This report was taken from Autosport Magazine on 8th November 1990
There's probably just one place in Europe you can explore fully the performance of the Lotus Carlton. Predictably, it's Germany. But it's not the autobahnen which these days are full of Trabants with straight line stability problems. One of these wandering into your path as you max the Carlton is not recommended.
About the only place to extend the Lotus and see if your £48,000 has been money well spent, is to pay an extra 13DM and indulge in a lap of the old Nurburgring. It is possible, apparently, to hit the Carlton's maximum along the final straight before the pits.
There's certainly nowhere in the UK where you can legally match the 176mph reached by Italian Authorities at the Nardo track deep in Southern Italy.
The best Vauxhall could manage for the press launch was a trip to the Lotus-owned Millbrook proving ground where we were restricted to 140mph on the high speed bowl. The G-forces involved in sustained higher speed running causes rear tyres to blow, while the angles adopted on the bowl confuse the self-levelling rear suspension into jacking itself up.
But, in any case, Vauxhall is keen to avoid talk of top speed. The press information avoids the subject completely, and only when asked will the speed achieved independently at Nardo be quoted. Vauxhall is far happier to talk about the car's phenomenal acceleration, it's handling and it's braking performance.
Inevitably, the top speed is going to be the most talked about aspect of the car and that will be missing the point. For the Lotus Carlton is a remarkable machine, a genuinely practical four seat, four door saloon with the sort of performance that would do a Ferrari proud.
It'll be as rare as a Ferrari too. Each Lotus Carlton takes 150 hours and just 1100 will be made by Lotus at Hethel over the next two and a half years, by which time a new Omega/Carlton must be due. In all, 440 Carltons will be sold in the UK by a hand-picked group of 17 Vauxhall dealers.
Built in a specially prepared unit that used to see service as the DeLorean development shop, the Carlton arrives form Rüsselsheim as a virtually standard 3000 GSi, and is then immediately stripped back to a bare shell. The seats are sent for retrimming, the engine returned to Opel and the body modified to accept the new engine and gearbox. Other changes ensure that the huge tyres don't foul the wheel arches.
But the real story of Lotus Type 104 centres in the engine and chassis. The engines are built up from all new parts by a small team, with one engineer assigned to each engine, Aston Martin style. Using the 3-litre 24-valve GM 'six' as a starting point, Lotus ups the capacity to 3.6 litres, stiffens the block, improves coolant and oil flow and adds a new induction system and manifold.
There are new Mahle pistons, new connecting rods and a new crankshaft, the latter with a dozen counter weights for smoother running. A pair of liquid cooled Garrett T25 turbochargers completes the package.
The original design concept demanded 100bhp per litre. It's a figure Lotus actually bettered, the new engine producing 377bhp at 5200rpm. More impressive are the torque figures. At just 2000rpm there's some 300lb ft on tap, rising to a peak of 419lb ft at 4200rpm.
Translated into performance, that means 0-60mph takes 5.2secs and 0-100mph just 11.5secs, while 50-70mph in third takes an incredible 2.8secs according to Vauxhall. Given that one of the most dangerous things about overtaking is the length of time you spend on the wrong side of the road, the Lotus Carlton must be one of the safest cars around.
When under development, the only gearbox available that could handle all the torque was ZF's 6-speeder used by Lotus in the development of the Chevrolet Corvette ZR1, and accordingly it has found its way into the Carlton. Indeed, at one stage Lotus considered dropping the entire ZR1 V8 engine/drivetrain into the Carlton shell but the idea was canned, partly because of space restraints and partly, one suspects, internal politics.
Other drivetrain modifications include a heftier clutch, a new Holden-derived rear axle and three-piece propshaft. Suspension modifications include the adoption of an extra link on the standard GSi semi-trailing arm, twin tube dampers with automatic self-levelling and, at the front, new Lotus-tuned MacPherson struts. Myriad geometry changes centre mainly on optimising camber angles.
Specially developed Goodyears - 235/45 ZR17 on 8.5in Ronals at the front and 265/40 ZR17 on 9.5in Ronals at the rear - supply the grip, while AP provides the stopping with four pot Group C- derived calipers on huge 330mm ventilated discs at the front and twin pot ventilated discs behind. The standard GM/Bosch ABS is retained.
The package is completed by a wind tunnel developed body kit with a deep front air dam and boot mounted rear spoiler that provides zero lift, and a high level of standard equipment. Along with the expected electric windows, sunroof and central locking, features include air conditioning, Conolly leather, liberal splashings of expensive looking veneer, heated front seats, a CD player and, thankfully, deadlocks and alarms to protect the investment. The only thing that seams to be missing is electric control of the seat adjustment.
Vauxhall's launch route was clever - first impressions were of the car were gained on a short run to Millbrook through villages on slow, winding A and B roads crowded with lorries and other traffic. We knew all about the Carlton's performance potential, but how would it cope with everyday traffic and everyday speeds?
Answer: perfectly. Aside from a heavy clutch - it's not as bad as that in the M5, though - and the odd metallic clunk as ZF cogs were swapped, the car was docility itself.
Next came a blast around the Millbrook bowl where it cantered up to the 140mph limit with contemptuous ease. At those speed the engine is turning over at around 2900rpm in sixth... top is so high that under normal circumstances it will never get used.
From there it was to the handling circuit where it was only thanks to a damp surface that the back end could be made to step out of line. Breakaway was also progressive and controllable, though, and in the dry you'd have to be trying pretty hard to unstick the rear.
Criticisms are few. The test car - number 004 -according to the dashboard plaque - had a few more buzzes and rattles than you would expect for this kind of money, but the biggest concern is the gearbox which verges on agricultural. Alpina's 5-series based B10 Bi-Turbo develops almost as much power and torque and uses a delightful new Getrag 5-speeder.
Rivals are also few. The M5 is cheaper but less powerful, ditto the Audi V8, while the Alpina Bi-Turbo is another 10 grand and left-hand drive only. For around the same money you could get a 911 Carrera 2: hopeless if you want four seats. A Lotus from Luton might not have the cachet of a BMW or a Porsche - bet there's a heck of a lot else going for it.
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