with the six-cylinder 225 appears in 1982 and a six-cylinder Diplomat in 1983, both under 97 mph. The books count both among that year’s police package cars; the 1983 book says the six-cylinder Diplomat was tested only for acceleration, and neither car has a braking figure.
• The package code changed in 1984. Chrysler’s A38 code ran until 1983 and was replaced by a different code from 1984, so a Diplomat or Gran Fury police car is coded differently depending on its year. The option codes page explains A38; where to find the tag and how to read the VIN are on identifying a genuine police package car.
• The speedometer. According to The Golden Age, citing Code 3 Garage, the certified speedometer on the 1982–89 Diplomat and Gran Fury read to 125 mph.

Was the 1980 Aspen 360 faster?

Mostly, but not on every measure. The Dodge Aspen with the 360 four-barrel, tested in 1980 at the manufacturer’s request for information only, ran 122.2 mph and reached 60 in 10.96 seconds. No 1981–89 Diplomat or Gran Fury in these books went faster than its 122.2; the closest is the 1986 Diplomat’s 121.5. But the 1984 Gran Fury was quicker to 60, at 10.88. The Aspen could not bid: the 1980 book says the mid-size specification required the smaller engine.

Where they sit in the record