Taking the bat back home

The road going CSL’s 206bhp peaked at 5600rpm and its 211lb ft at a rather high 4200rpm. The transmission and final drive ratios were standard CSi but the CSL gained a limited-slip differential.

The engineers kept the front wishbone and rear trailing arm suspension but cranked on an extra degree of negative camber at the front to improve stability and handling, strengthened and made the coil springs more progressive, and ditched the standard dampers for Bilstein gas pressure shockers. That allowed the front and rear stabiliser bars to be axed. They dropped the ride height by 20mm to lower the centre of gravity, too.

Fat 7in wide alloy wheels carrying excellent Michelin 195/70VR14 XWX radials replaced 6in rims and lesser tyres and the steering was uprated to ZF-Gemmer worm and roller specification with a slightly slower ratio.

To deliver the ‘Light’ part of CSL, the M boys formed the door skins and bonnet from alloy, tossed away the front bumper in favour of a deep chin air dam, replicated the rear bumper in light black plastic and reformed the windscreen from special Verbel laminated glass. At 255kg less than the CSi, the CSL weighed 1270kg, quite a contrast with the new M4 CSL’s 1625kg  – although, of course, with 542bhp the 2022 car has 336bhp/tonne, more than double the 162bhp/tonne of its grandfather.

And did that outrageous-looking package of air dams, guides and wings work? You bet: drag dropped by 16 per cent, delivering a speed boost equivalent to having an extra 50bhp, BMW reckoned. Fuel consumption decreased and straight line and cornering stability improved thanks to the slug of downforce.

As we – I had two passengers – began our run to Bavaria that January Wednesday in 1975, in the bitter 5am cold, the white and triple-striped CSL fired up immediately and idled tamely before easing through thin drizzle out of London. No hint of histrionics here. It promised to be an effortless trip, first by Dover-Dunkirk ferry then the new autoroute running past Lille and Liège to Aachen on the German border.

I’d settled back comfortably in the rally-type bucket seat. It lacked backrest adjustment but was as close to ideal as most drivers would want. Distances to the wheel, pedals and gearlever were correct, instruments and controls easy to read and reach, and vision from within that big glasshouse excellent.

The leather-covered, drilled-spoke wheel sat high in a way that seemed old-fashioned even then, but it was comfortable and, when the time came, would facilitate deft applications of opposite lock.

When we refuelled in Tournai the figures showed that, even with running around in London before the trip and then sitting at 75 to 80mph, we’d logged 22mpg. The next fill up, near Frankfurt, confirmed the figure – 22.2mpg, and we’d been travelling at 90 to 100mph in the faster German traffic. There was no doubt that the Batmobile’s aero frills eased its path through the air: we wouldn’t have seen such pleasing figures (for the era) in an unadorned CSi.

The German border guards had eyed us quizzically. The fins might have been illegal but they made a fine German product look dramatic and potent, and we got the impression that it was good luck to das verrückte Englisch (never mind that two were Aussies) for disregarding the whole fins affair.

Bolting back out onto the autobahn, winding the CSL right out in the lower three gears to slip into the traffic flow, listening to the well-mannered rumble from the SOHC six and watching the tachometer needle spin to its 6400rpm red line (where I had 38mph in first, 65 in second and precisely 100mph in third) revealed an aspect of the CSL I hadn’t been able to explore much before: its acceleration.

It wasn’t shattering, for this wasn’t a big stick supercar, but it was fast, getting to 60mph in 7.0 seconds and pushing driver and passengers deeply into the seats as the bonnet lifted and the growl from beneath it deepened. The CSL might, for the most part, have felt refined and even docile but it had a degree of mailed fist/velvet glove and, when asked, it responded. Most of all, it seemed especially well balanced: engine to chassis to brakes.

Up to 90mph, it felt much like a big BMW saloon: supple, smooth and fairly if not entirely precise. Above 90, things began to change and beyond 100mph you felt the spoilers’ presence. The CSL grew taut, much as a professional runner might instantly switch on for a race after a warm-up jog. The steering solidified and became pin-sharp but not heavy.

The ride stayed comfortable yet devoid of wallow. You could really feel the car sitting down on the road, with everything clicking into place. It was one of those special ‘fingertips and seat-of-the-pants’ feelings that make driving a good car such a high.

And so the miles down through the CSL’s home country disappeared with increasing ease. Police discouragement in those fuel crisis days, when Germany had an advisory 80mph limit, held traffic speeds to around 100mph although I did brave a burst to 130mph where rock-like steadiness was even more apparent.

With me all the while were pleasing speed and power reserves  – 100mph was 4500rpm, just above the torque peak – that meant a quick prod on the throttle thrust the BMW cleanly past trucks on the narrow two-lane autobahns, and out of harm’s way.

By then, I had developed respect and affection for the CSL – something of a surprise because I had previously disliked the BMW CS coupés, which were disappointing compared with the 3-litre saloons. The CS wasn’t a coupé version of the equivalently powered saloon: it was based on the 2000 CS chassis dating from 1965. It was now clear how much careful development – including input from race drivers Chris Amon and Hans-Joachim Stuck – had gone into the CSL.

Our map showed a side road leading from the A3 autobahn down to a series of villages on the River Main about 50 miles beyond Frankfurt. Marktheidenfeld, where we stopped, was one of those quaint and quiet little wine towns, full of pokey streets, ancient houses and wine cellars.

The landlady at the Anker Hotel directed us to a restaurant called ‘Mainblick’ – River View – which looked onto the river and moored barges. The food was excellent and, hard to believe though it now is, the bill, including a good deal of lager, totalled £2.30 each. The hotel was £3 a head. At 5.5 Deutschmarks to the pound, it was a lesson in how cheaply you could travel in Germany then if you stayed off the main routes.

We were within 200 miles of Munich now and our plan for Thursday was to take minor roads down through the hills of northern Bavaria. The weather was clear and bright and the frost thick but in the high country we drove into mist, properly icy roads and snow.

I proceeded cautiously, using only third and top. But after several miles it was obvious that the CSL had an unusually high level of traction and adept handling if the grip evaporated. Soon, even in those grim conditions, I was driving the car full out, snuggling back in the rally-like bucket, getting precise responses from the engine to the movements of the throttle and lapping up the fluidity of the steering.

A tight and constant radius uphill curve looked tempting. I took it at full power at 60mph in second and there was no hint of the tail creeping more than a few inches. That bend sealed my faith in the CSL.

It was all downhill after that: literally because we’d crossed the range and figuratively because I felt so much at ease with the car. We completed our journey by streaking along the pleasing and almost deserted roads that snaked through the hop fields close to Munich and switched off the grime-spattered CSL at our hotel at 6pm, not in the least tired and very happy.

The CSL’s fins and wings might have seemed offensive and its very being anathema amid a fuel crisis, but the aero aids were the visible indication of the thoughtful work done by clever and passionate engineers to meet a goal.

BMW, newly invigorated by motorsport lover Bob Lutz, wanted a car to win championships and Neerpasch’s team responded in remarkably short time with a car that, on one hand, duly dominated its racing category for the rest of the decade and on the other, in road form, was a very fine coupé capable of taking three or four people across countries fast, comfortably and enjoyably. Those founders of M-Sport had given us a glimpse of the gems to come over the next half century and a badge, in CSL, to be revered.

In its 50th anniversary application – where, BMW says, CSL stands for the subtly different Competition Sport Light – it will be interesting to see whether the track-focussed M4 CSL is today a car of such broad and satisfying capabilities as was the Batmobile half a century ago.