The Prius Experiment

[mpg_numbers_guy]

Thoughts on just deleting the passenger side mirror altogether? With a panoramic rearview mirror, you might not need the passenger side at all.

How big are the mirrors?

[Blacktree]

I'm not willing to delete the passenger mirror, because that could be a safety issue. I drive in an urban environment, often with heavy traffic. Being able to see into my blind spots is pretty important.

That said, a camera setup might fill the role. But I'm not sure where to put the screen. Also, there's the question of cost-to-benefit. For example, if replacing the mirror with a camera only improves fuel economy by 1%, is the juice really worth the squeeze?

[ps2fixer]

With my corolla I saw a sizable gain, I think it was something like 3-5%. It was enough for me to keep it off. I tried the little mirror just inside the window and it didn't work too great. Visibility was good in the corolla, just had to look over my shoulder when changing lanes like you should already be doing. It's called the blind spot because you can't see it in your mirrors! The only issue I had with removing the mirror was for backing up, you can't see how things line up on that side of the car. It took a little bit to get used to, I drove through Detroit rush hour (to and from work) two days in a row for work with no problems, bumper to bumper traffic and you better be in the correct lane a good mile ahead of time kind of traffic.

[Blacktree]

For me, removing mirrors is not an option. My driving is mostly urban, including plenty of parking lots. So in addition to watching out for vehicles, I also have to watch out for pedestrians who will brazenly step into your path and dare you to hit them (so they can sue you).

Replacing a mirror with a camera might work, but that may be more time/effort/cost than I care for. I'm mainly looking for cheap easy stuff that will have a measurable effect.

I already have a "real" project car (an older BMW). So the stuff I'm doing with the Prius is just a few minutes here and there, when I have some free time. Actually, pretty soon I'll be launching into a complete suspension overhaul of the BMW. So I may not have time to tinker with the Prius for awhile.

[hayden55]

Mirror is probably not worth it. My passenger mirror has been off for 6 years now and its kinda annoying.

[Drifter]

I'd remove my passenger mirror except I use it when backing into parking spots where my passenger side is right next to a planter box island. This is my preferred parking lot location because it is often in the shade and gives my driver's side the most room between other cars which prevents door dings and scratches.

[Blacktree]

Just a quick update: another fillup since installing the smaller mirrors. And this was my best fillup to date! It came out to 63.45 mpg! That's 3 fillups since installing the motorcycle mirrors, with an average of 62 mpg. The 3-tank average before installing the mirrors was 60.8 mpg. So the mirrors seem to be making a difference. So I guess I won't be reinstalling the stock mirrors. Next up will be the pizza pans.

That said, driving conditions can have a huge effect on fuel economy. Over the course of several hundred miles, that can add up. And it can wash out any gains (or losses) from modifying the car. So I wouldn't take these mpg results as gospel.

I'm thinking of doing a coast-down test. That might provide more conclusive data. But coast-down testing each individual mod will be very tedious. And to be blunt, I just don't have time for that. So I would like to do a "stock vs eco-modded" test. For example, I would test the car completely stock, then install some eco-mods (grille block, mini-mirrors, wheel covers) and compare the results. At the very least, we should be able to see if eco-modding is worthwhile.

Let me know what you think about that.

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[Blacktree]

Summer has arrived in Florida, and I'm using the A/C every day. As a result, fuel economy has dropped. Before, I could easily get mpg in the low 60s. Now I'm struggling to get mid 50s. So I'm thinking I should run out a couple tanks of gas before continuing the mods, so we can have a better comparison.

[ps2fixer]

Temps up here in the extreme north (Michigan) are hitting 60's and in a few days it's going to the 80's, crazy how it went from basically just above freezing to boom middle of summer lol.

AC takes a lot of energy, not sure if much can be done to lower the load besides putting less cooling demand on it (higher temp setting). Pretty sure it's electric in your car, so it won't need to run the engine, but it's quite a draw on the hybrid battery.

If you have a grill block, you might see gains opening it back up some since the heat from the heat pump action of the AC system is pushed to the condenser up front

Another idea I just had, when you first get in the car, turning the AC on would help warm the engine up a little faster (heat pushed into radiator), but it's also likely will be loading the engine indirectly when still not up to operating temp. Couple ideas to play around with at least.

The steering wheel has an AC button, you can turn it on/off as needed, but I suspect the auto controls work fairly well at cycling the pump.

[Drifter]

Originally Posted by ps2fixer

AC takes a lot of energy, not sure if much can be done to lower the load besides putting less cooling demand on it (higher temp setting).

Phase brought this up recently in his thread ( https://ecomodder.com/forum/showthre...tml#post666421 ), but using a higher temp setting usually uses more energy because most cars use the heater to warm the air conditioned air.

From Toyota's "neural network" AC diagram, we can see that in addition to controlling the compressor, blower speed, recirculation setting, etc Toyota uses the "air mix damper servo" for "temperature control correction." I.e. it can send varying amounts of air conditioned air through the heater core to achieve the desired cabin temperature.




I only recently started using my scangauge on my gen3 Prius, but it does have a gauge for the number of watts used by the air conditioner. So far the temperature has been mild so I haven't experimented with it yet, but I suspect seeing AC on max low and adjusting the fan speed will be best. If that is too cold, manually alternating between AC on and AC off will probably beat the "neural network." But we'll see this summer...