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Splitter tunnels (front diffuser)

Name: Splitter tunnels (front diffuser) dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

What are splitter tunnels and what ramp angle should they use? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: splitter tunnels, front diffuser, splitter diffuser, splitter ramp angle, kickline, front underbody diffuser, splitter tunnel design, wheel well diffuser, splitter venturi, front tunnels

Exact dimensions. True size, with no printing tolerance added.

sizes: 5 in table

Notes

Splitter tunnels are small diffusers cut into the splitter that expand the air from the splitter floor up into the wheel well, deepening the low pressure under the splitter. HPA says this can roughly double front downforce compared with a flat splitter.
HPA recommends a 10-12 deg ramp (low end for low ride heights) with a ~100 mm kickline radius, starting at about a third of splitter length on short overhangs or half on long ones.
The file is a reference example built by Xem Studio from the numbers above (11 deg = middle of HPA's 10-12 deg ramp; tunnel width illustrative.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

Splitter tunnels size chart

parameter	value or range	source
Tunnel ramp angle	about 10-12 deg	HPA splitter
Kickline bend radius	about 100 mm	HPA splitter
Kickline start	~1/3 of splitter length (short), ~1/2 (long)	HPA splitter
Outboard tunnel wall	~50 mm outboard of inside tyre shoulder	HPA splitter
Front downforce gain vs flat splitter	roughly double	HPA splitter

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

High Performance Academy

Aerodynamic performance devices for club level cars: front splitters

web

Publisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

splitter-tunnels-front-diffuser-splitter

Front splitter 200 × 300 mm with an up-turned lip at 11° (illustrative where noted)

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Plain text: sheet.txt · JSON: /api/geometry?object=splitter-tunnels-front-diffuser