Engines : O-Series Turbo, take one

Whatever your opinions are of the styling and overall packaging of the MG Maestro and Montego Turbo, there’s no denying that they remain revered to this day for their scintillating acceleration and mid-range torque.

However, we could have seen the engine a whole lot earlier had it not been for a strange turn of events.

Canley’s boosted O-series

A Longbridge developed O-Series Turbo under the bonnet of a Canley-built Maestro prototype. Would ARG have enjoyed a head-start had it introduced the Canley O-Series turbo engine a couple of years sooner?
A Longbridge developed O-Series Turbo under the bonnet of a Canley-built Maestro prototype. Would ARG have enjoyed a head-start had it introduced the Canley O-Series turbo engine a couple of years sooner?

BACK in the early 1980s, forced induction was big news at the time; Formula 1 and Group B rallying were powered by turbochargers, and all the major car manufacturers were jumping on the bandwagon to produce hot versions of their road cars using the same of gaining power. Austin-Rover was already in the pound seats – its engineers had worked closely with Lotus to produce the MG Metro Turbo – this was just the beginning of a fertile period of Norfolk-Birmingham cross-polination.

In fact, the company has a long history of turbo development work. “Longbridge had been thinking of an O-Series Turbo for quite some time, because one was tried out in Princess in the late 1970s – Roy Brocklehurst told me that it was highly entertaining,” Ian Elliott recalls.

He added, “The first turbo-petrol work at Longbridge involved a rather ad-hoc combination of a big truck (diesel) turbo and an MGA 1500, in the 1950s. One imagines that it would have been a little laggy but explosive at the top end! And some turbocharging work was carried out on the 1.8-lire B-Series diesel for potential use on Sherpa, but it didn’t get beyond experimental. The old East Works Research department did a lot of very advanced stuff, most of which was ignored by Issigonis and Harriman.”

It was around 1982 when the Austin-Rover’s Engine Department based at Canley recruited a new Chief Engineer from Lotus, and things became more serious. The Norfolk-based company had been an early adherent of of forced induction, and although its Formula 1 team arrived there late in 1983 via a Renault engine deal, the Esprit Turbo that appeared in 1980 was already impressing the right people. The Lotus way of gaining power had been by the use of a twin Weber carburettor set-up and Garrett turbocharger… so it should come as no surprise that Canley would soon be thinking along the same lines.

Very quickly, the O-Series Turbo and R-Series HPD (High Performance Derivatives) projects were born under under the direction of the ex-Lotus man. The life of the 1600 R- and S-Series with their Weber induction was very short indeed; they had failed to impress under the bonnet of the MG Maestro 1600, and did little to disguise its hastily-conceived origins. Ian added, “…a twin SU job might not have been so quick on song, but at least it would have been completely usable and economical.”

Replacement by the 2-litre O-Series EFi unit was a blessed relief. However, the short lifespan of the twin Weber R-Series probably saved Austin-Rover a fortune in warranty costs. But compared with that, the life of the Canley O-Series Turbo was to be shorter still; it never even made it as far as production.

Not a flying start

Ex-Canley development engine, John Deacon recalled, “The O-Turbo project did not get off to a great start. The new Chief engineer decided that the Canley Engine Department did not have the experience required to design and develop the engine itself, so the job was outsourced to a third-party tuning company – possibly Janspeed – and that left the staff at Canley was to play a supporting role. It soon became apparent that the project was never going to make the grade as a production engine.

“The tuning boys could produce results fast, but had no idea what they were doing when it came to the production realities of emissions compliance, durability or production feasibility. However, a running engine was soon fitted to an old TR7 Emissions Test car – its livery was glorious shabby white and still with identity numbers painted on the wings, and that made it a great Q-car. A second engine was then fitted to a test bed for development and tuning work.

“It was at about this time that rumours of a fraud involving Noel Edmonds and a powerboat engine began to filter through and it all centred on our tuning firm. After frantic discussions, the development shop van was dispatched to collect as many of the turbo project parts as possible before the police sealed the place. The job was to be transferred to its rightful location (Later, a man called Wainwright who also claimed to have developed the super-econimical ‘Butterfly’ engine received a three-year sentence for defrauding Noel Edmonds of £70,000. He was also implicated in several other frauds around the world)

“It did not take long before the engine was running on a test bed at Canley and new parts were being made to improve the induction system. Meanwhile, the TR7 was used for carburettor tuning work, and a third engine was installed in a brand new SD1 for appraisal. This was a beautiful car in black with tinted windows and alloy wheels plus some sporty additions to the interior. It was designed to impress.”

The project comes home

TR7 prototype was the first recipent of the Canley O-Series Turbo...
TR7 prototype was the first recipent of the Canley O-Series Turbo...

“The TR7 spent days hacking up and down the Warwick by-pass with frequent stops to change carburettor jets and emulsion tubes, but a satisfactory tune could not be obtained. This was due to the on- and off-boost fuelling requirements being different, and there being no boost related adjustment available. It was eventually decided that a switch to Dellorto carburettors was required, as these could be supplied with a boost-sensing feature.

“Even so, the outright performance was outrageous! It was helped by the fact that the turbo wastegate was too small, causing the boost pressure to increase at high speed. A Lotus Esprit Turbo in Essex colours (one of only 104 made?) was borrowed for a week to make some comparisons, and the tatty old TR7 could hold its own up to the legal limit from a rolling start.

“The TR was always a hoot to drive and would leave black marks on the road as it exited roundabouts. No doubt this was helped by the suspension and tyre technology of the time, but it was still a powerful car. I once pulled up alongside another TR7 at the traffic lights outside the Canley plant and could not resist inching forward a couple of times and raising the revs to gee-up the other driver a little. When the lights changed, I allowed him to move first then dropped the clutch, spinning the wheels through both first and second gears. Glancing back in the mirror to check on progress, I found that he was nowhere to be seen. The view was completely obscured by tyre smoke. Oops!

“Although the SD1 Turbo received favourable comments from everyone who drove it, the project was going nowhere. There was no gap in the product line for it to fill and probably no public demand for such a car. I suspect that it never had official status in any case; such was the lack of budgetary control in those days! Before the end, we took the TR to MIRA to obtain some performance figures. I seem to remember a 132mph lap average and 0-60mph in the 6 second bracket. Both cars were than sent to the crusher…”

About a year later, the project was officially revived, this time without the Lotus influence and the Longbridge version of O-Turbo that we all know and love was born. We know the rest of the story from there…

Keith Adams


  1. I know I’ve ask the following question on how much power this version of the O-Series Turbo put out a while back though having read MG: The Untold Story, was this engine in the TR7 the same as the 140 hp 2.0 O-Series Turbo (with the potential to put out 160 hp) mentioned in page 160 of the above book that was apparently put in an MGB prototype during the final years of the latter’s production?

    On the one hand, it may indeed be the case that the O-Series Turbo in the TR7/SD1 in this article and the O-Series Turbo mentioned in MG: The Untold Story are one and the same, yet I find it hard to believe given the figures the TR7/SD1 Turbo were putting out though I guess it is a testament to the O-Series Turbo’s capabilities if it was doing those figures while making do with around 140-160 hp.

  2. “Both cars were than sent to the crusher…”

    Where that might have been the case with the Rover the bean counters at Triumph sanctioned the sale of all the O series development TR7’s at the end of the project (all be it less running gear);


    Scroll down for the fate of these cars.

    The Turbo car survives, and I have seen it in the flesh. It is still in the hands of the ex-experimental guy who bought is back in June/July 1981.

    He had intended to fit V8 running gear bought at the same time from the factory, but its still sitting on the pallet it was delivered on.

  3. Another BL back of a shed pet project for a commercially blind bearded engineer that ended up devouring millions from a development pot that was virtually empty. The money would have been far better spent making cooking 1.6 and 2.0 litre cars better in the first place rather than this wasteful turd polishing exercise.

    • @ Paul, possibly, but I’d love to have seen a Princess 2.0 Turbo make the market in 1978, as it would have made the thirsty E6 redundant and endowed the Princess with the sort of performance seen in a Saab 900 Turbo. Allied to a five speed Rover gearbox, as it’s likely the standard four speeder might not have been able to take the power, a 120 mph Princess could have been a very interesting Q car if owners debadged it.

  4. This article implies only one TR7 turbo existed but if my dad’s memory is correct there may have been at least one other and development may have begun several years earlier than 1982. He clearly remembers a friend who worked at Canley visiting in a white US-spec TR7 convertible with an O-series that he is sure had a turbo. This was almost certainly during 1978 as my parents lived in Towcester at the time and they moved house in ’79, and he remembers the car looking new, not the shabby old one described above. Could this have been YRW 573S? That one’s spec matches my dad’s memory and it is the only O-series car on the Canley Classics list that fits with the dates, the rest (including the only one explicitly listed as a turbo) weren’t registered until 1980. Did YRW have a turbo or is my dad mistaken and the car in question had a naturally-aspirated O-series? One thing he is certain of is that it was definitely O-series powered.

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