Making the Ioniq slippier

[Phase]

Originally Posted by freebeard

That was remnants from MultiCraft Plastics in West Eugene. One popular usage is in sign shops.

There are three price levels, retail wholesale and distributor, generally about $100 for a 4x8 sheet.

https://nudo.com/p_polymetal.php
https://www.maxmetal.com/
https://www.copeplastics.com/materials/alupanel/

any thoughts on thicker abs sheet with some type of structure to keep the shape? 100 bucks is still a bit pricey

[Phase]

Originally Posted by Drifter

Are you using the Ecomodder calculator? Here it is with the assumptions I used (3500 lb with driver, .24 Cd, 23.5 Frontal area, .007 rolling resistance, 1000Watts parasitic load, 36% thermodynamic efficiency, 85% drivetrain efficiency, summer gas): https://ecomodder.com/forum/tool-aer...ToStep=5-200-5


That spits out ~20 horsepower aero drag and 42mpg at 80mph. Changing the CD to .20 results in ~16.5 horsepower aero drag and ~48mpg:
https://ecomodder.com/forum/tool-aer...ToStep=5-200-5


Plug in a Cd of .145 and you can get within a rounding error of 60mpg at 80mph.

in the real world when there are no head winds and its warmer weather (75 or 80 degrees and above), my car actually gets about 50-52mpg when i have cruise control on at 80mph. hybrids definitely dont like cold weather is one big thing ive noticed

[Drifter]

The ecomodder calculator has a setting for rho with some preset values in the drop-down for different temperatures.

Which Ioniq do you have? Apparently the Blue model has better mpg, but I found this speed vs mpg chart from cleanmpg for the Limited trim level at 60F temperatures:



I can pretty closely duplicate those mpgs with:

Weight: 3200
Rolling Resistance: 0.007
Cd 0.25
Frontal Area: 25
Summer fuel
0.36 engine efficiency
0.91 drivetrain efficiency
1500 watts parasitic drag
1.225 rho (59F)

Speed_tested MPG_modeled MPG
50_____71.5______71.4
55_____66.0______65.5
60_____59.2______59.8
65_____54.4______54.5
70_____49.9______49.6


Using that model, here is how temperature affects mpg:
Speed_14F MPG__59F MPG__80F MPG
50_____68.1______71.4____73.3
55_____62.1______65.5____67.4
60_____56.5______59.8____61.7
65_____51.2______54.5____56.3
70_____46.5______49.6____51.4


In the "real" world with limited atmospheric wind, you should beat the modeled mpg because of the corridor effect (other cars on the freeway going to same direction create a bit of a tailwind)

[Phase]

Originally Posted by Drifter

The ecomodder calculator has a setting for rho with some preset values in the drop-down for different temperatures.

Which Ioniq do you have? Apparently the Blue model has better mpg, but I found this speed vs mpg chart from cleanmpg for the Limited trim level at 60F temperatures:



I can pretty closely duplicate those mpgs with:

Weight: 3200
Rolling Resistance: 0.007
Cd 0.25
Frontal Area: 25
Summer fuel
0.36 engine efficiency
0.91 drivetrain efficiency
1500 watts parasitic drag
1.225 rho (59F)

Speed_tested MPG_modeled MPG
50_____71.5______71.4
55_____66.0______65.5
60_____59.2______59.8
65_____54.4______54.5
70_____49.9______49.6


Using that model, here is how temperature affects mpg:
Speed_14F MPG__59F MPG__80F MPG
50_____68.1______71.4____73.3
55_____62.1______65.5____67.4
60_____56.5______59.8____61.7
65_____51.2______54.5____56.3
70_____46.5______49.6____51.4


In the "real" world with limited atmospheric wind, you should beat the modeled mpg because of the corridor effect (other cars on the freeway going to same direction create a bit of a tailwind)

i have the blue version. it weighs a little less and has aero hubcaps. its rated at 59 highway, the newer models are rated 60 highway, no idea why

and most of my trips dont let me have the corridor effect since its middle of nowhere fast driving in idaho or utah. not really any other cars

random question regarding temperature, everyone says that 77 to 80 f is the sweet spot. does mpg go up when it hits 100 degrees? what about 120 degrees in phoenix? or is there a point where mpg goes down because the engine is getting too hot?

[freebeard]

any thoughts on thicker abs sheet with some type of structure to keep the shape? 100 bucks is still a bit pricey

What do you think? duckduckgo.com/?q=3mm+ABS+4x8+sheet&iax=shopping&ia=shopping I see prices in the $70-80 range.

Then you have the structure. Composite sheet would need some as well, but it's pre-finished. So long as it doesn't get scratched up in fabrication, there's a big savings compared to fiberglass and likely ABS.

I don't trust this link but it's interesting: https://www.alibaba.com/pla/3mm-pe-d...dmRpZD05MTY2OA

If you truncate it after .html is fails to a search page, but the append calls out a Google search while I found it on DuckDuckGo. Anyways, those architectural panels they make Toyota dealerships out of cost the contractor less than $10 in quantity.

[Phase]

Originally Posted by freebeard

What do you think? duckduckgo.com/?q=3mm+ABS+4x8+sheet&iax=shopping&ia=shopping I see prices in the $70-80 range.

Then you have the structure. Composite sheet would need some as well, but it's pre-finished. So long as it doesn't get scratched up in fabrication, there's a big savings compared to fiberglass and likely ABS.

I don't trust this link but it's interesting: https://www.alibaba.com/pla/3mm-pe-d...dmRpZD05MTY2OA

If you truncate it after .html is fails to a search page, but the append calls out a Google search while I found it on DuckDuckGo. Anyways, those architectural panels they make Toyota dealerships out of cost the contractor less than $10 in quantity.

i probably wont need THAT much in material for the rear spoilers. im mostly looking at abs for the undertray, unless you have some suggestions

spoilers will probably need to be a bit stiffer since they can only be mounted at the tip of the car

[freebeard]

What you see in the picture was cut from a scrap/remnant/cutoff left after MultiCraft sold less than a full sheet. Try sign shops. I've gotten larger pieces at BRING, the local recycler; typically an outside corner when someone cuts a circle out of a square.

Polymetal or equivalent claims rigidity equal to 5/8" plywood, but it's 3 [or 6mm, or with thicker skins] and waterproof. Apparently its used for wings on dirt track race cars.

[Phase]

Just an update for everyone. Tried to mount wheel skirts and the foam poster board from dollar tree wasn’t wide enough to add the curve near the bottom. I need a better way to trace the outline too and much better scissors. Haha. But it does kind of look cool actually having this tape and board mount. I think the Ioniq can pull off the look. Hoping to do a gift test possibly next week. Forecast is showing 9 days straight of rain here in Portland. Just like the last few weeks. Today was the only fully dry day that I was able to get out and quickly fab this up!

[aerohead]

1) Aero drag would fall off a bit with lower air density. ( Raw barometer and ambient conditions can be input'd into online air density calculators) AWOS from a local airport won't help you, as the barometric pressure they report is already 'fudged' for the pilots.
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2) The Air Conditioner will be working overtime. AC blower fan will probably be on 'HIGH.' Radiator shutters will be wide-open, with a Cd 0.005-.007 penalty. Condenser electric fans may be pulling full current in traffic or stops. The IONIQ should be designed for 122-F operation ( Furnace Creek, Death Valley, California ).
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3) There can be significant 'weather' during summer. Strong wind spectra. All directions, depending.
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4) Hot asphalt pavement may have tire tread-blocks 'squirming' with extra hysteresis loss as they roll, with potential R-R penalty. ( GM designs for 220-F tire temps, with sidewalls @ 10-F over ambient )
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5) The gasoline itself has an API, thermal coefficient of expansion. 'Cold' fuel dispensed into the tank will 'grow' as you drive, with infrared forcing from the hot roadway. The mass air sensor will track air density, but I'm unsure of fuel. If you're doing 'tank-mpg' backup, technically, this would have to be tracked and accounted for ( why universities use 'mass' not 'volume ).
Some stations will be able to provide actual storage tank temperatures, whether below, or above ground. Just ask. If not, something like a Wexler, 8-inch, stainless steel stem thermometer can be placed directly in the filler neck as you refuel. It's what I've done.

[aerohead]

Originally Posted by Phase

i probably wont need THAT much in material for the rear spoilers. im mostly looking at abs for the undertray, unless you have some suggestions

spoilers will probably need to be a bit stiffer since they can only be mounted at the tip of the car

ABS is just a 'diaphragm.' It has no strength to speak of.
Typically, it's vacuum-thermo-formed over some tooling which either creates 'ribs', or compound-curve 'egging' to resist deformation. Its natural frequency must never be experienced while in service.
Aeroelasticity would be a real thing at 80-mph!
The pieces of car bellies I find laying in intersections with 'dips' all have a fiberglass pre-form embedded within the sheet-plastic matrix. They aren't 'flat.' Always 'curves', or 'fins', 'ribs', or submerged NACA inlets molded in as stiffening 'corrugations.'
Coroplast or sheet metal might be better for underneath. And with a bonded reinforcing structure behind them.
Lots of examples here and elsewhere.