Volkswagen have combined safety, performance and economy in a remarkable turbocharged diesel-powered Golf.
The chances of driving a manufacturer’s unique development prototype are always slim, but when that prototype represents a revolution in passenger car power plants such opportunities might be described as remote. Almost by accident we were on a Volkswagen trip to see the Wolfsburg plant at the time just such a car came our way recently.
Called the IRVW (the first two letters standing for Integrated Research) this special Golf was built to show the American federal transportation authorities that a small diesel car could deliver performance, fuel economy and pass both emissions and safety tests, including “full frontal” impact at 40 m.p.h. with a solid barrier. The appropriate American department supported the project with over half a million dollars, and has just awarded the Volkswagenwerke another similar sum (the first award was $605,000) to investigate the application of turbocharging to petrol engines under American regulations.
A young development engineer brought the unique 2-door Golf to the small (compared to their main facility at Ehra Leissen) Wolfsburg banked circuit for appraisal. The white body is actually five years old and contains all the safety equipment built into IRVW II: a safety study built to show that a small car could survive the 40 m.p.h. impact previously mentioned.
Not surprisingly the safety reinforcements, which include an extra body frame and a mobile version of the padded cell, have left the Golf well overweight at 2,072 lb. compared with 1,694 lb. as the production weight given for a 3-door European Golf.
Though you can feel the weight in the steering and handling of the small car between massive bumpers, it still hangs on well with 175/70 Continentals wrapped around the usual optional alloy road wheels.
But the meat of the matter comes when you lift the bonnet. Still transversely mounted, but with an induction system bearing all the marks of the handwork that had contributed to this successful installation, there lies the normal diesel 1 1/2-litre VW engine. Connecting rods, bearings and major components are all as in production. The compression ratio has been lowered “very slightly” (it is given as 23:1) and a new camshaft profile complements the Garrett AiResearch turbocharger and modified production diesel-injection which features a much-altered Bosch Pump.
Holset turbocharging has also been tried but neither turbocharger specialist company is likely to actually build the turbochargers if VW go into production. Neither have sufficient capacity to cater for the demand, according to VW.
Mechanically speaking, interest then switched to a new five-speed gearbox which is also undergoing development at VW and which unit is installed on the IRVW. The gears fit inside a slightly modified production casing and the change pattern is the now common four-speeds in an “H” with fifth placed out on a limb to the right, furthest from the driver in this I.h.d. car. Racing Sciroccos utilise five gears too, but we were told, with a broad grin, that the units had nothing in common.
At 0.6 atmosphere boost maximum the 1 1/2-litre unit releases 70 b.h.p. or slightly more at the peak of 5,000 r.p.m. On a 3.7 to 1 final drive this means you can cruise right on peak torque (close to 90 lb. ft.) at an indicated 100 m.p.h.! Cold figures but they help us understand how the car, which has been intensively developed over the last 18 months in this form, can return 42.76 m.p.g. at an indicated 100 m.p.h. Yes, those were the figures recorded when the young engineer drove the car flat-out to Holland for a number of weekends. The official figures are even more sensational, including an overall American figure of 60 (US) m.p.g., 100 m.p.h. true top speed and acceleration from rest to 60 m.p.h. in 13 1/2 seconds. If the turbo diesel were installed in a normal Golf we could expect a second or so to be removed from those acceleration times, and economy would be even better.
VW say it would take 2 to 3 years to put such a diesel turbo power plant into production, but there is a 1 1/2 petrol-engined turbocharged Scirocco close to production now. It seems likely such a Scirocco would exceed 130 m.p.h. (development models have recorded 142) and VW have steadily repeated their conviction that the turbocharged power plant, petrol or diesel, will offer better fuel economy than the equivalent normally aspirated engine.
To drive, the IRVW was fascinating. It sat on the company’s skidpad ticking over with a typical diesel note, slightly hushed by the turbine blades inserted within the exhaust system. Clamber in, and a seat belt (attached to the door frame) automatically reels you within its grasp as the door is closed. The seats are huge and comfortable, but without backrest adjustment, as that would spoil your chances of survival when ploughing into the revered barriers at 40 m.p.h.
The engine proved absolutely docile, but without the gutless chugging normally associated with a small capacity spark-less unit. With four adults aboard it faced a tough test, but even then the handling was quite reasonable, and we did 8 – 10 laps of a high-speed bowl at a consistent 90 plus m.p.h.
Under acceleration the turbocharger simply turns the diesel into an acceptable engine for enthusiastic use. The boost comes in at a low enough point to prevent any of the normal laboured puffing and grunting one would expect, even from the highly regarded 1 1/2-litre Golf diesel that is presently offered in this country and which (in Europe as a whole) now accounts for 30 per cent of all Golf sales!
Having driven a number of turbocharged petrol cars I seem to remember that, Porsche Turbo or humble Avenger conversion, they all seemed to provide power surplus when I didn’t want it at the end of a straight and about to decelerate. The diesel car is a lot better in this respect because there is not much power, but what there is can always be used.
Noise levels at speed are remarkable in the IRVW. Those adults all chattered away in normal tones at 100 m.p.h.: not hushed, but certainly civilised. I slowed down to the American limit of 55 m.p.h. and found the car astonishingly silent, despite the hard life it had obviously led, and the type of power unit.
Depressing the throttle fully from 55 m.p.h. in top brought little perceptible increase in readings from the American market m.p.h. speedometer at first, but once the needle had crawled past 65 m.p h. with this heavy load on board, things got a lot better. The British 70 m.p.h. limit induced some boom from the body, boom that was absent at an indicated 80, 85 and 90 m.p.h., all of which came up apparently faster and faster as the turbo got to work.
On slower going around an infield track that demanded second and third gear only, the IRVW proved safe but uninspiring. The weight was all apparent and emphasised by the load on board. However the throttle response, driven hard in the lower gears to ensure full boost for the majority of tight corners, was very acceptable and I could not detect the dreaded turbo lag. Providing approximately 70 lb. ft. of torque from little over 1,500 r.p.m. of the 5,000 permitted r.p.m. helps a great deal.
The high performance diesel’s day has arrived, assuming present American regulations persist. It genuinely seems as though longer engine life will be combined with the kind of fuel economy (and much better) that W.B. has talked of for years in small cars. I would still (Just) prefer to drive a normally aspirated petrol car but I am delighted to see that the turbocharger is delivering some of the benefits we anticipated when writing about it much earlier in the seventies.
I did express my only serious disappointment to a VW engineer that we did not seem to be doing much about small passenger car diesels in the UK to be told, “Ah, British Leyland have a marvellous little engine for the Marina. I drove it some years ago and it was first class.” Perhaps we will see this unit actually materialise, now that governments are beginning to realise the emission and economy benefits of the diesel. It is not just that the engines do more miles to the gallon or litre at the refining stage you can actually extract more diesel fuel for a given quantity than it is possible to realise for the same mass of crude and petrol. – J.W.
New from Polaroid
It is important that in driving on sunny days or in bright light sun-glasses are worn, to protect the eyes and ensure sharp vision. “Polaroid” means good sun-glasses and this well-known supplier of eye-protective spectacles has just brought out something that must make an important contribution to road safety and driver comfort. In recent times there have been sunglasses that adjust automatically to alterations in the brightness of the prevailing light. But these are usually expensive and they have earned criticism because of a time-lag in the required adjustment taking place. It is to combat this that Polaroid have introduced their Polamatic sunglasses. These enable the lens density to be adjusted instantly, by simply sliding a little control on the top of the frames. The action is obtained by using double lenses sliding one over the other, the outer pair detachable for cleaning both. This Polarnatic action gives the right amount of anti-glare vision for individual tastes and varying requirements. Polaroid claim that their Polamatic sun-glasses have a wide viewing field, are well protected against shatter-damage, are over 2 1/2 times harder, and therefore more scratch-resistant, than other plastic lenses, a that they eliminate, with this simple adjustat action, 100% of potentially harmful ultraviolet rays and tip to 99% of reflected glare. The filter range eliminates from 68%, to over 90% of visible light or brightness, they say.
These technicalities apart, as one with sensitive eyes to bright light and who does much morning and evening driving against the sun endorse the effectiveness of these ingenious new Polaroid Polamatic sun-glasses. They are light in weight, are guaranteed for a year, and the price seems likely to be between £16 and £20 a pair. They should be in the shops now. The makers address is Polaroid (UK) Ltd.., Ashley Road, St. Albans, Herts.
Steam Power of Kirk Michael, IoM, inform that they now have small steam engine, a 90 deg., vee-twin compound, double-acting unit developing 35 b.h.p. at 2,000 r.p.m. at 1,000 p.s.i. boiler pressure. Known as the Panther, this engine, which weighs 168 lb. and has dimcnsio of 28″ x 19″ x 18 1/2, is said to be suitable for us in cars and light commercial vehicles without the employment of a clutch or gearbox. They claim that this engine can be used with solid, liquid or gas fuels and that it will steam down to 40 p.s.i or less. An illustrated brochure is available, but it costs £1.50 or 4-dollars to the USA and Canada
Moss Goes Mowing
Stirling Moss, Derek Bell and Tom Hazelwood won the unlikely-sounding 1978 Wisborough Green 12-hour overnight endurance lawn mower race at the end of June. Driving a Westwood Lawnbug, the winning Templar Tillars team covered 1,042 laps of the 0,46 mile circuit. Twenty-four hours at Le Mans must ha been nothing in comparison!
Road Impressions Mercedes Benz 450SL Most of the publicity which has been given to the 450 S-class range of cars which Mercedes-Benz announced last year to supplement the 350 S-class…
Monte Carlo Rallye Historique
Following the barely melted tyre tracks of mid-January’s WRC event, the ACO’s Monte Carlo Rallye Historique used most of the same stages a few days later to test the mettle…
Around and about: comment on the racing and club scene, January 1972
Aintree lives—just The passing of the Aintree circuit near Liverpool from the International calendar seems to have evoked remarkably little comment yet it does not seem so long ago that…