transmission question - Kia K900 Forum
 
LinkBack Thread Tools
post #1 of 3 Old 06-16-2018, 02:47 PM Thread Starter
Senior Member
 
Join Date: Nov 2017
Posts: 292
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Default transmission question

I was browsing K900 YouTube videos, and ran across one that said the three top gears of the 8-speed are all overdrive.

Is that true? What could be the use of so many? In around-town driving, you could probably never use them at all, and I don't see a need for three even on the highway.
K9Intender is offline  
post #2 of 3 Old 06-18-2018, 11:55 AM
Member
 
Join Date: May 2017
Posts: 93
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Default

Improved performance and better fuel economy. More gears means a greater ratio spread between them, meaning the engine has more options for optimal operation. Transmissions with more gears allow for a higher first drive ratio, and a very low ratio overdrive gear. If the transmission is calibrated properly, more can also provide smoother shifting, and so more comfortable driving.

That said, the improved performance/comfort aspect seems to account for about 10-20% of the reason. The remainder is improved fuel economy, which is extremely important for meeting CAFE fleet averages. 0.1 or 0.2 mpg is essentially irrelevant to the owner of the car, but it can mean millions of dollars for the manufacturer in terms of avoiding government penalties. CAFE is also the reason for direct injection engines, start-stop systems that shut off your engine at stoplights, the elimination of spare tires in many models and other changes that make little sense otherwise.

So long story short, small improvements to fuel economy that boost CAFE fleet averages are why manufacturers are almost universally using 8, 9 and even 10 speed transmissions in new cars.
Zathras is offline  
post #3 of 3 Old 06-18-2018, 05:54 PM Thread Starter
Senior Member
 
Join Date: Nov 2017
Posts: 292
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Default

All true, no doubt, but I'm still wondering why three overdrives? That seems like overkill, even considering CAFE, etc.

BTW, I'm not finding that either the multi-gear trans or the ECO drive mode do much for the K900's fuel economy. It REALLY likes gas, and mind you, I generally drive a Town Car, so I'm not easy to impress in that regard. But I'm impressed.
K9Intender is offline  
Reply

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome