Presented by Nine Lives Racing
1 2 3 4
Tazz9924
Tazz9924 New Reader
1/27/22 12:33 p.m.

In reply to Cedricn :

I know the correct wing placement, an analysis was done on the 914 some years ago and it was found the best place is level with the roof and as far back as practical. I could extend the roof or my idea was curve it at the back to better promote air to go down towards the decklid area. 

Cedricn
Cedricn New Reader
1/28/22 4:02 a.m.

In reply to Tazz9924 :

Yeah, a slightly curved extension was my first thought. But i assune you won't run with an open top like the cfd picture? I would probably measure it anyway when the wing is there to be sure, especially if it's DiY cfd, i worked with it enough to understand how easy it is to get wrong results, especially for more complex tasks. Though it looks kind of reasonable. 

Tazz9924
Tazz9924 New Reader
1/28/22 11:24 a.m.

In reply to Cedricn :

I just grabbed the google example, they university did it under all conditions. Im glad the curved roof but us tracking right, i tried finding stuff on trucks to help inform me in a similar situation.  

Doherty847
Doherty847
2/14/22 4:22 p.m.

Aero

 

Hi. My name is Ben. 35years old. From UK.  I’m a electrical maintenance engineer. I’ve been teaching myself about chassis and suspension set ups for short track, tarmac oval racing. I have done motocross my whole life and probably broke every bone in my body. I’ve stopped now. I’ve done banger racing and I’ve done karting. I can teach myself most things. I’m too stubborn to give up. BUT

 

 

I’m am really struggling to get my head around if the uk 2.0 national hotrods oval racing with speedeworth are using aero or is it mainly mechanic grip. I’m helping Peter number 43 and so far we have managed 2 wins. I want to take this sport to the next level as they seem to be stuck in time still using tigras. They don’t have a windscreen or rear window, side windows and I don’t believe they are going fast enough. A lot of cars are running massive rear spoilers but I believe they are just getting negative performance as understeer into the corner and a higher centre of gravity  

A simple yes or no would point me into the right direction. I’m happy to pay or donate if needed. All aero videos I find or info I find is with windscreen so the air hasnt seperated. I believe a big front splitter is doing good and a really high rear wing over the rear wheels would be good. It has a kind of flat floor. The rules can be found on the spedeworth website and youtube to understand what I am talking about https://youtu.be/GMxn-85gZao

 

Hope this hasn’t waisted anyones time too much reading this or hope it has made someone smile

 

Thankyou for your time

 

Ben Doherty

RACINGNUT
RACINGNUT
2/19/22 2:03 a.m.

In reply to Doherty847 :

Having read a good bit of the rules, it seems to me most of the grip is achieved by mechanical grip.  Having such open rules about the suspension bits, I also think one of the area to focus on would be the engine placement left to right, (+\- 25mm tolerance), and trying to keep as much weight on the right side and between the tires.  Combined with a good susspension focus would be of concern.

Having said that, the roll center height and the position of it, (left-to-right), would also be a very desirable area to focus on.  If you're running a double wishbtone front suspension, is the 'bumpsteer' of the LF & RF correct?  There are some considerations for a 4-bar setup for that rear axle to take advantages of rear roll center height and locations.  Look at the current US dirt car videos on youtube.  While their motions of rolling through the corners are exaggerated to your car's, there are lessons to be learned through investigations.  https://m.youtube.com/watch?v=Wg_3sDeElhQ

The rear wing height is a defined rule, as is the depth and width.   Although, a wing design seems to be wide open.  I don't see anything being bad about diving in to some thought, maybe even a secondary wing added as well.  Most cars I see don't run a front full windscreen.  There may be advantages to trying one to see how in interacts with the wing.  The front splitter can't hurt anything, although might be less effective in the tight traffic situations.  Running out front of the pack is always better for the splitter to work.  Of course the same might be said for the rear wing as well.  

In the end, yes the aero would be a A PLAYER in the car package in this racing.  However, not THE PLAYER.

Southerncross
Southerncross
2/21/22 7:09 p.m.

I've got an aero question. I have a hatchback, a Nissan Juke Nismo RS to be specific, that I want to either design/build or adapt an existing functional spoiler/wing onto the hatch area to balance the splitter I'm building for the front. I'm open to ideas. A picture will probably tell you the direction I'm headed. 

 

emre2blue
emre2blue New Reader
3/31/22 2:49 p.m.

Hello I have some little questions. I have an Alfa Romeo 159. I know it's a heavy car but I want to race with it. I have the project going on. And I did some templates of Aero Features in the car that I want to share with you. If you could review them I'll be happy. 

I've bought a broken front bumper. First I cut the lower part of the bumper and made a lip from it.  ( Also Car will be down for 2.5cm with new CoilOvers )

Also In the picture as you see front of the car. Wheels can be seen. I want to expand the tip of the bumper to block incoming air to meet with wheel surface.

In the picture it seems there is too much opening. But It will be covered with fog lights + Mini Front Disc Cooling Duct.  There is no Disc Cooling on front wheel arch from factory :( 

As in this picture I want to add a wheel arch went 

I'll apply under tray cover.  Just for those picture what would you suggest me? 

golfsierra
golfsierra GRM+ Memberand New Reader
4/5/22 9:14 p.m.

Hey guys,

I was watching a Jay Leno video covering the Huracan STO, and at 7:14s the guest from Lamborghini mentions, and I'm paraphrasing here, "increasing downforce without increasing drag by removing frontal surface of the car"

This got me thinking, as my understanding of ducting was that it was always some kind of sacrifice in favor of cooling performance, and a dam is aerodynamically superior?

Obviously I don't understand the system at all, so I was wondering if someone could shed some light on this...

Is it infact, aerodynamically speaking, more efficient to route air flow THROUGH something, rather than around it?

 

 

sleepyhead the buffalo
sleepyhead the buffalo PowerDork
4/6/22 9:31 a.m.
golfsierra said:

Is it infact, aerodynamically speaking, more efficient to route air flow THROUGH something, rather than around it?

The shortest answer is:
"it depends"

Another, less short, answer is:
Yes, it can be more efficient to route air through something rather than around... when the shape in question has certain mandatory physical elements, and the benefit to pressure distribution/drag outweighs the increase in skin-friction drag.

standard caveat:  "imho"

NOT A TA
NOT A TA UltraDork
4/6/22 11:30 a.m.
golfsierra said:

Hey guys,

I was watching a Jay Leno video covering the Huracan STO, and at 7:14s the guest from Lamborghini mentions, and I'm paraphrasing here, "increasing downforce without increasing drag by removing frontal surface of the car"

This got me thinking, as my understanding of ducting was that it was always some kind of sacrifice in favor of cooling performance, and a dam is aerodynamically superior?

Obviously I don't understand the system at all, so I was wondering if someone could shed some light on this...

Is it infact, aerodynamically speaking, more efficient to route air flow THROUGH something, rather than around it?

 

 

His guest was the president of Lambo USA (probably not an aerodynamicist) and may have misspoke a bit when saying that the NACA ducts on the top of the rear fenders reduced frontal area.  Can't see the NACA ducts in the frontal pic shown at 3.49.  Perhaps he intended to infer that the ducts had a similar effect to reducing the frontal area.  By routing some (high speed low pressure) air at the top of the rear fender through the NACA duct it probably helps fill in behind the car and also increases pressure (reduces lift) on the surface of the rear deck area by reducing the speed of airflow on the deck surface.

I also noticed he said the front fender vents were to reduce heat build up in the wheel wells.  Seems to me that while heat might be a consideration, they'd be more useful to reduce pressure in the wheel well thereby also reducing lift.

jh36
jh36 GRM+ Memberand Dork
4/6/22 2:24 p.m.

While there is a little activity in this corner, let me pick your brains!  smiley  I have been a little concerned that I don't have enough air flowing through the radiator on my tube frame.  When I changed the front, I had to decrease the duct opening by about 10%.  In my testing, I didn't see any problems, but those were cool days.  For insurance reasons, I am wanting to pop in two additional air supplies.  My question is, will bringing in two 3" hoses of air into the top 1/3 or so of my plenum (or whatever you call the radiator airbox on a car) disrupt the flow of air coming from the intake (located just above the splitter)? 

Do you think bringing in any additional air would be better higher (closer to the radiator) or lower (closer to the intake opening.  For pictures and hopefully a better explanation, please click below.

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/gen-1-camaroasa-stock-car-build/177739/page26/

 

sleepyhead the buffalo
sleepyhead the buffalo PowerDork
4/6/22 11:03 p.m.

In reply to jh36 :

it's a little hard to decipher what's going on there.  I recall there being a duct before, but maybe I'm remembering one that was an existing duct from the previous 'sillouette' car?  Or is the one on page 26, one you built to fit between the splitter and the camaro's valence?

General rule of thumb is you want the entrance area of the duct to be ~30% the area of the face of the heat exchanger you're ducting too.  Sometime it can be smaller, sometimes it needs to be larger than that... 'depending on conditions'.

If you're under that area... I wouldn't try to get too fancy.  You can plumb from a front pickup into the duct, but you probably don't want to have a reduction of area from the additional inlet before you feed it into the duct... outside of some fancy options... that's mostly just going to disrupt the flow that's being overslowed and shoot a bunch of "high velocity, high pressure" air at a portion of the radiator.

is there only a radiator?  or is there an oilcooler being fed in there too?  If so, you could use the new smaller duct to solely feed cooling air to the oil cooler... outside of the radiator duct.

jh36
jh36 GRM+ Memberand Dork
4/7/22 7:54 a.m.

In reply to sleepyhead the buffalo :

Cool...thanks.  The current air intake is below the valence, above the splitter as you note. I will measure the openings/ratios, but I do not believe I'm at 30%. 
I modified the duct from the original body and due to changes in the distance from the nose to the radiator, as well as the available height, it has a slightly reduced surface area compared to the original ASA car. 
The oil cooler is in the rear, so not an option. 
"You can plumb from a front pickup into the duct, but you probably don't want to have a reduction of area from the additional inlet before you feed it into the duct... outside of some fancy options... that's mostly just going to disrupt the flow that's being overslowed and shoot a bunch of "high velocity, high pressure" air at a portion of the radiator."

So if I pop two additional 3" lines into the main duct, could that be counterproductive and disrupt the air/cooling?  I think you are saying, yes...maybe. 

Since the intake literally sits on top of the splitter, I hoped that extra high pressure in that area might compensate for the slight reduction in surface area, but now I'm getting paranoid(see image below)  

I was thinking if I could put the intakes near the primary opening, above the splitter, the three bodies of air might merge better and distribute more evenly across the entire radiator surface. But I might be overthinking this whole thing. Appreciate the input. Let me know if I'm off base with your thoughts. Sorry I don't have better supporting images to explain my case. I've been laid up a few days and haven't been out of the house. 

jh36
jh36 GRM+ Memberand Dork
4/7/22 7:58 a.m.

NOT A TA
NOT A TA UltraDork
4/7/22 10:46 a.m.

In reply to jh36 :

In stock form the Camaro had a body panel on the top of the cowl with vents to provide air for the HVAC. The body panel extended forward far enough to have the gap between the hood and and the cowl panel forward of the high pressure area at the base of the windshield. So high pressure air at the windshield base went either through the vents into the cabin or to the sides and over the roof.

Your fiberglass hood eliminates the two piece design and brings the rear edge of the hood to the windshield base.  If the rear edge of the hood isn't sealed to the windshield base/cowl area the high pressure air at the windshield base may be getting under the hood into the engine compartment area. While you don't have inner wheel wells and do have the hood vents high pressure air from the windshield base might still increase the under hood pressures and be reducing the pressure difference between the front/back of the radiator and therefore flow through the radiator.

jh36
jh36 GRM+ Memberand Dork
4/7/22 6:40 p.m.

In reply to NOT A TA :

Valid thought. I thought I had this covered with my open/vent areas, but that is sure possible. The FG hood does get very close to the lexan...close enough that I am fearful of scratching it, so maybe I can put a seal on the trailing edge...I will check that out. Thanks for that. 

NOT A TA
NOT A TA UltraDork
4/7/22 8:25 p.m.

In reply to jh36 :

A piece of pipe insulation works well on 2nd gen F bodies. Perhaps try something similar? If you see the water temp drop (even a little) you can also probably expect a reduction in lift.  The hood and tops of the fenders is a lot of surface area (almost 5000 Sq. In.) so even a slight drop in under hood pressure will increase the weight on the front tires at speed. Because the windshield is at a much steeper angle than modern cars the high pressure area at the base of the window has more of an effect than on a modern sports car.

 

jh36
jh36 GRM+ Memberand Dork
4/8/22 5:24 p.m.
NOT A TA said:

In reply to jh36 :

A piece of pipe insulation works well on 2nd gen F bodies. Perhaps try something similar? If you see the water temp drop (even a little) you can also probably expect a reduction in lift.  The hood and tops of the fenders is a lot of surface area (almost 5000 Sq. In.) so even a slight drop in under hood pressure will increase the weight on the front tires at speed. Because the windshield is at a much steeper angle than modern cars the high pressure area at the base of the window has more of an effect than on a modern sports car.

 

Great idea. This will be tested. Thank you. 

Patientzero
Patientzero Dork
4/8/22 6:11 p.m.

Is there a "rule of thumb" to estimate how to balance out front to rear aero?  For example;  I have been thinking about a 9lives wang on the back of the stang (<see what I did there?) but how do I know if it will overpower the front splitter?  Just go off feel?  Is there a way to look at total surface area or something along those lines?  My gut tells me my splitter does not create near enough downforce to balance out a wing but how do I actually know that?

jh36
jh36 GRM+ Memberand Dork
4/10/22 10:03 p.m.
NOT A TA said:

In reply to jh36 :

A piece of pipe insulation works well on 2nd gen F bodies. Perhaps try something similar? If you see the water temp drop (even a little) you can also probably expect a reduction in lift.  The hood and tops of the fenders is a lot of surface area (almost 5000 Sq. In.) so even a slight drop in under hood pressure will increase the weight on the front tires at speed. Because the windshield is at a much steeper angle than modern cars the high pressure area at the base of the window has more of an effect than on a modern sports car.

 

I knew it was close, but that's extremely tight. Some very thin material will seal it completely. 

NOT A TA
NOT A TA UltraDork
4/11/22 10:45 a.m.

That's much tighter to the windshield than I thought it would be looking at pics. A strip of foam insulation tape would be cheap and likely work perfect and not be visible.

In other info:  I have some 3" duct openings that were made by Pratt Miller for the C-7 factory race cars if you have a use for them. Combination of aluminum elbow with fiberglass transition. Free, if you're interested send ma a PM.

[URL=https://app.photobucket.com/u/NOTATA/p/e3e3d6e2-4333-4d82-83ae-b4e397a67c0f][/URL]

fidelity101
fidelity101 UberDork
4/11/22 2:05 p.m.

I need something to keep me level in jumps but also not sap my speed because the car struggles to get to 100mph 

but also comply with this rule:

and I have nothing off the shelf. 

 

I don't even know where to begin

jh36
jh36 GRM+ Memberand Dork
4/11/22 10:08 p.m.

In reply to NOT A TA :

That is very cool!  I'd love to use a couple for nostalgic purposes...I did a little work with the c6 car. I will attemp pm!  Many thanks. 

footinmouth
footinmouth Reader
6/13/22 6:41 a.m.

I'm not sure where to start with this ,I have an 01 tacoma that I use for tack days and would like to learn about how to make it better than it is now ,I've lowered it about 3 to 4 inches  and put more money into it than it's worth . All the suspension is one off parts that I had made based on guessing and asking lots of questions . The only thing I've done for aero  is the bed cover with a 4 inch spoiler at 65 degrees . I would like to put a splitter up front and a flat floor . Where can I learn about how to do this right ? 

 


Bmsluite
Bmsluite New Reader
7/17/22 8:19 p.m.

In reply to footinmouth :

There is a book called "modifying th aerodynamics of your road car".  Buy it.  All your answers are in there

1 2 3 4
Our Preferred Partners
zfowCHJ25LW6P9RCFWLo2BvxeJtZVpvnVArYmSOP3f9zYnIlg13vv4DAcma47Fv9