The Prius Experiment

[Phase]

Originally Posted by Blacktree

That's true, especially in the summer. Even if the temperature is bearable, the humidity can still make you feel "icky".

Also, the 90*F temperatures are back. No surprise there. I was able to average ~60 mpg the last couple days, with the A/C running. I'm not sure how much of that was the driving environment, and how much was me. But I set the temperature a little higher (78*F). That's the warmest it can get, before I start to sweat. And I noticed the A/C pump cycling off every so often. With the temp set to 75, the pump seemed to run continuously. This will probably vary depending on ambient temperature.

My strategy was a 3-step procedure:
1) Drive for a minute with the windows open, to expel the hot air.
2) Roll up the windows and turn the A/C to max, with the fan on medium/high.
3) After a few minutes, bump up the temperature and turn down the fan speed.

The idea was to remove excess heat and humidity quickly, then run the A/C just enough to maintain it. Obviously, that won't work for short trips. But if you're going to be driving for extended periods (like I do), it might help.

Edit to add: I wonder if adding insulation would make a noticeable impact on HVAC efficiency. When I removed the door skins to replace the front speakers, there was basically no insulation in the doors. I wonder if the roof has any insulation?

I do the same thing. Windows down and max ac fan when first driving to get the hot air out then roll windows back up and put ac at lowest fan speed once I get it to the right comfy temps inside. Insulation helps. Look up thermal jute mats to block outside heat. And obviously tinted windows. I also use a sunshade for windshield. Black cars suck lol

[19bonestock88]

There isn’t usually a lot of insulation in the roof of many cars, I added some to my Saturn to make life without AC a little more bearable

[Phase]

Originally Posted by 19bonestock88

There isn’t usually a lot of insulation in the roof of many cars, I added some to my Saturn to make life without AC a little more bearable

ill be adding insulation to my roof when my friend can come help take out my roof liner. looks like a pain to remove alone

ive only done my floors

[ps2fixer]

Cars generally have little to no insulation, so adding insulation could help with heating and cooling as well as cut down on noise. The material for the roof give a tiny bit of insulation, but from what I've seen for typical cars, there's next to nothing.

Something flexible that can be glued in would probably be idea. Ridged Styrofoam gives nice R values, but it's not too friendly for being installed in a car, works well with large flat surfaces like houses though. I suspect something would be better than nothing even with the little bit of added weight.

Maybe someone can chime in with more experience.

[Phase]

https://www.secondskinaudio.com/heat.../heat-wave-pro

i installed this in my floors with some kilmat sound deadening. i was able to drive in -15 degree weather in colorado thru steamboat and summit county at night with the heat completely turned off

hoping to stuff it in the roof this summer to see if it can help keep the heat from the black roof from radiating inwards

[Blacktree]

Florida is called the sunshine state, for good reason. At this latitude, the sunlight is more direct. And it can be absolutely brutal.

I don't have much to report, regarding the Prius. I took a mini-vacation for my birthday. When I got back home, there was a trailer hitch waiting for me. So I installed it.

https://www.youtube.com/watch?v=hc2C98_fuFg

Also, the car just gave a P1121 error code. I think that's for the coolant control valve. Looks like it controls coolant flow through the heater core and the thermos bottle. So I ordered a replacement.

Like I mentioned earlier, the BMW is about to undergo major surgery. The Prius eco-mods will be put on hold, while I focus on that. But I'll try to work in some maintenance on the Prius... like the aforementioned water valve, and the front control arms.

Edit to add: I forgot to mention, so far the upper grille block has not caused any overheating. The highest coolant temperature I've seen is 90*C. And the ambient temperatures are 90-95*F. Yep, I just mixed units. LOL

[ps2fixer]

Nice work on the vid, I have to finish up my hitch install yet, wonder if mine will have the same fitment problem.

I've hit high 80F here and coolant temp max hits 190F. I haven't setup the scan gauge to monitor the inverter temps yet which is more what is effected by the lower grill.

I go about 5 mils and it hits around 170F, maybe a little warmer with the warmer weather.

I mounted the trailer connector box to the passenger side body with the provided double sided tape. I routed the wire so it can be tucked away next to the battery and is still long enough to reach the trailer hitch area. The place you used seems like a better spot though. I wanted it far away from things that are common to be moved around and the concept of putting it to the body is it might give a slight cooling effect, of course in the sun it's going to heat it up, so maybe not the best idea lol.

Good luck with the BMW project.

[Drifter]

Just got caught up with your videos - nice job with the camera work! I also had to spread apart the mounting flanges on my Curt receiver for my Tundra - I think it got bent a little in shipping, but I've had no problems once it was mounted...

I keep debating putting a receiver on my Prius and selling my Tundra. Using a cheap ~500lb 5x8 utility trailer I could keep 90% of my loads under 1,000 lbs. For example, my last pickup load was a junkyard engine that probably weighed 500 lbs. I'd save enough on registration & insurance to rent a pickup 1-2 x a year for the heavier stuff. But I'd really prefer to tow with something rated for 2000-3500 lbs (the Prius is rated for 0 lb in the US and ~1500 lbs in Europe) - especially since I'd see 110-120F temperatures on mild rolling hills at 55mph driving 100-200 miles at a time.

I also worry that the receiver would muck up the diffuser aerodynamics and scrape the ground leaving steep driveways when not in use. Since you keep such good track of your mpg I wonder if you'll see a decline because I assume it'll hurt aero more than your mirror helped...


PS: Did your Prius come with Firestone Champion Fuel Saver tires already? I've never bought a second hand vehicle with low rolling resistance tires already installed and always find myself debating throwing out perfectly good tires for marginal mpg gains...

PPS: I notice you blurred your license plate in the last video - if you're concerned about privacy I don't think you did so in the first video.

[ps2fixer]

Yea, I'm also wondering if there will be any clear MPG effects of the hitch. It's in the air stream slightly, so I'm expecting it to decrease a little. I suspect it wouldn't be too hard to mod up something to help the air get over the hitch with out hitting a flat face and remove most/all of the negative effect.

[Blacktree]

Originally Posted by Drifter

I also worry that the receiver would muck up the diffuser aerodynamics and scrape the ground leaving steep driveways when not in use. Since you keep such good track of your mpg I wonder if you'll see a decline because I assume it'll hurt aero more than your mirror helped...


PS: Did your Prius come with Firestone Champion Fuel Saver tires already? I've never bought a second hand vehicle with low rolling resistance tires already installed and always find myself debating throwing out perfectly good tires for marginal mpg gains...

Those tires were on the car when I bought it. That was a nice bonus.

I'm also curious to see how the hitch receiver will affect aero. Hopefully not much. But if/when I make a belly pan, it can attach to the bottom of the receiver. That may change the departure angle of the diffuser section, but at least there won't be a bar hanging down into the airstream.

Speaking of which... while I was under there I took a look at the underside of the car. Looks like it shouldn't be difficult to make belly pans for the front 1/3 and rear 1/3 of the car. The front 1/3 looks especially easy, since the subframe has bolt/screw holes all over the place. And the front bumper has conveniently placed holes on the bottom of the front lip.

Edit to add: I got a utility trailer instead of a truck, for the reasons you described. I don't need a truck often enough to justify the cost of ownership. On the rare occasion when I need to transport something too big / heavy for the trailer, I can rent a truck or pay for delivery.