driving-style failure

[jcantara]

Hello Folks,

I'm not a complete stranger to the world of eco-modding, just didn't know it had a name or community I currently have an 05 Focus Hatch, but haven't 'done anything' to it yet.

My previous car (93 Plymouth Laser AWD Turbo), I rewrote some of the firmware in the ECU to give me different ignition timing, and fuel maps (in addition to some performance enhancements, like a two-step rev-limiter for drag racing). I had a palm-pilot hooked into the ECU's diagnostic output (OBD-I) to monitor the fuel, timing, and knock, so I could run it really lean and advanced without having to wonder if I was causing engine damage. If I tried I could get about 30 mpg on the Laser (if I didn't try it was more like 18 though, go turbo). I was in the process of working out a lean-burn mode in the ECU for the highway only, but then the valves and pistons got together and ruined my day.

I'm actually a little disappointed in the Focus in terms of MPG (everything else is quite good though, especially for the price). If I drive like I normally do (typical mass-hole) I get about 29.5 mpg. For a couple of tanks of gas last year I wanted to really see what driving style could do to help me out in terms of mileage, being upset that the mileage is supposed to be 30 city 36 highway. I tried really hard to lay off the pedal, drive carefully, and relatively slowly, try to coast as much as was safely possible, draft behind larger vehicles (safely) when possible on the highway, and ended up at... 30.5 mpg. That extra 1 mpg took so much effort and concentration and just doesn't seem worth it. I don't know how you guys do it, for the 2nd tank of gas I even tried bare-foot which I'd read could lead to more sensitive pedal application.

It stinks that the Focus which is nearly 1,000 lbs less, non-turbocharged, and smaller (though probably not sleeker) gets pretty much the same mpg as my last car, which was loud, fast, fun, and definitely not what you'd think of as 'an economy car' while the focus is definitely 'an economy car'. Admittedly I haven't done any tweaking, but still a little bit disappointing. Secondly, I was astonished that trying really hard to change my driving style and doing a lot of things I'd read about that seemed reasonably safe and non-interfering resulted in a net gain of 1 mpg. Any thoughts?

-Jesse

[Lazarus]

Welcome to the community. Is yours automatic or manual transmission and whats your commute like? Do you have any instrumentation that will give you instantaneous feed back as to current MPG?

Since you're no stranger to eco-driving it tough to tell without more info but driving habits along you should easily be able to beat EPA unless you have a really bad commute. Do you turn the engine off at light instead of idling?

[jcantara]

It's a manual, and it's mostly highway, then back roads with few stops, there is traffic some days, but it rarely stops, just slows, where I try to coast.

I don't have any instrumentation on the Focus yet. I just go by how much gas it takes to fill it up at the pump. This was my first real attempt at mpg-by-style aside from just 'taking it easy'. The last car I had would vary 13 mpg from 'taking it easy' to 'drive like a jerk', while the focus only seems to change 1 mpg between the two; it's just very curious.

To get into more detail, when I get 29.5 mpg here's my typical commute to work:
Start car, pull quickly into busy street, if I'm not braking I'm flooring it, or idling stopped. Get onto the highway at full-throttle, blast up to 85 mph. Speed to work for 20 mins braking for traffic. Take the exit, blast down the hilly, twisty back roads having fun going fast then braking hard for the turns.

When I got 30.5 mpg here's what I did:
Start car, very gingerly pull out into traffic making sure to keep back far enough so the stop-and-go turns into one smooth, slow drive forward. Coast as much as possible to stop signs and lights, then get on the highway gently at the least amount of throttle necessary to merge. Stay in the slow lane behind a big, steady moving truck the whole way to work, going 55-65. Get off the highway and drive slowly through the back roads giving myself plenty of time to coast for stops (nobody behind me at this point to worry about).

[Lazarus]

Originally Posted by jcantara

It's a manual, and it's mostly highway, then back roads with few stops, there is traffic some days, but it rarely stops, just slows, where I try to coast.

I don't have any instrumentation on the Focus yet. I just go by how much gas it takes to fill it up at the pump. This was my first real attempt at mpg-by-style aside from just 'taking it easy'. The last car I had would vary 13 mpg from 'taking it easy' to 'drive like a jerk', while the focus only seems to change 1 mpg between the two; it's just very curious.

What kind of speeds and rpm are you turning on the highway and are you up north where it's still relatively cold? Sorry just re-read it. Curious indeed. Is this the only 2 tanks you have checked?

[jcantara]

I edited my post with details

[MetroMPG]

That's really odd. Are you comparing driving styles/tank results from different times of year? EDIT: Just re-read your post. You did say that your attempt at efficiency was some time last year... but what season?

Depending on how far north you live, the impact of ambient temperature differences could easily dwarf the savings you'd see between those two driving styles (if the more efficient attempt was done in much colder weather than the fast driving).

If I were you, a ScanGauge would be on my ecomodding to-do list as item #1.

And... welcome to the site.

[LostCause]

I'm siding with the weather & ScanGauge suggestions, but others areas might be:

1.) Featherfooting isn't usually the best for fuel economy. You should see a noticeable difference from leadfooting, but the ideal is accelerating under load.

2.) Drive 55mph consistently. Accelerating and deccelerating between 55 and 65mph is worse then driving a constant speed. You should have seen a noticeable change anyways, though.

3.) You may have not been really getting 29mpg with your previous driving style or you might have gotten more than 30.5mpg by ecodriving. You'll know after repeated, full tank fillups.

I would try again for a longer period of time. Even if it doesn't net you any benefits, driving in a more relaxing and interactive manner should be enjoyable. If you see ecodriving as a chore to save a couple of bucks, I think you might be missing some of its more far reaching benefits.

[jcantara]

I definitely get 29.5 MPG with my normal driving style consistently. I keep track of every tank of fuel (for reasons other than mileage, it's a good barometer for problems with the engine too). 29.5 is my yearly average, in winter it averages 28, in summer, it's nearly 31. When I was doing the testing it was spring, so I was actually getting my average 29.5 driving normally. I ran through two whole tanks on the attempted-economy driving style, and only saw the 1 MPG increase on both tanks consistently, went back to my old style of driving, and right back to 29.5. I really forced myself to attempt to do it 'the right way' too, no cheating, though now that you say featherfooting isn't all that great, that was primarily what I was doing, just going slow and taking it easy.

I think I'm definitely more interested in (and capable of) mpg through mods. My last car, I had rewritten some code in the ECU to help with fuel economy unfortunately the newer the car is, the more complicated and locked down it becomes, so ECUs are less accessible; boo.

[jcantara]

Interesting stuff:
I just entered in the Focus to the system here, and went looking for data such as the drag, frontal area, mileage, etc. According to this website:
http://www.fueleconomy.gov/Feg/noframes/20703.shtml
The economy (city/highway/combined) is listed as:
22/32/26

Whereas I'm absolutely certain the window-sticker said 30/36 for city/highway when I bought it... I hate how numbers like these seem to change willy nilly, and apparently are just made up by the manufacturer to suit their needs. Anyway, it makes me feel better about my 29.5 MPG average I suppose.

Also interestingly, I looked up the aero info on my last car that annoyingly got the same mileage as the Focus, and it has a Cd of only .3 and a frontal area of only 19.3. It was a lot shorter, sleeker car.

[Lazarus]

The EPA changed how they rate the cars in 2008 to be more realistic. I think on there website they just post new numbers for everything. Those are probable the old EPA numbers.