How Do You Keep An Auto Trans In The Highest Gear?

[sbergman27]

Originally Posted by bronsin

Let me tell you something about engineers and scientests. They are IDIOTS just like...

Wow. Did an engineering student once steal your girlfriend or something? You may want to consider seeking help for this unhealthy obsession.

Using coolant temperature as a factor in adjusting the fuel map, ignition timing curve, or whatever, is hardly creating a "rat's nest". But you're certainly welcome to investigate your options for re-flashing the whole ECU with your own software image. Then you could set it so that only 4th and reverse were available.

You'd need the proper interface equipment and communications software. A decompiler, a compiler. Some knowledge of embedded programming. A firm grasp of the details of the Yaris' various systems. And also of the relevant legal codes for your country and province. I'd be daunted by the task, even though I'm a programmer. But you seem really smart, so I expect you'd have no trouble.

And surely *that* would be enough to get you from point A to point B on these fictitious... err... desolate Canadian roads where it takes every last drop in the Yaris' 11.2 gallon tank to get you from one gas station to the next.

But first, you might want to verify that the existing transmission control algorithm is actually hurting, and not improving, overall fuel economy. You could enlist the help of someone with a 5 spd and a Scangauge II to do some preliminary testing. Not a perfect simulation, to be sure, since it leaves the torque converter, among other things, out of the equation. But nonetheless, it would be interesting to see the results.

-Steve

[bronsin]

Originally Posted by sbergman27

Wow. Did an engineering student once steal your girlfriend or something? .

-Steve

No. They were so imcompetant it nearly cost me my job.

[sbergman27]

Originally Posted by bronsin

No. They were so imcompetant it nearly cost me my job.

I'd suggest being careful when tempted to make wild generalizations.

At any rate, if you are serious about this, one thing you definitely should consider is a block heater. Why trick the ECU into thinking the engine is warm when you can actually make it so? With a good hefty one (say 1500W) you could either put it on a timer, if your schedule is predictable, or toggle it on a half hour before you leave the house.

Also, I'm quite serious about partnering with someone on the board to take some actual measurements of how fuel use varies with transmission shifting strategies during warm up. Also interesting would be engine wear info... which is not something that we're going to be able to do in a home-spun way.

Driveability and emissions requirements are other possible reasons for the lockouts. The more I think about it, the more "emissions" seems like a likely reason. I don't pretend to know the answers. But clearly, you want to have some understanding of the strategy you are modifying before you modify it.

In fact, when it comes to these kinds of things, the long-term educational aspects almost always outweigh any perceived short-term goals. For me, the short-term goals are usually just convenient motivators to make the game more exciting.

In my heyday in the 70s, I did a lot more fiddling with the 1968 Cadillac Fleetwood Brougham that I was forever trying to "upgrade" to compete with the 1976 Fleetwood, which I considered to be the bee's knees at the time. (Truth be known, I kinda still do.)

I learned a lot. But I ended up eventually ruining the car. (Though it took me 20 years to do it, and another 10 to realize that I had.) Fortunately, I had another... a twin... which had originally belonged to my father's business partner. And it survives to this day, though I don't drive it much, these days.

Anyway, the point is that there is much value in studying the theory, however much fun soldering in the mods might be.

And do be careful what you wish for. ;-)

-Steve

[bronsin]

I have a 700 watt hot plate I used to use under my 240D on cold mornings. Set on a timer to give a half hour burn before departure time, you could feel the warmth on the valve covers.

That would also have the effect of warming the engine much nearer to operating temps. Which could be very good!

[SAV912]

Originally Posted by bronsin

And the reason is...THEY ARE MORONS!

Yeah, right. A wild generalization based on some engineers you worked with in a category that had nothing to do with automobile manufacturing.

You know what would be a lot easier than creating a potential problem by programming an ATX to do something it wasn't intended to do? A block heater. Engine is warm upon start up, and you get your shift to 4th right away. Rest of the country in winter has this figured out, don't know why it's so difficult.

And as far as the best fuel economy, cruise control isn't the way to go either, yet you added that to your car. Maybe you'll get a little more respect with your answers to your threads after you stop painting an entire industry of people with one brush. Not all of us are the idiots you proclaim us to be because you had an incident with a select few several years ago.

To answer your question for this thread though, it's about 30 MPH, but it all depends on load. Drive as if there's an egg under the gas pedal, you'll be in 4th gear nearly all the time.

-C

[bronsin]

Well I would like my transmission in the highest possible gear as soon as possible. I seldom drive more than 6 or 7 miles at a time so every little bit helps. Doubly so now that they are putting mileage robbing alcohol in our gas and charging us $4 a gallon (and soon to be more?) for it. If I could drive a manual I would but I cant. I have no sensation in my feet and pushing in a clutch pedal (over time) makes it almost too painfull in my left foot to walk.

[sbergman27]

Originally Posted by bronsin

Doubly so now that they are putting mileage robbing alcohol in our gas and charging us $4 a gallon (and soon to be more?) for it.

Let's try to limit the misinformation. E10 fuel contains about 3% less energy than E0. And indeed, controlled testing generally shows a +1% to -4% change in fuel economy, with an average around -3%.

I'm not sure about Canada, but in the US E10 is generally about 3% (~11 cents/gal) cheaper. So the effective price is essentially equivalent.

-Steve

[jambo101]

Originally Posted by bronsin

Or: what is the slowest speed you can go in a Yaris and still be in 4th? I ask because I may be driving in remote sections of Canada this summer where roads are bad and fuel infrequent. I will need to maximize fuel economy at times.

Thanks!

I cant believe there are normal roads in Canada where a 700km range wont get you to a gas station.if you are worried about running out of gas just pack a red plastic 5gal gas tank for the long stretches..

[bronsin]

Originally Posted by jambo101

I cant believe there are normal roads in Canada where a 700km range wont get you to a gas station.if you are worried about running out of gas just pack a red plastic 5gal gas tank for the long stretches..

You are probably right BUT sometimes stations are closed or out of fuel. You dont take chances period. Or at least I dont. 30 years of flying airplanes and riding motorcycles makes me plan every move very seriously.

These roads arent normal though. They are the roads from Dawson to Inuvik and Fairbanks to Prudehoe Bay (Alaska I know)

[sbergman27]

Originally Posted by jambo101

I cant believe there are normal roads in Canada where a 700km range wont get you to a gas station.

Yep. That new-fangled Trans-Canada Highway thing of yours has really changed the face of driving in the Great White North.

I remember when I was growing up in the 70's, I'd occasionally encounter an out-of-stater who would admit that he had thought that we still drove to work in covered wagons. :-)

-Steve

[sbergman27]

Originally Posted by bronsin

You are probably right BUT sometimes stations are closed or out of fuel.

Pay-at-the-pump has pretty well done away with "closed" gas stations. These days, I'm seeing more and more which are completely unattended. No associated convenience store or payment booth. Just a CCTV camera and some pumps with credit card slots.

Or at least I dont. 30 years of flying airplanes...

Yep. Sucks when the Astro-Shell runs out just when you really need it.

These roads arent normal though. They are the roads from Dawson to Inuvik and Fairbanks to Prudehoe Bay (Alaska I know)

You're going to want a good GPS that covers that area anyway. Go ahead and Amazon one in ahead of time to calm your nerves. Plot the route and select Destination->Point of Interest->Along route->Gas stations. I can set my TomTom unit to alert me when I am within x miles of a station.

BTW, while NAVTEQ maps are not my favorite, they do seem to have the most complete list of points of interest, including fuel stations.

I prefer my TomTom unit, but it seems not to know about many gas stations which do, in fact, exist. At least in OK, KS, CO, NM, and TX which is where I mostly drive.

P.S. And my! What a beautiful drive this will be!
Route on Google Maps.

[MadMax]

[MUSKOKA800]

Originally Posted by bronsin

Or: what is the slowest speed you can go in a Yaris and still be in 4th? I ask because I may be driving in remote sections of Canada this summer where roads are bad and fuel infrequent. I will need to maximize fuel economy at times.

Thanks!

I honestly think that lugging your engine would yield worse mileage than driving with the rev's in the desired torque band where efficiency would be at it's max. Just be gentle on the pedal and let the Toyota engineering keep you in the pink.
Enjoy your trip!

[41magmag41]

I checked gas mileage yesterday morning with my scan gauge during the warm up run to work. It was 31 degrees out. With the transmission lock out until warm up at 40 mph in third gear the scan gauge read 32 mpg the entire time before the car reached 137 degrees and it kicked into fourth. I don't consider that lousy gas mileage.

I think all this yaking about overriding the computer to get better gas mileage for a couple of minutes will do more harm than good. I've just offered proof that the car still gets decent mileage when it's in the warm up mode before 4th gear is available. Why not leave well enough along. My girl has 98000 miles on her and I average 38 to 41 mpg year round when averaged together. I don't baby her in the interstate, run 75 to 80, and still get good economy.

Much to do about nothing other than to hear yourselves talk. Have a good day.

[bronsin]

Originally Posted by 41magmag41

I checked gas mileage yesterday morning with my scan gauge during the warm up run to work. It was 31 degrees out. With the transmission lock out until warm up at 40 mph in third gear the scan gauge read 32 mpg the entire time before the car reached 137 degrees and it kicked into fourth. I don't consider that lousy gas mileage.

I think all this yaking about overriding the computer to get better gas mileage for a couple of minutes will do more harm than good. I've just offered proof that the car still gets decent mileage when it's in the warm up mode before 4th gear is available. Why not leave well enough along. My girl has 98000 miles on her and I average 38 to 41 mpg year round when averaged together. I don't baby her in the interstate, run 75 to 80, and still get good economy.

Much to do about nothing other than to hear yourselves talk. Have a good day.

Yeah yeah yeah.

[41magmag41]

Originally Posted by bronsin

Yeah yeah yeah.

My point exactly about wanting to hear ones self yak. Proof given and even then we can't let the item go.

[bronsin]

Now that you mention it... should be charging admission?