Tuning topics
Blydenstein’s A pack Cavalier SR
This month we concentrate on two road cars that typify the performance industry’s approach to the eighties. Inevitably one of them is turbocharged, but first a look at a car that is in terrible danger of being totally overlooked as a boring 1.6-litre rep’s box, when it actually toilers a lot more than current image-conscious Fords.
At very short notice W. B. “Billy” Blydenstein agreed to let on try a very simple A pack cylinder head and exhaust manifold conversion. As good fortune would have it the car turned out to be that overlooked new performance option from Vauxhall, the £6,062 Cavalier SR.
Now the SR designation on this example of the new GM Opel front drive design provides Recaro front seats; low profile 195 / 60 HR x 14 tyres (Pirelli P6 for us) and a deeper version of the standard front spoiler, with a tailgate spoiler at the rear of the five door hatch back we tried. Also very useful are the firmer damper and spring settings that come with SR, for Opel engineers felt at the model launch that they had erred a little on the side of softness with the rest of the range, feeling that sporting buyers will go for the considerably smaller Kadett / Astra series.
You will notice in that above paragraph that SR does not provide any extra power to compliment a very fine chassis indeed. Blydenstein’s men set out to rectify this omission in the simplest manner possible, preparatory to a later turbocharger conversion of the same vehicle.
They decided to provide an extra 10-12 b.h.p., or over 100 b.h.p. from the normally 90 b.h.p. and virtually “square” (80 mm. x 79.5 m.m) Family 2 SOHC GM power unit, an engine Blydenstein describes with awe as having the potential for “prodigious” power with its deep crankcase and advanced design. GM have already said that there will be a competition 1800 version with 16-valve cylinder head.
Meanwhile Blydenstein at Shepreth take this engine and its easy 7,000 r.p.m. capability to provide a £205 (plus £30.75 VAT) package that includes fitting at the works. Or you can buy the components for £135 plus £20.25 VAT. Vauxhall have paid Blydenstein the compliment of saying that their work, provided it does not increase compression ratio, does not invalidate warranty: on more complex conversions a separate guarantee is provided from Car Care Plan.
What do you get? an exchange Stage 2 cylinder head, a freeflow tubular exhaust manifold and some detail work to the fixed jet twin choke carburettor which make it run, “very slightly richer because the standard one is set on lean,” according to Mr. Blydenstein.
The head is really a cleaned and gasflowed example for no parts, valves or otherwise, are replaced and compression remains at 9.2:1. Only the top exhaust manifold is provided (sub-contracted to Janspeed) because there is a very clever damper on the next stage of the exhaust system that prevents typical four cylinder resonance. Bill learned that one the hard wav… but there is also no real need for a larger bore throughout the exhaust system on such a mild conversion. Replacing the normal cast iron manifold, the Janspeed top section runs a conventional 4-2-1 tube pattern and was rather unattractively pockmarked on this low mileage demonstrator, a victim of the direct frontal position and Britain’s atrocious weather. Yet shouldn’t we be looking for an attractive permanent finish on a £60 plus VAT top manifold?
YNK 919X recalled the pre-1971 Vauxhall racing activity with those arch supporters of Gerry Marshall and Blytlenstein, Shaw and Kilburn providing the Cavalier SR.
We were provided with a Sun Powertrack report showing the following figures for horsepower at the front wheels before and after conversion.
These interesting figures portray a horsepower curve of classic conventional tuning gain at the top end, but on the road it is a different story, Blysienstein reports 0-60 m.p.h. times of 10.8 sec. or so compared with 12.3 sec. of the standard car, but it is the way that the car will pull strongly in third gear city conditions that makes the initial impression.
The normal Cavalier is smooth running and obedient under such conditions, but this SR felt as though Mr. Blydenstein had gone back to his “you can’t beat a big four” philosophy, so effective was the torque in crowded conditions.
You can make the car run without a hiccup from 1.400 r.p.m. in fourth. Because of speedometer error, of the usual gross variety that Ford and GM offer when you get a performance model on low profile tyres, my observations do not not exactly tie in with the table. What is important is that from 40 odd m,p,h. and 2.000 r.p.m. this Cavalier is performing with some interest in top, while from 3.000 to 5,000 r.p.m. in top gear motorway conditions the Cavalier really gets the job done.
Vauxhall have provided a good air-cleaving body for the hatchback. The extra Blydenstein sparkle encouraged some startling averages to be maintained. This Cavalier was capable of running an honest 90 m.p.h., shown as 97 m.p.h., and 5.000 r.p.m. in fourth with no stress at all. Now the normal car will do that, possibly a little less economically as the throttle opening appears to be more, but will it then go on to astound you by pulling some 110 m.p.h., still with less noise than Ford offer at 90 m.p.h. in their admittedly smaller f.w.d. Escort?
Yet to make an account of any SR, especially the modified car, on the basis of its town and motorway prowess would be criminal. For the safe, vet thoroughly enjoyable, way in which the Blydenstein SR dismissed country road mileage was an object lesson in front-drive family car manners.
The steering is not the most informative in the world, but the accurate rack and pinion, allied to those Pirellis and effective suspension, mean that the best can be extracted from the modified engine, even over bumpy roads, for ride comfort is excellent throughout.
Owing to the shortness of my test, two nights and a day or so, my fuel consumption period was unacceptably short. I obtained 22.4 m.p.g., including performance testing during an 80-mile check. Colleague Andrew Marshall from Motoring News managed 30.94 m.p.g. over a longer test spell and I accept that the car is likely to return 30 m.p.g, or more driven with brio and passing respect for the law.
Overall I liked both the well mannered Cavalier SR and the straightforward Blydenstein conversion very much indeed. Only the extra pulling power and the slightest of “tingles” from the exhaust system tell you that this is a converted car, and the m.p.g. is unlikely to suffer by such work. Well done: the Vauxhall-Blydenstein alliance lives on.
Janspeed Escort XR3-turbo
I would refer to this Janspeed conversion it Ford’s XR3 with the new breed of Rotomaster RM 60 “small” turbocharger as a prototype, save for the fact that 15 have already been sodld. Yet there is no much more to come, including a reversion to the Ford production twin choke carburetter (Weber DFT) and the installation of an intercooler that will eventually allow the Janspeed XR turbo owner to also specify air conditioning, along with the electric windows and sophisticated sunroof that manufacturers optionally offer. Also to come, and presently being assessed at Salisbury for Ford in this turbo charged application is the production five speed gearbox, which is a necessity to get the best from the XR3 turbo’s motorway potential.
The installation we tried was within a basically standard XR3, one of an early batch with all the extras fitted. It had detail suspension differences to the XR this publishing group has run for the past 12.000 miles and which we used as a direct comparison for this appraisal. Jan Odor’s car has covered 7,000 miles, has a little of the front suspension positive camber adjusted out and a ride height over half an inch lower than our car at the rear. Our car has Dunlop tyres to the same standard dimensions as Jan’s Pirelli P6.
In the engine bay is where the £1,178.75 (inc. V.A.T.) workshop fitting and mechanical breakdown insurance, conversion makes sense. The XR is tailor-made turbochargers, offering an exhaust system smack hang in the airstream and a cool home for the latest Rotomaster to do its boosting work from 2.000 r.p.m to a 6,250 r.p.m. maximum imposed for the test. At the higher point there should be 7 lbs. boost — the beautifully responsive and clear VDO dial within showed 6 lbs. occasionally, 5 lbs. regularly on full throttle — and maximum power is a reported 122 b.h.p. at 5,500 r.p.m. That is compared with the Ford figure of 96 b.h.p. at 6,000 r.p.m.
The test car had a tubular exhaust sitter, in steel but cast iron is a production certainty in the future. Perhaps the most significant change underbonnet is that Janspeed have obviously now seen that the market is willing to pay the price of the more sophisticated and expensive pressurised carburetter layout for their turbocharger kits. The example we tried was equipped with a single 36 DCNF Weber downdraught twin choke with a very neat little pressurisation box. Under development in the workshop is the XR engine with a much larger pressure chamber and the expectation of working with the normal Ford carburetter (with new gaskets to account for pressurisation) in order to try and overcome the present depressing m.p.g. figures on full boost.
The safety valve wastegate is backed up by a further electronically triggered overboost failsafe in the turbo-to-chamber delivery pipework. The latter is set at 8 lbs. The high fuel pressures demanded by the pressurised turbo layout are catered for by the Italian made Lotus fuel pressure regulator, mounted to the O/S of the Weber pressure chamber
Normally the XR3 carries a 9.5:1 cr. Much too high for a turbocharger installation. The motor we tried had those multi-compound Ford researched piston domes shaved off to lower compression (still 8.6:1) but it is hoped that an enlargement of the combustion chamber will allow Janspeed to offer a compression below 8:1 eventually.
Jan paid tribute to the Ford engine as, “a tough little unit: it has survived 15 lbs overboost already”! He also found the standard electronic ignition useful but added the sophistication of a further master system to allow instant advance and retard adjustment; a rev limiter and it will have the precautionary pressure relief in the intake system, referred to earlier.
Other detail changes include a crackle black rocker cover and a very large bore exhaust system that is continued to the tail of the car. This emits a very pleasing combination of civilised idling burble and full throttle brutality, the spinning vanes of the turbocharger removing the otherwise offensive hard edge to the exhaust note.
Inside there is the boost gauge to the right of the main fascia and a manual choke. Only the spectacle of a digital clock that goes out when the lights are switched on, and a largely unlit speedometer, tell you that any work has gone on.
Before we checked the performance, there were several hundred miles of hurried countryside running to be completed and a delivery errand to the City of London.
The Janspeed Turbo Escort added a new dimension to the meaning of small car acceleration. To try and achieve a perspective I note from a Mini-Cooper book I have just completed, that in December 1968, it took a works replica Cooper S to produce the kind of acceleration I took for granted in the Janspeed XR. Naturally the Janspeed car could also be driven through town with no qualms. Any overheating tendency being reserved for the brave who run more than 5,000 r.p.m. and 90 m.p.h. in fourth persistently. Even then it’s only that the gauge moves higher than normal, nowhere near the point of triggering the electric fan.
When the five speed gearbox comes, things will be better for Janspeed and the normal owner. As the regular driver of the XR this publishing house has, I have been thoroughly intrigued by both performance and noise levels, for there is both a soundproofing kit and an update on the carburation which Ford quietly offer some owners of earlier examples.
On the road the turbocharged car backs up the Janspeed pamphlet’s aggressive statement: “in standard form they tend to lack any real urge.” A comment on the standard car which is supported by the statement “in third and fourth gear however the turbocharger gives them that extra sparkle which makes the car sit up and go in any gear.” The Janspeed XR feels a lot quicker in any situation. Even the slightly improved roadholding and handling of Jan’s example, compared with our own, reaching a definite pitching and jumping limit. The speed with which 6.250 r.p.m., some 110 m.p.h., comes up in fourth is breathtaking in such a small car. Overtaking performance is superb, even if you don’t drive sympathetically, trying to provoke that old “Turbo lag” chestnut.
While Jan borrowed our standard car and I drove his, our road conclusions were agreed: you will be a gear higher in the turbocharged model for any given situation and the speed is likely to be 10-15 m.p.h. greater in the turbo model. However, this depends if you have just filled up and are still conscious that m.p.g. can easily be dragged below 20 on 5 lb. boost! With the smaller turbo, boost is available from about 2,000 r.p.m. and 35 m.p.h. in fourth with full boost arriving by 3,000 r.p.m. and less than 60 m.p.h.
There were some driveability points we noted. The present carburation is easy to stall until you are familiar with the sharp, long tray, clutch and comparatively large chokes. There is sonic surging in boost under part throttle and the oil consumption was horrendous. I did some 500 miles in all and added close to 3 pints of oil. Most lubricant was released on slowing from speed, when a tap of the throttle made the rear end haze reminiscent of my old Arid Arrow 2-stroke motorcycle under hard acceleration.
Cold starting was extremely prompt, once you had remembered to pull the manual choke in placed of the normal automatic equipment. Hot starting required half throttle but was otherwise so good as not to warrant further comment.
Fuel consumption? The average figure for “my” Teesdale publishing XR3 is given alongside the Janspeed Turbo’s figure for the same trip. It may be rewarding to know that I filled the tank of the Janspeed car three times during the test and got figures of 17.2, 21.2 and 20.56 m.p.g., confirming Jan Odor’s fears that the consumption of the present carburetter is not acceptable in really hard use. A fact already pinpointed in rolling road tests, which had revealed that the test car was giving a healthy 130 b.h.p. from its 1.6-litres. In those tests constant speed consumption varied from 37 m.p.g. to 14.5, showing that it’s only under boost, when the performance is putting an enormous smile on your face, that the m.p.g. is giving your bank manager cause for another of those cosy chats.
Finally I could not resist the challenge of finding out “wottle she do Mr?” under comparative conditions. I decided to pit my standard car, at 11,800 miles and rather desperately in need of a 12.000 mile service, against the Turbo. Same day, same track, same watch, same 6,250 r.p.m. limit, myself driving and an average of four runs in either direction.
From curiosity I tried revving Teesdale’s poor little XR to 6,750 r.p.m. in second, saving the gearchange that is demanded by a 6,250 r.p.m. limit (56 m.p.h.). I ran this test only once, but the 8.72 sec. recorded confirmed to me that the high r.p.m. potential of the CVH engine has yet to be exploited. Overall, I thought the standard car, which we have owned from the start of its life, emerged with great credit from this exercise. After all its last service had been 5,800 miles before and the XR3 is maintained in a routine manner by a non-RS Ford Dealership.
The normal XR3 is noisy and there are lots of details that need further work (rear suspension for one) but to get such invigorating performance and handling, while close to 30 m.p.g., seems attractive to me.
Janspeed’s Turbo XR3 previews an ever more sophisticated and speedy future small car. As Jan Odor, exhaust tycoon and raging enthusiast says “imagine this little baby with 200 b.h.p. and air conditioning…!” – J.W.