Diffuser

[Brd.Prey]

The frame work from the engine on back pitches up. Does the diffuser follow this line? If so would aerodynamics speaking the diffuser going back level instead of pitching up would produce more downforce right? If I brought it straight back I could use the extra room for exhaust.

[DanielsDM]

It is the angle that makes the diffuser work. Check out this page for more explanation.
https://www.racecar-engineering.com/tech-explained/diffusers-engineering-basics-aerodynamics/

[Sgt.Gator]

Another great source for Diffuser engineering:

Willem Toet, former Head of Aerodynamics at Ferrari F1, explains the fundamental principles behind motorsport diffusers.

https://www.racetechmag.com/2017/08/willem-toet-explains-motorsport-diffusers/

[Brd.Prey]

I haven’t said anything but I really want to design a bottom exit exhaust to increase air velocity under the car. But I’m not seeing the room.

[Mitch Wright]

I also mounted the diffuser a couple of inches further back.112755112756

Your car is looking fantastic.

[Sgt.Gator]

I have a blown diffuser on my STI. There are lots of tradeoffs to them. I only did it because it was convenient and lighter, not to increase the under-car velocity. If you google "blown diffuser" you'll see the reasons it does and does not work so well. Here's a good start: http://www.formula1-dictionary.net/diffuser_blown.html

I don't have it on my 818 nor would I think it's worth doing it. My STI with aero testing wool tufts attached:

https://vsusng.by.files.1drv.com/y4m4Lg7oPqmXRnk8GzefaIvcRgu9qdS-BdV_Fow4vYJ3gpfdf3IS4Cw27h8mkQicZwyShPUZ7L_jc3LNgi jOFsYwxy_qeGdw8UBc8LpMCLXaf6wPZUZEoIlPs_Y82klAsbsV z0Cgc_CjaxiuffV5UhPAGczhQuFkeVIhpwykMgYQVvUwN5bhiG 6vbUr_CU6Q4QfFH9QTy7h4NcPAWTDkixmGQ?width=915&height=1024&cropmode=none