Blydenstein’s tiny turbo boosts Astra 1.3
The distinction of the smallest turbocharged engine we have tested now belongs to the 1,297 c.c. Vauxhall Astra. The previous incumbent of the title was Renault’s fascinating mid-motor, exactly 100 c.c. larger, 5 Turbo. The 5 is a lot more powerful at 160 b.h.p. versus the 90 b.h.p. W.B. Blydenstein report for the Rayjay of Southern California-equipped Vauxhall. Of course the Renault represents the results of a massive engineering programme incorporating all the expertise of several years’ research that produced the intercooled 5 powerplant. Yet the six months development by Bill Blydenstein and Frank Swanston (the latter of Turbo Tork who supply the tiny turbocharger and a black box of ignition wizardry to guard against extraneous detonation) has resulted in a very smooth running Vauxhall, exhibiting a useful measure of extra performance without complicated ancillary engine modifications.
At £1,227.05 including VAT, this Blydenstein conversion does not alter the production 75 b.h.p. Vauxhall/Opel SOHC four’s 9.2:1 c.r. The Swanston-developed black box ensures the engine does not pre-ignite and response is naturally extremely good with such a high effective c.r. Unfortunately you cannot guard against a tankful of dirty fuel — and just that circumstance did make the car pink heavily in Eire, until we could replenish a few gallons of what had obviously been two star, or worse, with four star.
For the 3,000 miles previous to our test, the Astra had been re-equipped with a Weber twin choke carburetter, fed pressurised air (to a maximum 5 p.s.i.) by Rayjay’s smallest unit across the transverse cylinder head cover. Much of the original development mileage was completed using the interesting Fish carburetter, but the lack of a cold starting device, and the Weber’s better m.p.g. performance, ruled the Fish out. In 1,774 miles recorded whilst on Circuit of Ireland duty, the Astra Turbo recorded a fine 27.8 m.p.g. This included some very spirited motoring on loose surfaces and a constant demand for performance that a standard Astra, or Opel Kadett 5, could not have supplied.
To wit, a genuine 100 m.p.h. capability, even under adverse road conditions, coupled to a maximum in the 105 m.p.h. region. A couple of seconds had been removed from the 0-60 m.p.h. sprint too (just over 10 sec.) by our reckoning.
Perhaps most impressive was the top gear pull, for one has the nipping ability of a small hatchback allied to 2-litre performance.
The standard Astra chassis seemed to cope well, only soft “Comfort Setting” Bilsteins added after mild criticism of the car’s ride. Remarkable standards of hard cornering without fuss were established by the Michelin 175 XZX 70 series radials installed on the optional production alloy rims: these covers a rare item in the UK, at the time of our test, according to our information.
The 5-door body was decorated subtly with grey paint to highlight the wheelarches, a combination commented upon favourably by onlookers, none of them believed the Turbo badge was anything but a joke. When the same vehicle was seen to draw away from 2-litre saloons and cope with the odd unwary RS2000, interest quickened. . . .
Considering the importance attached to boost pressure — for running-in it is limited to 1 1/2 lb. and the engine to 4,500 r.p.m. — the boost gauge is badly mounted, off one’s regular driving eyeline, low down upon a centre console.
More useful were the twin Cibie lamps for maintaining an astonishing nighttime pace over the deceptive crests and tightening curves of the Republic. Theory would indicate that the turbo would work better in the denser and cooler night air, but we have yet to take performance figures to substantiate such a subjective feeling.
Driven to the r.p.m.-limiter in the lower gears, Astra Turbo scuttled to 30, 45 and 72 m.p.h. commendably. Once in fourth gear, there was a tendency not to use the longish travel production brakes unless a sudden drop below 65 m.p.h. was demanded. Then, using the boost gauge instead of a tachometer, the Vauxhall could be built up to 5 p.s.i. in each of the gears again to regain cruising pace rapidly, but comparatively expensively.
Left in fourth gear, having patience for speed to be regained. allows 30 m.p.g. easily.
Flexibility, in the sense of the range in which the engine will pull smoothly, and with less offensive exhaust rasp then standard, is improved. Yet, the feeling on the engine front is akin to the old 1-litre Imp conversions: keep it revving and it will provide smooth, astounding performance. Lose concentration and the whole plot feels dead, so that you might as well potter along peacefully.
A bouquet for Opel/Bilstein/Michelin. Despite the hectic circumstances of the test, this f.w.d. flyer never felt as though it was going to plough off the road. If a corner had been entered too fast — and the chassis has such reserves that this was a notably rare occurrence — then the driver could decelerate and always find some extra grip at the front wheels to complete the corner safely. It becomes a pleasure to drive across country in a car whose capability, even in vividly remembered production 1.3 S form, is equal to that of the legendary Alfasud. In fairness to Alfa I should add that their engineering integrity in providing four-wheel disc brakes in this class is rewarded by unmatched retardation.
According to our information there will be a 1.6-litre engine for Astra/Kadett this autumn. For those who cannot wait, Blydenstein also offers a £718.75 enlarged 1.5-litre version of the GM SOHC four, more in line with familiar Blydenstein work on machines like the 2.4-litre Cavalier and the 3 1/2-litre Royale.
Trendy turbo, or traditional big bore, long stroker, the amiable expatriot Dutchman remains firmly in touch with tuning today from his base at Station Works, Shepreth, Nr. Royston. Herts. (Royston 60051). An art now ruled by petrol pump prices as much as 0-60 m.p.h. figures and top speed tables — J.W.