Mileage on long trips with cruise 98% on...

Went to Mesa Arizona from Seaside Oregon in March 2010. 3 people with luggage, vehicle gross weight, 3,850 lbs.

MPG average was 48 MPG and change. Mostly hwy from 60-75 mph.

This is round trip MPG calculated not computer generated.

alfon

 

My 2010 seems to like the hot weather.

Over the memorial day weekend I went to my folks house, 160 miles away, with the A/C on (but set like at 78), 91 degrees outside, no cruise control.

I got 68.4 mpg on the trip up and 69.7 on the trip back, according to the car. Normally that trip consumes a tank of gas with my other cars, but not this time. I'm up to 550 miles on the current tank, and still have 40 miles left (according to the car). Typically the computer is 2 mpg high, so I figure around 66 mpg.

My driving technique for most of the trip was just to give enough gas to maintain speed....no p&g except for when I was below 50mph on rolling hills at the very beginning and end of the trips.

 

Ouch!

For that distance and elevation change, the downhill leg should have been about 7 mpg better than the uphill, unless headwinds or other factors interfered.

My trip last fall through Mammoth -- and Manzanar National Historic Site, Lake Tahoe, Glacier National Park, Little Bighorn Battlefield, Devils Tower NM, Mt. Rushmore, Custer State Park, Badlands NP, Rocky Mountain NP, Pikes Peak, Canyon de Chelly NM, Route 66, and gobs of other sights along the way, with probably well over 100,000 feet of elevation change -- netted 51.6 mpg at the pump.

But I don't go over the posted limit.

 

I would never recommend using cruise control while expecting even average mpg results. Although I ubderstand why people use cruise on longer trips...it can be an mpg killer...especially at higher speeds and most especially on lengthy mostly uphill climbs.

With the prius in car instrumentation its quite easy to see what excessive speed does to mpg while using cruise. Just watch your mpg meter while at 50, 55, 60, 65, 70 and 75 mph. With cruise on you have no control of rpm's and the difference at 55 or 75 mph could be 25 to 30 mpg for miles and miles.

It doesn't take much effort to monitor mpg...and it can be fun to try and improve. Not to mention it saves fuel and money.

 

I just returned from a 4500 mile, cross-country trip. Two passengers with luggage. Overall, the G3 (IV) delivered 48.3 mpg (calculated). I ran 73 mph (indicated) with the A/C on most of the way. I did use cruise control. BTW, at 73 indicated, the actual speed was 71 mph (also had my Garmin CS-760 that reads out speed). No problem maintaining 73 mpg on hills, or passing other vehicles.

I was delighted with the ride and comfort. One day we put in 735 miles, and I was not overly tired at the end of the day. Across Kansas I feared hail storms, but we did not encounter any. Road noise on some road surfaces is excessive and annoying. On smooth asphalt, the noise is minimal, concrete is more noticable. In areas where pebbles have been added to liquid tar ... the noise is awful, but I suspect that is true with any car.

I really appreciated the A/C. It is fantastic! I could not determine that it hurt my fuel efficiency to any degree. I enjoyed the DVD player and sound system. We listened to three books on DVD ... that makes the trip much more enjoyable.

We learned a lot about the NAV system. The display was good, and we learned to use the voice commands while on the move. With a destination 100's of miles off, it kept telling us to exit on secondary roads, even tho we had told it to stay on the Interstate ... we stayed on the Interstate. The time to destination is WAY-off ... by a magnitude of hours ... possibly because it recommended (perhaps shorter) roads that would have been much slower than the Interstate. Finding nearby addresses was great.

It sure was great to pull up to a pump after driving all day and filling with 8 or 9 gallons. TX, OK, KS and MO have significantly lower priced gasoline than CO and UT.

Today I must remove a thick layer of bugs off the front surfaces.

.

 

I drive about 5 miles in with alot of stop lights then 15 miles with cruse set at 68ph. Then another 15 miles with cruise set at 57 mpg. I have been getting 50-53 mpg doing this trip each way to and from work everyday.

I can't tell any difference when i don't use cruse, so i just use it. Also i don't slow down going up hills when i'm not using cruse, so maybe thats why.

 

I never understood why cruise takes more gas. Please explain. What you seem to suggest is that cruise control tends to make people drive faster, in which case, mpg is a function of speed. Can't I not cruise at 55mph?

 

Matt, I don't understand your logic.
Cruise control saves gas. My A3 gets up 34 mpg on highway when it is on cruise, once it is off the mpg drops to 30. I haven't tried use cruise on Prius yet since it is still under 600 miles. But I believe it will decrease fuel consumption. Unless you have hard evidence to prove I am wrong.
Thanks

 

I do not know if I can add to the question re cruise control. On the flat, I do not hesitate to express a belief that cruise control saves gasoline. In the mountains, or hilly country, it will maintain a constant speed .... I suspect that is where the issue arises. Going up the grade, the speed is held to a constant, and frequently the HSI display moves oven into the red, and the ECO light is extinguished. Going down hill, the speed remains constant, and "glide" may even be retarded to control speed.

I use cruise control all the time on the flat open road. In the mountains, I do not. Few up grades are absolutely consistent, so I make an effort to maintain speed, but if there is a short even steeper grade ahead, I will permit the speed to lower slightly so as to not extinguish the ECO light, or move into the red on the HSI display. On the down hill, I let her "run free" and practice a bit of hypermilling. If the speed climbs excessively, I use the "B" feature to slow things down.

I think this works. Last month my overall mileage on a 4500 mile trip was 50.3 mpg ... mostly highway, some flat, some mountains, and some city driving.

 

Cruise control saves gas...IF...you can't drive more efficiently than the cruise control does.

For some drivers, I would agree 100% that cruise "saves" gas compared to driving without it because they normally drive inefficiently. But, for those that practice highly efficient driving using various techniques...cruise uses more gas than not using cruise.

I just took a weekend trip from MA to PA...about 1000 total miles...mostly highway. On the way home I used cruise...mainly because I was tired of driving...and it was clear that I was using more gas with cruise than not. Evidence was the high rpm's on uphills (verified with my SGII).

The cruise control's entire goal is to keep the vehicle at the speed you choose. To do this, the cruise control does not efficiently monitor rpm's when keeping the car at the desired speed...it just does whatever is necessary to maintain the desired speed. This is especially true on an incline...and the steeper the incline the worse it is for rpm's. I saw 3000-3500 rpm on some climbs when normally without cruise I can avoid 3000+ rpm's...usually in the 2500 rpm range. While I may lose speed and drop from 65 mph to 60 mph...I regain the speed on a decline and get back up to speed.

So...cruise does save gas...if you cannot drive more efficiently than the cruise.

 

Ok, so it wasn't a really long trip, only 100 miles one way, but I drove to another city and back yesterday and watch the mpg meter during the trip. On the way up there, driving at 65 mph, I averaged just over 50 mpg for most of the way. For about a 30 mile stretch of it, I was able to draft behind a low cut diesel truck and was averaging between 65 and 85 mpg the entire time. For one 5 minute stretch, I actually dinged 75 mpg on level grade. For the ride back, I drafted behind normal diesel trucks at an average of 69 mph @ 57.4 mpg.

 

i commute from LA to San Diego and back every day. i always set the cruise at 73mph and consistenly get 51.5mpg on the trip. yesterday i decided not to use cruise. my speed varied from 65mpg-75mph with traffic, i was keeping up with the fastest, almost. i was surprised to see that i had an indicated 54.5 to SD, and a 54.8mpg back home to LA.
this is what i noticed the difference between my foot, and the cruise control is: when i see an uphill slope coming i will allow the car to accelerate a little more on the down to carry my up. the cruise will not allow this. it will keep the car slow, lose 1mph or so, and then on the uphill push the gas harder to make back that 1mph it lost keeping my slow. that extra acceleration is what i see as the loss of mpg for cruise control.
but, if you can't control your right foot, cruise control is best.

 

How do you play DVD? I thought the sound system only plays CDs.

Thanks

 

Hmmm. I'm not so sure that I agree - completely anyway..... it's not about being able to "control my right foot...." but more about my personal comfort and conveniece.

When I drive short distances (0 ~ 30 minutes ... ok, ok, maybe a lilttle more), I prefer to "use my right foot" - and generally get better mpg vs the cruise control.

For longer distances (my drive to my inlaws is 6 hours) I "prefer" to use the cruise control for the long stretches of interstate driving at 70+ mph.

Since I normally put anywhere from 25,000 ~ 30,000 miles / year on a car, the cruise control will get used quite often.

The mpg hit is about 1~2 mpg, but if I anticipate the hills in front of me, I can speed up a bit to compenstate for the loss in expected momentum of the car as it climbs the "rise" in elevation .... prior to the speed sensor kicking it into high gear .... to try and maintain the set speed thus avoiding the sudden acceleration of the ICE to "warp speed" and loss of seemingly significant mpg.

....just my .02

 

Just an FYI on using A/C and it hurting FE. On long highway trips you will not see your mpg display tick down continuously like you would in city traffic moving along at a slow pace.

Where you will see A/C hurt FE is if you watch your trip display showing "miles to empty." Over the course of 100 miles with the A/C on at 65-70 mph this trip display ticks down almost twice as fast as it does with no A/C. And while it's not an exact measurement of distance to empty...it is a generally accurate display of the effect of A/C on FE.

 

I just made a trip of 840 miles from Central Texas to north of the DFW area and then to Shreveport, La and back to the DFW area before returning to Brownwood in Central Texas. My trip to the DFW area included I-20 and I got 52.5 mpg calculated with A/C and cruise on a very hot day in the high 90s. The mpg indicator was showing 52.7mpg.
My trip from DFW to Shreveport and back to DFW was just over 53.1mpg, also with A/C and cruise. In Texas heat, it would be a very uncomfortable trip to not use the A/C. Our temps now are averaging in the high 90s and low 100s.

I am happy with my numbers and it seems it is getting better. I don't understand the average speed indication on the car's display though. It is showing an average in the 30s when my speed was always in the 60s and 70s on the trip. Are others having this problem too with the display?

My first fill up included 141 miles on the odo from when the dealer was still showing the car. It kills my overall average on the car to 48.6mpg but I expect to overcome
that average as I drive the car. It only has 1497 miles on it now.

 

Lots of folks on PC seem to be able to improve mileage by turning off cruise control. Not me. It always seems to me that my touch on the accellerator is unsteady enough that my mpg goes down. Any other clumsy folks like me out there?

 

+1.

I have had mine for three weeks, and have driven mostly up and down hills through western PA. If you run on cruise, it gets behind if you just let it lug into a hill. When you start up a hill, it pulls on the throttle to try to make the speed catch up. I think you are better off to try to pick up speed to make a run at the hills, it seemed to help me a bit.

1800 miles = 54 MPG