TRANSMISSIONS
THIS MONTH WE ASK THE EXPERTS FOR THEIR VIEWS ON PERFORMANCE CAR TRANSMISSIONS, INCLUDING THE PROS AND CONS OF EACH TYPE, AND WHAT THE FUTURE HOLDS FOR THEM
THE DUAL-CLUTCH TRANSMISSION (DCT) SEEMS TO HAVE BECOME THE DEFAULT GEARBOX FOR ALL TYPES OF VEHICLES. CAN IT BE BETTERED?
Richard Moore, propulsion director, Lotus: ‘The beauty of the transmission is that there is no perfect answer. For driver engagement a manual transmission is very compelling. The DCT offers a great combination of quick powershifting and connectivity, plus fun features such as launch modes are easy to implement. DCT works best when paired with a high-performance engine, so a low-performance engine, perhaps one developed primarily for economy, will not be optimised.’
Simon Leleu, transmissions specialist at Prodrive: ‘As someone who waited an extra three months to get a build slot for a manual version over a Dct-equipped car, I clearly think so, but driver engagement aside, the DCT is still probably the better gearbox, certainly to most people and in most situations. However, I also think there are certain vehicles where autos are still by far the better option. With the increasing drive towards electrification I think we’ve passed the point where there will be a new technology coming along to directly replace the DCT; the lifespan will be too short to warrant the design and development costs.’
Howard Marshall, head of transmissions and e-drives at Ricardo: ‘The cost of automated transmissions for smaller vehicles has come down significantly. Together with increased traffic congestion, more drivers appear to prefer the convenience of an automated transmission. As a result, car makers are selling more autos and a good automated transmission solution is becoming a stronger brand differentiator. Part of the attraction of automatics is that DCTS and AMTS [automated manual transmissions] in smaller vehicles are widely viewed as being sportier compared to more traditional planetary [torqueconverter] automatics.’
Apart from weight and cost, are there any downsides to the DCT?
‘To get driver engagement levels through aggressive shifts, you need to over-engineer the clutch and actuation system,’ says Moore. ‘Shift maps can be easily done badly – a lot of work has to go into the mapping. Conversely, you will always get a perfect shift map with a manual transmission because your brain is doing the controlling!’
Leleu reckons it depends on the vehicle or what you want from it: ‘DCTS offer limited creep or hill hold compared to a torque-converter auto and increased complexity compared to a manual.’
‘It’s largely market driven,’ says Marshall. ‘There’s competition to offer small-car automatics at lower prices and this is driving the change. The manual transmission will remain the option [subject to legislation] for certain types of sports car, where if it’s not a manual transmission, it might not be considered a true sports car.’
When is a conventional, torque-converter automatic a better solution than a DCT?
‘Large saloons, SUVS and 4x4s all benefit from having a torque converter instead of two discrete clutches,’ says Leleu. ‘The smooth launch and gearshifts, plus the infinite creep ability of a really good automatic can’t be matched even by the best DCTS in my experience.’
‘High-performance rear-drive vehicles with front engines and tunnel transmissions favour torque-dense planetary-gear autos,’ says Marshall. ‘Shift speeds can be made sportier like a DCT, and torque-converter lockup clutches can be engaged earlier to achieve a package-appropriate,
high-torque, sporty transmission. This approach is typified by BMW’S move from DCTS to planetary autos in the current BMW M5 and M6 vehicles.’ (And, as has just been announced, the new M3 and M4 too – see page 70.)
What’s the secret of a great manual gearshift?
Moore says there are three requirements for a great manual gearshift: speed, feel and definition. ‘Speed comes from the rotational inertia of the clutchdriven plate, synchro torque capacity and gear ratio step. Shift feel is driven by the design of shift mechanism, which needs to be low-friction, highstiffness and low-float. Definition is the H-gate profile, which is how accurate the shift movement feels to the driver, and that the gears engage in a positive and definite way.’
The environment is important, too, he says, including the proximity of the gearstick to the steering wheel and how the gearknob feels in the hand. ‘As with all Lotus cars, linearity of response and input related to output is key. The efforts should be what are expected – not too light, not too heavy.’
‘A number of elements make up a great manual shift, and getting any one of them wrong can ruin the whole experience!’ says Leleu. ‘Get the effort, bite point or over-centre feel wrong on the clutch pedal, get the synchro effort or capacity wrong, get the linkage ratios, compliance, isolation or weighting wrong… all can spoil it all. Even a poor gearknob can detract from the experience! The best get them all right.’
We also asked Hideki Kakinuma, Civic Type R project leader at Honda, for his thoughts on the secret of a great manual gearshift. ‘Honda has always built cars with great gearshifts, and sports cars from the ’92 NSX. It’s a tradition within Honda,’ he says. ‘All the development and design principles are already high, including rigidity of transmission cases, bearings and shafts, also the linkage, lever ratio and load – all these specs, these basic requirements, are already on a very high level. Then we fine tune, optimise, an already good shift for cars such as the Type R.
‘It comes from a motorcycle background. Many aspects of Honda are related to its motorcycle heritage: high-revving engines, lightweight design and shift feel. It’s Honda’s DNA. Comparing Hondas with the competition, what’s different is we do not have the rubber feel, which may be there on purpose for damping.’
What is surprisingly crucial to a great manual gearshift?
‘Transmission oil,’ says Moore. ‘It’s vital to have the correct additive pack in the oil to ensure that the transmission works at its best, for the gears, synchromesh and all other moving parts.’
Marshall says he’s certain that a great transmission with a well-designed and developed shift mechanism can be ruined by a poor handset design and poor-quality shift cables. Integration to a vehicle is just as important, he adds.
Leleu reckons it’s a combination of things and how they interact, but says that perhaps surprisingly, the level of compliance in a mechanism can be the difference between a great shift and a rubbery, imprecise one.
Generally, hav e emissions requirements compromised gear ratios?
‘Manual transmissions have a disadvantage because legislative emissions test cycles require defined shift points to change gears,’ says Moore, ‘which is not a requirement for auto transmissions.’ He says this often leads to the auto version having a lower CO2 rating, though in the real world the manual version, driven carefully and with economy in mind, will normally have a lower CO2 due to the higher efficiency of its transmission.
‘Whether it’s marketing led or emissions led, there has always been a compromise away from truly optimised gearing,’ says Leleu, ‘whether to get to 60mph with one less gearshift or taller gearing and additional ratios to improve fuel consumption.’
What car has the best manual gearshift you’ve tried?
‘The Ford GT [2006] was highly technically acclaimed,’ says Marshall. ‘The whole transmission was developed by Ricardo, including the handset. At the time it was a clear demonstration of the full-system approach of Ricardo to manual transmission shift quality. It still represents a great benchmark.’
‘There’s something lovely about the manual shifting of a classic car,’ says Moore, though he admits they aren’t necessarily that good, just that they feel like an event and can be a joy to use. His current favourites? The ‘rifle bolt’ mechanism in the Elise, Exige and Evora. ‘Partly due to the lever position, throw and linearity, plus the exposed gate on the Elise and Exige is really neat and helps make each shift a memorable, mechanical event.’
‘Unfortunately, for one reason or another, a couple of the best I’ve tried didn’t make it to production, at least in the same form,’ says Leleu. ‘I’ve not tried the later models but there’s a reason why the earlier MX-5S are so lauded – they have a really positive, precise, short shift. In current cars, the Porsche six-speed manual is hard to beat.’
Will we see any gearbox innovations before EVS become the norm, or once they do?
‘I expect to see DCT being adapted for EV use,
’s ‘T will enable future electric motors to work at their most efficient and allow smaller and less powerful motors to be used in city cars, for example.’
‘Manual transmission synchroniser technologies are continuing to improve through material, surface treatments and lubricant developments,’ says Marshall. ‘This continues reducing part size and cost for the required levels of performance, helping the package and cost of manual transmissions.’ He adds that most of these technologies benefit the DCT too because it also uses synchronisers.
‘Electric machines for a given power can be made smaller if able to run at higher speeds. However, this is at the expense of low-speed demanding applications, higher-speed motors combined with the appropriate multi-speed reductions provide a more optimised EV solution.’
‘There will always be innovations, they just might not be large steps,’ says Leleu. ‘Once EVS become the norm the innovations will keep coming, because the weight, efficiency and cost balances for transmissions will change as battery weights, efficiencies and costs become less overwhelmingly dominant.’ He suggests that with greater volumes of less expensive hybrids, the
lighter than a DCT) might make a bit of a comeb electric motor to assist launch and torque fill, thus ‘conquering its shortcomings’!
‘IWAS BORN IN MACCLESFIELD BECAUSE that’s where my mother was sent while my father was in the army. He’d been one of the last people out of Dunkirk. I didn’t realise until much later that I was born at the same time and place as future racing driver and sponsorship guru Guy Edwards. There’s a photograph I have of a nurse holding two newborn babies in her arms and in one is me and in the other is Guy. One day I’d end up designing racing livery for him.
My father was a painter, a good one, but you couldn’t earn a living and support a family doing that so he ran a furniture museum in the East End. He wasn’t particularly interested in cars but my mum’s younger brother was. His name was Denis Jenkinson.
According to my grandmother my first words were ‘Look, Jeep!’ She bought me a Dinky Jeep, which I’ve still got. When Jenks realised that I was interested in cars and mechanical things he used to come around – we were living in St John’s Wood by then – to show me what he was driving. One time he turned up in the mid-engine Rover concept. I saw a lot of Jenks.
I didn’t know there was such a thing as a car designer but my uncle proved to me that you could actually earn a living with cars. He fuelled the passion for cars and perhaps from my father I got the skills in art. Anyway, I went to the Central Saint Martin’s School of Art. It was an amazing time to be there. Peter Blake was my painting tutor and
Anthony Caro my tutor for sculpture. You covered all the disciplines at the school.
I really enjoyed sculpture so after Saint Martin’s I went to the Royal College of Art to study product design under Misha Black, the industrial designer who, among other works, designed the Westminster street signs and the underground trains used on the Victoria line until 2011.
The girlfriend of Charlie Watts [of the Rolling Stones] was in the sculpture school and David Hockney was a student there, too. Pete Townshend used to come in driving his Lincoln Continental convertible. Hockney had an American boyfriend who had brought to England his metalflake green Ford Model T hot-rod, which was often parked in Kensington’s Jay Mews. When I was younger
I’d bought a copy of Hot Rod in one of those newsagents in London that has an eclectic mix of imported magazines. Reading it fuelled a love of hot-rods and custom cars that’s never left me.
It was in the last year of this four-year course that someone from Ford visited the college with a view to starting a vehicle design course because the company didn’t have a formalised way of training young designers. I and my friend Dawson Sellar were chosen to be the first students on this two-year postgrad course.
Ford actually paid us for doing the course and the money was fantastic for the time: £1200. I immediately went out and bought an Abarth 750 ‘Double Bubble’ and Dawson bought himself a
Porsche 356 Speedster. After we graduated we both went to work at Ford’s Design Centre in Dunton. One day later that year it snowed heavily one afternoon and when we left work we found loads of people skidding around a snow-covered car park in their Mk1 Escorts. Dawson in his Speedster and me in a Baja Beetle that I’d bought had no such grip issues with our rear-engined cars. These cars were hated by almost all at Ford, particularly when we just drove away!
They said that if you wanted to get on at Ford you had to stay for life, which many people did. Dawson didn’t hang about and went to Porsche, where among other projects he worked on the interior of the 928. Back in Essex one of my first jobs was the interior of the first Granada, a rather less exotic machine than the Porsche. However,
I was very proud of the very nice winding handle that I did for the car’s sunroof, but rather ashamed of the square headlights on the Mk2 Capri that were also my work.
My mentor at Ford was a Jamaican-born designer called Ron Saunders. He was certainly the only black designer at Ford and probably in the world. He was brilliant at drawing, a complete natural. He had a Lotus Seven but he and I would often borrow a Twin Cam Escort each and go and mess about on Duxford airfield in them. It was hanging around with Ron that made me terribly aware of racial prejudice. We once went to a pub in Hampstead and the barman made a big thing about not understanding Ron’s heavy West Indian accent. The barman turned to me and said: ‘What’s your mate trying to say? I can’t understand a word.’ I replied that Ron had asked for two beers and that he could f**k off because we were going somewhere else.
We were very impressed by what GM were doing. Ford brought out the Mustang and GM did the Camaro, which was a much better piece of design. Same with the Capri and Opel Manta. Ron and I had a theory that when GM’S designers encountered a design issue they removed clay to sort the problem whereas at Ford they added it.
While I was at Ford I worked on the liveries for the Broadspeed and Alan Mann racing Escorts. I’d always loved racing of all types and used to get given free tickets for events such as the BOAC 500 at Brands Hatch and even F1 races also at Brands. When we were young my brother [who was also arty and became a picture restorer] and I were obsessed with
Colditz and used to forge our own bus passes just for the fun of it. We also copied the Jenkssupplied race tickets.
I stayed at Ford for a year after Dawson Sellar and then left for Ogle Design. There I worked on the Reliant Kitten and a stillborn sports car that had a wedgy shape and looked a bit like the Esprit. We also did trucks at Ogle, which was a very interesting and useful experience because these are products that people actually have to earn a living with. I even worked on a knitting machine and on Mogul toys, which were rivals to the successful Tonka toys. Doing all this varied stuff really helps with the imagination.
In around 1976 I went freelance and did all sorts of projects, from working with ERF trucks to doing the graphics at Brabham for Bernie [Ecclestone]. In the early ’80s I got involved at Lotus, who were in a right mess after the death of Chapman in ’82. He was such a figurehead and so in control that people were running around saying things like, ‘How do you turn the lights on in the boardroom?’ At the time they were working on an affordable sports car or modern Elan. I was brought in as a freelance but I ended up creating a whole design department.
When I went to Lotus I was plagued by the fixation that ‘Italians are the masters of design’. I wanted to escape from that, which is a reason why I rounded off the Esprit when I did the facelift. It made the car stiffer, too. I
‘MY BROTHER AND I USED TO FORGE OUR OWN BUS PASSES, JUST FOR THE FUN OF IT’
was very proud of what we did with the Elan, especially the Mk2. Lotus had a lot of clients with front-wheel-drive cars and by this time had got very good at engineering them. Especially John Miles.
John and I had been at primary school together and in the ’60s I used to go help him when he was racing his Austin Seven vintage race car. I remember trying to push-start him in a paddock and by the time we got it going the race was over.
The Jaguar XJR-15 is another one that I think was a job well done. We did it with a very small team and a tiny amount of money. But I’d still like to do an amusingly rational car. My favourite Giugiaro cars are his rational stuff like the Panda and original Scirocco. I’ve got a 2CV van and that’s the sort of thing I’m thinking of. Perhaps with three seats.
There aren’t a huge number of modern cars that I find interesting. The retro cars such as the Mini and Fiat 500 seem to me like going through the dressing-up box in the loft, pulling out various bits and adding them all up.
I also don’t buy into this idea that the EV revolution is an opportunity to create a new era of novel designs. The huge battery packs tend to go in the same place because of the weight – you can’t start sticking batteries in the A-pillars or doors for example. It’ll be interesting to watch what happens.
Meanwhile I’m still in love with hotrods and right now should have been at a vintage beach race in France with my Model T roadster, but the virus has knocked that on the head. I shall be going next year instead.’
TLette r used on car badges, generally to denote ‘turbo’ unless we’re talking about the Ferrari Mondial t, where it meant the engine (but not the gearbox) had been turned lengthways, or the Cizeta-moroder V16T, where it stood for ‘transverse’, or the Daihatsu Charade Gtti, in which only one of the Ts stood for turbo and it was never entirely clear which.
T-bone
Road traffic incident in which one car drives into the side of another in a delicious meaty way.
TA
Traffic announcement. Car audio feature designed to scare the crap out of you in a rented or unfamiliar car as a different voice suddenly comes over the speakers to tell you about a traffic jam 47 miles away at 100 times the volume of whatever you were previously listening to.
Tachograph
Device that records vehicle speed, distance covered and driving time, not to be confused with a tachometer, which can’t do any of those things.
Tachometer
Device that reports engine crank revolutions per minute, not to be confused with a tachograph, which can’t do that.
Tail happy
Description applied to an oversteer prone car. Strangely, cars given to heavy bouts of understeer are rarely referred to as ‘nose happy’, perhaps because understeer isn’t enjoyable. Or because that phrase sounds like 1980s music industry slang for drugs.
Tailgate
1. Large, usually top-hinged door that permits access to the boot on hatchback and estate cars, e.g. the Audi A4 Avant. 2. To drive far too close to the car in front because you are a pushy but dim-witted bellend in a reasonably new car, e.g. the Audi A4 Avant.
Tappet
Contact point for the cam lobes, turning the circular motion of the camshaft into the linear motion that opens the valves.
The part of the engine responsible for the sound of many small Fords (1976-2002).
Targa
Generic term for a car with a full-width removable roof panel, first used by Porsche and inspired by the Targa Florio road race. At one point Porsche were going to go with 911 Flori before someone suggested that Targa sounded better. True fact.
Tarmac
Generic term for road surface derived from the compacted crushed stone road-building techniques pioneered by Scottish engineer John Mcadam, which Welsh inventor Edgar Hooley refined by mixing the aggregate with tar to bind and smooth the road surface, thus creating tarmacadam. Modern roads are actually surfaced with asphalt but ‘tarmac’ is still in common usage, at least in the UK. Probably because there’s an industrial building materials company still called that and you see their lorries everywhere.
Tax disc
Obsolete method of proving Vehicle Excise Duty had been paid, the tearing out of which from its paper surround was the most casually perilous task an adult human could undertake.
Telepathic
Word describing purported ability to transmit thoughts between people without any conventional sensory contact. The same word is sometimes applied to the steering of cars when very sensitive and rich in feedback. Two different use cases, united by the common quality of being total bollocks.
Telescopic
Of dampers and adjustable steering columns. Also, telescopes.
Thrash
1. To drive a car towards the limits of its capabilities (good).
2. Of a cam chain, to move around noisily thanks to inadequate tensioning (less good).
Throttle
To control the intake of fuel and air into an engine and therefore its power output. Also what Homer Simpson does to Bart a lot.
Thumb rest
Steering wheel rim feature briefly fashionable in the ’90s, an era famed for high levels of thumb tiredness.
Tickle
What one can do to throttles (if you want to make them giggle).
Tifosi
Word applied to passionate fans of the Ferrari F1 team, literally meaning people who have a fever due to typhoid. Although having actual typhoid might be more enjoyable than supporting Ferrari during the 2020 season.
Tilt-slide
What factory-fit sunroofs used to be described as, back when it was worth mentioning such things.
Tin top
Casual way of referring to a fixed roof car, ignoring that car roofs are rarely, if ever, made of actual tin, pending the advent of a new Cornish sports car.
Tip in
The initial response to pressure on the accelerator pedal. Often surprisingly aggressive on American cars, and those aimed
at the US market, largely because their traffic lights don’t have the amber lamp in the middle.
Tiptronic
Special system that made Porsches less good.
Titanium
Metal of high strength and low weight, and a Ford trim level that is neither of those things.
TMS
Modern feature in which the traditional spare tyre is replaced by several old men talking slowly about cricket.
Toe in
Of a car wheel, to be angled inwards at the front when viewed from above.
Toe out
Of a car wheel, to be angled outwards at the front when viewed from above. Shake it all about Of a car wheel, to have something very wrong with it.
Ton up
To do 100 miles per hour. As famously immortalised in the lyrics to ‘Merry Xmas Everybody’ by Slade, the quintessential British Christmas song (which was actually recorded in New York in the summer. True fact).
Torque
A measure of a force that causes an object to rotate around an axis. The meaty stuff, as opposed to horsepower, which is just flailing in space.
Top end
The upper reaches of the rev range, sometimes where the good power lives.
Torque convertor
Handy town-centre shop in which one may purchase second-hand rotational force with a patch on the bottom where someone else’s name and address has been crudely sanded off.
Torsen differential
Type of limited slip differential with a name derived from the words ‘torque’ and ‘sensing’. Also one of Sweden’s most promising new tennis stars.
Torsion bar
Suspension springing system based around twisting a firmly anchored metal rod. Simple and effective, unless you are Wil E Coyote, in which case you’re about to get a smack in the face again.
Torsion beam
Rear suspension system based around trailing arms affixed to a transverse twist beam. The main advantages are simplicity, compactness and the fact that it’s a lot cheaper than an independent rear end and most people won’t notice the difference.
Total loss lubrication
Engine lubrication system in which oil is constantly removed from the system, either as part of the combustion process, as in twostroke motors, or by exiting the engine in significant quantities, as in many British Leyland cars of the 1970s.
Traction control
System which detects loss of grip under acceleration and reduces engine output/brakes an individual wheel to reduce wheelspin/ annoys the driver who had got this perfectly well under control, thanks very much.
Trade plates
Distinctive red and white temporary plates that allow motor business people to move cars around on the road without having to register and/or tax them. Can also be removed from a car and held aloft on a motorway slip road as a way of saying please may I have a lift.
Traffic calming measures
The reason your 20,000-mile car needs new suspension bushes.
Traffic warden
Parking regulations enforcement officer created by the government in 1960 in order to provide an ongoing source of predictable jokes for lazy comedy writers.
Tramline
Of a car’s wheels, to undesirably follow the contours of the road until they end up back at the depot.
Transmission
A mechanical device that connects the engine to the driving axle so that it may dance dance dance to the sound of the radio.
Transverse
An engine mounted crossways rather than lengthways in a car, as pioneered by the DKW F1 of 1931, paving the way for the Mini, which in turn inspired the Lamborghini Miura.
Tread shuffle
Movement felt from the tyres under hard cornering as the blocks of rubber in their outer construction move around and a good way of knowing if someone describing the public road handling of their car is talking absolute nonsense.
Tumblehome
The inward slant of a car’s upper body when viewed from the front. Drop this word into casual conversation to convince people you’re a car designer, although remember to wear a lot of black clothing and a madly elaborate watch otherwise the ruse won’t work.
Turbo
Exhaust-driven compressor, forcing more air (and fuel) into the combustion chambers to the benefit of power output. Also what literally everything marketed at men was called during the 1980s.
Turn in
The initial off-straight steering and chassis response of a car. Often paired with words like ‘crisp’ and ‘soggy’, rather like toast.
Twin Spark
Exciting sounding name given by Alfa Romeo to its two-spark-plugs-per-cylinder in-line four-cylinder engine in the 1980s (although actually the company had been using this technology in racing engines since the 1910s and it’s long been common in aircraft engines for reliability reasons).
Umberslade Interchange
Official name of the union between the M40 and M42 motorways in the West Midlands, the angle of which makes cars on the joining carriageway appear to be doing 240mph.
Understeer
Cornering state in which the car follows a wider line than one requested by the level of steering input. If only evo had a photograph that captured such an event.
Undriveable
Harsh description of a car, perhaps because it has more power than its chassis can comfortably handle, e.g. an AC Cobra, or because it’s so awful you don’t want to get in it, e.g. a Mitsubishi 3000GT.
Unleaded
Petrol with no tetraethyl lead added to it. Since petrol doesn’t naturally have lead in it, calling it ‘unleaded’ is a bit like referring to black tea as ‘unmilked’.
Urea
Liquid used in solution to reduce nitrous oxide emissions from diesel engines. Widely available urea additives for cars are made using synthetic ammonia but urea is also found in wee. So yea, wee cleans diesel.