View Single Post
Old 12-25-2007, 11:45 PM   #1 (permalink)
MetroMPG
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,527

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 54.46 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car Mirage - '14 Mitsubishi Mirage ES (base)
90 day: 62.14 mpg (US)
Thanks: 4,078
Thanked 6,976 Times in 3,612 Posts
VW's 7-speed DSG more efficient than traditional automatics; *also permits gliding*

It's clear a DSG will outperform a typical lossy automatic, so if people insist on driving the damn things, they may as well use this type (or CVT's).

Quote:
VW Golf: Coming with 7-speed DSG

For those not intimately familiar with VW’s DSG technology, the basic concept is relatively simple to grasp. Imagine a manual transmission, but instead of one gearset there are two - one for the even gears, another for the odds - and each has its own clutch. That clutch is computer controlled, as is the gear selection, so that while you are in second gear and accelerating, the computer has preselected third on the other gear shaft and only has to disengage the clutch from the active shaft and engage the clutch on the inactive shaft to change gears, allowing a seamless transmission of power between gears.
Aside from the efficiency gain of a direct motor/wheels connection (vs. a torque converter), the most interesting tidbit I learned is that the transmissions can be programmed to automatically de-clutch any time the accelerator is released... a true neutral glide!

I have read this was a feature that some drivers disliked on the super-efficient VW Polo model. Expecting engine braking and not getting it could be disconcerting.

And bonus: the speed freaks like the DSG gearbox too - because it makes the car faster than a traditional manual.

Here's a YouTube vid showing a DSG in operation:


__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote