Citroën M35.

When Citroën launched the Xantia in 1993 it also launched a new slogan: “vous n’imaginez pas tout ce que Citroën peut faire pour vous.” Literally translated from French it meant “you can’t imagine what Citroën can do for you.” In 1969 the brand had a different approach to showcasing what it can do: it gave customers the opportunity to purchase and test a prototype, the M35.

If the image of a gaudy Japanese sedan entered your head after reading the name "M35", shake it out. The M35 was a rolling laboratory of future Citroën technology. Under the hood was a 49hp/50lb-ft 995cc monorotor Wankel engine developed by Comotor, the company founded by NSU and Citroën to build rotary engines. The 995cc ran with virtually no vibrations and with the help of the M35’s aerodynamic design powered the car from zero to 62mph in 19 seconds, topping out at a respectable 89mph. While the Wankel felt at home on the freeway its infamous lack of torque made driving up a hill a byzantine task. Nevertheless, the engine operated so quietly and revved so freely that Citroën found it necessarily to equip the tachometer with an audible alarm that went off when the engine got to its redline of 7000 rpm, though certain period road tests note that it was capable of reaching 8000 rpm.

The Wankel was bolted to a new four-speed manual transmission commanded through a dash-mounted shifter, the same setup found in the Dyane, the 2CV and the Ami 8, though the M35 had its own shift pattern that appears to have been designed in a house of mirrors. The front disk brakes were mounted inboard on the transmission while the rear had to settle for a pair of more conventional hub-mounted drums.

To complete the package Citroën mixed and matched DS and 2CV suspension bits to create a new version of its hydropneumatique suspension. By replacing the 2CV’s horizontal suspension bits with hydraulic ones, Citroën gave the M35 a 2CV suspension system modified to function with a DS/ID’s hydraulic system. With the addition of front seats designed to recline just above the occupant’s waistline the M35 shined as one of the most comfortable cars on the European market. The familiar Citroën monospoke steering wheel and the emergency brake located to the right of the steering column both came directly from the Ami 8’s parts bin, though the M35’s steering wheel was upholstered in vinyl, a feature not found on the Ami 8. The dashboard was not directly pulled from the Ami 8 but was put together using Ami 8 bits and pieces.

Few found the M35 entirely pleasant to look at. Citroën couldn’t be bothered with building it in-house so they outsourced it to French coachbuilder Heuliez. The M35 sat on an Ami 8 platform and the two looked similar from the B-pillar forward though modifications were made to the front end to fit a radiator, something the Ami’s air-cooled flat twin obviously did not need. Almost immediately past the B-pillar the roofline sloped towards the back, creating an odd fastback coupe shorter than the Ami 8. The latter’s gas tank proved insufficiently small compared to the Wankel’s astonishing thirst for fuel and Citroën fitted a larger 43 liter (11.3 gallons) tank to increase the M35’s autonomy.

The initial plan was to secretly provide the M35 to customers to avoid the bad publicity that potential failures would summon. Someone at Citroën realized how unlikely it was that the secret would remain one so the project was made public and Citroën announced it was taking orders for the car.

Not everyone could purchase an M35. The first setback was that it cost 14,000 francs in 1969, a hefty price to pay for a small, experimental car when one takes into account that a base model DS, the DSpécial, listed at 13,800 francs. The second setback was that Citroën engineered the whole operation as a way to test the M35 over several hundred thousand kilometers so if its owner drove it to the store and back once a week, it wouldn’t help their cause. Consequently, only customers who could prove they drove at least 30,000kms (18,641 miles) annually were considered. And the third setback was that Citroën was only going to produce 500 M35s.

The first cars were delivered in 1969. With the operation no longer a secret each car had “Prototype Citroën M35 No. X” written in white letters on the driver’s side fender (replace the X with the car’s serial number.) When the cars ran they were brilliant to drive but unfortunately for those who had paid DS money for an Ami 8 coupe the engine shared other Wankel engines’ tendency to self destruct prematurely; few got to 40,000 miles without a rebuild. Citroën was aware of potential issues with rotary engines and offered a two year powertrain warranty with roadside assistance on all M35s and a loaner car was available for owners should their car stay in the shop for a prolonged period of time. When dealers took the cars in for repair the service department took careful notes of what was repaired and sent them to Citroën headquarters.

In 1971 when the test period was over and Citroën got the data they were after they tried to buy back the cars at higher than market value in order to destroy them but there was no obligation on the owner’s part to sell them and about a third of the total production run survived. There is a catch: in the end Citroën ended up building 267 M35s, a number very short of the initial 500 planned. 6 were built in 1969, 212 in 1970 and 49 in 1971. The numbers written on the fender were reportedly adjusted to make it look like 500 were built and rumor has it that several cars bore “Prototype No. 1” When all is said and done most sources agree that fewer than 100 M35s are still around today.

Many aspects of the M35 made it to regular production. The rotary engine was strangely deemed satisfactory and a dual rotor version of it was used in the GS Birotor in 1974; the gearbox used in the M35 was the GS 1015’s gearbox (albeit with a normal shift pattern); certain suspension bits found their way into the GS line when it came out in 1970 and the seats that reclined just above the waist were found in none other than the SM.

Exterior shots of the M35:

The M35's 995cc Wankel engine:

The M35’s interior; note the seats:

Below: this diagram of the M35’s hydropneumatique system from a 1969 issue of Auto-Journal clearly illustrates the mix of 2CV and DS parts used. The engine-driven high pressure pump used to circulate the LHM fluid is visible as well. Ride height was adjustable thanks to a lever placed between the front seats.

The M35’s shift pattern:

-
Note: with the exception of the first photo and the shift pattern we did not take any of the above photos and do not take credit for them. The first photo was scanned out of a period magazine for Ran When Parked and the diagram of the shift pattern was made by Ran When Parked.