In search for more aero

[racebronco2]

Recently i installed vortec generators and the results are that air is flowing over the rear window alot better then without them. The yarn on the drivers side has the vg's installed and the passengers side does not.

Shot at 2008-03-21

The vg's help the aero but also helps to get clean air to the rear spoiler. I really like the cobra "r" wing but it is too much. I have heard the steeda wing works pretty good also but i wanted something a little less noticable (yeh right then why do i drive an orange cobra). I cut and mocked a spoiler extension out of clear 1/4 plexiglass. The height was determined to maintain 55-60 degrees from the factory spoiler to the top of the plexiglass. I will do some more yarn testing. One reason i need more downforce is t8 at big willows entry speed is over 120mph and i would feel more confident if the rear felt as though it stuck better. I have already bought some aluminum to make the some underbody belly panels. So what's you opionion

 

[sunburned]

I say sweet deal! I do know a little about aero stuff, but only the basics. I say its time to make some belly pans, as well as some sort of diffuser for the rear bumper. If you can run a sheet from the rear bumper to the IRS somehow, that could clean up the aero under the car in the back. A few Mitsu Evo companies are doing it, if you are copying the VG from the Evo, why not other aero mods too, eh? lol

 

[93SVTCobra]

It really depends on how serious you are about area doesn't it. Ideally you'd want a nice big wing in the back to provide plenty of downforce wouldn't you but it doesn't appear that you want something that big. I'm not sure where you got your data on Steeda's rear wing being "functional" but I can assure you it doesn't produce any more downforce than it weighs (which I guess isn't half bad because it means it doesn't provide any lift either). The one thing the yarn test won't give you an indication of is drag. By inceasing the size of the factory rear spoiler you will create a larger air pocket behind the car which will cause a good amount of drag.

Have you thought about adding spats in front of the wheels to block the air? I don't mean on the side of the vehicle but underneath? Have you made a front belly pan yet? I toyed around with making a rear diffuser modelled after the Ford GT's which would be fairly straight forward with the IRS but it would need to be removable as you'd damage it pretty easily on the street.

 

[SKMCOBRA]

Griggs sells a spoiler for 94-98's which is said to function really well, but you have to bolt it to your deck lid which I don't want to do. I am in the same boat as your trying to decide what improvements I can make for downforce w/o chopping up the car badly. I started this thread on corner-carvers a few months ago and it turned out to be a really good thread. There's a link in one of the posts to a Circle Track article which really explains areodynamics, lift and downforce. http://www.corner-carvers.com/ Do a search for "More air into radiator on 97 Mustang Cobra".

 

[gcassidy]

Good info, keep it coming.

Guess there's no hope for a convertible like mine, though. I have to have the top up sometimes, and down others. :shrug:

Wouldn't mind some aero that keeps my nose down a bit, though.

 

[Snake Eyes]

I cant find where I saw it but a few people have attached a Dodge Viper rear diffuser to a mustang. It was attached to the gas tank shield and the rear bumper cover. It didnt look terable...

 

[LargeOrangeFont]

Carlos - Check your PMs.

The wing and the vortex generators should work well together.

There is definately a low pressure area from the middle of the rear window down to the trunk. I was looking to adapt a vortex generator from an EVO. Great work Carlos.

I have been thinking of making a rear diffusor to seal the tank to the back of the bumper as well. We should get together and make a couple of them. On the weekends I have access to a machine shop and a lift in Long Beach.

 

[racebronco2]

The vg's are from agent 47. Corey (owner of agent47) tells me that the vg's do not help with the wing they have on their AIX car. Their wing is actually about the same height as the roof of the car and a little wider then their car.

I have thought about a diffuser and seen on a a fox body but it had a fuel cell in it and they were able to raise the center about 2 inches higher then the sides.

I have also thought about about a front belly pan. I bought enough aluminum to do the front belly pan, side belly pans and a rear diffuser. But for now it's one project at a time.

 

[racebronco2]

Griggs sells a spoiler for 94-98's which is said to function really well, but you have to bolt it to your deck lid which I don't want to do. I am in the same boat as your trying to decide what improvements I can make for downforce w/o chopping up the car badly. I started this thread on corner-carvers a few months ago and it turned out to be a really good thread. There's a link in one of the posts to a Circle Track article which really explains areodynamics, lift and downforce. http://www.corner-carvers.com/ Do a search for "More air into radiator on 97 Mustang Cobra".

"More air into radiator on 97 Mustang Cobra" I remember when you started the post over there. My screen name there is c.mejia.

 

[racebronco2]

I'm not sure where you got your data on Steeda's rear wing being "functional" but I can assure you it doesn't produce any more downforce than it weighs (which I guess isn't half bad because it means it doesn't provide any lift either). The one thing the yarn test won't give you an indication of is drag. By inceasing the size of the factory rear spoiler you will create a larger air pocket behind the car which will cause a good amount of drag.

Have you thought about adding spats in front of the wheels to block the air? I don't mean on the side of the vehicle but underneath? Have you made a front belly pan yet? I toyed around with making a rear diffuser modelled after the Ford GT's which would be fairly straight forward with the IRS but it would need to be removable as you'd damage it pretty easily on the street.

Thanks for the info on the steeda wing. I did forget about the added drag with a bigger spoiler so i guess i will go with the "r" wing.

I will incorporate the spats in the side belly pans. I am not sure if the front of the car needs them since i added a larger ? (lost for the correct wording) plastic piece at the radiator support.

So much work to do and so little time.

 

[Snake Eyes]

There is a good example of a rear splitter on a mustang:
http://s260.photobucket.com/albums/ii30/Ramsey_Family_Racing/Mustang Diffuser/

It's for sale here:
http://www.tamparacing.com/forums/ramsey-family-racing/460351-mustang-rear-diffuser.html

 

[racebronco2]

There is a good example of a rear splitter on a mustang:
http://s260.photobucket.com/albums/ii30/Ramsey_Family_Racing/Mustang Diffuser/

It's for sale here:
http://www.tamparacing.com/forums/ramsey-family-racing/460351-mustang-rear-diffuser.html

I've seen that diffuser but it's not made for the 03/04 cobra's which have a lower bumper cover then the previous years. I would like to make one similar to the one below but again our bumper covers are a little. lower.http://www.cardomain.com/ride/344858/2

Started fabbing up the rear diffuser and the metal supply cut the piece at an angle:shrug:, so i can't use it. Mounting the diffuser looks to be pretty easy. I just need to find some type of material to make the slat(?) out of. I am thinking some type of thick plastic.

 

[AnaheimE]

Do you post on Corner Carvers? I think there is a post just like yours over there. I'm interested in them as well. I'm personally working on a rear diffuser as well. There is a member on another forum I frequent that is supposedly an aerodynamasist. He said he even took his car in the wind tunnel. With the VGs on the roof and some other parts he said he got 4.5 mpg increase, which I think is too much, but I'm betting something like 2 is probable.

http://www.3.8mustang.com/forum/showthread.php?t=213936

There is some good info once you get past most of the comments, but there are like 6 of us that are serious about racing (I'm Bluesix, btw)
match?

Also that rear diffuser on that black car is worthless. The angle of the hypotenuse is much to high (it should be something like 8-14 degrees I believe, and it doesn't protrude far enough ender the car. Also the car needs to be much lower than that and the front "splitter" he has does not extend past to the bumper so it does not create any low pressure under the car. That and any low pressure under the car is most likely lost from the high side-skirts, it will just "leak" out. Also the air under the car is still very turbulent and still needs to be controlled before you get a "good" effect from the rear diffuser.

I also have a hunch the vertical pylons he has don't do much and I think I have a good design as to how the diffuser should be formed at the exit. It should make a small venturi effect and help make it more effective.

 

[racebronco2]

Do you post on Corner Carvers? I think there is a post just like yours over there. I'm interested in them as well. I'm personally working on a rear diffuser as well. There is a member on another forum I frequent that is supposedly an aerodynamasist. He said he even took his car in the wind tunnel. With the VGs on the roof and some other parts he said he got 4.5 mpg increase, which I think is too much, but I'm betting something like 2 is probable.

http://www.3.8mustang.com/forum/showthread.php?t=213936

There is some good info once you get past most of the comments, but there are like 6 of us that are serious about racing (I'm Bluesix, btw)
match?

Also that rear diffuser on that black car is worthless. The angle of the hypotenuse is much to high (it should be something like 8-14 degrees I believe, and it doesn't protrude far enough ender the car. Also the car needs to be much lower than that and the front "splitter" he has does not extend past to the bumper so it does not create any low pressure under the car. That and any low pressure under the car is most likely lost from the high side-skirts, it will just "leak" out. Also the air under the car is still very turbulent and still needs to be controlled before you get a "good" effect from the rear diffuser.

I also have a hunch the vertical pylons he has don't do much and I think I have a good design as to how the diffuser should be formed at the exit. It should make a small venturi effect and help make it more effective.

Yes i post on corner-carvers see post #9 above. On our cars to make them correctly they would be too low and would get damaged going over speed bumps. It's always a compromise.

 

[LargeOrangeFont]

I've seen that diffuser but it's not made for the 03/04 cobra's which have a lower bumper cover then the previous years. I would like to make one similar to the one below but again our bumper covers are a little. lower.http://www.cardomain.com/ride/344858/2

Started fabbing up the rear diffuser and the metal supply cut the piece at an angle:shrug:, so i can't use it. Mounting the diffuser looks to be pretty easy. I just need to find some type of material to make the slat(?) out of. I am thinking some type of thick plastic.

Titanium so it make some pretty sparks...

Carbon fiber, fiberglass, or plastic would work well.. Rivet the mounts on, and use nylon nuts and bolts to attach the fins. In case of an OT excursion, the fins could snap off and not destroy the entire piece.

 

[AnaheimE]

There is a good example of a rear splitter on a mustang:
http://s260.photobucket.com/albums/ii30/Ramsey_Family_Racing/Mustang Diffuser/

It's for sale here:
http://www.tamparacing.com/forums/ramsey-family-racing/460351-mustang-rear-diffuser.html

That diffusor is not going to work. It has much to high an angle and it does not extend very far into the underside of the car. Also it is not anywhere near low enough to the ground to properly control the air.


I've been working on a rear diffuser for a while, but unfortunately I'm 160 miles away from the car (school). For the vertical pylons I think you should separate them into two pieces that get screwed into place for the track, and have a shorter one for the street. (hey, it looks cool!). Also have you conisdered "boxing" in your side skirts. I have an idea of taking some think rubber molding and mounting them to the underside of the car to keep the air in, and use replace as necessary.

 

[sunburned]

How about pieces like this...

(yes I know the fins are backwards, this isn't my picture)

Good info, keep it coming.

Guess there's no hope for a convertible like mine, though. I have to have the top up sometimes, and down others. :shrug:

Wouldn't mind some aero that keeps my nose down a bit, though.

Greg, since a flat undertray would be hard to do with your cobra front bumper, you might look into getting some canards for the sides. These should add a little downforce to the front end and not compromise your ride height or weight.

 

[dtheo]

looks to me like most of the front and rear diffusers are custom made jobs. An aftermarket racing gas tank would totally change how the rear diffuser would be made, and exhaust, etc.

 

[BlackBolt9]

If you guys are seriously looking to get some actual data contact your local college that has a wind tunnel and aero program. I would have loved to do my senior thesis on race car aerodynamics. Instead we tested propellor efficiences for our Design Build Fly team. The wind tunnel time wouldn't cost you anything more than getting a model built for them to test. Price would reflect accuracy obviously.

These were the facilities I worked with while in college.
http://www.wmich.edu/mae/research_labs/applied_aerodynamics/ADWT-Report.pdf
If anyone wants to get in contact with someone there about having the students do some testing for them send me a PM because I think I know a couple people that are still there.

 

[gcassidy]

Greg, since a flat undertray would be hard to do with your cobra front bumper, you might look into getting some canards for the sides. These should add a little downforce to the front end and not compromise your ride height or weight.

I downloaded the templates to see if they'll fit.
Could these actually help with front downforce?