Is This All I Should Expect?

Cooper CS5 are not great mileage tires but good tires non the less. I expect them combined with the bike rack are causing the poor mpg. Just an example my last vehicle was an SUV and if I left the crossbars on it would take a hit of 1.5-2mpg. The Prius is very aerodynamic so I imagine anything non-aerodynamic could mess that up.

 

This is also a site with enthusiasts who are a little more than casual car owners so they will be above average with their results. 2007-2009 Prii at fuelly are averaging 43.8 mpg among all users and there is nothing wrong with the vast majority of those cars. The same is true for the few of us 2008 owners that still report our mileage at fueleconomy.gov. I would contend that those of you who get 50+ mpg (American mpg) are not the norm. You show what can be accomplished in some circumstances but those results are really not to be expected.

 

In winter, you can block the front grill. Just blocking 50% of the lower grill is very safe, That'd be one 1.5" OD pipe insulation tube pushed onto a grill slat and secured. You might also be able to keep the engine bay a bit warmer with more of that insulation along the seam between the hood and the fender.

 

i don't see how a rear bike rack is 'towing'. does a hitch by itself meet the definition?

 

Getting down to -8C (+17F) at night here, highs still below 0C. That unusually cold for us though.

I'd concur with your plan to get the block heater. Got it installed on our 3rd gen when we bought it new, use it all the time, year round.

 

I kept my grill blocked "100%'" year round without incident. With temps below freezing I don't see how the inverter will be able to overheat.

Grill blocking will keep the heat generated by the engine in the engine compartment. You'll get more cabin heat faster and the engine won't run as much just to keep itself warm.

There is also some aerodynamic effect and the foam in front of the radiator will prevent some strikes.

I don't know how long the car is idling while while you remove ice and snow but the fuel economy is taking a hit from the defrosters.

Tony S. started the definitive thread on grill blocking. The tubes on the bottom can pop out so it is a good idea to tie them down. I use twist ties. The upper pipe insulation is "compression fit" but don't push too hard.

Frost King sells a package of the tubes for the bottom. I use sections cut from a long length of pipe insulation for the top. There's no waste as whatever you don't use for the car can be used for--pipe insulation. Some of my pieces are 9 or 10 years old seeing service on my 2006 and now the 2010.

You may also find a ScanGauge useful for the additional instrumentation, especially coolant temp and inverter temp.

 

@JimN both upper and lower grill blocked 100%, year 'round? With the inverter coolant radiator behind the upper grill opening (on third gen, not sure where it is on 2nd gen), I'd be reluctant to block upper more than 50%, and certainly not year 'round.

2010 Prius Grill Blocking strategy | PriusChat

 

(+17)

 

Oh man...

 

Very true! Honestly an average of 44mpg (I'll round it up) isn't bad for a 2nd Gen Prius. I think EPA ratings were 48/44/45 or something like that. I know a few non-enthusiasts who achieve upper 40's but that's pretty standard.

 

Here's a link to Fuelly 2007 fuel economy figures:

2007 Toyota Prius MPG - Actual MPG from 330 2007 Toyota Prius owners

 

I just checked the EPA numbers a 2007 Prius is rated at 48/45/46 city/highway/combined. Not much higher than your winter mpg.

 

For what it's worth, my last tank of fuel from my 2008 Prius T Spirit gave me the equivalent of 48.7mpg US from my regular 36 mile return commute. That's about 58mpg UK for a vehicle which got as high as 64mpg during summer. I did make 72.9mpg on one trip to work once. It's turned quite cold here, and I've had a few sub-zero early morning commutes too. It warmed up a tad, but mornings are still 9c or below, damp, occasionally foggy, with wet roads. I also got 546 miles (UK) from my last tank of fuel.

Personally, I've come to an agreement that anything over 500 miles from my 45 litre tank during winter is a privilege not to be sniffed at.

I never forget I had a 1.6 litre engined car with a 50 litre tank, that once gave me only 180 miles from a winter tankful.


iPhone ?

 

One thing I just now thought of: A failing 12V battery can cause low mpg numbers as well. When the inverter detects that the battery has a low state of charge, it cranks up the voltage to charge the battery. However when the battery is failing the inverter always thinks it's low, so it constantly feeds charge to the battery when it isn't need it, wasting power. If you have a voltmeter, it's worth taking a look at your 12V battery voltages with the car off, in IG-ON with your headlights on, and in Ready mode. Below around 12.1 for the first two or above 14 for the last would indicate a failing 12V.

 

With the car right off, anything less than 12.5 I'd be immediately charging, and/or shopping.

 

Apologies for the malfunction that caused my last message to be duplicated 4 times - I was getting an error message indicating the message had not gone, and inviting me to resend it.


iPhone ?

 

yeah site's been acting up again the last day or two.