Tiptronic: everything you need to know
Total 911 takes a closer look at the semi-automatic gearbox choice for Neunelfers from 1988 to 2008
Technical, historical and practical information on the semi-auto gearbox used in 911s from 1988-2008
Atrawl through automotive magazines and websites will quickly find often vociferous debates about the merits of manual versus automatic gearboxes, and nowhere is that more true than in the world of sports cars. Naturally, the 911 hasn’t been immune from such debates, fuelled in some areas by Porsche’s decision to equip some models only with the PDK transmission (introduced with the 997.2 generation), the 997 Turbo S and 991.1 GT3 being cases in point. That’s a more recent issue, though, because our focus here is on the transmission that introduced a proper automatic (as opposed to the Sportomatic launched in 1967 – a manual ‘box with the clutch operated via a micro-switch in the gear lever) to the Neunelfer for the first time. Tiptronic debuted in a model that was already marking a generational shift for the 911 – the 964…
History and tech
Described as ‘revolutionary’ by Porsche at the time, the Tiptronic gearbox first introduced in 1988 was a four-speed electro-hydraulically controlled unit that was developed in conjunction with ZF and Bosch. A conventional torque convertor transmission, it appeared to offer the best of both worlds: left in ‘Drive’ it would shift ratios by itself like any other automatic, but flicking the selector lever to one side allowed the driver to indulge in manual shifting by pushing the lever forward to change up or backward for down-changes. A display in the speedometer showed which mode/ gear was selected. Yes, being just a four-speeder was a limitation and meant the spread of ratios was wider than was truly ideal, but Porsche countered this to some extent by equipping the Tiptronic ‘box with an ‘Intelligent Shift Programme’. Controlled by an ECU that monitored inputs such as vehicle and engine speed, throttle position and lateral/longitudinal acceleration, it could pick from one of five shift programmes that adjusted gear change points according to whether the driver wanted to cruise or extract maximum performance. And this electronic control brought other benefits, including the avoidance of over-revving by automatically upshifting at maximum revs, and preventing gear changes at inopportune moments, such as when cornering.
Naturally, there was a weight penalty to all this technology with a Tiptronic-equipped 964 C2 tipping the scales at some 30kg heavier than a manual version. As for performance, the figures reveal that choosing just the two pedals still held an advantage: maximum speed dropped from 162mph for the manual to 159mph for the ‘Tip’, while the 0-62mph sprint increased from 5.7 to 6.6 seconds (although this was far easier to replicate without the risk of fluffed gear changes). And while of less importance to most buyers, fuel economy was almost identical. Perhaps the advent of an automatic 911 was something buyers had been waiting for all along, or maybe the thorough changes wrought for the 964 made those same buyers more amenable to this new choice, but whatever the case, Tiptronic accounted for around a third of all 964 Carrera sales in the first year.
With that level of take-up it’s no surprise that Porsche chose to stick with the automatic option when the time came to launch the 993. Available on the Carrera 2 variant, the transmission was carried over from the 964 virtually unchanged, although there had been some minor improvements to the electronic control systems and mapping. The impact on performance was similar to that of its predecessor, with 0-62mph taking a second longer compared to the manual car, but one notable change was the introduction in 1995 of steering wheel switches to select ratios (thereby becoming the Tiptronic S).
You could still use the gear lever if you preferred, but the ability to shift ratios with the flick of a thumb brought an added level of involvement to the driving experience. Okay, so it wasn’t the motorsport experience delivered by today’s shift paddles, but it was progress all the same.
By 1998 the 911 was about to undergo another step-change with the arrival of the 996, and the takeup of water cooling, so it was no surprise that other mechanical aspects received attention, including the automatic gearbox. It was still broadly the same unit that had debuted in the 964, but now boasted five ratios to better cope with the performance on offer, and incorporated 250 different shift maps within its electronic brain. Now sourced from Mercedes-benz, the C2 was equipped with the A96/00 unit while the C4 got the A96/01, although the ratios were the same for both. Performance differences were again slim compared to a manual, with both a C2’s and Turbo’s 0-62mph dash taking less than a second longer, and top speed down by just a few miles per hour. Although, the C2 was 0.2 seconds quicker from 50-75mph (the same time that Porsche claimed it took gear changes to be completed using the steering wheel switches).
And while the indicator for mode/gear selected would migrate to the fuel/water temp dial for the 996, other more notable changes included the addition of an oil/water intercooler for the transmission fluid and a swap from a single-plate to a twin-plate arrangement for the lock-up clutch. And choosing the Tiptronic meant a weight penalty of around
60kg compared to the manual car. By 2000 Porsche had made further changes in a bid to keep the Tiptronic option competitive, including the ability to manually select a gear for eight seconds even when in automatic mode, while manual gear changes were now via the steering wheel switches only. Before we leave the 996 it’s worth noting that the Turbo was the first blown 911 to be available in automatic form, the A96/50 unit being unusual in featuring two reverse gears; selecting first gear before reverse engaged the lower-geared of the pair.
Which brings us to the last outing for the Tiptronic ‘box. The 997 arrived in 2004 and this time all the variants available at launch could be had with the five-speed Tiptronic S option, and given the pace of 911 development it was no surprise that Porsche had introduced further improvements. As well as being beefed-up for the greater torque of the 3.8-litre engine, the transmission also benefitted from a ‘warm-up’ programme that used higher engine revs to heat the catalytic convertors more quickly, while tweaks to the electronics made for better engine braking during descents and improved acceleration when climbing.
The performance gap between auto and manual models was now more slender than ever, the former now taking only around half a second longer to crack the 0-62mph benchmark. Unless, that is, you’d bought the Turbo, where it was actually quicker by about the same margin. But four years after the 997’s arrival, the Tiptronic transmission bowed out, to be replaced in the 997.2 by the rather more sophisticated – and hugely impressive – PDK gearbox.
Maintenance
So that’s the history, but what about the prospect for ownership of a Tiptronic-equipped 911? Well, the good news is that – assuming it’s not been neglected or abused – this is a gearbox with a well-deserved reputation for strength and reliability. And according to some specialists the key to keeping it that way is to have the oil and filter changed at a sensible interval; taking the 996/997 as an example, it appears that Porsche recommended doing so at around 100,000 miles, but we’ve been told halving that is a more sensible approach. That said, both Ray Northway at Northway Porsche and Will Jameson from Philip Raby Specialist Cars say that jolting or lumpy shifts (especially from first to second gear) are worth watching for, and fresh oil may improve this. Otherwise it’s probably best to leave a service until Porsche’s recommended interval. Of course, using the correct lubricant is vital. So the decision is yours, but a specialist will charge around £300-400 for the job, so it’s not a major expense in the grander scheme of 911 maintenance. And when you consider that a specialist rebuild could set you back a couple of thousand pounds – and a complete replacement ‘box an awful lot more – it’s a wise investment. As for any other issues, it seems that early cars can suffer from a stiff gear linkage, although it’s an easy fix, while the later Mercedes-sourced unit can exhibit oil leaks from the rear of the transmission and from around the electrical multi-plug connection.
It’s also worth checking the 996’s transmission cooler pipes for corrosion. The occasional faulty sensor can crop up, too, and bear in mind that a new ECU costs four figures, so you’d want to be wary of any example displaying evidence of electronic gremlins. A test drive should suffice.
Lastly, Jameson also points out that the job of upgrading an IMS bearing on a 996 takes a little longer on a Tiptronic car, adding very slightly to the cost. There’s just one last thing to consider, and that’s the question of converting a Tiptronic car to a manual one. We know that it has been done on 964s, although generally speaking as part of a more comprehensive project build, so the job is certainly possible, although whether that’s a route you’d want to consider is a matter of personal preference. Costwise, a figure for a 964 of around £15,000 wouldn’t be too far off the mark, and while that’s a substantial sum it could make sense depending on the car you’re looking at, and the cost of acquiring a manual example in your preferred specification.
“Tiptronic debuted in the 964, a model that was already marking a generational shift for the 911”
Values
The other point to address is values. There’ll be plenty of 911 enthusiasts out there that consider an automatic gearbox nothing short of sacrilege, and it’s unlikely they’ll be swayed no matter what the advantages may be – financial or otherwise. But for those where the idea appeals (and there’s no doubt that the ease of use in congested urban driving is a definite plus), or need an automatic for practical reasons, they’ll discover that the difference in values compared to a manual counterpart could be smaller than might be expected. It rather depends on who you ask, though, so while a Tiptronic car will be worth less, putting an exact figure to this isn’t straightforward given the potential for variation in history, mileage, condition and specification (issues that should arguably take priority in any case). Depending on the generation, and the rarity and desirability of the model being considered, the price differential could turn out to be somewhat wider. Ray Northway estimates a Tiptronic being somewhere in the region of 10-20% cheaper depending on whether it’s an air- or watercooled model, adding that the difference is likely to be greater for Coupes, on the basis of Targas or Cabriolets being less price-sensitive as buyers may be happier to accept the Tiptronic’s more relaxed nature. Also, Will Jameson says that if you were to consider a good 996 Coupe with around 80k miles, then a manual would likely be priced £1,0001,500 higher.
So, to our verdict. If the idea of an automatic 911 from this era takes your fancy then we certainly wouldn’t dissuade you. It’s true that the PDK gearbox is light years ahead, but that’s a very different, more technologically advanced beast, so the Tiptronic must be judged on its own merits and here it stands up better than naysayers would have you believe. Okay, so the more modest power and torque of the 964 tended to highlight the deficit of ratios (but as one specialist pointed out to us, dropping in a Varioram 993 engine works wonders…) but later, more powerful generations overcame such reservations. Ultimately, taking the Tiptronic path with such a revered sports car could be considered a brave move by Porsche, but its subsequent popularity means it can only be judged a success. And make no mistake, there’s still plenty of pleasure to be had driving a 911 thus equipped.