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Discussion Starter · #1 · (Edited)
Working to gain more downforce at Higher speeds. I now get a read "tail Wag" in high speed curves. For example, exiting the top of the Esses at Watkins Glen under full throttle at about 130 MPH. The suspension is all set, car balanced and corner weighed, new motor has amazing power, the car just needs to plant it's ass more.

Will not add a wing. Nope. Not doing. Period.

I already have a first attempt at a diffuser in the car. Bit it's split with the tank in the middle, and a flat upper surface.

Tire Wheel Vehicle Automotive tire Hood


I know I can improve, so doing research.




Looking for members who have done this with success, can share their results, efforts, findings.

Two additional notes:
1. Will not add a full belly pan, as the car comes apart alot. It has already been suggested to help the diffuser and airflow
2. I will increase the depth of my side skirts between the wheels, make nore of a channel under the car.

Winter brain exercize!

Dan
 
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Discussion Starter · #2 ·
Considering this to mount under the fuel cell:

Automotive mirror Automotive exterior Rectangle Eyewear Fashion accessory
 
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Discussion Starter · #3 ·
Up front, I have a front spoiler, not that big, and small winglets on the sides. The front feels good, does not get light, feels very stable, so not changing that.

Just working on aero balance, moving the CG rearward with aero.
 

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Discussion Starter · #4 · (Edited)
A last thought is that the horizontal area of my two diffuser areas is flat. If I can add a curved surface near the exit to more replicate what is typically shown, could that help what I have to work better? Or add an extension at the rear with a curved roof to help accelerate the air?

Handwriting Rectangle Slope Font Parallel
 

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In one of your other threads there was information and a link about a 201 mph Superformance roadster. The rear diffuser appeared to me to be mounted slightly lower than the body so that there was an inch space between the top of the diffuser and the body. I'm thinking this feature of the diffuser and it's mounting turn it into both an underbody wing and a diffuser.
 
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Discussion Starter · #6 ·
Yes, I saved the pics and looked at what was done. Hence looking at adding under my tank.

I'm trying to keep using what I have currently, easily modify if I can
 
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I agree you could add a panel to you existing pieces. The current flat panel could be the top while the bottom has a bit of a curve to give more of a wing profile. Like this 'flat bottom' but upside down of course.
nNcxy.png (660×158) (imgur.com)
I have always wondered what is best at the front so I like Robert's idea. Seems to me it would be more effective as a wing in the air stream than just shaping the underside and more or less ignoring the top surface. I see more and more like this.
BE17C573-27EE-447B-815B-17BB0E108FB2-621-0000003A32C83E8D_tmp.jpg (3500×2333) (slipstreamnetwork.com)
 

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Discussion Starter · #10 ·
Yes, the pic of the Ford GT is similar to how I am considering re-configuring my set-up. Add curvature to the "roof", and add a curved extender out back, detachable for track use.
 

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Dan, the angle of the roof of your 'diffuser' looks too step to me. I think a safe 'slope' is somewhere around 10 degrees. Perhaps your diffuser might work at lower speeds but I'm sure it would have issues at high speed and may not actually be adding any downforce. If the air coming out of the diffuser is just turbulent then combined with the round back end of the car you might actually be generating lift.

Something like the factory diffuser on an Elise would be a good thing to copy.

 

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Discussion Starter · #12 ·
Thanks Mike. I'm going to re-look at many pics I took of earlier Indy Cars that had the side pods with the tunnels, they generated massive downforce. Agreed, I need to curve my "roof". I'll also look at extending the back, and lowering the sides, see if I can make it closer to the ground.

This is my favorite part of this forum, putting up the deeper, more technical projects, and getting great feedback.

Dan
 

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Discussion Starter · #13 · (Edited)
Found this great technical article. I can actually do some design work, and figure out how to modify my existing diffusers. I'll definitely work on the undercar, create more of a tunnel, split the airflow to the two diffusers.


So, some initial thinking and noodling results that if I have 6" of clearance between my diffuser skirts and the ground, and use 10' as a working distance (Behind front wheels to rear of car), along with improving my side skirts, I could create some downforce.
 
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