PDA

View Full Version : Aero benefits?



JohnW8
07-28-2011, 10:48 AM
Does anyone have any data to show benefits of adding aero to a ITA Miata? Namely adding a splitter and removing side mirrors.

I am curious if any one has an opinion on aero mods.

Thanks

PDoane
07-28-2011, 01:42 PM
Since drag is directly related to cross sectional area, removing the mirrors has to be an improvement. The rest is very dependent on how the air flows in those areas before you make the mod.

Chip42
07-28-2011, 02:53 PM
splitter adds some drag but helps in cooling and "downforce" (maybe just lift reduction, but the effect is the same).

check directly with ISC - thier splitter is quite popular, at least in this part of the world.

http://www.iscracing.net/miata_fiberglass.html

CRallo
07-28-2011, 03:19 PM
Theoretically adds drag due to increased frontal surface area? Or has this been tested?



splitter adds some drag but helps in cooling and "downforce" (maybe just lift reduction, but the effect is the same).

check directly with ISC - thier splitter is quite popular, at least in this part of the world.

http://www.iscracing.net/miata_fiberglass.html

Chip42
07-28-2011, 03:39 PM
in theory, yes.

shwah
07-28-2011, 04:47 PM
The article that was in Racecar Engineering several years ago indicatee that a splitter can reduce drag and increase downforce.

It forces more air over the aerodynamically cleaner top of the car. Thus it has less resistance, and there is slightly lower pressure on the bottom of the car.

mossaidis
07-28-2011, 04:49 PM
EG Civics go 2-5 mph faster in long straightaways when splitter/airdams were installed.

Chip42
07-28-2011, 06:50 PM
I hear ya on air dams - big splitters I've had opposite results from. but it's all seat of the pants - I could be (and appear to be) wrong.

lateapex911
07-28-2011, 07:52 PM
I think the Miata needs help up front badly. I'd build an airdam that was nearly the full outline of the car, and I'd have my splitter be adjustable.
My (Completely POOMAD!) sense on that car is that drag reduction is a much greater issue then lift/downforce.
heck just getting an airdam out there will reduce lift, and drag.

On the mirrors, I would get smaller ones tucked into the windows, if only to reduce the need to replace them every time things get dicey and side by side....

Xian
07-28-2011, 09:19 PM
Having seen the ISC Miata's (and their airdams) in use at Daytona, I can definitely say that they make a big difference to the top-end. Well worth either buying a turn-key option or fabricating something. The "issue" with the Miata is how much front tire it shows to the wind. Get the air moving around/past the tires and you'll be in business.

Christian

billf
07-28-2011, 10:53 PM
As the car travels thru the air, the air is forced to flow around it...over it...under it. The air molecules don't go away, they just move.

The sources I've read through the years have all taken the position that the effects of a front air dam are two fold:

First-it increases the frontal area, and that leads to increased drag.

Second- it reduces the amount of air that is able to pass under the car, and forces it to flow around the car (and over it) which reduces the drag of the car (less air under the car equals less drag). The surfaces around the car are more aero, and the surface of the underside of the car is "dirty" creating more drag.

The sum of the influences are: The drag reduction under the car is greater than the drag created by the increased frontal area. Ergo, the sum effect is less drag, and more speed.

A splitter increases the amount of air forced to flow over the car.

We tend to forget the extremely dirty underside of the vehicles, and the negative influence it has on performance.

Good racing.

Bill

TStiles
07-29-2011, 10:39 AM
Here's a discussion from miata.net

http://forum.miata.net/vb/showthread.php?t=402663&highlight=ITA+Aero

red986s
07-29-2011, 02:09 PM
I don't have any data but I currently run the Tougerun spoiler. I finally found a sweet spot in my setup and didn't want to screw it up fiddling around. I just wanted a touch more grip up front. The Tougerun did the trick. The car is very neutral in the corners now.

IMHO the stock mirrors are worthless. I removed those and bought some 5" convex mirrors and attached them to my roll bar with Ram mounts. Couldn't be happier with them. Side visability has greatly improved. Again IMHO aero was improved. Ever stick your arm out the car window at 70 mph? Nuff said. Check out my YouTube channel to look at the setup.

My lap times have improved but I can't say it was just because of these two mods.