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Old 06-07-2022, 12:59 PM   #321 (permalink)
Phase
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Location: oregon
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Black Bullet - '19 Hyundai Ioniq Hybrid Blue
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Quote:
Originally Posted by aerohead View Post
1) While you're experiencing a 'trend' in the data, the test methodology isn't rigorous enough, nor data points of sufficient extent to enable the use of the mathematics.
2) Coastdowns must be conducted just as proscribed in the SAE Handbook.
3) Every rotating component in the car must be quantified for moment of inertia, or estimated according to SAE instructions.
4) You need your own weather station, or, perhaps timely AWOS ( automated weather observation service ) updates from a local airport, adjusted to raw barometer. ( I paid CAR and DRIVER road warriors to test my CRX at the Chrysler Proving grounds for top speed, and coastdowns. They threw in skidpad testing for free ). Chrysler has a sheltered straightaway, designated specifically for coastdown testing. Cost was equivalent to 1-hour in a wind tunnel, in 2014-2017 dollars ( DARKO or A2 ).
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5) We don't know what happens to the IONIQ's engine BSFC when the cars' drag is reduced at a constant test speed.
6) We don't know anything about it's actual rolling resistance.
7) We don't actually know if it's published Cd was @ radiator shutters fully-closed, zero-yaw, crosswind-averaged, etc.. We do know that the wheels were rotating in the wind tunnel.
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8) MPG data would only help, fully-warmed, at a constant speed, without any hybrid function, in both directions, just the engine operating at a constant speed, with weather monitoring. And at an accuracy you're comfortable with.
Yeah it’s really hard to do some of these tests in the real world in crowded places. Wish I had a test track but nope

Sure the data points were limited and the test was quick

But all I can say is the car did feel smoother and more stable, acceleration felt slightly faster, barely, when I put the car in sport mode and stomped the pedal to the metal to get up to speed as fast as possible, and wind noise went down a little bit. Obviously these aren’t reliable data point, but the car felt like it glided a little better even within those few minutes of driving with the skirts on. I’ve put 107k miles on my Ioniq in 2 abs a half years. I practically live in it. So I know how it feels. It’s like an extension of my body. It definitely felt different with the skirts on. I would have left them on the remainder of the road trip, but I didn’t want to risk possibly getting pulled over for cardboard skirts from a cop that’s in a bad mood or possibly ignorant. Was already driving without side mirrors and “ technically illegal” tinted windows. I want to fabricate the metal and permanent black rear wheel skirts though this summer. Just really hard to tell how much it helped mpg

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