With paddle shifted robotized (Electrohydraulic) transmissions being all the rage, are their days already numbered before they have even come into wide spread use?
While the traditional manual transmission is still my preference, I have to face the reality that most people these days do not know how to drive stick. Because of this, manufacturers are reluctant to develop new manual boxes or offer them as an option in their cars. Lamborghini, Ferrari and even some Porsche models no longer offer a manual (which speaks volumes about their owners); and the vast majority of corvettes are most likely going to be ordered with a automatic. It looks like, in a few more years, the traditional manual is going to be very hard to find if not extinct.
I have to say that I do not have a lot of experience with any of the newer double-clutch transmissions on the market, but I have had some experience with the early E-Gear system in the Gallardo and Murcielago. While that system was fun on an open road, it was horrible at slow speeds and down right atrocious if accelerating on a hill from a stop. Furthermore, the first gen E-Gear system only lasted about 10k miles before it started to get moody, and it was known to eat clutches to the point where it would make owners think twice about driving the car hard.
I know that the new systems today are much better and I have driven the PDK in a 997.1. I did not drive that car at low speeds in bumper to bumper traffic, but that trans was obviously a huge improvement over the old Lambo system. I understand that the VW DSG /Audi systems are also very good.
I was thinking that double-clutch transmissions are the future, but then I drove ZF’s HP8 transmission in a SRT Cherokee. I was shocked at how quickly that transmission can up-shift through the gears, it might have been faster than the first gen PDK, plus it had 8 gears. I do think the downshifts needed some work though, they were quite sluggish.
But this raises the question: if they are able to make a slushbox trans that’s as fast or faster than a double-clutch transmission; whats the point of having a double-clutch trans? At first I thought that the automatic ZF would weigh significantly more than a double-clutch system, but the HP8 weighs about 200lbs according to the Wikipedia entry on it; which is about the same as the VW DSG which comes in at 205lbs. The HP8 not only weighs about the same, but it has more gears and holds much more torque than the VW box as well. For contrast, manual T-56 six-speed trans is about 120lbs and can hold about 450ft-lbs of torque (non-viper/magnum version).
Furthermore, the ZF box, being a true automatic, has a torque converter which makes slow speed parking lot maneuvers, hill starts, and bumper to bumper traffic a breeze.
The only issue I can think of with an automatic is heat. When raced hard, automatics tend to generate a lot of heat and can suffer greatly from this. But, automatics have road raced in the past which shows that the heat is manageable.
GM has also developed a new 8-speed trans called the 8L90 which will be released soon. This trans will be found in many of their cars and trucks including the Corvette, and they are already claiming that it shifts faster than the current PDK. Here is a video of it in action:
It looks pretty good, though it does look a little sluggish on the downshifts. It’s a little hard to tell on this track because there isn’t any heavy brake zones.
I’m anxious to see what the future is going to hold for these new automatics.
2 Comments to "Are 8+ gear slushboxes the future of transmissions?"
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Stick is alive and well in Europe!.
Over here automatics have mostly been limited to upscale powerful cars, where the drawbacks like parasitic power loss and extra weight were of little consequence.
To a macho young man implying he isn’t a gifted stick shift driver is tantamount to suggesting he is a flop in bed. The smaller cars over here mostly have light slick easy to use manual transmissions, and automatics haven’t made much impact, although they have improved greatly since the ubiquitous Borg Warner 35 and 65 slushpumps.
There is a steady market for small automatics, mostly elderly drivers and people with restricted mobility, but it is a niche that hasn’t grown significantly since the late ’60s when reliable automatics became generally available.
Modern automatics tend to out perform manuals, as far as MPG is concerned, in pretty much every application i have looked at. With 5, 6, 7, 8 or even 9 gears and a torque converter that locks, the parasitic loss doesn’t seem to be an issue anymore. Look at the Subaru BRZ for example, the automatic is rated for better MPG.
I think there is a reason for this though, and it’s that manufacturers put relatively quick top gears in manual cars to prevent the driver, heaven forbid, from downshifting on the highway. At highway speeds in my 350z, I’m cranking nearly 3000rpm and have more than enough power to pass anything if a choose. I feel that, that much power is wasted since i typically cruise at a constant speed. I would have been happy with the better millage if the car was at 2200rpm or so at these speeds.