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Old 05-28-2020, 07:11 AM   #1 (permalink)
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From airtabs to underbody

So got some air tabs to try help with some higher speed drag on my 2009 Mazda 2,

Car in question


Quetion is, because of the raised front of the spoiler im questioning installing them in front of the wing or on the wing?


Any insight would be great


Last edited by Furai; 08-05-2020 at 04:49 AM..
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Old 05-28-2020, 07:31 AM   #2 (permalink)
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They won’t do anything measurable to reduce drag in either location.

And you have them orientated backwards!
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Old 05-28-2020, 05:40 PM   #3 (permalink)
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Quote:
Originally Posted by JulianEdgar View Post
They won’t do anything measurable to reduce drag in either location.

And you have them orientated backwards!
I forgot to mention speeds will be around the 100mph area if that makes any difference?

Haha good spotting! I just did a quick Paint chop for positing effect as you may be able to see they are not painted or mounted yet
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Old 05-28-2020, 05:55 PM   #4 (permalink)
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Quote:
Originally Posted by Furai View Post
I forgot to mention speeds will be around the 100mph area if that makes any difference?

Haha good spotting! I just did a quick Paint chop for positing effect as you may be able to see they are not painted or mounted yet
Drag forces don't suddenly change with speed; they go up with the square of the speed. So if they work at 100 mph, they will also work at 50 mph - but just not so much.

I've not seen any independent evidence that Airtabs reduce drag when placed as you have shown. However, I have seen evidence that vortex generators (not AirTabs) increase drag when placed on a car of your shape, in the approximate position you have shown them.

If you are trying to reduce drag, a full-length undertray will give you the greatest reduction. Not as easy as sticking on some Airtabs though!
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Old 05-28-2020, 09:19 PM   #5 (permalink)
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Quote:
Originally Posted by Furai View Post
I forgot to mention speeds will be around the 100mph area if that makes any difference?

Haha good spotting! I just did a quick Paint chop for positing effect as you may be able to see they are not painted or mounted yet
Hey man, glad to see you here. Welcome. How about we think differntly about your drag and lift plans. Do you have a chin spoiler, undertray, and/or difuser yet? What sorta rims are you running? Got pics of your car?

I gotta agree that the airtabs are unlikely to help you, and I don't know of any research suggesting they would. The Evo used them but only to direct flow to the large wing on the rear decklid.
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Old 05-31-2020, 06:14 AM   #6 (permalink)
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And if you want quicker lap times, getting less lift (or even gaining downforce) will be better than reducing drag - especially with a road car on a track.
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Old 06-05-2020, 10:03 PM   #7 (permalink)
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Thanks for the tips, as I already have them I will try them reguardless as they may offer an increase in stability or an other area and I will draw comparison on lap times for that.

As per the suggestions Im going to start with a front undertray as the car is otherwise stock. It has slightly lowered suspension but because ive had issues with brake cooling I run a rather unaerodynamic wheel I guess.

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Old 06-05-2020, 10:38 PM   #8 (permalink)
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Quote:
Originally Posted by Furai View Post
Thanks for the tips, as I already have them I will try them reguardless as they may offer an increase in stability or an other area and I will draw comparison on lap times for that.

As per the suggestions Im going to start with a front undertray as the car is otherwise stock. It has slightly lowered suspension but because ive had issues with brake cooling I run a rather unaerodynamic wheel I guess.

Front undertray sounds good - if you currently have consistent lap times, I'll be surprised if you cannot see an improvement. If that undertray can curve slightly down and then up again, it will be even better.

Your wheels are excellent for brake cooling - covering them completely (that would reduce drag) would not be so good!
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Old 08-05-2020, 05:01 AM   #9 (permalink)
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Skirts?

Right so ditched the airtabs, did some research and tested then made an undertray.

Made it as far back as I could go but due to exhaust/rear beam etc it will be quite difficult to go further.
Good results though as at 23.9% throttle went from 90kmh to 95kmh on the same stretch(Sadly not a long stretch so could be bigger differences but NZ has alot of hills).

Looking for some improvement though obviosly, thinking about mudflaps or ways to help deflect or decrease wake.
Also considering rubber skirts due to the ride height as an attempt to increase effectiveness of the area I have created.

Thoughts or ideas would be appreciated as the time spent trying to make a mock up of the skirts I could actually make some from rubber, I dont know how stiff they have to be though?
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Old 08-05-2020, 06:19 AM   #10 (permalink)
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Fantastic looking trays!

I can recommend some deflectors in front of the tires. They're coming kit on many new cars. For example:

https://ecomodder.com/forum/showthre...tors-2945.html

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