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Aero for 180 TW tires.

 
Old 10-05-2018, 09:00 PM
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Default Aero for 180 TW tires.

i run is a series where the required tire is a DOT spec 180 TW. Are there any considerations when applying aero when the tire is limited to DOT 180 TW.

I asked this question on the " Show your DIY areo" thread and Emilio suggested I post it as a new thread subject.
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Old 10-05-2018, 09:12 PM
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I'm not an aero expert, but my intuitive response is that aero strategy does not depend on tread wear rating. The objective of aero is to provide as much downforce as possible; if you have sticky tires, so much the better. Friction force is a linear function of force perpendicular to the road surface (downforce), and the coefficients of friction of the tire and road surfaces (tread wear and road material/surface finish). Increasing either one increases the force that the tires can exert on the road.

So, the short answer is, do the same aero things as you would do for any other tread wear to maximize downforce.
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Old 10-05-2018, 09:53 PM
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Maybe a more direct question, Is there any aero difference between race slicks and street tires?
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Old 10-06-2018, 10:09 AM
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Time to employ the Socratic method.

What is the effective difference between slicks and street tires? Why do you use one over the other for a given scenario?
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Old 10-06-2018, 10:23 AM
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We run in a similar series. 2D wing, air dam, splitter, rear bumper removed.
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Old 10-06-2018, 10:25 AM
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Are there any aero restrictions in your class? What do the people who run out front do?
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Old 10-06-2018, 11:09 AM
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Originally Posted by nigelt View Post
Are there any aero restrictions in your class? What do the people who run out front do?
Others do run areo. This situation pertains to two different cars in the stable. A na we currently run and most importantly, a nb under construction. The current na has no areo presently.

We we are waiting for the 2019 rules package before making any decisions but wanted to start doing the google/forum research. We are sure that aero should be applied to each car and wanted to get some additional input.
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Old 10-06-2018, 11:46 AM
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Sprint race car's primary objective is to go as fast as possible. Enduro car's primary objective is to complete as many laps as possible in a given timeframe.

Thus, the enduro car is trying to go as fast as possible, while using as little fuel as possible to limit the required number of fuel stops. To do this, you need to burn as little fuel as possible, and waste as little of the energy generated as possible. Everything on an enduro car should be designed to this end.

For the most part, horsepower generated is equivalent to fuel burned, so a very well-tuned engine is where you start, but there's lots more to be gained in wasting less of that energy.

Thus, the question you should be asking is not "what aero is best for 180tw", but instead "How do I make my aero package as efficient as possible"
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Originally Posted by codrus View Post
Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 10-06-2018, 12:57 PM
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Originally Posted by Savington View Post
Sprint race car's primary objective is to go as fast as possible. Enduro car's primary objective is to complete as many laps as possible in a given timeframe.

Thus, the enduro car is trying to go as fast as possible, while using as little fuel as possible to limit the required number of fuel stops. To do this, you need to burn as little fuel as possible, and waste as little of the energy generated as possible. Everything on an enduro car should be designed to this end.

For the most part, horsepower generated is equivalent to fuel burned, so a very well-tuned engine is where you start, but there's lots more to be gained in wasting less of that energy.

Thus, the question you should be asking is not "what aero is best for 180tw", but instead "How do I make my aero package as efficient as possible"
YES! Do you have any general thoughts?

i believe a good starting point is the areo package used by the Supermiata S1 cars. Any more than that could impact the efficiency as you pointed out. Is this a fair assessment?

And yes these are endurance cars.
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Old 10-06-2018, 02:13 PM
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Supermiata S1 is a good start. Limit your splitter stickout to 3-4" at most. Make sure the front tires are completely shielded. If your rules allow, get spats on the rear quarterpanels to shield the rear tires. Get rid of the side mirrors and move to shielded convex mirrors. Invest money in a good wing. The Singular APR GT-250 setup is the best low-drag aerofoil on the market today. Don't run more tire or wheel than you need to - unless the car has 300whp you don't need a 245 in an enduro environment. Make sure you have hood vents. Limit the frontal opening so that you don't have more airflow than is absolutely required to the radiator.

From there, just focus on details. Shield the tires, reduce frontal area, reduce drag.
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Originally Posted by codrus View Post
Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 10-06-2018, 07:27 PM
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Originally Posted by Savington View Post
Supermiata S1 is a good start. Limit your splitter stickout to 3-4" at most. Make sure the front tires are completely shielded. If your rules allow, get spats on the rear quarterpanels to shield the rear tires. Get rid of the side mirrors and move to shielded convex mirrors. Invest money in a good wing. The Singular APR GT-250 setup is the best low-drag aerofoil on the market today. Don't run more tire or wheel than you need to - unless the car has 300whp you don't need a 245 in an enduro environment. Make sure you have hood vents. Limit the frontal opening so that you don't have more airflow than is absolutely required to the radiator.

From there, just focus on details. Shield the tires, reduce frontal area, reduce drag.

Thanks for the run down Savington. Could you elaborate on the rear quarter panel spats. Would these be forward of the tire?
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Old 10-06-2018, 08:25 PM
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Originally Posted by WRLracer View Post
Thanks for the run down Savington. Could you elaborate on the rear quarter panel spats. Would these be forward of the tire?
Yes
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Old 10-08-2018, 10:23 AM
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All right guys, I've searched everywhere and can't find any info on a "shielded convex mirror". Any hints or clues????
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Old 10-08-2018, 11:21 AM
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i think he is referring to something like the last picture on this post:

https://www.miataturbo.net/build-thr...3/#post1407422
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Old 10-08-2018, 01:45 PM
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He is saying mount a convex mirror inside the car off of the door frame near the a-pillar and protected from the airflow. You don't want something hanging out there in the breeze creating drag.
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Old 10-08-2018, 06:30 PM
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Got it! Thanks for the clarification!
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Old 10-08-2018, 06:56 PM
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We run no side windows and have naca ducts in the 1/4 glass frames to aid in driver comfort. One car has a light weight top with lexan rear window. Would drag be reduced if the rear window was vented some way? I was thinking of aircraft snap vents.
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Old 10-09-2018, 09:47 AM
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Originally Posted by WRLracer View Post
We run no side windows and have naca ducts in the 1/4 glass frames to aid in driver comfort. One car has a light weight top with lexan rear window. Would drag be reduced if the rear window was vented some way? I was thinking of aircraft snap vents.
I have heard that venting the rear window has led to faster lap times from several sources. I don't know if they perform better at the top or bottom, but I would guess the top of the window.
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Old 10-09-2018, 12:36 PM
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At the base of the hardtop/softtop joining the boot there is a high pressure area (we have a CFD somewhere on here) so i would guess not at the base.
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Old 10-09-2018, 01:16 PM
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Originally Posted by rrjwilson View Post
At the base of the hardtop/softtop joining the boot there is a high pressure area (we have a CFD somewhere on here) so i would guess not at the base.
I am assuming you mean a high pressure area on the outside not the inside. ???
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