The Premier's Limo: 2004 Toyota Prius "winter beater" ecomodding thread

[MetroMPG]

Well, I finally ran through a tank of gas. This is my first full-emtpy-full, so I was able to calculate some results...

5.1 L/100 km over 734 km (456 miles)

That's 46 MPG US. HOLY CRUD THAT'S BAD.

How bad? 46 mpg US combined is the 2004 Prius EPA rating (48 city / 45 highway).

I never just get the EPA rating in any car. Something's wrong. If the calculated MPG is right, that's the worst fill-up (vs. EPA) I've gotten in years and years. Super-ironic considering the vehicle in question!

The car's fuel economy computer told me the tank was at 4.4 L/100 km / 54 MPG US; the un-calibrated ScanGauge II said 4.5 / 52 MPG. I thought those numbers were reasonable for the kind of driving I'd been doing (about 20% city short trips, 80% relaxed rural highway driving where I'd see trip numbers in the high 50's to low 60's).

I've read that the flexible bladder in the fuel tank can cause inconsistency in fill-ups (in terms of volume, that is: sometimes less, sometimes more fuel goes in depending on temperature and ???).

Hopefully that's what I'm seeing here. We'll know more at the next fill-up... and the one after that, averaging things out.

I don't think anything's wrong with the car itself. It runs well, seems to roll OK, glides very nicely. There's a big exhaust leak (muffler broke off), but I wouldn't think it'd cause a massive MPG loss.

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No recent mods to report

Maybe that's the problem!

I haven't done anything to the car since the kill switch & coro wheel discs. This fall I've used up all my tinkering time on a big project at the mansion. But I'm nearly done, so plan to spend serious time modding the Limo starting in January.

[oldtamiyaphile]

I bought my G2 just after you did, but I've already burned through three tanks partly because it came with a used car warranty so I wanted to get some miles done in case it needed something that the warranty might partly cover.

My MFD reports a steady 4.4l/100km, and my fill ups have all been 4.6. This car does all those short trips that are so bad for Prius mileage.

Since your MFD shows the same as mine, I wonder if it's just the bladder contracting as the weather cools? But that would give you 'better' mileage...

If the bladder accepts 40L on a warm day, but only 35L on a cold day your 'cold' fill looks better.

[MetroMPG]

Thanks for the comparison data!

I'm hoping it's just a case of a short fill last time. Both fills were to 3 clicks, but I did fill verrrrrrry slowly today and it is unusually mild. Maybe I stuffed more fuel in it than usual.

We shall see!

I'll have more mods on this tank as well.

[Insight for life]

Definitely the bladder.

[Gasoline Fumes]

On a recent highway trip in my parents' 2008 Prius, I got 50 MPG one way and 45 MPG coming back. That's from the built-in display, I've never tried calculating the MPG. My GPS reported an average speed of 50 MPH. The same trip in warmer weather was more like 50-55 MPG. I've gotten as high as 70-80 MPG in Priuses on shorter trips at lower average speeds.

[MetroMPG]

^ I'm seeing similar numbers at that speed.

Originally Posted by Insight for life

Definitely the bladder.

Merci. I hope so. We'll find out in a month or 2 when I fill up again!

[MetroMPG]

I was distracted with other (non-car-related) projects this fall, but I'm finally getting a chance to do a few more things to the Limo. Fortunately, the winter weather is cooperating enough to let me! It's been super mild around here.

First up...

Grille blocks!



Coroplast for the bottom, super high-tech variable grille block up top. (Hey, I was in a hurry! Yes, that's an old sweatshirt stuffed in there... I need to pick up some pipe insulation, which seems to be the more popular method for the upper block.)

Considering how slow this car is to warm up, and how it tends to lose heat more than other cars because the engine spends so much time shut off, this is both an aero + heat management mod.

Side mirror mods!



Above: passenger mirror delete.

FYI, side mirror removal on a 2nd gen Prius is probably the easiest/quickest of any car I've done this to. It's a 5-8 minute job. The door card comes off super easily with 2 screws and a bunch of those plastic pop-in clips/holders around the outside. (What are those called?) Then disconnect the plug for the wiring and remove three 10mm nuts.

If only someone made 3D printed Prius mirror blanks, I wouldn't have covered the opening with black duct tape.



Above: driver's side auxiliary convex mirror

So I can fold the mirror back on the highway.

Next up:

I think I'm going to do rear wheel skirts out of coroplast.

Following that, the biggie: I'll figure out how to tailor the Civic Tail to fit.

[Vman455]

Originally Posted by MetroMPG

Above: driver's side auxiliary convex mirror

So I can fold the mirror back on the highway.

Did you make that mounting bracket yourself, or is this something that's available? I might go this route now that my driver's side mirror is back on.

[MetroMPG]

I made it. It's just a piece of flat aluminum, bent. 2 self-tapping screws into the bottom of the mirror, one into the back of the little convex one.

Re-used from last year's Civic winter beater.

[MetroMPG]

I raided my stock of cardboard to make a template.



I was going to just duct tape it on since it only has to last the winter, but then decided to make ghetto brackets instead. They're plywood and they pinch the 90 degree lip in the wheel arch to give attachment points for screws.

They're actually very secure. I can move the metal lip by wiggling them. Wood sucks as a long-term approach of course; hunks of plastic or 3D-printed pieces would be ideal.

And the 2 brackets on the top of the wheel arch have to be much shorter for tire clearance.





This one doesn't come out from the tire quite as much as I'd like. There's probably only about 1 cm / 3/8" clearance.



Now to make one for the other side...