Pure City Driving MPG

[bronsin]

Originally Posted by jayeh

Anyone track their average speed with a scan gauge?

From what everyone here is reporting there must be something terribly wrong with my car since I'm only getting 23-25mpg per tank, but I'm willing to bet that it's because everyone does far more suburban driving than I do. My average speed for the last tank was 24mph and I got 23mpg.

I doubt you got into high gear at all.

[shepd]

Winter hurts your mpg because the car is open loop until the engine warms up. In the summer, that's really fast. In the winter, you could be driving for several minutes with horrible gas mileage. Idling doesn't really help because it's still open loop and it takes a very long time to get the engine warm when it doesn't have a load.

[edmscan]

Originally Posted by shepd

Winter hurts your mpg because the car is open loop until the engine warms up. In the summer, that's really fast. In the winter, you could be driving for several minutes with horrible gas mileage. Idling doesn't really help because it's still open loop and it takes a very long time to get the engine warm when it doesn't have a load.

I just checked my mileage and this is so true. I have gone from a high of 5.4 L/100 km (43.53 mpg) to a low of 9.63 L/100 Km (24.43 MPG). That is with .. very very little highway driving. I hate going on the highway.

That was obviously in the summer and winter respectively. My ScanGauge backs up my thoughts .. mileage is bad bad on any short winter trips.

[Ben_]

I get something around 24 when I'm driving on the race track at miller motorsports on a tank

During regular driving (75% city less than 45mph) I get about 32-36mpg with somewhat not mpg oriented driving

[Jcp123]

Pure city...anywhere from 17ish loaded with myself, wife, and two kids in Dallas CBD with A/C running full blast to mid-30s running errands around home. Depends on the errand trip though, I can manage lower 40s on certain drives.

[BennyLava]

I don't understand the disparity in mileages here. Are you guys a bunch of leadfoots? LOL

I usually see low 30's. The lowest I ever got in pure city was 29. This is all tested at the pump, I don't have a scangauge. Then again, I don't do traffic jams either. I either won't go to the city, or won't go during traffic times. I work in a smaller town.

[Amdkt7]

Using a Scan Gauge to monitor the fuel economy during driving can be very revealing. Watching the instant MPG read out you will see something like 4-8 mpg in first gear (moderate acceleration). Shift to second and it goes up to around 12, third around 18 MPG, fourth gear 23 MPG, and fifth would be around 26.

The important take away from that is that fifth gear is where you want to be. The more time you spend in the low gears the more fuel you burn with out actually moving on down the road.

Of course when you are at traffic lights your efficiency goes to zero.

I mainly monitor my average and pay little attention to the instant reading as pulse and glide works better than a light foot. Get up to speed as quick as you can, traffic permitting. One half throttle does not seem to be too much, and shifting too early is wasted effort as well. Best to shift around 3k RPM so as to operate the engine in the most efficient band, then once you can get to the highest gear you can then back off and drive with a light foot at low rpm.

[Jcp123]

When I stayed at a hotel in Dallas CBD, my trips were 17-28mpg when I had no or precious little freeway use.

[Jcp123]

Originally Posted by Amdkt7

Using a Scan Gauge to monitor the fuel economy during driving can be very revealing. Watching the instant MPG read out you will see something like 4-8 mpg in first gear (moderate acceleration). Shift to second and it goes up to around 12, third around 18 MPG, fourth gear 23 MPG, and fifth would be around 26.

The important take away from that is that fifth gear is where you want to be. The more time you spend in the low gears the more fuel you burn with out actually moving on down the road.

Of course when you are at traffic lights your efficiency goes to zero.

I mainly monitor my average and pay little attention to the instant reading as pulse and glide works better than a light foot. Get up to speed as quick as you can, traffic permitting. One half throttle does not seem to be too much, and shifting too early is wasted effort as well. Best to shift around 3k RPM so as to operate the engine in the most efficient band, then once you can get to the highest gear you can then back off and drive with a light foot at low rpm.

Actually, low rpm/high load is where the gold is at. SG or an UltraGauge (what I'm now using) can calculate load, typically you want the highest load you can get without popping the car into open loop.

Doesn't work as well for us with autotragic transmissions. My Echo basically lives under 2000rpm.

[Jcp123]

Originally Posted by shepd

Winter hurts your mpg because the car is open loop until the engine warms up. In the summer, that's really fast. In the winter, you could be driving for several minutes with horrible gas mileage. Idling doesn't really help because it's still open loop and it takes a very long time to get the engine warm when it doesn't have a load.

My Echo really doesn't run open loop for very long. A half-mile is the longest it's ever taken for it to heat the O2 sensors enough to run closed loop.

[Amdkt7]

I have experimented with both low rpm/high load and just get to fifth as quick as possible. I could not really tell any difference, I could still exceed 50 mpg on my 20 mile commute to work even when I raced away from every traffic light.

Think about how long it takes to get to 5th when you shift too early. I find that getting in 5th as soon as you can saves in the long run. Try it and see if you notice any difference. I'm getting good results with a automatic Corolla doing the same thing.

[Amdkt7]

The Yaris does warm up fast when driven, however on short trips no matter what I do that warm up costs so much that it takes at least five miles to get my average mpg up to 40. Short trips suck, best to combine them if possible.

[Jcp123]

No matter how you do it, getting to top gear early is beneficial.

My SVT Focus was good at this. In 6th by 30mph. Only averaged 28mpg in that thing though, plus it needed hi-test.

[Jcp123]

Originally Posted by Amdkt7

The Yaris does warm up fast when driven, however on short trips no matter what I do that warm up costs so much that it takes at least five miles to get my average mpg up to 40. Short trips suck, best to combine them if possible.

True. My commute is 7.5mi each way, and it takes a while to bust through the 40mpg mark.