Prius 75-91mpg

[Nathan jones]

Finally my new tiny torque wrench arrived 5-25mn to test the nuts and bolts, plus had half a day off so a 10 year late rub down, or hammer down and paint. I didn't choose pink it's red oxide paint. The other side can wait a week or two

Also couple of blobs of lead solder on the exhaust that haven't melted yet

A few more tests and I may scrap the titanium and make riveted aluminum system from the cat to tail

[freebeard]

Originally Posted by Nathan jones

So I figured I will brush paint my car with the cheapest exterior black from October then back to white the end of April time. I will post the most hideous pics

Originally Posted by myself

My thinking is instead of the stock white, an automotive Ultrawhite with titanium dioxide. Probably in a Rustoleum base. As a palliative for not having air conditioning.

I just posted this in another thread.

To elaborate, Titanium dioxide radiates heat in all but direct sunlight. Recent experiments with [IIRC] calcium chlorate show it can radiate heat even in direct sunlight. So I misspoke in the other thread. hee's the homework: www.youtube.com/results?search_query=paint+cools+in+sunlight

How To Make Infrared Cooling Paint (Electricity Free Air Conditioning)

Youtube is full of videos on how to paint cars with Rustoleum

Rust-Oleum® Stops Rust® Gloss Protective Enamel Metal Paint Masstone Tint Base - 1 qt.
Model Number: 7507502 Menards ® SKU: 5515008

edit: Maybe that's backwards? You want to promote heat gain? I'll revert to my default suggestion -- Black Plastidip.

[Nathan jones]

Thanks, yes I noticed with the exhaust titanium does not conduct heat very well, or electricity for that matter. Colour this year made a massive difference in 35c heat and last winter cold day battery performance was almost zero, 2-3c saw the ice on 80-90% of the time, the worst so far

I have plenty of white so I will consider adding the dioxide

[Nathan jones]

So well finally the laser thermometer thing arrived and I figured a 3-4 hour trip would stop any conducted heat loss and give me a very top exhaust temperature to work with.

Towards the end of the trip I had to drive with the brakes on high to keep the ice revs up. I jumped out the car and would say there were only 5-10 seconds after the engine stopped. The cat went down a degree every couple of seconds

Fair to say my car is ALWAYS in open loop. Bad news for future generations smog but I can make my exhaust from even softer aluminium's although 6061 will do. Was really surprised although that was an outside figure after a 180 mile trip. The engine only ticks over most days

..the 39c part was the titanium centre section and the parts in 70's were after that ??

[Nathan jones]

Some aircraft alloy from china. A test piece but will need riveting if it's used as welding or brazing will weaken/add stress

[Nathan jones]

Replaced the not so great window replacment. Hole is for rear view camera. Still only 700g less than original. The new door at xmas should save 28kg so not such a time/gain this one. Should have more time next year, more doors and roof

Also on the doors the latch will be retained but the handle and hinges I will try and make

p.s I will also test the bolts, torque only clamp load is fine when I get a moment. Also buy an old rear box so I can copy it...

Making good stuff is so much easier and cheaper. Pattern stuff has to made to fit takes longer

[Nathan jones]

Also as far as clear plastic goes for small quarters 0.5-1mm is plenty, this was 2mm which is also for door glass

[Andyinchville1]

Originally Posted by Nathan jones

The dimples next year will be on new wings and areas of medium pressure

HI,

I like the dimpling idea and the lower air dam but it looks like alot more frontal area (maybe it's just the sheer volume of white).

Has the front end mods and dimpling helped alot (I saw the drag reduction percentages but what does that equate to in terms of MPG improvements. Also how did you figure drag reduction ?).

Thanks

Andrew

PS - Great thread .... come to the USA and I'll put you up to make my jetta in carbon fiber!

[Andyinchville1]

Originally Posted by Ecky

I'd probably opt for white and call it a day, considering there's a lot less solar energy to collect in winter. Best I can tell, it's cloudy ~76% of the time in London, and it only gets worse as you go north.

All of those layers of paint will eventually add up to a lot of weight.

HI,

I was just thinking that too ... About paint weigh that is.

Now this may seem a little radical but with so much of the car being converted to non metals how about simply stripping off all the paint and running the sheet metal au natural (OK I know you don't want rust so I guess you can rub her down with some sort of oil to keep that from happening .... a light film of oil is bound to save some weight VS layers of paint..

Also thought about titanium lug bolts (or studs / nuts if that is what a Prius uses .... In a Jetta , the titanium saves a fair amount of weight).

Lastly, I read somewhere where a person put SMALLER rotors on the front (based on a jetta that would be like using the rear rotors and using them in the front).

I believe Wilwood also makes Aluminum Calipers whch may save weight also).

Andrew

PS - Maybe to eek out the last bit of MPGs ditch the gas engine and go with a small Turbo Diesel instead ....

All this is hard core .... I like it!

[Nathan jones]

Hi

The frontal area is the same, from an above angle it may appear more as the bumper angle is different, on a regular prius from the grill down air is directed down, on this all is pushed upwards or to the side.

Dimples create turbulence which strangely enough restricts the size of the boundary layer of air and also when it departs from the body in low pressure areas, so my wings or bonnet for example the air will be controlled and kept closer just after curves and angle changes or near the windscreen. So even though turbulence is created there is less overall area of the vehicle as a whole. Like a bubble is created around the car which is smaller than the bubble of a car without dimples. Personally I should have really started at the back of the car where most negative pressure is. I have started my 4th rear bumper and as of yesterday redesigned it again. The mean reductions are so low as stated because the shape of the car is not so square to start with. The main reason I change it is because if I am making new parts to reduce weight I may as well add a few shapes at the same time. To me and my experience mass has a bigger effect.

I cannot and don't bother measuring it's effectiveness as so many things change. The time I leave and where I go changes, also temperatures and trip lenths. These affect mpg far more than an approximate 1% of a dimple bonnet. But physics laws says it must work so I throw it in with a bunch of other stuff. Between 60 and 90mpg I would say, 60 being a frosy morning and 90 35c. But as I said, subjective numbers, I do not measure it. Just keep working. My definite two week record of 102 was without rear doors, plus having small wheels and a heatwave.

Thanks. As far as fiber products go I am more leaning back to polyester and csm glass. If well structured it can be as light and with much greater flex modulus. Also with the high styrene resin it rebonds to old resin but epoxy doesn't. I will still use epoxy as a surface layer when molding a painted part so the paint does not get wrecked. I found that however I try to hand lay woven glass, carbon or kevlar on the tight part of weaves it does not infuse. Even rollering sections for half an hour, sawing them up reveals dry weave centres, especially above 200g. I will keep my kevlar, unpick it and make a kind of biaxial cloth for the drivers door

Best thing is to buy stuff and try it. From my own experience stick to csm and hand lay. I have a vacuum thing but it takes longer is more expensive and is more likely to go wrong (but could be my impatience). See what works for you, you may be tidier with air leaks and have more and patience...

Also with polyester I can add less catalyst, have a great pot life and then leave it in the sun which you can't do with epoxy.

Incidentally if you are sure about using epoxy, german 'di-poxy' laminating epoxy is available on amazon for £11 a litre. Along with a few other tricks you can create cf for less than £10 a metre. Takes the punch out of mistakes

Originally Posted by Andyinchville1

HI,

I like the dimpling idea and the lower air dam but it looks like alot more frontal area (maybe it's just the sheer volume of white).

Has the front end mods and dimpling helped alot (I saw the drag reduction percentages but what does that equate to in terms of MPG improvements. Also how did you figure drag reduction ?).

Thanks

Andrew

PS - Great thread .... come to the USA and I'll put you up to make my jetta in carbon fiber!