Gas Mileage with my 2009 Yaris Sedan

[voodoo22]

Originally Posted by Rick

Voodoo22,

How many miles between cold-start cycles are you running? I live in the exurbs and commute into the outer suburbs via 2 lane county roads. I'm close to tank averages of 47 MPG but wonder if it can really get much higher with basically a cold-start cycle every 23 miles. As others have noted, the cold-starts are a big MPG killer.

HI Rick,

averaging 47mpg is fantastic. With numbers like that you don't have much margin of error to gain more, but I'd wager you could get it over 50 at least some times. If you aren't already, try accelerating slower and keeping your speed under 55mph if possible. Supposedly 45mph is the sweet spot. I generally go between 50-55mph on the hwy I travel.

My commute is 52kms or about 32miles each way. The cold start is definitely a killer. I've really put a lot of effort into combining short trips udner 20 kms together or not driving all together when possible. When I recently got my best tank ever of just over 55mpg, I had virtually no short trips that tank, like the 2 km drive to pick my wife up at work.

From what I've read written by people with scan gauges, it takes about 23 kms or 14 miles for our cars to warm up into the optimum operating temperature range.

[Woody_Woodchuck]

Voodoo is correct again! Except part of “If you have a MT you can go faster and use more elaborate techniques” We can use more techniques but we can not drive as fast, the manual transmission has higher rpm’s for any given speed.

45 to 50 mph is the sweet spot I found, depending on terrain. If it is flat, 45 all the way! At 40 mph you have nothing to accelerate with and need to downshift. If there are rolling hills you will need to press 55 mph at times, bleeding to 45 or 50, to make sure you have momentum to make it over them. 50 is a good all around cruising speed, you can accelerate if needed without flooring it. I have to do 55 on the highway because of traffic and the speed limit is 65 mph.

It took me 23 tanks to break 47 mpg, you are doing great! How have you accomplished that, what are your driving techniques?

A big gainer for me is in the first part of my 30 mile daily commute the back country roads are free of traffic most of the time. I can shift and let the car ‘idle’ along at the high idle 1,500 rpm’s in 5th gear. Within a mile I can be up to 55 mpg but, there are small rolling hills and in 1.5 miles I am around 35 mpg. Accelerating as slow as you can stand is also a big gainer. There is no need to shift to a higher gear and lug it, the SG actually reports lower mpg’s doing that. I can ‘feel’ when it is time to shift, you will notice no more acceleration in that gear without pressing much harder on the gas than you did to get to where you are (the speed you are currently at). Not sure of the rpm’s at each shift, I just go be feel. But, using the SG2 I rarely go over 3,000 rpm’s on any commute.

Sorry to hijack from Tomsters original post. Give it a couple tanks Tom, my first one was way low as the dealer did not fill completely.

[voodoo22]

Originally Posted by Woody_Woodchuck

Voodoo is correct again! Except part of “If you have a MT you can go faster and use more elaborate techniques” We can use more techniques but we can not drive as fast, the manual transmission has higher rpm’s for any given speed.

Thanks for correcting me. I guess when AT's started closing the gap on MT's on the FE numbers it wasn't actually an improvement in the AT technology as much as manufacturers gearing MT's more aggressively.

Thanks for posting such definitive information, it's stuff like that which helps out everyone interested in better FE.

[roxy1]

Originally Posted by voodoo22

Thanks for correcting me. I guess when AT's started closing the gap on MT's on the FE numbers it wasn't actually an improvement in the AT technology as much as manufacturers gearing MT's more aggressively.

Thanks for posting such definitive information, it's stuff like that which helps out everyone interested in better FE.

as i mentioned in another thread, the difference in rpm's between auto and manual yaris is minimal compare to, for example, the honda fit. i think that is more than offset by parasitic losses in the auto. fueleconomy.gov has a good sampling of real world numbers for yaris drivers. for any given speed the yaris manual is alway running ~200 rpm's higher, yet still averages out 4 mpg's higher than the auto yaris. by the time one gets to interstate speeds, i believe overcoming wind resistance becomes a much greater factor than a couple hundred rpm's.

[anonymous user]

Originally Posted by voodoo22

From what I've read written by people with scan gauges, it takes about 23 kms or 14 miles for our cars to warm up into the optimum operating temperature range.

If this is true, and most of my driving is under 14 miles per leg, then i must say that i'm getting pretty good results. One could only imagine how i'd do on longer trips, and with less traffic and crazy drivers. There are 597 square miles on this island, only about the size of houston, tx. But our population is close to a million! Traffic, congestion, ahh it sucks.