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Discussion Starter · #1 ·
The two ways I know of getting more air out of the wheel well are the louvered vents atop the wheel wells and the small vent behind the wheel in the body panels (ala the GT4/GTE/GTC/GX/whatever).

If you were to only do one - which one would be more beneficial with less disturbance of the lamellar flow?

Ideas?
 

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With stock bodywork, I would do the top of the fender. Behind the front wheel is better with wider front fenders and a re-shaping of the inner well. You have to look at the flow.
 

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I'm sure there is a reason why Lotus chose the behind wheel vents for the GT4 and GTN. I would expect that to be the better solution, if not for looks itself
 

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Discussion Starter · #6 ·
Lol - I completely missed the cooking bit - I like it.

As for paint/bodywork. Either way is going to be an undertaking.

The wheel liners are also going to have to change for either/both as well so that is moot.

I am just really more curious as to which one would be the most beneficial.
 

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A panels are not hard to remove much less work than slotting above wheel in clam and reversible. Fact that lotus uses the a panel location on the GT cars including Leman version should tell you enough on technical merits. Flow out depends on vent being in lower pressure zone than inside well. A panel definitely is lower pressure, top arch on this type body may still be gaining pressure above wheel, as fender continues to rise.
 

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There is probably little, if any laminar air flow behind the wheel opening due to the scalloped sides of the bodywork. The purpose of louvers on top of the fender is to relieve high air pressure, that is created there, in an effort to aid down force. I imagine it would also help evacuate some heat although I'm not sure it would specifically help cool your brakes.
 

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The two ways I know of getting more air out of the wheel well are the louvered vents atop the wheel wells and the small vent behind the wheel in the body panels (ala the GT4/GTE/GTC/GX/whatever).

If you were to only do one - which one would be more beneficial with less disturbance of the lamellar flow?

Ideas?
Is disturbing laminar flow always bad?

There is no easy way to tell without doing some measurements as the modeling is beyond most.
Even if you move the air in the wheel well there is certainty that much will move around the rotor.
It may be possible measure the pressure on each side of the clam, but measuring flow would be better, which kind of requires at least a second-hand clam.
Visually here is something appealing about a hose aimed that the brakes.

Firstly though, is there evidence that more cooling is required?
Either IR readings or the paint that changes color?
Modifying the fenders for a non problem is not a financially effective move if there is not an actual cure taking place.
 

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Are you having brake cooling issues? You could probably plumb your own aeroduct hosing and modify some brake cooling kits already out there...a switch to improved rotors (BOE or forthcoming Sector111) would probably help as well as I don't believe the OEM rotors are directional vanes.
 

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The two ways I know of getting more air out of the wheel well are the louvered vents atop the wheel wells and the small vent behind the wheel in the body panels (ala the GT4/GTE/GTC/GX/whatever).

If you were to only do one - which one would be more beneficial with less disturbance of the lamellar flow?

Ideas?
The extraction of air from the wheel well through venting would occur because of Bernoulli's principle (the physics of which, i.e., allow airplanes to fly, soft convertible tops to bulge outward at speed, and spray bottles to spray). the amount of venting I would think is due to the speed of airflow in the area over the vent opening, in your query either the top of the fender or the lower back of the fender. I would expect Lotus with their wind tunnel testing/knowledge would choose the most effective of locations, and perhaps this is why they chose the lower venting area for the race cars.......just a thought........
 

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There is probably little, if any laminar air flow behind the wheel opening due to the scalloped sides of the bodywork. The purpose of louvers on top of the fender is to relieve high air pressure, that is created there, in an effort to aid down force. I imagine it would also help evacuate some heat although I'm not sure it would specifically help cool your brakes.
Thanks for clarifying that, that's primarily for downforce. Ducting is the best way to cool front brakes but, even with DTC70's, I have yet to get any fade issues, and I've been pretty brutal on them.
Cooling is always a good thing, but what issues are you having requiring this??:scratchhead:
 

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Discussion Starter · #13 ·
Only twice in the many miles around the track have I had true fade but when it happened, they were done. My thoughts were both visual as well as just a little more cooling. Adding downforce isn't horrible either I'd think but I'm also doing this for fun and shaving extra 1/10's is only for me, not a spot on a podium or sponsorship.

My thoughts were echoed here about how Lotus would hopefully use the best method on their racecars in the A panels. I'm just trying to learn as I go here.
 

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CF A Panels

After over two full seasons with the GTN A Panels and now with the CF versions I have not experienced any brake fade. Maybe a pad issue?
 

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Wi

After over two full seasons with the GTN A Panels and now with the CF versions I have not experienced any brake fade. Maybe a pad issue?
^Exactly^ It could be pad or fluid.

Without knowing the cause, or even the rotor's or calliper's temp, then the solution may not address the causal mechanism(s) that are resulting the observable problem's symptoms.

You may want to note that the paint sticks and/or temp sensitive stickers are pretty cheap and designed to provide this insight.

Personally I would suggest initially investing $10 in the stickers over buying a hole saw. As well as understanding what exact problem needs to be solved, especially when few seem to have similar problems that are not addressed with more conventional methods.
 

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^Exactly^ It could be pad or fluid.

Without knowing the cause, or even the rotor's or calliper's temp, then the solution may not address the causal mechanism(s) that are resulting the observable problem's symptoms.

You may want to note that the paint sticks and/or temp sensitive stickers are pretty cheap and designed to provide this insight.

Personally I would suggest initially investing $10 in the stickers over buying a hole saw. As well as understanding what exact problem needs to be solved, especially when few seem to have similar problems that are not addressed with more conventional methods.
Good recommendation.
Whether it is pad or fluid fade, the solution is to get more air to the rotors. That is much more important than getting the air out of the fender well. With vented rotors, the air ducts should be directed to the center of the disc. The vents on the front bumper panel, which are blocked off on the NA cars, looks like an ideal place to pick up the air.
I have 3 inch ducts on the Bobsy, with shrouds over the non-vented rotors, on a car that weighs 1350 lbs wet with driver. With 2.5 inch ducts and no shrouds, I routinely boiled Motul 600, and fried the pads, and had to bleed the brakes after every session. Now I only bleed the brakes before each race weekend, as a preventative measure.
 

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Right you are.

And it is usually also worth knowing the "before and after". And if the before is not too bad, or really bad, that knowledge helps one to determine what exactly should be done in terms of a solution... As well as if the solution is working at all, and/or working enough.
For all we know it is only a problem at one particular track or with old fluid.

As the OP's question was directly asking about best cooling, rather than specific of temps, ideal temp ranges, and ways to achieve optimal solutions... that generally leads to solutions in-line with the question... Rather than an open ended question.
 

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Discussion Starter · #18 ·
I'll get some of the paint and use them on the new rotors to get a good idea.

I had been using the stock rotors and DTC-70's for pads. New Motul RBF600. Turn 2 at Hallett. (Not me but the turn in question :) https://www.youtube.com/watch?v=eESy5n0P0Dw)

I like the way those carbon A panels look - I haven't seen a good picture up close like that...
 

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I'll get some of the paint and use them on the new rotors to get a good idea.

I had been using the stock rotors and DTC-70's for pads. New Motul RBF600. Turn 2 at Hallett. (Not me but the turn in question :) https://www.youtube.com/watch?v=eESy5n0P0Dw)

I like the way those carbon A panels look - I haven't seen a good picture up close like that...
That's the turn the GTRs & muscle cars have to slow way down to make, while Lotus cars just glide on through. :D

I'd really like to have some vented A panels. I would have mine painted to match the body though.
 
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