Fuel Efficiency and the Yaris

[Hershey]

we drive from start up if possible . Depends if there's frost , ice , or snow on it .

[Hershey]

The ECO-METER shows good amount of fuel consumption when using the AVERAGE M.P.G. MODE if have to let it defrost thanks to higher idle at start ups and the tranny remains in 3rd gear until car reaches normal operating temperature ( blue light goes out ) .

[R2D2]

I'm in the drive easy until it warms up crowd. I give it a good 15 sec after I start it then drive very gently and keep the rpms down until it warms up. I clear the ice and snow before I start it. I do use a block heater when it's cold though.

R2

[sbergman27]

Originally Posted by Hershey

and the tranny remains in 3rd gear until car reaches normal operating temperature ( blue light goes out ) .

Yeah, what's up with that? I Just checked by starting and immediately getting on the 60 MPH expressway and the transmission really does wait that long to kick into 4th. In fact, whereas the light goes out at 130F, the transmission actually waited until more like 139F. Although the temperature was increasing fast enough that those events were actually within about 10 seconds of each other.

I'm wondering what the rationale is for locking out 4th at low engine temperatures. I tend to want the transmission to keep the RPMs *lower* when the engine is cold.

-Steve

[Hershey]

takes ours about 1 mile before it's capable of using overdrive . We drive under 40 m.p.h. to help keep the R.P.M.s down . Also try to leave the heater core on cold to cut off flow of antifreeze to speed up the use of 4th gear . Then turn on heat if needed . Figure less distance for coolant to travel letting the anti-freeze go around engine picking up the heat generated to help with quicker normal temperature operation so blue light disappears and idle drops sooner . Thus saving some fuel . Is a nuisance .

[Hershey]

since removal of 4 studded tires and warmer weather the 2010 3 door with auto is now getting 40 + miles per gallon . This is VALERO 87 octane ( 10% ethanol ) at 1 click of nozzle at full speed ( always same pump ) , tires set at 36 p.s.i. , 2 people , some headwinds of 25 + m.p.h. , and an average of 50 m.p.h.. Before were lucky to get 36 . Not sure if summer blend has reached our region as of yet , if not can possibly see more of increase . 1st fill after removal of studded snows the calculated mileage was 44 while the ECO-METER read 41 . Which one should we believe . That's the most the E.M. has ever been off ( wonder if E.M. was only familiar with the studded snows ? ) . Before the E.M. has been only off by less than .5 below the calculated mileage . Either way I'll take it . 44 be nicer . Since the 2nd fill the car lost the 1st bar at 80.1 miles and is averaging 41.1 on the E.M..

[sbergman27]

Originally Posted by Hershey

Also try to leave the heater core on cold to cut off flow of antifreeze to speed up the use of 4th gear . Then turn on heat if needed .

Note that this practice makes a *substantial* difference. Even in relatively mild winter weather, say 50F, the Yaris is unable to maintain a coolant temperature of more than about 155F at idle with the heater on high. It's 30F here right now and I just got back from a trip to Walmart. I know from experience that with the heater off, the engine reaches 130F and the "cool" light goes off before I get to the Walmart parking lot. This morning, I left the heater on high. It didn't hit 130F until I was almost *back home* on the return trip. And when I pulled into my parking space, the temp was 136F. That's still 4 degrees shy of when the transmission would have made 4th gear and converter locking available. (And the interior wasn't exactly toasty yet.)

The heater on the Yaris can accurately be considered an auxiliary radiator.

-Steve

[Hershey]

. Literally .

[BailOut]

All the more reason to use a grille block in the cold months. I just took mine back out last weekend. I'll put it back in sometime in November or December.

[sbergman27]

Originally Posted by BailOut

All the more reason to use a grille block in the cold months. I just took mine back out last weekend. I'll put it back in sometime in November or December.

There was a post on teamswift.net some time back from a guy who lived in (I think) Alaska... or Antarctica... or somewhere. He posted an interesting HowTo on lining the bottom side of the hood of his Geo Metro with a heat reflective blanket with a layer of insulation bonded to the back of it. The idea being to reflect any radiant heat back onto the engine, while providing extra insulation, as well.

As you know, I'm a sort of show-me-the-data kind of guy... so I'm not actually advocating this. But it is, at least, an interesting idea. Especially for perpetually cold climates. I assume that he already used a grille block.

Funny... those fake louvres we see on some cars as decorations (Hi 1979 Lincoln Mark V! I'm thinking of you!) used to actually function, back in the day. The driver had a pull-knob to close them to facilitate warm up. Then again, the driver also had a choke pull-knob and an ignition timing pull-knob. Always remember to pull both of those before trying to start the car. Failing to retard the timing could actually be deadly to the person turning the starting crank.[1] But that issue was a bit earlier, back in the 1900s and 1910s. It was a fellow whose friend was killed in just such a timing/crank accident who invented the electric starter which Cadillac introduced in 1912.

-Steve

[1] Consider what happens when the timing is advanced before TDC.

[sbergman27]

Originally Posted by R2D2

I'm in the drive easy until it warms up crowd.

Me too. This morning, I did run a test to get an idea how much (or little) fuel it actually takes to warm the engine to 128F (when the "Cool" light goes off), and to 140F, when the automatic transmission makes 4th gear and torque converter lock-up available. I found the answer to be a bit surprising. At an ambient temperature of 43F, it's only 0.03 gallons in both cases. (Scangauge doesn't go beyond 0.01 gal precision.) The "Cool" light went off just as the readout clicked over to 0.03. This is significantly less than I would have guessed.

-Steve

[Loren]

Sounds insignificant when you put it that way. And for someone who puts a lot of miles on their car every day, it probably is.

My typical trip is 3-5 miles. At 40 mpg, that's an average of about .10 gallons per trip.

If I let the car sit and warm up before every trip, I'd use 30% more fuel!!!

(even if you only count the .03 gallons on the initial start-up, it still adds up to 15% of my total fuel usage on a typical day)

Needless to say, I'm in the "drive it easy until it warms up" contingent. I get in the car, buckle my seatbelt, put the transmission in gear (manual trans), release the handbrake and check my mirrors all before turning the key. As soon as the engine is started I'm letting the clutch out and backing out of my driveway!

Unless the air temp is fairly cool (below 60-65 degrees), the "cool" light is usually off after the 3rd stop sign in my neighborhood, just before I turn onto the main road.

[sbergman27]

Originally Posted by Loren

Sounds insignificant when you put it that way. And for someone who puts a lot of miles on their car every day, it probably is. My typical trip is 3-5 miles. At 40 mpg, that's an average of about .10 gallons per trip.

Yes, indeed. I'm not necessarily *prescribing* anything. My usage is substantially skewed towards longs trips where I get in the car at 6 AM in Alamogordo, New Mexico, and get out of the car, not knowing what time it is, in "What Town Was This, Again", Montana. No one even bothered to find out what the warm up fuel consumption was before having a back and forth discussion of the relative merits of warming up the car earlier in this thread.

I'd just like to see more quantitative discussions.

City driving *is* admittedly a lot messier, though.

-Steve

[sbergman27]

Originally Posted by Loren

My typical trip is 3-5 miles. At 40 mpg, that's an average of about .10 gallons per trip. If I let the car sit and warm up before every trip, I'd use 30% more fuel!!!

No. Because even driving gently, you'd be using a lot more fuel than the tiny sip the engine takes at idle. And that additional fuel would be used under cold conditions in which the engine would be consuming significantly more fuel per horsepower-second than it would if it had been warmed up (investing that 0.03 gal of fuel) first.

My *intuition* agrees with you. But my intuition could be as wrong as yours. We need to test experimentally. (My bad. I haven't gotten to it.) Otherwise, we're no better scientists than was Aristotle.

-Steve

[Loren]

I get what you're saying. Potentially, the fuel used to warm-up plus the first mile or so of driving a WARMED UP engine could add up to less fuel usage than driving a cold engine for a mile or so. Maybe in some super-cold climate this might be possible. I can tell you from my observations in MY climate (Florida, almost always above 60 degrees) using a ScanGauge that eliminating the warm-up gives me better results. I don't need to quantify it more than that for my own purposes.

I'm not a "pure numbers" guy. I understand the physics and usually have a grasp on the math involved, but I "live" the philosophy derived from it.

[sbergman27]

Originally Posted by Loren

I can tell you from my observations in MY climate (Florida, almost always above 60 degrees) using a ScanGauge that eliminating the warm-up gives me better results.

You know what? If your State weren't so damned far away, I'd likely be there every weekend from November through March.

A simple Golden Girls episode on this difficult and thorny social issue would have been nice. I'd love to have seen Betty White trying to work the ScanGauge...

:-)

-Steve

[rene0023]

Very useful information...

[Chaldon]

jeeze, 11 pages!!! I'll have to take a break and come back...