The Prius Experiment

[Blacktree]

We have our first "real" fillup since installing the pizza pans. As mentioned earlier, the maintenance issues have been fixed. And the result is 61.1 mpg. As usual, I'll do 2 more fillups before passing judgment.

BTW, if you want to see the fuel log, you can click on the sig below.

[Blacktree]

We have another fillup with the pizza pan wheel covers. This time, the fuel economy was just under 60 mpg (59.9 to be exact). So the combined average of the 2 fillups is about 60.5 mpg. Not bad.

Also, I went on a road trip today. It was mostly highway cruising at around 65 mph. I filled the tank before and after the road trip, so the FE data will be separate from my normal driving. But on the road trip, I drove 230 miles and got about 55 mpg.

Anyway, I'll do one more fillup before passing judgment on the pizza pan wheel covers. But so far, the results are promising.

[Blacktree]

OK, we have the 3rd fillup with the pizza pan wheel covers (highway trip notwithstanding). And the average for those 3 fillups is 59.4 mpg. The average before installing the pizza pan wheel covers was 56.6 mpg. That's not a big difference, but an improvement nonetheless.

Also, I noticed something interesting. The ecomods seem to have offset the fuel economy penalty for running the A/C. Back before I started the ecomods, I wasn't running the A/C because the weather was cooler. Now it's summer, and I'm running the A/C all the time. But the fuel economy now vs then seems to be about the same. So I'm basically getting A/C for free.

Now I'm going to take a break from the ecomods to work on the BMW. I've hinted at that before. But I finally have all the parts for that project. So we're hitting the pause button on the Prius Experiment. When we come back to the Prius, I want to remake the existing ecomods (grille block, mini-mirrors, and wheel covers) using something more permanent... and more aesthetically pleasing.

But I'll keep logging fuel economy. That info is readily available. Just click on my signature.

[aerohead]

Originally Posted by Blacktree

OK, we have the 3rd fillup with the pizza pan wheel covers (highway trip notwithstanding). And the average for those 3 fillups is 59.4 mpg. The average before installing the pizza pan wheel covers was 56.6 mpg. That's not a big difference, but an improvement nonetheless.

Also, I noticed something interesting. The ecomods seem to have offset the fuel economy penalty for running the A/C. Back before I started the ecomods, I wasn't running the A/C because the weather was cooler. Now it's summer, and I'm running the A/C all the time. But the fuel economy now vs then seems to be about the same. So I'm basically getting A/C for free.

Now I'm going to take a break from the ecomods to work on the BMW. I've hinted at that before. But I finally have all the parts for that project. So we're hitting the pause button on the Prius Experiment. When we come back to the Prius, I want to remake the existing ecomods (grille block, mini-mirrors, and wheel covers) using something more permanent... and more aesthetically pleasing.

But I'll keep logging fuel economy. That info is readily available. Just click on my signature.

When AeroStealth got his 2014 F-150 EcoBoost and was conducting baseline mpg testing, he noticed that at certain speeds, the truck got 'better' fuel economy WITH the AC 'ON.'
A friend with a Tundra experienced the same.
All we can figure is that, under some conditions the engine is 'unloaded', and by engaging the compressor, it moves the engine into a more efficient BSFC island of operation.
Wolf H. Hucho got into this in his 2nd Edition, with respect to aero mods and gear-matching.

[Blacktree]

Here's another thing to consider. My car uses an electric A/C compressor. So the energy consumption is fairly constant (after the initial power spike). But aero drag increases with vehicle speed. So naturally, there will be a point where the A/C is more energy efficient than having the windows open.

That said, most of my driving is at speeds below 50 mph. And my A/C use is dictated by the weather, regardless of vehicle speed.

[Blacktree]

Wow, it's been a month since my last post. The good news is, the BMW suspension overhaul is going great. The front suspension is done, and the rear suspension is underway. The car should be back on the road in a week or two.

As for the Prius, I've been driving it and acquiring FE data. As mentioned earlier, the average FE before installing the pizza pans (3 fillups) was 56.6 mpg. We now have 6 fillups with the wheel covers (highway road trip excluded), with an average of about 59 mpg. That's about a 4% improvement. TBH, I was hoping for a better improvement, but it's still better than nothing.

For my next test, I'm going low effort. The BMW project is still underway, and I don't want to be sidetracked from that. But I've always wanted to test friction reducing additives, to see if they're worth the trouble. So I ordered a couple bottles of Liqui Moly Ceratec. I've seen it tested on the Project Farm youtube channel, with good results. They also did a fuel economy test using a lawnmower engine. Not sure how applicable that is to an automobile engine.

Since the Prius doesn't run the gas engine all the time, that means any fuel economy improvement will be reduced. I mean, you can't reduce friction of a non-running engine. So I'm also going to put some Ceratec in the transmission oil. The Prius doesn't have a traditional automatic gearbox. There are no clutches or bands. It also doesn't have a belt, like a typical CVT. So the friction reducing additive shouldn't affect the transmission operation. But if we can reduce internal friction in the transmission, that might improve the efficiency of the electric motor. We'll find out soon enough!

[Blacktree]

Hey guys, still no updates. Sorry about that. But the hurricane tossed a monkey wrench in the works. Hopefully things will get back to normal soon. In the meantime, here's a glimpse of the massive flooding in the central Florida area.

https://www.youtube.com/watch?v=3E-lJNN82r8

On a side note: After the hurricane rolled through, the weather cooled off. I was able to drive without A/C for a few days, and the fuel economy numbers were amazing! I was getting daily averages of 66-67 mpg. So now my goal is 70 mpg with the A/C turned off. That should be attainable.

[Andyinchville1]

Originally Posted by freebeard

Thanks, that's a better angle.

It shows the mirror is well back from the A-pillar. That stub likely has almost as much drag as the mirror itself, based on the gnarly shape.

Hi,

Exactly....

How about getting rid of the add on mirrors and attach a small 1"tall by 2 or 3 inch wide mirror on the stub itself (may have to use some foam or other material to make it more aero on the wind side.

Andrew

[Blacktree]

The original intention was to attach these mirrors to the stubs, but that didn't work out. So I improvised. I'm not happy with the arrangement, and will eventually re-do it. But other things are higher on the priority list.

Lately, I've been checking out sport bike mirrors. That might be the ticket.

Side note: The hurricane cleanup is mostly complete. Life is getting back to normal. I also had time to finish the BMW suspension overhaul. The Prius is due for an oil change, so I'll toss in the Ceratec stuff.

[Blacktree]

The Prius was due for an oil change, so I added the LiquiMoly Ceratec in the process. The instructions say the bottle (which is 300 mL) can treat 5 liters of oil. That's a 6% solution. And my engine holds just under 4 liters. So I put 240 mL into the engine oil.



I also added some Ceratec to the transmission oil. The instructions specifically say not to put it in transmissions with wet clutches, or in clutch style limited slip differentials. The transmission in my Prius doesn't have any clutches in it. So it should be fine. I decided to add 200 mL (a 5% solution) to the transmission.

Now I just have to wait and see what the fuel economy data looks like.

Also, a side note about the pizza pan wheel covers. I haven't checked the tire pressure in awhile, because the pizza pans don't have access holes for the valve stems. And as a result, the tire pressure got pretty low. That's on me.