It has changed a great deal in our ATF additive formulation work.
------- Trying to simplify my life...
November 05, 2019, 04:30 PM
kramden
With 5-6-8-and 10 speed transmission virtually everywhere now they are all Overdrive Transmissions.
November 05, 2019, 04:48 PM
Hamden106
We used to run Columbia rear ends in Continentals. Not sure of the actual ratios though
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November 05, 2019, 05:07 PM
beltfed21
Hi Max, in a nutshell, they are OD’s without having a named OD. You know my Vette. It has a 7 speed manual transmission in it. Sixth and seventh are OD gears. I only use seventh at interstate speeds. At 78mph in 7th the engine is only turning at 1400rpm.
******************************************** "On the other side of fear you will always find freedom"
November 05, 2019, 05:26 PM
hrcjon
2 posts above you. 2017 MX5, 1:1 in 6th gear, with the 6MT.
Uh. that's a stick. Original post "auto". I am still thinking there isn't any auto currently available without overdrive.
“So in war, the way is to avoid what is strong, and strike at what is weak.”
November 05, 2019, 06:43 PM
Budlum
quote:
Originally posted by Pipe Smoker: The overdrive gear in my dad’s 1950 Ford had free-wheeling capability. Going down a hill, the engine just turned at idle speed. I know of no cars that have that capability nowadays.
This would waste fuel in a modern engine as the injectors don't fire when coasting without a torque demand on the engine, i.e. no throttle input.
November 05, 2019, 07:28 PM
hrcjon
Technically it wouldn't waste fuel, but it is unnecessary and complex for the result..
“So in war, the way is to avoid what is strong, and strike at what is weak.”
November 05, 2019, 08:58 PM
Pipe Smoker
quote:
Originally posted by Budlum:
quote:
Originally posted by Pipe Smoker: The overdrive gear in my dad’s 1950 Ford had free-wheeling capability. Going down a hill, the engine just turned at idle speed. I know of no cars that have that capability nowadays.
This would waste fuel in a modern engine as the injectors don't fire when coasting without a torque demand on the engine, i.e. no throttle input.
There are safety issues with free-wheeling down a hill, but there’s no way that it would waste fuel.
Serious about crackers.
November 05, 2019, 09:14 PM
kkina
quote:
Originally posted by maxwayne: With the number of gears constantly increasing, do modern auto transmissions still have overdrive?
Depends what you mean by overdrive. Do you mean modern trannies where anything 5 and above is an overdrive ratio, or a separate OD gearbox that makes all output overdrive (and thus has a separate shift lever or electic switch to activate)?
Whenever the driver takes their foot off the accelerator without braking, the Coasting function (part of ECO PRO mode) cuts the power between the engine and drive in vehicles with an automatic transmission. The vehicle rolls along without any resistance from the engine, which rotates at idle speed consuming minimum fuel and with low emissions.
Not minority enough!
November 05, 2019, 09:15 PM
Budlum
quote:
Originally posted by Pipe Smoker:
quote:
Originally posted by Budlum:
quote:
Originally posted by Pipe Smoker: The overdrive gear in my dad’s 1950 Ford had free-wheeling capability. Going down a hill, the engine just turned at idle speed. I know of no cars that have that capability nowadays.
This would waste fuel in a modern engine as the injectors don't fire when coasting without a torque demand on the engine, i.e. no throttle input.
There are safety issues with free-wheeling down a hill, but there’s no way that it would waste fuel.
An engine at idle decoupled from the transmission requires fuel. An engine rotating above idle coupled to the transmission is not metering fuel to the injectors and is not using fuel.