Low MPG, Why?!?

1) New tires get lower MPG for about the first 5000 miles.
2) I am hoping you mean Nitrogen, as Nitrous would be bad. (Nitrogen is inert, Nitrous is an oxidizer)
3) I like 40F/38R, that should be close to ideal.
4) I have not driven a c, but the very similar Gen 2 engine did very well to 60 MPH, but got worse MPG than Gen 3 above 60. The c is not as aerodynamic as a Gen 3, so high speeds should be avoided, I bet there is a right lane on the freeway with Semis going a sensible speed.
5) How long is your commute? I was still seeing improved MPG after 50 miles of warmup.
6) Is your 12 battery original? There is a failure mode for a battery where one cell is dead so 10 Volts is about max. The Inverter/Converter will spend a great deal of power trying to get it to 12 Volts. Open the battery tray some evening, and measure its voltage in the morning before you use the fob or start the car. If you have under 12 volts, consider a new battery.
7) Wheel alignment is a potential MPG drain
8) If you want to change your behavior, google 'Pulse and Glide' and Glide down hills, instead of taking your foot off the gas.
9) I live where it is very flat, so for me, Cruise Control is very useful, if you have hills, you can drive better than CC will.

Perhaps a real c driver will have c specific tricks.

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Perhaps your buddy is fool'n you?

The good news is it's a great opportunity to optimize/improve your car... The bad news is your car is within the range of normal MPG and you most likely aren't going to find anything to "fix." Higher MPG can be highly dependent on things like ambient temperature, average speed and the mood of the person doing the driving.

But over time clean and inspect the whole car and look for issues. Also, experiment with higher tire pressure a little at a time. For example my best result are 47&45psi in a regular more heavy Gen 2 Prius.

Perhaps inspecting your undercarriage will lead to something? And for engine optimization I've found better results with 0W-20 full synthetic motor oil. And specific to your Gen3 engine an oil catch can / make sure your intake system is as clean breathing as possible is key. Also learn how to do "pulse & glide" driving.

Lastly, you can regularly charge and balance your battery pack to keep it as healthy as possible: https://hybridautomotive.com

 

From the looks of Toyota Prius C MPG - Actual MPG from 1,336 Toyota Prius C owners (fuelly.com) it appears your in the "normal" range for mpg's. 32.1 million miles recorded so I'd say that's a pretty good sample size.

 

Probably not.
His driving conditions and habits likely are different.

Both my C's have had "sweet spots" with the displayed MPG numbers.
During "warmup" the number is way low.
During constant stop and go, where you actually have to STOP very often, the number is low.
When you are going over 70 MPH the number drops off.

The sweet spot comes after it's initial warmup and you can drive a mostly constant 50-55 MPH with few or no complete stops.
You also can "induce" unrealistically high numbers by starting with the engine already warm and driving a few miles being VERY careful about your acceleration and never going over about 30 MPH.

Any chance of you trading cars with this "buddy" for a few days ??

 

youtube 'hypermiling'

 

Does he have similar routes, road and traffic conditions, speeds, and trip lengths? Differences here can create very significant MPG differences.

 

We did an effortless 60MPG on the long ride home from the airport last night. 55MPH, 66°F outside, no A/C needed.

I’ve done the same drive with much lower MPG in other conditions.

 

+1 Everything of what the others already posted

Will add: You will gain your most MPG by driving close to the speed limit. Not riding @$$ and passing peeps.
Also, braking at a stop sign or red light should be minimized by coasting as much as possible,
OR by keeping the regen bar in the zone, and not using friction brakes.
+Pulse and Glide, and also longer drives.
Big hit is first 3~5 miles for me in my C, and maybe a few more in Gen3

For my drive to my shop of 3 miles summer in my C is roughly 30-50mpg, winter 30-40mpg
For my drive to my other shop of 25 miles summer in my C is roughly 55-65+, winter 45-55

Depends a little bit on number of stops, and also AC or Heat.

Just went 120 miles to the beach 2 weeks ago. (took both cars due to 3 kids)
results:
My C 65mpg there and 64.5 back
My Gen3 61mpg there and 58 back
I was truly amazed at both!

Our Gen3 does a lot of "taking the kids to and from school~1 mile" so most tank mpg is ~40+/-
But I just got 70.1 mpg by "experienced prius driving" with a 30 mile trip!!!! might be the best in the ole 15 Persona

 

It can get some momentary gains, and it doesn’t destroy the transmission. It can be hard on your battery, so you should just decide whether you’d rather pay Exxon or Toyota. You’re just time-shifting the gains from one minute to the next but the weekly average isn’t likely to improve.

Remember, when it is in neutral it can’t harvest any energy to help you with the next uphill.

Sounds like you’re already doing it right and getting appropriate results.

You can get better scores, but you would need to be on other roads at other paces. You need to drive where and when you need to drive, right?

Also, “55-80 miles per hour” is a HUGE range when you’re focused on efficiency. Spend more time at 55 and less at 80.

 

While it works, it is no better than other methods, and it can lead to damage if you coast too fast.

If the ICE is spinning, idling and burning a bit of fuel, it shouldn't destroy anything, but it won't generate or brake either.

But if the ICE is stopped, e.g. in auto-stop such as when moving at lower speeds (available only below 46 mph in a Gen3 Liftback, slightly different speeds in the 'c' and 'v'), then coasting up to higher speed risks overspeed damage to MG1. There is some safety margin built in, but we don't really know how much.

However, coasting downhill in Neutral really has no real efficiency advantage over leaving it in D and using a light touch on the gas pedal to eliminate the light synthetic 'engine braking drag'. In a Liftback, just adjust to eliminate the bar on the HSI display, but your 'c' is using some other display.

Since D will automatically protect from any possible overspeed damage, and can be just as efficient with the right touch on the gas pedal, it is best just to stay there.

 

You should stop listening to that "someone".
First, coasting down a hill in Neutral is ILLEGAL.
Second, that defeats one of the best features of a hybrid; that is, the "engine braking" actually charges the batteries and recovers some energy.

 

Toyota is required by law to have an N. You never want to use N. I am betting N is not doing what you think. (the engine is just as geared to the wheels in N as in D)

I hear folks all the time saying "Everyone is speeding, I would be killed going slow!" without noticing an entire lane on the right going a sensible pace.

 

If you're going down a long, long downhill once you're battery is fully charged up you can put it in neutral and will travel with far less resistance and much further than when vehicle is in drive.

As for neutral not really being neutral, that makes no sense... Please explain?

As for it being illegal to drive in neutral, that implies all manual transmission are illegal because you have to shift into neutral every time you change gears... Please don't even try to explain that kinda crazy to me, I've heard enough!

 

With good gas pedal control (not coasting with foot off pedal), you can do the same without ever taking it out of Drive. The Gen3 Liftback's HSI display is perfect for helping get it right.

Unlike a traditional non-hybrid, Neutral in a Prius doesn't mechanically disengage anything. Everything keeps spinning as in Drive. Only the MG1/2 electric fields / controllers are shut down.

That is an absurd overreach. And doesn't excuse traditional automatics either, which also disengage one gear before engaging the next.

 

What ?? I suspect you didn't say what you really meant here.

 

You KNOW that argument is totally invalid, right ? It implies no such thing.

I said coasting downhill in neutral......which is quite different than a normal shift.

 

Mmm, makes perfect sense to me. No gears ever engage or disengage in a Prius transaxle with the exception of the parking pawl.

 

OK.....so that implies that the gas engine is never really mechanically connected to the wheels.
Is that true ?