Last year when Lancia introduced their Volumex supercharged engine, they appeared as something of a lone voice in the face of the turbo onslaught. Yet the development of mechanically-driven blowers has continued steadily, particularly in the United States, and a Bolton company, Westune, who specialise in tuning Alfas, have now employed an American unit in a bolt-on kit to boost the power available from the latest Alfa, the 33.
With its flat-four configuration, the boxer engine is relatively complicated to tune beyond the already generous specifications that Alfa offer, and turbocharging would either involve long exhaust runs and consequent lack of response, or two turbos with the attendant costs. The neatness of the installed kit, therefore, is all the more impressive, especially within the rather empty engine compartment of the 33 1.3. Alfa’s latest baby, intended eventually to replace the much-loved ‘Sud, is a thoroughly competent car, but being heavier than its predecessor is bound to seem a little less spirited using the same power-units. In addition, the fastest Ti version will not appear here until summer, and it is to fulfil an assumed demand for a rapid 33 that Westune have elected to offer an aftermarket kit. Development work in conjunction with the importers of the Magnusson supercharger, Auto Power Services of Daventry, has resulted in an installation which retains the standard intake manifold and places the small blower (it is about seven inches long) where the carburetter was. A toothed belt from a crankshaft pulley powers the constant-displacement blower, and a 1 1/4″ SU projects from the side. Neither exhaust modifications, wastegates, nor special lubrication is required with a system of this sort, which means it is relatively easy to fit, and Westune claim that at boost pressures of up to 5 Ib/sq in no internal engine work is needed either. Whatever the pros and cons of turbocharging, it has one big advantage over supercharging — noise. The constant whine of the Alfa’s blower was reminiscent of driving a 2CV, while in town the sporty but aggressive rasping note of the (optional) non-standard exhaust acted as its own deterrent to an open throttle. Nevertheless, the increased power (estimated as just over 100 bhp at the wheels) is apparent right across the rev-range, the little car easily spinning its wheels in second gear on its way to a top speed in excess of 115 mph. Some rough and ready stop-watching proved that it would better 9.5s to 60 mph, an improvement of a full 2.5s over standard. And remember this is a 1300!
It is not all good news, however. The test car arrived at Standard House on 185/60 Firestone tyres, and putting 100 bhp through front tyres of this width seemed to worry the 33. Straight-line acceleration was anything but, the car pulling to the left in gear and darting right during changes, while generally the car seemed to sniff out potholes as a dog does lamp-posts. Also, the slight hesitancy that the standard 33 exhibits about turning-in was amplified to the point where it was necessary to turn the wheel ahead of where the car should have changed direction. Once settled into a smooth corner, the car is nicely balanced and can be steered around ruts or made to change its line without drama, thanks to the improved wheel control of the front Koni struts which were fitted.
Very fast gear-changes are possible with the comfortably placed lever, and indeed are needed to make the tachometer needle behave itself, but I wonder just how long a standard clutch will last. In fact, the only weak aspect of the installation was that it was reluctant to pull away from rest without slipping the clutch briefly to maintain 2,000 rpm.
I say the only weak aspect; when I first looked under the bonnet I wondered whether the engine would continue to run if the rubber drive belt to the blower should break. I found out the day after collecting the car that it will. The belt did not snap cleanly, but gradually shredded itself due to some forward movement, releasing awful thrashing noise and fear in its driver of complete intake strangulation. In fact, after nursing it home (luckily a short distance) it transpired that the remains of the belt had disappeared and that it was running quite happily on normal induction, the blower rotors turning over easily in the draught. Fitting the spare belt was not difficult, but the company say that production kits will have a lip on the pulley which will prevent a recurrence.
Fitting the kit to a ‘Sud is of course no problem, and it may just fit under the bonnet of the delightful Sprint, a conversion I should be eager to try. Whether owners will consider the price of £1,420 to be a good investment is another matter: that would bring a new 33 1.3 up to £7,110. With standard width tyres, it would undoubtedly give the 33 that edge it so far lacks, and is inherently more controllable than any turbo; but it consumes more fuel and it does make that noise. Of course, if you are on your way to Brands, you’ll have your ear-plugs anyway. . . . — G.C.