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Thoughts on installing a rear spoiler

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I have a 2022 M3LR and I am considering adding a rear spoiler. While I like the looks of a spoiler, I would really only go through the trouble of installing it if it had a positive effect on range. After looking on the web I see differing views on the benefit. I realize that at slow speeds the spoiler is cosmetic only, but 90% of my driving is on a highway at 75 MPH.
What are your thoughts on the effects of a spoiler? Helps or hurts range? Or does nothing at any speeds?
 
I see. I'm not really interested in the downforce so much as the possibility of other aerodynamic effects that may result in increased range. I've seen web sites that suggest that at highway speeds the spoiler may change the airflow in a way that is beneficial to range. I was, and still am, doubtful, but I wanted some opinions here.
 
I see. I'm not really interested in the downforce so much as the possibility of other aerodynamic effects that may result in increased range. I've seen web sites that suggest that at highway speeds the spoiler may change the airflow in a way that is beneficial to range. I was, and still am, doubtful, but I wanted some opinions here.

Think of it this way. If this actually impacted range in any meaningful way, dont you think tesla would simply install a spoiler on every car? They dont, because it doesnt.
 
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I see. I'm not really interested in the downforce so much as the possibility of other aerodynamic effects that may result in increased range. I've seen web sites that suggest that at highway speeds the spoiler may change the airflow in a way that is beneficial to range. I was, and still am, doubtful, but I wanted some opinions here.
My opinion: highly doubtful, it will change the aerdynamics of the vehicle enough to alter range in any perceptible way. Lowering the car though, I've heard that helps.
 
I see. I'm not really interested in the downforce so much as the possibility of other aerodynamic effects that may result in increased range. I've seen web sites that suggest that at highway speeds the spoiler may change the airflow in a way that is beneficial to range. I was, and still am, doubtful, but I wanted some opinions here.
While a spoiler can reduce drag and thus improve range, you are looking at something like on the order 1%, best case. For instance if you look at the Unplugged Performance CFD study on their extra large aero efficiency spoiler: Independent Aerodynamic Study of Tesla Model 3 by Unplugged Performance

They claim from that CFD simulation a drag reduction of 2.3%, so assuming that this simulation is totally accurate and relevant at your highway speeds that would be like 5 miles of extra range if aerodynamic drag was the only resistive force when driving. But it isn't, there is also tire hysteresis (aka rolling resistance), and drivetrain friction. So you are looking at more like 2 miles extra range, *maybe*

That would be enough for me if I was convinced it was real, I love micro optimizations. Would love to see wind tunnel tests =)
By comparison the aero wheel caps (or Fastwheels Aero wheels) improve range by about 5%, or about 12 extra real world highway miles on a long range model 3
 
That would be enough for me if I was convinced it was real, I love micro optimizations. Would love to see wind tunnel tests =)
By comparison the aero wheel caps (or Fastwheels Aero wheels) improve range by about 5%, or about 12 extra real world highway miles on a long range model 3

5% more range with aero covers but 200% less aesthetic. :D imho
 
Think of it this way. If this actually impacted range in any meaningful way, dont you think tesla would simply install a spoiler on every car? They dont, because it doesnt.
I think it might be a more complex issue than their desire to optimize all their cars though… There’s also the aspect of “trim levels” and deleting the spoiler must save a lot of money when you’re talking about units numbering in the hundreds of thousands per year, and I think it’s been shown that Elon doesn’t mind thinking in terms of cost saving deletions vs capabilities with things like removing mobile chargers, matrix headlights, sensors, glass coatings, even floor mats etc. Since we pay a significant amount more for the performance trim, that additional cost is mitigated.

If adding the rear spoiler somehow involved no cost. Then I’m certain Tesla would have them on every trim level of car, but it may be more accurate to think in terms of Elon considering, “Yes, the spoiler improves range by 1% on average, but putting them on every car costs me 9 million a year”

It’s like the situation where that 1% is worth FAR more to the individual user than it is to Elon. His “loss” is worth more than the effect of your “gain”

I could be totally wrong about all this, but I often see issues similar, when one approaches the question with the values of an individual consumer, instead of from the perspective of a manufacturing giant; which makes sense, we each perceive the things we know. Maybe that’s why some of Elon’s decisions are so confusing to us :)

But on the use of a spoiler. It CAN have an effect on drag, and thus range, but it’s primary function is not to create “Downforce”, but to reduce “Lift” by causing the airflow to separate more cleanly from the rear of the car at speed instead of curling down the rear of the car and getting underneath the rear, lifting the rear and reducing traction. Drag reduction is simply a byproduct of the primary function. It’s called a spoiler because it “Spoils” or decreases lift. If it was primarily used to cause downforce, it would be called a deflector, or a control surface.
 
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