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Let's Talk Aero

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See what you like here:
https://www.americanmuscle.com/search?keywords=vents&generation=2010-2014&vehicleType=Mustang

Several styles to choose from and they aren't expensive at all, and I know Antman isn't afraid of taking a jackhammer to his car if it means going faster. ;)
The method they use for install is ridiculous, if you decide to get some I'll share my method with you. It wasn't hard.
I installed these 2012 factory style hood vents on my 2011 S197 and they really helped. Biggest benefit was allowing air trapped under hood to be evacuated. Greatly reduced visible hood lift at speed. Interestingly the low pressure area on a Mustang hood is located right behind the radiator yet the factory located these 2012 vents closer to the high pressure area nearer the base of the windshield. On S550's vent is in true low pressure area of hood. In any event they work well.
 
9
3
Exp. Type
HPDE
Exp. Level
3-5 Years
Los Angeles
Good morning y'all
I've owned my 350R for 5 years and have loved tracking it several times a year. I have DTC-60 pads, Girodisk rotors, camber plates, SPL rear camber arm, a cage, and 3R's. It's a great setup, but I'm starting to chase lap times.
I don't like flashy upgrades and want my car to retain its stock look and feel.

While following my car to the racetrack (I was in a 997.1 Road-Cup Car) I noticed the diffuser was hanging precariously close to the ground. Once we got to the track I took a look at it, and nothing was wrong per se, it's just kind of flimsy. I'm also pretty familiar with the underside of the car, and know it's far from flat and clean.

Alright I'll jump to the question. What are the hivemind's thoughts on the Venus Engineering fender evacuation kit, flat underbody panels, and rear diffuser? If they are effective they should be a way to improve the aero efficiency with extremely little aesthetic change.

I'm not expecting to shave seconds off my lap time, but I am a little bothered by the flimsiness and roughness of the car's underbody aero. What are your thoughts on whether or not these changes will have any positive change? Are those small underbody panels useless when the center of the floor is left exposed?




Fender Evacuation Kit - Ford Mustang Shelby GT350
Flat Underbody Panel Kit - Ford Mustang Shelby GT350
Rear Diffuser - S550 Ford Mustang
 

Fabman

Dances with Racecars
6,625
8,315
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Took these shots at Sonoma last weekend.....diffuser with no strakes.
What do we think of this?

IMG_6536.jpgIMG_6537.jpg
 

Fabman

Dances with Racecars
6,625
8,315
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I see 4 strakes. Also, I'd bet the rules limit exactly what they were allowed to do.
They are 3 separate tunnels…..those are more like ends fences for each individual tunnel, each with its own roof which is at a different height, length and curvature….
No single tunnel has a strake in it. I saw many different diffusers, some with many strakes, like a lot of them ……this one caught my eye because it had none.
 
They are 3 separate tunnels…..those are more like ends fences for each individual tunnel, each with its own roof which is at a different height, length and curvature….
No single tunnel has a strake in it. I saw many different diffusers, some with many strakes, like a lot of them ……this one caught my eye because it had none.
So since my diffusor is 5 separate tunnels does that mean it doesn't have strakes? Call them what you want, but a vertical deviation from the diffusor floor is commonly referred to as a strake, despite its size or shape. Its one of those general terms which is all to common in aero. And again, probably some sort of rules parity thing when the car was originally made to be in a specific performance window.
 

Fabman

Dances with Racecars
6,625
8,315
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
So since my diffusor is 5 separate tunnels does that mean it doesn't have strakes? Call them what you want, but a vertical deviation from the diffusor floor is commonly referred to as a strake, despite its size or shape. Its one of those general terms which is all to common in aero. And again, probably some sort of rules parity thing when the car was originally made to be in a specific performance window.
My interpretation of a strake is a divider within a set of walls that make up an individual tunnel.
I see 3 separate tunnels with no strakes.....but what do I know? That's why I asked about it here.
 

Fabman

Dances with Racecars
6,625
8,315
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
The question I was getting at was is this too much open area in that center tunnel?
Rules aside, wouldn't adding a couple strakes to it increase velocity?
 

Boone

Professional Thread Killer
Without pouring into a bunch of research that AJ likely can spew out on command... it's my understanding that the strakes encourage the air mass to stay laminar and "connected" to the surface of the diffuser. This attraction creates the downforce by maximizing the pressure drop as the area expands. If the air mass goes turbulent, (more likely without the strakes) then the air mass is expanding in all directions, and the difference in the air pressure is smaller. So, less downforce.

This is why diffusers are so much more effective with a flat floor. If the air is already turbulent when it reaches the diffuser, downforce suffers. If you don't have a flat floor, dial 1 degree more AOA on the wang, and save the diffuser work unless you have more than enough front downforce to balance things out with all the wing you have.

The appeal of a diffuser is the excellent downforce to drag ratio they can achieve... when done properly.

AJ, pleeeeaaaaase fact check this. I don't want to spread bad info.
 
Last edited:

Fabman

Dances with Racecars
6,625
8,315
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Without pouring into a bunch of research that AJ likely can spew out on command... it's my understanding that the strakes encourage the air mass to stay laminar and "connected" to the surface of the diffuser. This attraction creates the downforce by maximizing the pressure drop as the area expands. If the air mass goes turbulent, (more likely without the strakes) then the air mass is expanding in all directions, and the difference in the air pressure is smaller. So, less downforce.

This is why diffusers are so much more effective with a flat floor. If the air is already turbulent when it reaches the diffuser, downforce suffers. If you don't have a flat floor, dial 1 degree more AOA on the wang, and save the diffuser work unless you have more than enough front downforce to balance things out with all the wing you have.

The appeal of a diffuser is the excellent downforce to drag ratio they can achieve... when done properly.

AJ, pleeeeaaaaase fact check this. I don't want to spread bad info.
Yes, I believe the smaller tunnels they create accelerates the airflow and helps maintain attachment.
At least that's what I believe....this is NOT my area of expertise....which is why I ask questions. :)
 
9
3
Exp. Type
HPDE
Exp. Level
3-5 Years
Los Angeles
Good morning y'all
I've owned my 350R for 5 years and have loved tracking it several times a year. I have DTC-60 pads, Girodisk rotors, camber plates, SPL rear camber arm, a cage, and 3R's. It's a great setup, but I'm starting to chase lap times.
I don't like flashy upgrades and want my car to retain its stock look and feel.

While following my car to the racetrack (I was in a 997.1 Road-Cup Car) I noticed the diffuser was hanging precariously close to the ground. Once we got to the track I took a look at it, and nothing was wrong per se, it's just kind of flimsy. I'm also pretty familiar with the underside of the car, and know it's far from flat and clean.

Alright I'll jump to the question. What are the hivemind's thoughts on the Venus Engineering fender evacuation kit, flat underbody panels, and rear diffuser? If they are effective they should be a way to improve the aero efficiency with extremely little aesthetic change.

I'm not expecting to shave seconds off my lap time, but I am a little bothered by the flimsiness and roughness of the car's underbody aero. What are your thoughts on whether or not these changes will have any positive change? Are those small underbody panels useless when the center of the floor is left exposed?




Fender Evacuation Kit - Ford Mustang Shelby GT350
Flat Underbody Panel Kit - Ford Mustang Shelby GT350
Rear Diffuser - S550 Ford Mustang
Nobody?
 
Good morning y'all
I've owned my 350R for 5 years and have loved tracking it several times a year. I have DTC-60 pads, Girodisk rotors, camber plates, SPL rear camber arm, a cage, and 3R's. It's a great setup, but I'm starting to chase lap times.
I don't like flashy upgrades and want my car to retain its stock look and feel.

While following my car to the racetrack (I was in a 997.1 Road-Cup Car) I noticed the diffuser was hanging precariously close to the ground. Once we got to the track I took a look at it, and nothing was wrong per se, it's just kind of flimsy. I'm also pretty familiar with the underside of the car, and know it's far from flat and clean.

Alright I'll jump to the question. What are the hivemind's thoughts on the Venus Engineering fender evacuation kit, flat underbody panels, and rear diffuser? If they are effective they should be a way to improve the aero efficiency with extremely little aesthetic change.

I'm not expecting to shave seconds off my lap time, but I am a little bothered by the flimsiness and roughness of the car's underbody aero. What are your thoughts on whether or not these changes will have any positive change? Are those small underbody panels useless when the center of the floor is left exposed?




Fender Evacuation Kit - Ford Mustang Shelby GT350
Flat Underbody Panel Kit - Ford Mustang Shelby GT350
Rear Diffuser - S550 Ford Mustang
I can only speak on the parts that I have and that's their rear diffuser. The diffuser isn't necessarily a downforce creating diffuser with a large sweeping tunnel, but rather a flat piece that helps close off some of the open areas in front of the rear bumper. Personally I wish it went a little further forward and also wish it had a different mounting solution that didn't rely on the rear swaybar brackets as mine are moved back with the Steeda swaybars for better endlink angles.

I also have some little side spats that almost entirely close in the rear bumper area when combined. You'll also need to modify it to use the rear diff cooling ducts. Luckily they've since developed a kit with a cutting pattern and everything to simplify this since I modified mine. I also made slightly different rear mounting solutions for my car.

50737045298_d0c0b5fa63_o.jpg

Flat bottom/not upswept
50660284118_b2768d1c6b_o.jpg

Ducting
50661104802_0d9308a6c6_o.jpg
50661104797_6a20093e53_o.jpg
50661013506_186c419cb0_o.jpg
 
9
3
Exp. Type
HPDE
Exp. Level
3-5 Years
Los Angeles
Personally I wish it went a little further forward and also wish it had a different mounting solution that didn't rely on the rear swaybar brackets as mine are moved back with the Steeda swaybars for better endlink angles.
I also wish the diffuser pick up was further forward, and had already started planning on how to achieve that.

One option is to cut some aluminum sheet like DDozier did here: https://www.mustang6g.com/forums/threads/verus-engineering-rear-diffuser-group-buy.130501/
DDozier.jpg

Or I could do what RaiderJatt02 did and just transplant the forward portion of the original diffuser/ close out panel:
RaiderJatt02.jpg
 
Both solid options and I will probably look into an option like the first one you posted sometime this summer. Just need to figure out how to keep it work as I'm not running turndowns like he is so still need the exhaust to pass through.
 
355
370
I'm trying to understand the purpose of an oem part on my '11 GT. On the front undertray, under the radiator, there is a small air deflector that hangs down about 2" and runs the width of the car. This is the part:


On the standard Boss it looks like this lip is still present, although the front fascia in front of it is about an inch lower. On the Boss Laguna Seca, the lip is gone as the big front splitter runs smoothly all the way back to the finned undertray in front of the oil pan.

What is the purpose of this lip and what would be the effect of removing it? Does it create net lift due to slowing the air speed under the car, or net downforce similar to the low pressure area behind a wicker? Is it supposed to help suck the air out of the engine bay via the finned undertray?

Thanks.
 
355
370
I'm trying to understand the purpose of an oem part on my '11 GT. On the front undertray, under the radiator, there is a small air deflector that hangs down about 2" and runs the width of the car. This is the part:


On the standard Boss it looks like this lip is still present, although the front fascia in front of it is about an inch lower. On the Boss Laguna Seca, the lip is gone as the big front splitter runs smoothly all the way back to the finned undertray in front of the oil pan.

What is the purpose of this lip and what would be the effect of removing it? Does it create net lift due to slowing the air speed under the car, or net downforce similar to the low pressure area behind a wicker? Is it supposed to help suck the air out of the engine bay via the finned undertray?

Thanks.
Just bumping this up to see if any you aero experts have any insight on this? Can I cut off this little lip and expect hundreds of lbs of front downforce? :) Thanks all.
 
351
355
Exp. Type
Autocross
Exp. Level
20+ Years
So Cal
It looks to route air to the side, which creates a low-pressure area behind it. It looks like they're using that low-pressure area for the radiator exhaust. Aero people are quiet, because the first thing you learn is that whatever you think the air is doing; you're probably wrong. This is just my best guess. Do you have trouble keeping the car cool?
 
355
370
It looks to route air to the side, which creates a low-pressure area behind it. It looks like they're using that low-pressure area for the radiator exhaust. Aero people are quiet, because the first thing you learn is that whatever you think the air is doing; you're probably wrong. This is just my best guess. Do you have trouble keeping the car cool?
Thanks for responding, appreciate it. It's hard to tell from that link I posted but the lip hangs vertically across its width. Almost like a small ducktail spoiler but on the bottom of the car. So I'm unsure but it SEEMS like the air would flow under that lip, with a turbulent lower pressure area behind it, as opposed to being pushed out to the sides? I'm out of my depth here which is why I posted.

I don't have any problem with cooling and was wondering if it might reduce lift slightly (by smoothing and speeding up the underbody airflow) if I removed it?
 

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