list of gas saving tips from best to worst

[theholycow]

Actually, I thought of a reason that would be meaningful for some cars but is not universally practiced. If the direct drive gear is used on the way to 60mph then its better efficiency contributes to lowering 0-60 time. Seems like most cars reach 60 in 2nd gear these days, though.

[hoihoi]

I converted my regular bicycle into a moped using a Grubee Skyhawk bicycle engine kit from BikeBerry.com http://www.bikeberry.com/grubee-skyh...certified.html

My motorized bike has become my main form of transportation and now spend close to nothing on gas. It's a heck of a good time too

[theholycow]

Originally Posted by theholycow

Actually, I thought of a reason that would be meaningful for some cars but is not universally practiced. If the direct drive gear is used on the way to 60mph then its better efficiency contributes to lowering 0-60 time. Seems like most cars reach 60 in 2nd gear these days, though.

I came up with some guesses:
1. Marketing.
2. Packaging or engineering issues for really short gears in the transmission or really tall gears in the rear end.

I asked a retired Chrysler manual transmission engineer, and it turns out I was right:
http://standardshift.com/forum/viewt...325102#p325102
...making such an extremely short 1st gear is subject to packaging, engineering, and cost issues.

[theclencher]

Interesting. I knew that gearsets got more efficient as they approached 1:1 ratio, but I hadn't considered strength.

Even so, I can't get rid of the notion of a 1:1 direct top "gear" as being the ultimate for drivetrain efficiency.

[benfrogg]

HC-
Couldn't you still change your final drive or rear end ratio in Christine? Then, you could just avoid using the overdrive altogether. It would seem like an oxymoron to have a taller overdrive and not use it, but it would be an interesting experiment. Perhaps you could just swap on some very tall rear tires for a tank (and not use the overdrive) and see what happens? That assumes you have access to cheap/free/loaned rears that are a lot taller.
Just a thought.
B

[theholycow]

I thought of the same experiment. I'd miss using 5th gear but it should work.

Doing it by tire size wouldn't work; I'd need really huge tires which wouldn't fit under the car as well as changing too many variables. Doing it with gears is not within my budget or my DIY capabilities right now...I've read instructions and it doesn't look like I could do it right.

[theclencher]

I wouldn't try to swap the gears out themselves for that; I'd find a scrapyard axle with the desired ratio and stick the whole thing in. That's relatively simple, cheap, and easy.

[theholycow]

Good point. I think that's out of my budget too, but it is at least (probably) within my ability.

[theholycow]

Originally Posted by theholycow

I asked a retired Chrysler manual transmission engineer, and it turns out I was right:
http://standardshift.com/forum/viewt...325102#p325102
...making such an extremely short 1st gear is subject to packaging, engineering, and cost issues.

He posted again and pointed out that direct drive is only used in traditional RWD FR layouts. In FWD and MR/RR layouts it's not possible to have direct drive.


So, it wouldn't even be worth the development cost for manual transmissions...how many RWD manual transmissions are sold anymore? Very few!

[theclencher]

Sure looks possible to me... but at the expense of another gearset for the primary shaft to drive all the lower gears OR use the tall final drive only as the direct drive power path (Tempos have 2 final drives!)