Splitter Leading Edge Curves: Do They Actually Work?

CFD-Backed Aero Testing with Real Numbers – Part 1 & 2

At Nine Lives Racing, we don’t just guess—we simulate. In this two-part deep dive, we test the newest trend curved leading edges on splitters. The test using CFD simulations in TotalSim. This wasn’t just a surface-level experiment. We modeled multiple versions of a front splitter and studied how changes to the leading edge shape affect downforce, drag, and aero balance.

If you're building a track car and wondering whether rounding your splitter edge is worth the time, this is your post.

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Part 1: The Splitter Nose Curve Test

We tested three leading-edge shapes:

• 🟥 Flat nose (baseline splitter)
  
  

• 🟧 Slight curve (gentle radius)
   

• 🟩 "Elfe Shoe" (taller, sweeping arc)
  
  

All splitters were mounted to the same car model, tested at 150 mph, with the same wing configurations.

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💡 Key Results from Part 1

What the Numbers Tell Us:

• The Elfe Curve splitter adds the most front downforce: +77 lbs compared to flat.

• It does this at the cost of 75 lbs of rear lift, which ruins the balance of the car to 78/21.

• Interestingly, to see such a strong shift and feel in this orientation, the car will be substantially slower. 

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Part 2: Change the car to see if the lift is vehicle-dependent. 

In the follow-up video, we dug deeper using a different car that doesn't suffer from lift. Here’s what we found:



Test 2 conditions. Using our own race car, we added a .5"(13mm) radius curve and tested

 

✅ The Test:

• Base test with a flat nose splitter 
  

• Curve nose test, the slight curve, a .70" tall (NASA legal), thick part with a .5" radius. 

   

  
   
  

  splitter type	Front Downforce (lbs)	Rear Downforce (lbs)	Total Downforce (lbs)	Drag (lbs)	balance f/r
  flat nose	543	852	1395	619	38.9/61.1
  curve nose	571	885	1457	625	39.2/60.8

  
  

   

🌀 Airflow Behavior:

• With the slight curve, air enters under the car more cleanly and starts turning the diffuser on earlier.

• No lift detected. On this car it was all good news. no balance shifts nothing. 
  
  

• We gained More rear downforce than front, making this beneficial to cars with diffusers. 

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The Takeaway: Are Curved Splitters Worth It?

Yes—if you know what you’re doing.

The Elfe-style curved splitter is a powerful tool for generating front grip. But was awful for rear grip.

• Balance matters – You may need to run more rear wing to keep the car stable. on some cars 

• Increased front downforce – the curve fired up the splitter and made more downforce. 

• Note rear lift.  – do keep in mind that the curved splitter might sent more air over the top of a car and make rear lift. Do pay attention before entering very fast curved sections of track.  
  
  
  Download all the data from these tests here. 

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🔧 Want to build your own curved splitter or tune your aero package?
Check out splitter kits, airfoils, and DIY components at
👉 9livesracing.com