38 mpg on trip from LA to Miami in a 2010 Prius IV - 107k Miles

I know the feeling when your back is pinched to the seat back. It is well worth the cost of gas.

 

I think game is the best way to look at it. It's just a different game and state of mind then the 300Z TT (nice car BTW). Lot's of car guy's look down on it, but they don't quite get it.

 

I just finished a 3,385 mile trip from Maine to Florida and back last month. Drove with traffic on way down and way back... 70 to 85 mph, which is crazy, but I was being passed all the time, so I wasn't anywhere near the fastest car on the road. Trip mpg was 48.4 and that's the lowest MPG I've ever achieved with this car. Got down as far as your neighbor Ft. Lauderdale.

What brand and size tires are on your Prius?
What tire pressures are you running?
When did you last change your air filter?
What oil's in your engine?
How much stuff do you carry around in the car?

Generally we buy a Prius to save fuel. You're paying a bit more for the hybrid technology initially to save money in the long run. If you want to do that, you have to change some of your driving habits. Being Hispanic doesn't count as an excuse!! (by the way, in our family we call being late "Hispanic panic!") Leave a little earlier. Less prone to get into a bad accident too. Roads are too crowded and too many people are driving distracted by texting/internet/and all kinds of activities not related in any way to driving.

At least you noticed that if you slow up a tad, that you can get great MPG in your Prius! If you up the tire/wheel size to 17 inches, MPG will go down, unless you find very light wheels and LRR tires to go on them.

 

That's fab, my mate never manages much better than 47 MPG, but that might be his sporty driving, I told him don't buy a Prius, you're not going to save much, certainly not with all the extra electrical systems which undoubtedly cost more in servicing.

 

Next time you go out to your car, take a look at your tires... they will have a brand and some kind of model name on them. That will add some pieces to this story.

Tires lose about a pound of air per tire per month on average. Tire pressure goes down by 1 PSI per every 10 degrees of outside air temperature drop, and the go up by 1 PSI every 10 degrees of outside air temperature gain. Maximum "cold" (a tire not driven on at least 3-5 hours) tire pressure is printed on the individual tire and should never be exceeded. If your tire can handle it, and you live in an area where roads are pretty smooth, you can go over recommended PSI indicated on the car sticker by a few pounds safely. Again, this tire pressure is measured while the tire is cold, before being driven any distance and has been parked for those 3-5 hours. I run 40 PSI front and 38 PSI rear most of the time. Maximum tire pressure listed on my tire (Yokohama Avid S33D) is 44 PSI. It does help MPG.

The load you carried on that trip was way less than what I had on board during my trip. A lot of people use their cars as storage bins on a daily basis, so hope you don't do that. Usually these guys and gals will complain about their MPG... without thinking that extra the weight left in the car causes more fuel usage as you transport it around.

A clogged intake air filter can be very detrimental to MPG. Service department will replace it if needed. Ask your Toyota Service Manger to please use the recommended 0W20 sythetic oil that Toyota recommends for a Prius.

Low Rolling Resistance tires can help add a few MPG to a Prius. Not all LRR tires are the same. In any case, even with an LRR tire, it is likely that a 17 inch wheel tire combination will not quite get the same mileage that you get from the 15" Prius wheel/tire combination, but your Prius will look a lot better. That's for sure.

I put a 16 inch wheel/Summer tire on my 2005 Prius. It looked way better, but did lower the gas mileage a little. Make sure you get the right offset, if it's an aftermarket wheel. I think a 42mm offset puts the tire at the edge of the car. I've seen a few Prius on aftermarket wheels that push the tire outside the body (wheel well) by a few millimeters... and it doesn't look very good. Just FYI.

Here's the old Prius with aftermarket wheels... It did improve the way this car handled.

Will be interested to hear if you find any improvement in MPG. Good luck!!

 

Nope. See the study at the bottom of this page: Gas Mileage Tips - Keeping Your Vehicle in Shape
The service department would like to replace it either way, that's what rakes in the dough.

 

Interesting... but think I would still make sure that this maintenance has been completed. All dealerships are different... and I agree that replacing items that don't need replacement definitely makes extra money for service departments.

I don't know if this car has been maintained by Toyota or other mechanic, and remember that OP stated he left this car with a friend for some time.

Consider a modern fuel injected car (Prius) with a significantly dirty air filter, being driven by someone with a heavy foot. Engine response is knocked down due to the intake restriction, so driver simply pushes go pedal deeper to restore response. In a Prius, this condition would definitely result in lower MPG figures.

 

Offset +45 is good... +42 is close to being too far to the edge, so 45 is good. 16 lb weight for a 17" wheel is excellent, too. When you find a tire for it... and put it all together, you'll need to post a picture of the set up for us.

 

A 17 inch wheel at 16-19 pounds isn't considered "heavy". 20-25 pounds would be heavy territory. The lighter the wheel the better in any case. Check and see if at 16 inch wheel wouldn't do. Might find one that's lighter and still looks good... a compromise size kind of.

 

I have found that I have to change plugs in my 2003 prius to keep the milage up when the milage started to drop the first time at about 50000 miles I started looking and changed everything filter wise and checked then when I changed plugs the milage came back up the one my wife drives is a 2005 with 86000 mi and have not changed plugs in it but it gets high 40s to low 50s mpg