Not Just Engines, but Transmission will Make a World of Difference - Fuel Economy, Hypermiling, EcoModding News and Forum

SVOboy · 05-19-2009, 02:10 PM

Most of the time these pages are covered with discussion about electric, hybrid, or efficient combustion engine news and opinion. However, there is more to a car than the power source. An under-appreciated, but still very important part of any car is its transmission. In fact, as far as fuel economy goes, transmissions can either make [...] Related posts:

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Daox · 05-19-2009, 02:20 PM

Good thing you wrote that article. I could rant all day about the stupidity of short gearing.

Bicycle Bob · 05-19-2009, 09:13 PM

One guy driving my car didn't even bother trying 5th, because he was expecting a large jump to a super-economy gear. As engines become more flexible, there's more need for wide range transmissions, but not so much for close ratios. Adding more intermediate gears adds weight for a small performance gain. I'd like to see the usual cruising gear be direct drive, too. The customer might want to choose between having that as the top gear, or the next-to-top, for the urbanite.

LeanBurninating · 05-19-2009, 09:35 PM

Nice article!

Quote:

Originally Posted by Daox

Good thing you wrote that article. I could rant all day about the stupidity of short gearing.

Oh man would you hate race cars. I have friends with cars that they've modified so that they are doing over 4,000 rpms on the freeway. It makes em faster though! Some people care more about that.

roflwaffle · 05-20-2009, 02:40 AM

Quote:

Originally Posted by LeanBurninating

Nice article!

Oh man would you hate race cars. I have friends with cars that they've modified so that they are doing over 4,000 rpms on the freeway. It makes em faster though! Some people care more about that.

Well, at least until they run out of gear.

I can't say I'm opposed to a closer 1-4, topping out at ~80-90mph, and a super-low 5 for good highway mileage.

LeanBurninating · 05-20-2009, 02:55 AM

Then you would probably love a mustang. At least the 96-04s. Dunno bout the old 5.0s but the mod motor mustangs, when you shift into 5th from the very top of 4th gear it will drop the revs down below 3k... really low. lol.

bgd73 · 05-20-2009, 03:25 AM

the tranny does indeed need a world of genius all for its own engine. It is a big reason even sideways FWD is attractive for ecomod. Foriegn cars have been doing this a loooong time.
GM being a shame to me right now, did have a winner that I do not easily forget, because it was a first. Anyone remember the 200r4 mated to a 305 v8?
That one transmission allowed me to see the 20s mpg, and a longevity unheard of for the goofy v8 (200k+ miles on the odom and the norm 1500 miles per quart of oil). It goes to agree with the article, that transmissions can make or break an exact engine...even if the engine is less than perfect. I wonder if it can make or break entire corporations, then nations, then create great depressions and despair taken over by the gov't. All because the hot rod was a gear short and a day late.

Frank Lee · 05-20-2009, 03:46 AM

Quote:

Originally Posted by Bicycle Bob

As engines become more flexible, there's more need for wide range transmissions, but not so much for close ratios. Adding more intermediate gears adds weight for a small performance gain.

This close-ratio thing is to allow the heavy OD without acceleration penalty. IMHO people have gotten spoiled by excessive acceleration capability- you know, the whole new Civic having more power and faster accel. than older Corvettes thing. It just isn't necessary. With that in mind, I'd say I'm not impressed with more ratios; just give me wider ratios. Like Bob said, the extra gears add more weight... but the biggie to me is, at least in a stick tranny, ALL the gears are in constant mesh whether they are being "used" or not. Doesn't it stand to reason, then, more gearsets = more transmission losses? If I could have a wide ratio 3 or 4 speed stick because there is a driveline efficiency advantage vs 5 or 6 speed, that's what I would get.

aerohead · 06-09-2009, 02:37 PM

I think Lexus is up to 8-gears now.Mercedes has a 7-spd.-------- According to SAE,a 12-speed tranny offers the same BSFC efficiency as a CVT.I've not seen any remarkable mpg from the cars with CVT,as was promised in articles extolling the virtues of the Van Dorn transmission.I hope they can get it right,or get the 12-speed out.A tranny like that won't need to be bullet-proof and massive as the engine can just stay in the sweet-spot,crankin' out h.p. and torque with gentle splits between gears.