Driving style doesn't change mpg?

[supton]

Does a 2.5L I4 spinning at 3k burn more gas than a 5L V8 spinning at 1.5k? Seems to me that the air/fuel has half the time to expand in the I4--but waste heat into the cylinder walls & head is half the time so...?

I know in my truck, gentle acceleration will keep rev's below 2k, but the convertor won't lock up until 4th gear, so gentle acceleration stays in a somewhat lossy region. A good press on the throttle gets rpms up, slippage lower, and less frustrated people behind me.

My Camry does 30's for mpg all day long--takes nothing for my big V8 to drop below 20. Camry, sure it has to get driven harder to get up to speed, but it appears to burn gas under all other commuting conditions.

 

[Carbuff]

The ScanGauge is what convinced me that driving style matters. In my MT car, coasting (and slowing early for stops) got me 8% more MPG. (I document all fuel usage.)

Regards the coasting thing...I would never do it in an Automatic car.

But even though some cars shut off fuel when in gear with 0% throttle, the small amount of fuel used to idle the engine while I was coasting was more than compensated by the extra time I could cost without engine braking.

As usual, it's a skill that you can develop. It benefits fuel consumption more in some situations than others.

 

[OneEyeJack]

The company Prius gets 45-50 mpg in the hands of most drivers, 50+ in the hands of a few and 30-35 in the hands of others. So, I'd say that driving style makes a difference.

 

[Dyusik]

Wife gets just over 25 mpg in the RX, I get over 33. I get as much as 10mpg difference in the IS and the R1 if I drive like an [censored] or not.

 

[Andrew1972]

With the anemic output of the 4cyl, no variable timing, 4 speed auto and AC on full tilt not surprised. MPG was not really a thing then and I'd be happy with a rolling relic like that it starts and goes!

My wife achieves the same mpg with her 2005 legacy turbo wagon 5mt commutting and mixed short trips. I think it barely works though because of variable valve timing and turbo that moves it with extreme ease.

 

[Jetronic]

Just from switching the car from the normal or winter mode to sports, I see a 20% drop in economy off the freeway. On the freeway it makes no difference. That's because the transmission will be running the engine above 1700 rpm at all time in sports mode, and in the other modes generally below that.

If I also drive faster, like the sports mode suggests, then the drop in economy can easily be 50% or more. But I wouldn't have a drivers license for long if I wasn't selective about my rallye driving...

 

[d00df00d]

Originally Posted By: Bamaro
Driving style has a large effect on mileage. Not sure why yours doesn't. Maybe you are not modifying it as much as you think.

^ This.

 

[DeafBrad]

There are a lot of bad habits people have that make a difference. My car is rated for 34 mpg or something, and I get around 50 mpg. People instinctively give it throttle going up hills. Over 55 mph, it is a lot more work for a car to punch through the air. A 10 mph increase in speed can result in a 5 mpg penalty. Gunning the throttle at each light and then slamming on the brakes wastes gas. Accelerating too slow may decrease mpgs... and accelerating too fast will reduce mpgs as well.

I notice you live in AZ. Hot place. But sometimes do you have a cooler day where it is tolerable to run without ac? Turning off the ac can give you a 3 mpg increase.

People drive aggressively on the way home from work. It would help to relax a bit and just drive. Driving aggressively is not going to save a lot of time on an average commute, but will use a lot more gas.

An instant read mpg gauge helps a lot. There are many bad habits we have. A very small application to the throttle can go from 30 mpg to 13 mpg on an instant read gauge.

 

[Nick1994]

I don't really care what mpg it gets as long as it's decent. It's rated for 20 city and 28 highway, I at least get that. It also idles for probably 30-35 minutes a day with the A/C on.

 

[Nick1994]

Originally Posted By: DeafBrad


I notice you live in AZ. Hot place. But sometimes do you have a cooler day where it is tolerable to run without ac? Turning off the ac can give you a 3 mpg increase.
Nope, we get over 100 days a year over 100 degrees.

 

[supton]

I know as the temps climb, my Tundra loves to unlock the convertor (and waste gas). Ironically it will also unlock faster if I drive faster--sounds wrong but wind drag goes up by the square of the speed, so load goes up like that too. Anyhow, slippage is loss, so I never drive with cruise in this beast, as cruise will knock off mpg in a hurry. Letting my speed droop on hills (and/or boosting speed at the bottom) helps.

 

[DeafBrad]

Originally Posted By: Nick1994
I don't really care what mpg it gets as long as it's decent. It's rated for 20 city and 28 highway, I at least get that. It also idles for probably 30-35 minutes a day with the A/C on.


Idling for 30-35 minutes would hurt your mpgs in a very big way. If this idling time is for cooling the car off or something, there is maybe a 3-5 mpg increase by not doing it. If it is sitting in traffic and stop and go, not much you can do about that. Chalk that up as the cost of commuting in traffic in a hot environment.

 

[Quattro Pete]

Originally Posted By: Nick1994
It also idles for probably 30-35 minutes a day with the A/C on.

Well, there you go. Things like this plus driving in traffic are going to have big impact on your MPG. That's why those other times when you either do or do not floor it don't have as large of an impact on your overall MPG.

Your average mpg is similar to what I get in my 530i in mixed driving, but I don't ever idle it, so that explains it.

 

[HTSS_TR]

To verify MG difference just get either Scan Gauge or Ultra Gauge and try it for 2-3 miles on same stretch of near empty highway, 1 with cruise control set at 55 MPH and 1 with 75 MPH.

 

[Nick1994]

I leave early for school (university student) in case there is an accident or heavy traffic, and I let the A/C run until I leave for classes.

 

[panthermike]

Every vehicle I've had, the mpg is affected by driving style.

 

[jigen]

Ever drive a vehicle that lists real time MPG? That should give you an idea of how much driving styles affect it.

It's always more noticeable in a vehicle that makes you work for decent MPG. High powered turbo vehicles, or V8's.

If you drive all over the place in a fuel efficient car, you usually still end up in the mid 20's average.

 

[Quattro Pete]

Originally Posted By: jigen
It's always more noticeable in a vehicle that makes you work for decent MPG. High powered turbo vehicles, or V8's.

Yeah, even my I6 makes you work for decent MPG. When you see that instant MPG needle sink to the bottom of the scale, it takes all the fun away from driving it.

 

[Vikas]

When I am idling, my mileage is 0 mpg!

 

[HTSS_TR]

Originally Posted By: Quattro Pete
Originally Posted By: jigen
It's always more noticeable in a vehicle that makes you work for decent MPG. High powered turbo vehicles, or V8's.

Yeah, even my I6 makes you work for decent MPG. When you see that instant MPG needle sink to the bottom of the scale, it takes all the fun away from driving it.

I never looked at the instrument when I floored either the gas or the brake pedal.