Does anybody made a DIY rear undertray/diffuser ?

Hello

The GT350 has a undertray plate from the axle to the bumper and covers the carbon canister backpack. I think it would be a nice aerodynamic optimization for the S197, too.

Cheers




GT350 with aftermarket strakes:

I wonder how close in size the GT350 piece is to what would be needed on an S197, maybe could be adapted. But may be easier to find someone talented with ABS molding to have one done. When I was tracking my car, I always wanted to eventually make the entire underside as smooth as possible, using pieces like this. Never reached that point before changing direction on the cars purpose, but if bolt on pieces like this were available itd be a no-brainer

Close as I could find - https://www.evasivemotorsports.com/...fua0k8OaXpMuo3YQzGJAEsBz6bIoEdXVDM2Ql9UzicNS0

I haven't found the dimension of the GT350 part. The needed size is roughly 80x80 cm. The GT350 part is bolted to the bumper on one side and to a bracket to the underbody between the sway bar and the differential.
On our cars we must attach a bracket to the spare tire panel.
I was not able to find any information about the APR part, how long it is, where it is bolted, no instruction, no detailed picture.
These projects are always very down on the to-do list, it takes a lot of time just for the "how to bolt on" part. I spent many hours just to look at my front underbody to get ideas for the front undertray.

rocknrod said:

Close as I could find - https://www.evasivemotorsports.com/...fua0k8OaXpMuo3YQzGJAEsBz6bIoEdXVDM2Ql9UzicNS0

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Not worth the money IMO.
Mine's a simple DIY black plastic job that fills the void between the evap system and the rear bumper cover. This substantially reduces the amount of air that stacks up behind the bumper cover and potentially reduces drag, especially at higher road speeds.

Dino Dino Bambino said:

Not worth the money IMO.
Mine's a simple DIY black plastic job that fills the void between the evap system and the rear bumper cover. This substantially reduces the amount of air that stacks up behind the bumper cover and potentially reduces drag, especially at higher road speeds.

View attachment 96298

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Simple many times works best, even if it isnt as "pretty". I like this idea

Dino Dino Bambino said:

Not worth the money IMO.
Mine's a simple DIY black plastic job that fills the void between the evap system and the rear bumper cover. This substantially reduces the amount of air that stacks up behind the bumper cover and potentially reduces drag, especially at higher road speeds.

Click to expand...

Sorry, I'm German, no easy solutions allowed hahahaha..... look at Vanos from BMW

Do you guys have thoughts about that, except very expensive:

C2 aero makes some good rear diffusers that even cover the evap in the rear. APR sells the front one's that extend to the sides of the front bumper. Couple that with the 2010+ extension and louvered trays, should make a difference in cooling, hood flutter and stability on the road

Dallas281 said:

C2 aero makes some good rear diffusers that even cover the evap in the rear. APR sells the front one's that extend to the sides of the front bumper. Couple that with the 2010+ extension and louvered trays, should make a difference in cooling, hood flutter and stability on the road

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Thanks, that was helpful. I made an almost flat front undertray, it also lowered the wind noise.

Dallas281 said:

C2 aero makes some good rear diffusers that even cover the evap in the rear. APR sells the front one's that extend to the sides of the front bumper. Couple that with the 2010+ extension and louvered trays, should make a difference in cooling, hood flutter and stability on the road

Click to expand...

In addition to my DIY rear under tray, I've also done several front aero mods resulting in significantly better gas mileage, high speed stability, and NO MORE hood flutter:

Dino Dino Bambino said:

In addition to my DIY rear under tray, I've also done several front aero mods resulting in significantly better gas mileage, high speed stability, and NO MORE hood flutter:

Aerodynamics

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No mileage compare so far, but I noticed a much smoother ride on the Autobahn with the front undertray.

How do these splitter strut rods work? Are they stable in all directions or do they have a weak point? Are they adjustable in length?

Dino Dino Bambino said:

In addition to my DIY rear under tray, I've also done several front aero mods resulting in significantly better gas mileage, high speed stability, and NO MORE hood flutter:

Aerodynamics

Click to expand...

My 2010 doesnt have that louvered splash shield. Now I want it