30% under mpg rating, any tips?

The first thing I'd do is check your mileage at the pump with a Mk-1, Mod-0 pencil and paper. Don't use the MDF, and don't use some OUTCONUS site where imperial, metric, or US measurements have to be transmorgified into whatever you want to see at the bottom of your posts.

I don't have much stick time in G2s, in fact I have almost zero time in type. “My” Prius is a G3 (2010-) so PNG tips from me would be valueless. My personal observations over three months are that if I dedicate almost 100-percent of my cognitive efforts to driving 'efficiently', I can get almost 60-mpg, measured at the pump.
When I decided to drive my car like a normal car, it dropped off to about 50-53.
It’s a company car, so ‘my’ normal might not be your normal.
Since you're concerned enough about fuel efficiency to be measuring it, I'm guessing that there's a measurement or arithmetic error in your observed MPG.
Once....I drove my car for an entire tank doing WOT starts, speeding, using HVAC as I wanted to. In other words....I drove it like I stole it.
My MPG measurements dropped off to about 43-MPG.
I refuse to believe that you're getting 37.
Most of the hypermiling gains in Priuses (grill blocking notwithstanding) amounts to the same at it does for any other car. Try to avoid touching the throttle and brake pedals as much as you can, and make sure that your tires are properly (over)inflated, usually about 5-10 psi above the manufacturers specs, but never exceeding the max sidewall pressure, and avoid speeding. My ‘sweet’ spot for best highway efficiency seems to be about 55-60MPH. In some places, if you have to share the road with other drivers, this will get you killed.

Read some in the G2 section and you'll get TONS of advice on PNG techniques for your subtype.
Re-check your math.

GOOD LUCK!

 

Your going to get asked to do this any minute now so I'll post it first cause I like you.

http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html

Tell us about your situation using this form and we'll get ya figured out.

 

Oh and watch these.

Jim show's how it is done
In this first video pay close attention to what he says about lifting off the throttle then applying light pressure back on the pedal to make all of the arrows on the MFD disappear.

Our very own Doc Willy

 

Most cases of poor fuel economy in the Prius are from two causes:

1. Cold engine driving
2. Excessive brake use by the driver

(1) can be attenuated by radiator blocking and EBH use;
(2) is fixable by some drivers, and completely obtuse to others. I have watched my wife get 40-50 mpg for years while I run around at 60-70 mpg. She *wants* better fuel economy, but cannot change her driving habits to make it happen. In fact, she does not to this day understand where the fuel economy differences between us arise.

 

Things that stand out to me are:

1. Your Michelin Pilot Primacy tires. I do not believe they are LRR rated and that will cause your mpg to suffer despite having two of the best LRR tires available on the rear of the car.

2. Your 12v battery is weak if you only saw 12.1v with no load. That will cause mpg to drop.

3. Brake use: you shouldn't have to brake moderately. If you are leaving enough distance between you and other traffic then you should only have to brake lightly to co e to a stop. With no traffic you should barely be using your brakes to come to a stop. Some people think that they need to use the brakes a lot to charge the HV battery but it is actually MUCH more efficient to lift off the throttle earlier and glide for as long as possible before using the brakes to come to a stop. The best hypermiling tip is to drive like you don't have brakes!

4. Check your oil level. Some people have complained of mpg loss when their oil level is too high. This is applicable to nearly all vehicles. Ensure your oil level is no higher than the full mark and ideally it should be just below that for max mpg. Some people think they are doing you a favor by adding a bit more oil or they are just too lazy to fill it correctly. Don't trust anyone with your oil changes. Ensure they fill it correctly and if they overfill it then ask them to drain some oil until it is correct. It's your money they are wasting if they refuse.

 

Does sound low. Sounds like you bought a used 2009 car? Main implication unclear 12v battery condition as per F8L, which could be issue. Not sure what highway speeds you are allowed to travel, but over 60-65 miles per hour your MPG will fall off.
Too tired for metric conversions.

 

Me too.

Unless you have a fault with the car. Is the 12 volt battery still the original? Are your tyres low rolling resistance tyres and are they at the correct pressures?

There is no way you should be getting 37 mpg US in a Prius in Holland where it is flat. OK I have a gen3 but at 50 mph on the motorway/highway I can get over 75 mpg UK (62 mpg US) with ease. At 80 mph I get 55 - 58 mpg UK (45 - 48 mpg US).

 

I hope it is the Primacy's too. Let me know if you need help deciding on tires.

One trick to really up your mpg, or at least mitigate for those times when you were forced to drive In such a way so as to really hurt mpg, is to identify a section of road on your daily commute where you can glide for as long as possible before reaching a stop sign or place where you need to make a turn.

For example; on my daily commute I can choose to get off the freeway one exit earlier than normal. There is a stretch of road that parallels the freeway for 5 miles. There is only one stop sign on the section. I can slow down from my 60-65mph freeway speed to 50mph which will net better mpg for this part of my commute. Since there is rarely any traffic on this road and there are two lanes in my direction I can travel as slow as I like. Approximately 1 mile from the upcoming stop sign I will enter a glide at 50-55mph. From 55mph to 42mph I am using a very tiny amount of electric energy from the HV battery. Once the vehicle slows to below 42mpg all of the bars on the MFD disappear and I can glide the rest of the way using zero energy, or kinetic energy is you are being strict. As I approach the stop sign I am usually below 20mph and by the time I am ready to brake for the sign I am below 15mph and at the end of of my patience capacity. If everything is set up right i can usually glide for 1 mile here and it really pumps up the mpg. I then travel the next 2 miles before reaching my house using a sort of pulse and glide between stop lights.

The difference between staying on the freeway and taking this earlier exit could mean the difference of a few mpg over the course of a tank. Now apply this to a couple of places on your route or other places during the course of a tank and watch your average mpg climb!

At first it sounds like a lot of work but starting off with a hypermiling technique in just one or two spots during your commute is enough to make a difference and it's kinda fun. Pretty soon you get the hang of gliding and you can use it at every opportunity that presents itself like freeway off ramps, tall overpasses, between long stoplights where traffic is not a problem etc. in fact you should be gliding off of every freeway off ramp. It's easy mpg.

 

Depending upon exactly what is your definition of "moderately", it might not really regenerate very much at all. Light steady braking is the the best for maximizing regeneration.

 

How long are you driving?
What kid of driving is it?
And at least hear, it isn't really a manufacturer spec, they only conduct a specific - very specific test, specified by the gvmnt, and report the results. Toyota is in no way stating that you will get this mileage.

back in 2004, they actually tried to get permission to lower the MPG ratings they reported here in the US, their request was denied

 

How long are you driving?
What kid of driving is it?
And at least hear, it isn't really a manufacturer spec, they only conduct a specific - very specific test, specified by the gvmnt, and report the results. Toyota is in no way stating that you will get this mileage.

back in 2004, they actually tried to get permission to lower the MPG ratings they reported here in the US, their request was denied

My Prius gets better mileage than my motorcycle...

 

They're not low rolling resistance tyres are they? When I had 'normal' tyres put on my car my mpg's fell by about 10%. I couldn't get the mpg's over 60 UK mpg, how ever hard I tried.

Also, a simple diy to test your 12v is to leave the car overnight, then in the morning turn it on but NOT into Ready mode. Then wind all four windows down then up at the same time. If it is painfully slow but much quicker when tested again in Ready mode, then your 12v may have failed.

It is a weak 12v so if it has been run flat once or twice by accident it never recovers fully.

I did note that it was cold (0c) when you did your tests so that along with a poor 12v, wet roads and non low rolling resistance tyres might account for your poor economy.

Do you have winter tyres on? Are they required by law in Holland at this time of year? If so, that could be your problem.

Just to prove why we're all concerned;



This is a graph on the gen3 showing a 30 minute range in 5 minute segments, indicating I got over 75 mpg UK (3.7 litres/100km) for this time limit. Some five minute averages were 80 mpg UK or 100 mpg UK. I was on a flat road at an exact 50 mph (80kph). It can be done, even in a taxi.

The following pic is an 11 mile run (17 km) on a flat road at an average speed of 34 mph. Yes I managed 91 mpg UK/75 mpg US or 3.1 l/100km, but maxed the battery out and almost died of boredom and roadrage attacks.

 

This looks normal to me - what I got the last couple weeks.
At 75 mph, my mileage drops off to 42-44 MPG in summer and can go less <40 in winter. Keep in mind we are having winter (Aussie members notwithstanding). I average 47 MPG but thats ~50 in summer and 44 in winter cold = 0 deg Celcius (=32 deg F). In contrast to GrumpyCabbie, my MPG drops off precipitously over 65 MPH speed. So you are driving quite fast in cold weather. Sometimes I notice Prius hypermilers on the road - speed limit 65 for them means 60 with occasional peak up to 65.

 

Were you watching me drive to work this morning?

 

Originally Posted by R-P

Looks normal to me too. So there's your solution, just keep it under 65 MPH most of the time.

Now lets see why your "around town" fuel economy is bad. Do you know how to make the car "glide". Tell us about the speeds and traffic conditions for your shorter trips.