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-   -   New transmissions with no torque convertors... (https://ecomodder.com/forum/showthread.php/new-transmissions-no-torque-convertors-18743.html)

suspectnumber961 09-07-2011 05:31 AM

New transmissions with no torque convertors...
 
Passing Fear: Do Fuel Economy Gains Compromise Quick Acceleration?: Scientific American

"Let's say a driver approaches a red light at 80 kilometers per hour (50 miles per hour) and coasts to slow down, then the light turns green and he or she floors the accelerator. As the car slows down, the transmission automatically downshifts into lower gears, but a sudden command to increase speed reverses that process and the transmission has to find the proper gear for quick acceleration. With new technology introduced in the past couple of years to meet upcoming fuel economy standards, drivers of a small handful of the latest Ford, Chevy, GMC, Volkswagen, Mitsubishi models may feel engine hesitation when they goose the accelerator, which is a source of frustration, at minimum, to many drivers. But is it more than an annoyance? Is it a safety risk as well? Carmakers say no.

"It makes noises that are different and feel different, but it's performing and working exactly like it should," says Richard Truett, Ford's power-train communications manager.

Nevertheless, Jonathan Linkov, managing editor of autos at Consumer Reports, says it can be "scary" if a driver doesn't feel immediate acceleration as the car tries to zip in front of traffic. Linkov says Consumer Reports found such performance issues when testing the brands noted above. So, carmakers are working to respond to complaints from consumers about the performance changes without compromising fuel efficiency."

"The gear box in these transmissions is also about nine kilograms lighter, and thereby more efficient, than a regular six-speed automatic transmission, because a torque converter is no longer required to move fluid around to spin its input shaft. Truett says this system has resulted in fuel economy gains of 8 to 10 percent, compared with a four-speed automatic transmission."

Frank Lee 09-07-2011 06:47 AM

Perhaps giving consumers Accords that now have greater acceleration than older Corvettes has encouraged them to drive recklessly and take stupid risks as in darting into some little "hole" in traffic that they shouldn't try to be in anyway. If one is causing the trans to go into downshift mode frequently (when the vehicle is lightly loaded and/or not going up steep grades) that could be a sign that they are driving like an ass.

DonR 09-07-2011 12:15 PM

My Mitsubishi does that now. If you are cruising along & "smack the loud pedal" the transmission hesitates, as it downshifts a few gears, before it lets the fun begin.
As Frank so eloquently put it, it normally happens while driving like an ass.

Don

euromodder 09-07-2011 12:31 PM

Automated manual transmissions like DSG shift up when you let go of the throttle - mimicing coasting.
They shift down when speed drops below the threshold for a given gear.

Even on VW's highly acclaimed DSG boxes, forced downshifts are a tad slow and jerky compared to the brilliant upshifts.
Yet these gearboxes still shift faster than most mortals that drive manual cars.

wdb 09-07-2011 12:58 PM

Drive a car with a turbo if you want to experience real response lag! :turtle:

I have to agree with other commenters - this is a non-issue. Drive any car with an automatic transmission and a few miles on it, and you'll experience a time gap between stomping the pedal and having anything actually happen. BFD.

rmay635703 09-07-2011 01:22 PM

Quote:

Originally Posted by DonR (Post 259951)
My Mitsubishi does that now. If you are cruising along & "smack the loud pedal" the transmission hesitates, as it downshifts a few gears, before it lets the fun begin.
As Frank so eloquently put it, it normally happens while driving like an ass.

Don

I never really understood this or why an article would be written about it, on every autotragic I have driven over the last 16 years I have always selected the gear I wanted when I assumed I would be driving like an asse. In fact I've saved several transmissions this way because I noticed they were not shifting correctly. Dodge is notorious for the auto transmission not down shifting on its own, mine was staying in 4th at stop signs.

Perhaps people need to learn that they can control the car they drive.

mcguire 09-07-2011 03:01 PM

Now, just a darn minute....
 
Quote:

Originally Posted by suspectnumber961 (Post 259902)
Passing Fear: Do Fuel Economy Gains Compromise Quick Acceleration?: Scientific American

"As the car slows down, the transmission automatically downshifts into lower gears, but a sudden command to increase speed reverses that process and the transmission has to find the proper gear for quick acceleration."

Wait, what? Downshifting as you slow down should leave you in a better gear to accelerate at your new, slower speed.

Quote:

Originally Posted by euromodder
Automated manual transmissions like DSG shift up when you let go of the throttle - mimicing coasting. They shift down when speed drops below the threshold for a given gear.

Ok, that makes more sense. But I'm still not seeing the difference between that and a traditional automatic transmission that has to kick down into a lower gear when you whack open the throttle.

Ryland 09-07-2011 05:01 PM

The only two vehicles with automatics that I drive are the work truck with a partly wore out transmission and my bosses Saab 93 with twin turbos, both of them have a big lag, you get used to it in less then 5 minutes of driving, it's not a danger unless you are trying to cut someone off or driving in some other unsafe manner.


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