Aero upgrades for top speed...

[PInimodulo]

Hello everyone, I have a question that I have not been able to find a clear answer for here on the forum or anywhere else for that matter.
I am planning to run my Supra on the Bonneville Salt Flats and see what kind of top speed I can achieve. The car should hopefully be finished soon and be around the 550whp range.
I see many posts and comments about aero modifications for racing that focus heavily on downforce, but I almost never see discussions about aero designed specifically for top speed, which is obviously a different goal.
I know companies like Verus Engineering make very good real world tested wings and spoilers, and also Spage Sport Parts, but I cannot really find anything aimed specifically at reducing drag or improving high speed efficiency.
So besides the options of simply leaving the car's aero stock, or maybe a simple rear lip, or closing any undercarriage areas that are not flat (which I think I will not touch) or adding a bigger/better rear diffuser, are there any other aero upgrades that actually help the car cut through the air more efficiently for top speed applications? Has anyone here tested anything in the real world?
Thank you so much for any insights!

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[omfgzilla]

Cut holes on the hood for hood vents and front wheel well. Do a bumper cut behind the rear wheels. Add a big ugly ass rear defuser. Duck tape panel gaps.
Start to make the car look more like this

Best aero, is more airo into the motor with a fucktonof ethenol to reach the 250mph goal. Good luck.

 

[PInimodulo]

Wow so helpful thanks!

 

[i3igpete]

You're pretty much on the right track. Beyond what's already mentioned, folding in side mirrors, and blocking off the front bumper with tape is about all you can do. The hood vent itself only has a marginal drag improvement, but where it really shines is that you can maintain the same cooling with a smaller front opening. I'm sure the bonneville veterans will give you a good rule of thumb of how much you can block off

The Supra already has a very flat and well covered underbody compared to something like the Z. Maybe some downsized wheels and tires if you already have some laying around.

 

[PInimodulo]

You're pretty much on the right track. Beyond what's already mentioned, folding in side mirrors, and blocking off the front bumper with tape is about all you can do. The hood vent itself only has a marginal drag improvement, but where it really shines is that you can maintain the same cooling with a smaller front opening. I'm sure the bonneville veterans will give you a good rule of thumb of how much you can block off

The Supra already has a very flat and well covered underbody compared to something like the Z. Maybe some downsized wheels and tires if you already have some laying around.

Thanks for the info!

 

[Rustyscrew]

Mirror delete, The Shop CT makes some.

 

[PInimodulo]

Thank you for the comments guys. I dont think I will delete the mirrors but definitely folding them, yes.
Now, I may install a small rear lip since that might help a tiny bit. But if I install a Verus rear diffuser without the front splitter (which creates downforce and also slows down the car for what I can gather) will that upset too much the front-rear balance of the car at top speed to the extent of being dangerous? Meaning making the front tires try to lift before the rears or something similar?
I know I could ask Verus that question, but I am asking here since someone might already know the answer

 

[mack73]

Adro also has a new motorsports rear diffuser that looks real nice, and they do real cfd design and engineering

 

[PowerGetter]

For a high-speed run like that, the priority should be minimizing lift wherever possible rather than simply adding high-pressure downforce. A drag wing from Verus is a solid option. Up front, hood or fender vents — along with opened or cut fenders like EVS fenders — can help evacuate pressure from the front wheel wells and reduce front-end lift. From there, you can look into adding hood vents or switching to a vented hood to further relieve high-pressure air in the engine bay while also improving heat extraction.

 

[rwense]

Perhaps you could try aerodiscs (not turbofans)? From what I understand there's a lot of conflicting info and conjecture out there but there are well respected suppliers and *technically* OEMs out there doing it. A great example is Manthey and their kits for the GT3RS and GT4RS.

https://www.manthey-racing.com/kit-911-gt3-rs-9921

You can also try and smooth over some of the OE fake vents. Could be something as simple as tape or a 3D print.

 

[PInimodulo]

Thanks a lot for the info! I will look into the EVS style fenders since I was going that route already anyway. Also I will think about the fender/hood vents.
Even though I love the look of some of those aerodiscs and their functionality (in this case specifically) I already bought new wheels and I dont have the money for new ones
I wonder if changing the fender grilles to the open ones offered here in the forum would do anything to release a bit of pressure?

 

[PInimodulo]

By the way @Timmy_Jones , is there something you wanted to say or that you found funny on my original post?
I dont understand the laughing emote?
Maybe you have something to add that I didnt think of?

 

[Timmy_Jones]

By the way @Timmy_Jones , is there something you wanted to say or that you found funny on my original post?
I dont understand the laughing emote?
Maybe you have something to add that I didnt think of?

While I meant to leave the heart eye emoji as this is an actual new and cool
Topic, its next to the laughing, on mobile. I’ll leave the laughing. It’s much better this way.

 

[PInimodulo]

While I meant to leave the heart eye emoji as this is an actual new and cool
Topic, its next to the laughing, on mobile. I’ll leave the laughing. It’s much better this way.

Fair enough. Freaking mobile phones almost started a whole aerodynamic controversy there for a second

 

[Timmy_Jones]

Fair enough. Freaking mobile phones almost started a whole aerodynamic controversy there for a second

Nah mate, I’m really curious how this goes honestly. Get some videos and tell us how the whole experience is!

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