PH Blog: shifting expectations
The Ferrari 458 and Merc SLS share the same gearbox, so why do they behave so differently? Harris knows...
In the context of Monday's Mercedes SLS GT announcement, one area of conversation now seems particularly apposite - we were discussing the SLS. He was talking about the car, the way it handles, his technical input and driving the knackers off it. As someone who covered 10,000 glorious miles in an SLS last year, I was asking him about the gearbox. Because that really was the only downside to an otherwise spectacular machine, the point being why was it so slow to shift?
To recap, the SLS uses Getrag's Powershift DCT 7DCL750 transmission. That's a long way to say it has a dual-clutch 'box with seven forward gears capable of handling 750Nm of torque. I first drove it in a Ferrari California and it was one of the few things I liked about the car: smooth in automatic mode, barely perceptible in manual, but still retaining just the right slug of ker-thump to let the driver know something was happening. Best of all, you pulled either lever and the shift was instantaneous - you thought, it changed gear.
Six months later I was sitting in an SLS for the first time wondering what was going on. The same Powershift DCT 7DCL750 transmission had the most irritating delay on manual shifts. It felt almost reluctant to change gears, there was a much longer pause between pulling a paddle and the cogs changing. I phoned a car-testing mate. "Was it like this for you?" Yes, was the reply.
Even more surprisingly, the Getrag 7DCL750 is also used in the Ferrari 458, possibly the best deployment of dual-clutch technology ever seen in a sports-car, so intuitive and fast you wonder if the gearbox ECU is actually hard-wired into the driver's cranium.
Now I didn't quote gearbox designation codes at Herr Maylander (I didn't know them at the time) but I did ask him why effectively the same gearbox felt so different, and rather slow-witted in a Mercedes. He said it was simply a matter of calibration. AMG knew the capabilities of the transmission, but when it used the fastest response and shift-speeds, it couldn't pass the company's powertrain reliability tests, so it had to alter the calibration accordingly.
This piqued my interest, so I did a little digging on the web of truth and justice. Turns out the first Ferrari Californias did have some issues. And if you Google "Ferrari California gearbox failure / problems" or "Ferrari 458 gearbox failure / problems", you'll find of owners of both cars who have had issues and replacement gearboxes. It has to be said that almost all of them appear to have been treated very well by Ferrari.
Search for "Mercedes SLS gearbox failure / problems" and there isn't a single thread detailing such an incident.
Now this might just confirm that Ferrari owners are more active online than SLS owners, but if there were similar problems with AMG's version of the transmission, it's probably safe to say at least one owner would have made some serious noise about it. Maybe this blog will surface such an incident?
What I find fascinating is the different approaches of two carmakers to the same mechanical hardware. Honestly, there were times when I was driving the SLS in manual mode, especially when I was lapping the 'ring, that if someone had offered me a dose of Ferrari 458 shift behaviour with the outside chance of a whoopsie, I'd have leapt at the opportunity because even though I worked around the slow shifts, it was a glaring downside to an otherwise compelling dynamic package.
Of course I don't have Ferrari's view on this - nor do I have anything official from AMG. Viewed objectively, and taking into account owner profiles and brand expectations, it was impossible for Ferrari to deliver the 458 with the same gearbox calibration as the SLS. The media would have lynched it for being slow and rubbish. It had to give customers and journos the full-experience and deal with any downsides. In being both a Merc and GT car, the gullwing just about carried off its protective gearbox mapping, but it was a close call.
Bernd had a few things to say about other applications of the Getrag dual-clutch, but it's probably not fair to quote them here. What he did say was that I would soon get the chance to drive an SLS with a much faster gearshift, and that it was a real improvement. That car is the SLS GT.
Personally, I can't wait. It's as necessary as the extra 20hp is unnecessary. And it will still be my favourite sub-£200k supercoupe.
Chris
Harris versus the SLS's gearbox on the Nordschleife
As more of a super GT from mercedes this nod towards longevity and reliability makes sense, where as the all conquering 458 puts outright performance 1st, which is fair enough in my opinion.
I do wonder how modern day Ferraris would stand up to being driven every day, how long would that gearbox survive & what is the cost of a replacement, as you never see high mileage ones?
There's loads of examples where different manufacturers(Or even within one company) use effectively the same hardware yet the actual experience of using the respective products is almost the polar opposite from each other.
Just goes to show how important the details are, people often think that you have to change lots of components or uprate things massively to change the feel of a car, often thats just not the case
As more of a super GT from mercedes this nod towards longevity and reliability makes sense, where as the all conquering 458 puts outright performance 1st, which is fair enough in my opinion.
I do wonder how modern day Ferraris would stand up to being driven every day, how long would that gearbox survive & what is the cost of a replacement, as you never see high mileage ones?
So your margin for failure can be much bigger (lower?) with the 458 as you predict first that it won't go that far and also that in a lot of instances when seeing its occasional use it won't be driven close to its limits.
So Merc have worked with the supplier to devise a better box for the GT while original owners can motor on with confidence that 50k miles a year is not going to kill the car.
Mind you - one thing I do know about cars is something else is just waiting to drop off instead :-))
now, porsches water-cooled reliabilty issues please
I wouldn't be surprised at all if the press 458s had a more extreme gearbox setting and the customer cars have a worse, but more reliable set up. However typical ferrari mileages are so tiny they could easily get away with a compromise over longevity. In either event it's totally unacceptable for the SLS to have a sub-optimal gearchange, if nothing else for the eye-watering amount Mercedes are charging for it (doubly so given essentially the same engine is available in a C63). Trouble is with flappy paddles is, just like other high tech devices, computers or phones or camers, they go out of date so quickly. All this just so douchebags who can't change gear can pose in London? What a shame, supercars are being ruined and the infinitely more involving manual gearbox is all but over.
Automated manual gearboxes with paddleshift make it far, far more desirable for me than a manual gearbox.
also, my only experience of paddle shifting is with a Fabia VRS and, although not in the same league as the above, it was not a positive one. I couldn't put my finger on what I didn't like abput it, partly because it wouldn't go down when I wanted it too coming up to a roundabout (not far off, half a second maybe, but still...). All I know is the salesman for Skoda was a real petrolhead, to the extent he slagged off his product; I explained that the VRS wasn't powerful enough for what I wanted and my problem with the gearchanges and that the brakes were a bit st when pressing on and he off the record agreed. Tried to sell me his mates Focus ST instead
Indeed, I am often left wondering at the sledgehammer approach of aftermarket modifiers (both private persons and companies) - it's almost like they haven't quite figured out which weak spots of the original car to address, and took a scattergun approach instead. (Of course, 'demo/show' cars also exist to show off as much of a company's portfolio as possible which tends to compromise the effort in itself; a few notable exceptions notwithstanding).
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