Thread: 1975 Holden/Mazda Roadpacer AP.

The 1970's were a tentative time for the Japanese motor industry and Mazda in particular,the fuel crisis in the preceding years eroding its domestic market share amid concerns about the rotary engine's efficiency.In a show of support for it's favoured engine design,Mazda took the decision to install the rotary engine into a new,top-of-the-line,full-sized sedan.Only problem was they didn't have the time or the budget to develop something completely in-house.

Enter the HJ Holden Premier.It was large,reasonably appointed and right-hand drive.Additionally,Holden already had experience in exporting to the Japanese market,it's long wheelbase Statesman being sold in small numbers under the Isuzu(GM's Japanese arm) umbrella.

An agreement was reached in 1975,the Premiers departing our shores sans driveline as the awaited fitment of a Hitachi four-barrel fed 13B rotary taken from the RX4 and backed by a column-shift three speed auto.Called the Roadpacer AP,Mazda's intent was to take a slice of the lucrative diplomatic transport market.

To that point Japanese officials had preferred the 3.4L V8-powered Toyota Century and the 3L six-cylinder Nissan President,which when optioned with a 4.4L V8 gave 149kw...a true Japanese muscle car.Given the desired market the Roadpacer was opulently finished,with all manner of gadgets installed that would be completely foreign to the owner of an HJ Premier.

There was a small fridge in the boot,central locking that armed when the car reached 10km/h,a chime that sounded when 90km/h was breached,tinted windscreen,dictaphone,stereo controls for the front and rear seats,rear retractable seat belts and air-conditioning complete with ventilation from the rear parcel shelf.A warning chime also sounded if the lights were faulty,a dashboard light illuminated when the fluid levels were low.

Seats were trimmed in a plush synthetic fabric and could be ordered in five(front bucket) or six seat layouts,with woodgrain accents on the centre console and dash surrounds.The Premier exteriors were left largely untouched,save for the fitment of Japanese market required fender mounted mirrors and Mazda specific badging.A small diameter twin exhaust system added an additional touch of prestige status.

For all this fruit,the Roadpacer was priced at 3,835,000 yen,or around $9500 in 1975 money;not an insignificant outlay when you consider an Aussie could get himself into a long-wheelbase,308ci-powered HJ Statesman for $4748.

On paper the 101kw produced by the rotary was impressive,for it was saddled with emissions gear as a result of the fuel crisis.The output actually matched that of the standard 3300cc(202ci) powered Premier(and incidentally bettered the six cylinder Nissan President's 97kw),though their respective peak power speeds give away their character,the rotary needing 6000rpm to peak,the old red motor 4400rpm.

More worrying,the rotary needed 4000rpm to hit peak torque,and even then it's output was scrawny 187nm (138-ft).Compare that to the 202ci and it's 263nm (194-ft) being produced at 2000rpm and you don't need a degree in aerospace engineering to conclude the 1575kg Roadpacer had a performance problem,even with a 4,4;1 final drive ratio installed.

As a consequence judicious use of the throttle was required to get the Roadpacer pacing,and we all know how rotaries react to wide open throttle.Despite Mazda's claims of 8.5 kilometres per litre(24.1 miles per gallon) at a constant 60km/h,day-to-day use saw this drop to 3.2km/l,or less than 10 miles per gallon in the old money,thus ensuring the 75-litre fuel tank would need topping-up every 240km.It wasn't a good look in the intensity of a post fuel-crisis enviroment.

Once up to a cruise, the rotary provided smooth and reasonably quiet transport,the bendix variable-ratio power-steering system adding refinement and response when the going got twisty.In fact,it was in the corners where the Roadpacer realised a distinct advantage over it's Premier cousin,the rotary installation reducing weight over the front axle by some 45kg.The engine's compact packaging also allowed it to sit both lower and further back in the chassis,giving the Roadpacer decent road manners for it's size.

In the context of it's competition,however,the advantages of rotary propulsion were outweighed by it's limitations,sadly exacerbated in such a heavy car.While today you can still but a Toyota Century(complete with a 5L V12),the Roadpacer struggled to see 1977.Though 491 were produced in 1975,the following year saw that figure drop to 183,with a final run of 126 cars in 1977.It was at this point that the Roadpacer was dropped quietly from the Mazda range,to be succeeded by the top-end model we knew locally as the 929.With that,the Roadpacer become nothing but a mostly forgotten quirk in Mazda's and Holden's history.

It seems like it was a good idea,i guess the cars were just to heavy for the little rotary.And fuel economy makes my V8 disco look like a Eco car!!!!