New Prius only Averaging 38 MPGs...help

Drive sustained highway speeds (70+) in low temps (10-20F) - guaranteed to get low 40's if not high 30's.

 

I am currently get 48.4 mpg in 25 degree weather here in New England. My Prius has 1300 miles on it.
I can't complain.

 

Thank you, yes we have the 10% ethanol here in our state. When I travel to MD I get it there. Never realized our gas was different in DE until I noticed a big difference in MPG with my last car. Doesn't make sense to me if they require it for cleaner air, you use more gas? . .

 

I was just going through and noticed you responded to my ?. Thanks! New to this forum . . Guess I should check back but can't remember which thread I was in.

The stretch that requires headlights is in MD on Rte 404. It's one lane each way and they probably do that b/c you are allowed to pass. It is pretty scary when you are driving and headlights are coming towards you in your lane! Everyone talking about MPG haven't mentioned if they are driving with the ECO button. I didn't realize until I hit it by accident that you didn't have to choose one of the 3 buttons! I was wondering why it was a big sluggish.

The road is on the Eastern Shore of MD, towards the Bay Bridge by Annapolis.

Thank you!

 

I think I need to turn the little graph off and drive like normal again and see what happens!
:bolt:

 

My guess is that your 12 Volt battery is bad.

 

I'm averaging 37mpg for past 100km. It is about 3F for past 4 days. And I do mostly short trips. My baby hasn't been broken it yet. I drive normal mode.

In comparision, my 4cyl Accord got 24mpg in this temp.

 

Yeah, that kind of cold makes for an unhappy Prius - but you're still doing 50% better than your Accord. And in the summer you'll likely exceed 50mpg.

You might try grill blocking since you're doing short trips in really f-ing cold weather, but my personal experience suggests not blocking 100% (upper OR lower) if you do more than 30 highway miles at a time.

 

Sooo true. I've recently changed my highway commute (18 miles each way) from around 75 MPH to 65MPH. It takes a couple minutes longer, but my display went from 38MPG to 44+MPG. It's pretty hilly here, and we have "up to 10% ethanol" in our gas.

 

We had the same problem. The wife drives 4 miles to work and when the temps dropped into the teens the MPG dropped below 40. The car is garaged at night. I read the suggestion for grill blocking and tried it last week. I put two pieces of 3/4" pipe insulation on the lower grill. Last weekend we went to the luge challenge at Blue Mtn ski resort and put about 100 miles of combined driving on the Pri in 10 to 15 degree weather. The MPG was back to 50! The pipe insulation was $1.18 at the local building supply store and it took about 15 min to install. Still waiting to see the effect on the short drive to work, if any.
Bob

 

I looked into that. If they had a nicer option I'd be all over it like flies on poo. I had some 3/4" pipe insulation laying around so I experimented. It didn't seem secure with just by friction fit.

 

For a firmer fit, try 1/2" pipe foam - one piece per slot in the grill (i.e.: folded onto itself rather than straddling two slots). I found this to be very tight and difficult to install - most of my grille has 1" pipe foam which was slit in half lengthwise, then folded onto itself. (for some reason, the foam for 1/2" pipe has thicker walls than the foam for 1" pipe - go figure...)

 

Is that you Nostradamus?

 

some seem have that problem

 

I average about 52 calculated (54 by display average). I have tire pressure at 44psi, grill block made of coroplastic and use the cheapest gas I can find (usually wawa) the weather has not been colder than 15F (yet), and we have experienced 2 really bad snow storms this winter. Attached is my prius mileage log (also includes my other hybird (nissan altima) a photo of the grill block and misc pic of the snow storm in December. PS the wife is driving the Altima since we got the Prius, She does not drive efficiently, I averaged about 43 mpg in that car.
PS THIS IS NOT A GLOAT, just pointing out the prius capabilities.

 

I just tried upping the tire pressure yesterday, and while I don't have much data yet, preliminary testing showed nearly 3mpg improvement - at all speeds. And that was just going from 37/35 to 41.5/39.5 (shooting for 42/40 but missed).

I have a long highway trip (700 miles round-trip) coming up in a week and may push them a bit further - but I did a little 18mi trip in 30F and was seeing (displayed) almost 47mpg (should be about 44.5 calc'd). That is compared to the 41 (39 actual) I saw on a long highway trip in colder temps (18-20F). I'm sure colder temps will bring that back down again some, but I expect to stay above 45 displayed / 42.5 actual unless it gets really freaking cold.

 

At first, my mileage was around 41 mpg and has steadily increased as the car broke in (around 1000+ miles). I too was very gentle on the starts and stops. As soon as the car broke in and I started driving it without concentrating on mileage, my MPG went up drastically.

So, no I don't believe that you have anything seriously wrong with your new Prius. Just give the car time to break in and don't think about the mileage. It will come around.

The most helpful tip that I found was to forget it's hybrid and drive normally.

 

eamers:
I find the above to be true. I have a new IV as of 11-27-09. I now have 2400 miles on it and am seeing mileage like I expected to get to begin with and didn't. I was not impressed to begin with compared to what I saw here on the forum. I am not one to "ride on rocks" (tires pumped up so high you need a kidney belt to ride in the car), but after the first few tankfuls I was about ready to pump them up. I decided to just let it go and just drive the car. It drives better now, (or else I've learned how to drive it), than it did when first new, and I don't think about it being a hybrid, I just drive it. I now feel it's getting pretty close to what it should be, (what it's rated at). Maybe even a bit better, even though it has been cold here and that would just naturally have a detrimental effect on the mpg. Just enjoy it! Your getting probably double what most cars do! :welcome:

 

I think the sweet spot for acceleration may be higher than most people would think when looking at the HSI display - and this may be why PWR mode (and/or "drive it like you stole it") seems to work just fine.

I've been watching the display while also listening to the rpm's and there isn't a direct correllation - depends partly on speed also.

If the charts/graphs are to be believed, it looks like the highest efficiency is around 20-25kWh, which appears to be around 2000-2500 RPM. If Scangauge has a way to show RPM, it would be interesting to see where 2250RPM is on the HSI at various speeds - I would bet it's in the pwr zone, possibly near the rightmost tip at some speeds.

 

Can you explain your reasoning behind "close to what it should be, (what it's rated at)", what your expectation was and why?