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Why new front splitters seem to have an upturned lip? (AJ Hartman please help)

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I'm sure you guys have seen the new GTD and its crazy aero. like many new designs it has an upturned front splitter.
I specifically remember AJ Hartman recommending you do not tilt your splitter upward in one of his wind tunnel vids.. and it was backed up by data!

what now this trend to upturn the front splitters? See leaked GTD pic from last week. Look at the front splitter curved up like an angry kid's bottom lip.

leaked GTD.jpg
 
It is all depending where you want the downforce.
the upturned splitter allows for more air
To be squeeze under the car.
The More air squeezed. The faster the air has to accelerate to preserve the momentum.
The faster it goes to do that, the more suction you get.
Same concept with a splitter pointing down.
You reduce the "space " of the air btw splitter and ground. And you also create an expansion right after the lip (because the angle of the splitter)
So the concept is similar. What it is different is the place where you generate the low pressure. And the overall amount.

In a very general way. The upturned splitter tends to generate more DF and more "back" vs a splitter pointing down. (Where you have mainly DF in front)
You have to Imagine a turned up Splitter working together with the flat floor and the diffuser.
while in our "Normal"cars is more to focus DF in the front.

Similar Concept you see in the modern F1
Instead of having a air acceleration under the leading edge. You have the whole bottom of the car acting like a ...wing.(in f1 the peak of undercar DF is more in the rear than gtd)
Hope this could make sense.
Kyle engineer did a very nice video about it.

How-ground-effect-work-s-in-F1-2022-venturi-tunnel_channel-jpg-1030x547.jpg
 
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Exp. Level
10-20 Years
75024
Another benefit is under heavy braking there is less chance the splitter will choke off the air to the under body. So as not to cause a sudden reduction of DF and porpoise effect.
 
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Columbia, TN
So glad you asked this. I've noticed this on a lot of full on race cars too! Additionally my stock GT is higher in the center section, like the 30" or so directly under the radiator area. Seems OE cars are like this and full race cars are along with an upturned lip, but all sportsman setups are just a flat splitter all the way across. I saw a side view of the Ferrari's from Daytona and the upturn is crazy!
 
So glad you asked this. I've noticed this on a lot of full on race cars too! Additionally my stock GT is higher in the center section, like the 30" or so directly under the radiator area. Seems OE cars are like this and full race cars are along with an upturned lip, but all sportsman setups are just a flat splitter all the way across. I saw a side view of the Ferrari's from Daytona and the upturn is crazy!
Most sportsman class cars don't have flat bottoms or advanced underfloor geometry to make this configuration work properly so the flat splitter with diffuser tunnels is easier to implement and works better.
 

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