Rear eyebrow removal to add more range

[No Ice]

Hi has anyone had there rear eyebrow over the rear screen remove, because it looks like it causes more drag and less MPG,s, its 5 10 mm nuts and the high stoplight and rear wiper water wash tube to disconnect to do this, i.e. MG4 without this has more range than the MG4 with this and looking up on UT shows' video's of SUV,s having lower drag without the rear eyebrow , I have a 2022 smooth Kona electric and i have already fitter the front wheel arch flaps from a EV6, this seems to work well as there is a lot less water leaving the side of the front wheel wells, its pushed down on to the road instead, your thoughts please thank, as shown here


How to remove the rear spoiler Hyundai Kona

 

[michael8554]

Not surprised that styling gimmicks add drag.
The high-level brake light might be a legal requirement in the UK.
But "old" cars that don't have one don't have to be retro-fitted.

 

[JoeS]

In the early days of the i-MiEV some of us were obsessed with increasing its EPA 62-mile range; e.g., by adding rear wheel skirts, adding a long tail, not carrying unnecessary weight onboard, 60psi in the tires, etc.
Conclusion: driving style has a FAR greater effect on how far one can go - any hypermiler worth his/her salt can beat EPA by at least 20%. Featherfooting instead of lead-footing, judicious use of our paddles (especially zero-regen), disciplined driving 55mph (North America always in the right lane!) on highways while everyone zips past at 75mph, etc.; the results speak for themselves.
With the Kona's already-excellent range (compared to the i-MiEV), I cannot ever recall a situation where I was trying to eke out just a few more miles... and I drive it 'normally'.
In daily driving, do you think this mod would have a measurable effect on your wallet?
Sorry, didn't mean to rain on your parade, but good luck with your mod and do let us know the results if you perform a controlled before/after study.

 

[KiwiME]

Rear spoilers do just that, 'spoil' the airflow after it passes over the roof so that it breaks free at a consistent location. For the lowest drag, ideally the airflow would remain laminar all the way to the end, as it would if the car had a natural teardrop shape. But the abrupt end of a conventional car shape makes that impossible. If the flow is going to break away at some point and change to turbulent flow anyway, it's far better that it's done at a consistent edge to avoid flapping noises as the flow flutters between modes at rapidly-varying locations near the top of the glass.

So removing it is unlikely to lower drag, rather add noise but reduce the accumulation of dust on the rear glass.

 

[No Ice]

Rear spoilers do just that, 'spoil' the airflow after it passes over the roof so that it breaks free at a consistent location. For the lowest drag, ideally the airflow would remain laminar all the way to the end, as it would if the car had a natural teardrop shape. But the abrupt end of a conventional car shape makes that impossible. If the flow is going to break away at some point and change to turbulent flow anyway, it's far better that it's done at a consistent edge to avoid flapping noises as the flow flutters between modes at rapidly-varying locations near the top of the glass.

So removing it is unlikely to lower drag, rather add noise but reduce the accumulation of dust on the rear glass.

question then if i may, the ev6 all models of Tesla,s Do not have one and they are in the lowest drag range averable of cars to drive on the road

 

[JoeS]

@No Ice, the Kona's basic shape is 'boxy', as contrasted with purposely-designed aerodynamic vehicles. i'm astounded by the improvements Hyundai made to this box when they adapted it to an EV - note how little retardation there is at 70 mph when you kick it into zero-regen, compared with most other vehicles when you shift them into 'neutral' at speed. I believe there is a formal aerodynamics and rolling resistance test to see how far a vehicle can roll before it stops,

The spoiler was first introduced in a 'boxy' station wagon by aircraft manufacturer SAAB in the late 50's/early 60's. It had a slot for managing the airflow which had the added benefit of keeping the rear window less dirty. On the Kona it has the added benefit of keeping nighttime dew off the window.

@No Ice, all this academic discussion is ok, but, realistically, what measurable improvement (range or $) are you trying to achieve in a vehicle that already has the range to easily cross continents with today's charging infrastructure? What is the specific metric that the Kona is lacking to satisfy?

 

[No Ice]

@No Ice, the Kona's basic shape is 'boxy', as contrasted with purposely-designed aerodynamic vehicles. i'm astounded by the improvements Hyundai made to this box when they adapted it to an EV - note how little retardation there is at 70 mph when you kick it into zero-regen, compared with most other vehicles when you shift them into 'neutral' at speed. I believe there is a formal aerodynamics and rolling resistance test to see how far a vehicle can roll before it stops,

The spoiler was first introduced in a 'boxy' station wagon by aircraft manufacturer SAAB in the late 50's/early 60's. It had a slot for managing the airflow which had the added benefit of keeping the rear window less dirty. On the Kona it has the added benefit of keeping nighttime dew off the window.

@No Ice, all this academic discussion is ok, but, realistically, what measurable improvement (range or $) are you trying to achieve in a vehicle that already has the range to easily cross continents with today's charging infrastructure? What is the specific metric that the Kona is lacking to satisfy?

Thank you for your thoughts, my answers are as follows,
1 because I can, freedom of choice thing,
2 I am i Australia same size as the conventional USA ,but with only the same amount of people as in Texas 27 mill , so a lot less chargers per 100 miles of road.
3, here on the main roads the chargers are about 150 miles apart and NO backup at all as no people living along the main road, if there is they are usually on a station or your ranch with the house 20-30 miles of the main road,
4 Have see how easey it is to do ,like 20 min max,
5 I have had the reverse cam on when driving in the rain and seen how big the disturbed air wake behind me at 62mph ,its big,
6 have done a few tests over the last 5,000 + miles and have an average MPKWH of 3.74.
7 have a 45 km test track 22.5 miles each way ,running at a steady 62 mph i get 3.75 mpkwh average.
* so yes i am looking for rang improvement 5 to 10 % possibly, the testing will tell,
8 its a service to other Kona owners if it works and if they want more range, then know to get it.
thanks for reading this Jim

 

[JoeS]

Jim, thank you for your clarification, and look forward to your test results.
Questions:
1) Has Tesla Supercharging been enabled for the Kona CCS2 in Australia?
2) Which specific regions do you travel long distances?
I ask because the next time I visit your wonderful country I was hoping to rent an EV. I spent a few years cruising your entire East Coast (Hobart - Lizard Island) on an Aussie Seawind catamaran.

 

[No Ice]

Jim, thank you for your clarification, and look forward to your test results.
Questions:
1) Has Tesla Supercharging been enabled for the Kona CCS2 in Australia?
2) Which specific regions do you travel long distances?
I ask because the next time I visit your wonderful country I was hoping to rent an EV. I spent a few years cruising your entire East Coast (Hobart - Lizard Island) on an Aussie Seawind catamaran.

1 yes it has all ev,s in Australia use the CCS2 connectors, here is a map all the chargers in red are other car enabled, you just need the Tesla app.
https://www.tesla.com/en_au/findus?...678093,-37.249418003527055,110.17608033428093
2 in west Australia that's as big a Texas and has a coast line nearly 13,000 miles long

 

[caillou]

According to my understanding of aero, removing the spoiler should reduce range
To improve range, spoiler lenght should be increased
But, since it's quite easy to remove and you have a nice test loop, it's always great to have the experiment!

MG4 spoiler has a weird shape with 2 parts and big holes that reduces range indeed

To improve range you can:
EASY COSTLY change tires (in the EU, best tires for range are michelin e-primacy and continental ecocontact 6 or 7 but 7 does not exist yet in the kona size), and inflate at ~3bars
EASY close wheel rim holes with tape
EASY add a gasket in the hood opening (google "car hood gasket" for pictures)
EASY seal all panel gaps
https://www.torque-alliance.com/pro...ion-kit-rubber-seal-for-glass-roof-panel-gaps
HARD close rear wheel arch
EASY COSTLY remove roof rails, requires the plastic parts to replace
Limited roof rail removal | Hyundai Forums
EASY remove subwoofer in the trunk if you have one
EASY COSTLY lower the car 1.2inches by replacing the suspension springs with eibach kit
https://www.hyundaikonaforum.com/threads/lowered-kona-ev-and-spoiler.7818/
EASY increase the size of the walls in front of each wheel
HARD improve the smoothness of the underbody

HARD replace side mirrors with cameras
https://www.crvownersclub.com/threads/replacing-passenger-side-mirror-with-camera.199308/
EASY change gear oil with lower viscosity (KiWiME is the expert!)
HARD built a full aero tail...
https://newatlas.com/aerodynamic-long-tail-improves-fuel-efficiency-15/13678/

 

[No Ice]

well, i have removed the rear spoiler, and found it needed 5 different size of plugs to fill the mounting holes,
first thing i noticed after the first drive was how much quieter it was insider the car, a lot less rear tire noise. then about 15 watts les power used per KM or 20+ per mile.
the rear stays clean even in the rain, air flow removed the rain very well, so have removed the rear wiper blade as well.

 

[caillou]

Could you describe your comparison ?
You did twice the 45km loop ? the same day ? with and without the spoiler ? where do you read the measurment ? you mean 15Wh/km ? like from 150 to 135wh/km ?

 

[No Ice]

done the 45 km test 40 times now at 90 kmph as the test with the spoiler on and am finding an average of 18 watts per km less power used so yes that's from 166 watts per km down to 148 watts per km, only done less than 1,000 km so far, will do 8,000km + at different speeds like before to make sure about this as its a lone term test, over about 3 months in all weathers and temptures as well.

 

[No Ice]

photos of rear now, sorry unable to invert photos for some reason, did not matter what i did they still came out upside down, any one that can help please do thank you

 

[brianc35]

Hi, try uploading the images again. I applied a fix.

 

[JoeS]

@No Ice, thanks for posting your initial numbers, but perhaps you meant to use Watt-hours (Wh) (energy) instead of Watts (power)?
Initially, removing the spoiler seems to results in a significant 10.8% improvement.
Just to be clear, the numbers represent battery-to-wheels (as indicated by the car) and not wall-to-wheels?
Looking forward to your long-term test results.

 

[insightman]

photos of rear now, sorry unable to invert photos for some reason, did not matter what i did they still came out upside down, any one that can help please do thank you

Do you mount the un-aerodynamic rear wiper just before it rains?

 

[No Ice]

thank you for the help with the photos, the grime and the wiper cleaner area are from when i removed the rear eye brow 3,000 kms ago.
left it to see what difference there would be over time, the dust coat on the unwiped area disappeared with the first rain, rained 15 20+ times
in the last 3,000 km and the screen stays the same, I have also noticed it not necessary to clean the rear view camera any more.
Just to be clear, the numbers represent battery-to-wheels (as indicated by the car)
I am using watts per km traveled as per the dashboard in the car, so 148 watts HRS per Km or 6.756 km per kW HR of power.
the wiper blade is staying off as it seams not to be needed without the rear eye brow.

 

[caillou]

Any news after a fews months ?

 

[No Ice]

good timing, as i have just covered a further 8,000 km or 5.000 miles and the numbers are in at 62 mph or 90 kmph the average is 145w per km or
6.896 km per kwh and the rear window is still clean after 5,000 more km from the photo above,
also the 105 km average is only 152 w per km ,so its only using 17 whatt per km more to go 15 km faster,
the speed limit here is 110 kmph over the whole state,
my thoughts are the SPOLER will stay OF until i sell the car sometime in the future, have just passed 102,000 kms on the Speedo, and fixed the not working cruse control bar thing with some electric lube spray, its like new again, the one for the +- 10 kmph speed change.
need some new tires now as i only seem to get 50,000 km from a set, have chosen TOYO CR1 as good price and they are optimized for EV, s low rolling resistance , in 225/55R/17 size
I am going to get the front and rear Axle Toe set to zero instead of the factory setting of around 2mm, this will lower the cars overall rolling power used and because it rolls easer down hills also increase the regen back to the battery, this may if my thought are right lower the watts used down to somewhere in the low 130 whatt range at 90 kmph, as you have may have noticed i am working towards the 500 kms range that was once advertised as possible, I just want it at 90 kmph and not at 70 kmph that i could get with the standard car. the GOM is showing 442 km range at the moment, and yes i have solar so charge to 100% all the time 3+ times a week
when i by a new EV it will NOT have a Spoiler on the rear window as standard, so it may have to be something like a IM5 or a CLA. both of which have good range and no window spoilers.
just as a comparison here is my car rear window and my wife,s Kona iron man after the same time from a car wash.5,000km same roads.