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I am puzzled but hopeful that there aren't any offerings for brake ducts. I picked up my new, to me, '05 Elise last week and have my first open trck day next week. Coming from a supercharged Z06, then a moderately modded STI, both cars NEEDED brake ducting - I'm looking for the usual suspects of brake ducts....and can't find them.

Is it that they are not needed? No boiled fluid or scorched pads? If that is the case, then that is awesome.

On a side note - the front pads for the Elise arethe exact rear pads from my STI's Brembos!!!! It looks like I have a couple of sets of good pads to use for this season...Pagid Yellows and race Blacks...:coolnana:

Be good,
TomK
 

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Congrats on your Lotus, welcome to the tribe.

You are only bringing 1900 lbs to a stop, as opposed to 3200 lbs (or whatever those cars weigh these days).

Less weight = less energy that needs to be converted into heat by your brakes. Happier brakes. No ducts needed. Brakes last longer. Driver smiles.
 

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F1 cars have brake ducts and they weigh less than the lotus.

:shrug:
I didn't say that a Lotus couldn't benefit from brake ducts, only that they don't *need* them. :)
 

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tom,
the stock brakes are great.
take the car out and see, and then if you dont like it, then change it.
its a light car that is easy on the brakes, so save the $ for things like tires and track time IMO.
 

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No worries. I have recalled the ninja crew that was dispatched to find you. LOL
 

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That is an interesting thought about the F1 cars and brake ducts. Besides the obvious that we could use them but dont need them, I thought of this.

F1 cars can generate about 4 times more traction than our cars. Most of that is from downforce and a little is from super sticky tires. Therefore, when they stop, then decelerate with 4 times more magnitude. Therefore 4 times more energy absorption by the brake system in the same amount of time.

That is why they need brake ducts. Also remember that they are still using 13" wheels so the brakes are much smaller than ours.
 

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Also remember that they are still using 13" wheels so the brakes are much smaller than ours.
Great points re: sticky rubber and downforce...

I've been told that the 13" wheels were required by the rules in order to limit speeds... less brake can fit within the 13" wheels, therefore cars can't stop as fast as they would with larger brakes, therefore speeds will be kept in check.
 

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That is an interesting thought about the F1 cars and brake ducts. Besides the obvious that we could use them but dont need them, I thought of this.

F1 cars can generate about 4 times more traction than our cars. Most of that is from downforce and a little is from super sticky tires. Therefore, when they stop, then decelerate with 4 times more magnitude. Therefore 4 times more energy absorption by the brake system in the same amount of time.

That is why they need brake ducts. Also remember that they are still using 13" wheels so the brakes are much smaller than ours.
Actually brakes turn kinetic energy into heat... and brakes are rated in energy dissipated per unit of time. Let's compare an F1 car decelerating ~5G, from 200MPH with a Lotus decelerating from 100MPH at ~1G.

Kinetic energy of F1 car: 1/2*m*v^2 = 0.5 * 600kg * (90 m/sec)^2 = 2,430,000 Joules

Kinetic energy of Lotus: 0.5 * 900kg * (45 m/sec)^2 = 911,250 Joules

At 5G, F1 car goes from 200mph to zero in 1.85 seconds
At 1G, Lotus goes from 100mph to zero in 4.6 seconds

F1 car brake energy dissipation: 1,313,513 Joules/sec
Lotus brake energy dissipation: 198,100 Joules/sec
Roughly a factor of 6.6 difference.

Yes, I know I'm rounding a few numbers and neglecting a few effects, but I think its a good back of the envelope calculation

EDIT: 5G from 200MPH to 0 might be a bit optimistic... as downforce comes off braking would drop to just over 1G... but the average is probably between 3G and 4G... that would bring the dissipation down to just about 925,000 Joules/sec; still 4.7 times greater than the Lotus...
 

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Back to the original question!

I have an 07 Exige S and toasted the rotors w/ the OEM pads on the second session of my first track day w/ the 07 car. For years earlier I ran a heavily modded STi and had to have the brake ducts. The Exige does and will not need them, however I would seriously invest in some Cobalt race pads, both front and rear....check out www.adrenalineracing.com Talk to Eddie and tell him Dylan sent you. He knows how these cars move! Other wise get in touch with me and I will chat with you!:evil:
 

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Interesting - I get about 1200 track miles out of my front oem pads. Sounds like you may be overbraking which defeats the point of these momentum cars. Very different than a heavy, powerful car like a modded STi. The faster my laptime get the less I wear my brakes. Never smelled or saw smoke from my pads and never had more than a slight amount of fade on the hottest days.
 

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I am puzzled but hopeful that there aren't any offerings for brake ducts. I picked up my new, to me, '05 Elise last week and have my first open trck day next week. Coming from a supercharged Z06, then a moderately modded STI, both cars NEEDED brake ducting - I'm looking for the usual suspects of brake ducts....and can't find them.

Is it that they are not needed? No boiled fluid or scorched pads? If that is the case, then that is awesome.

On a side note - the front pads for the Elise arethe exact rear pads from my STI's Brembos!!!! It looks like I have a couple of sets of good pads to use for this season...Pagid Yellows and race Blacks...:coolnana:

Be good,
TomK
It's been done - most easily by tie-wrapping ducting hose to the cross brace on the lower A-arm and then directing the end to the disc center. Some have fab'd aluminum backing plates.

Be warned that there's no good way to pick up ambient air at the nose so you'll be picking it up under the car and directing anything else you pick up to... your brakes.

Most will say it's not needed.

Use the car first and decide for yourself.
 

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That is an interesting thought about the F1 cars and brake ducts. Besides the obvious that we could use them but dont need them, I thought of this.

F1 cars can generate about 4 times more traction than our cars. Most of that is from downforce and a little is from super sticky tires. Therefore, when they stop, then decelerate with 4 times more magnitude. Therefore 4 times more energy absorption by the brake system in the same amount of time.

That is why they need brake ducts. Also remember that they are still using 13" wheels so the brakes are much smaller than ours.
apk919 answered most of it...

But if you had the same F1 car with regular tires and no downforce then:
1) Yes it would stop slower
2) The energy required to be absorbed would be the same!

It is only speed and weight (mass)...
The G force has nothing to do with the energy being absorbed, (but a lot to do with the work.)
 

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It is only speed and weight (mass)...
The G force has nothing to do with the energy being absorbed, (but a lot to do with the work.)
The G force has to do with how much TIME that energy has to be absorbed/dissipated in.

Heck, my ass cheeks can dissipate a bit of heat over time with no ill effects. But not so much that they would stand up to stopping a gokart from ten miles per hour in less than thirty seconds. That would cause them permanent damage I'm afraid. Spread the heat generation out over a couple of minutes and my ass cheeks could probably take it and dissipate it.

xtn
 

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Just to compare the braking requirements of two "competitive" cars... if you're comparing a Lotus with a Corvette, assuming that both cars can decelerate at about the same rate and from the same speeds, the reduced braking effort would be linear, i.e. proportional to the ratio of the two car's weights (900kg vs. 1420kg, or 63%). If in addition the Lotus can corner faster than the Corvette, and the Corvette has a higher speed entering the braking zone (assuming both cars had similar lap times, this would be the case), <strike>than the effect is roughly "doubled" due to the squared velocity term in the kinetic energy formula... i.e. if the Lotus needs to decelerate 5% less for a corner, it requires about 10% less energy dissipation to accomplish this (which takes the 63% down to 57%).</strike>

EDIT: Oops... after looking at the equations again, the relationship between differential energy dissipated and differential speed reduction is not doubled... so a 5% reduction is speed decrease equals roughly a 5% decrease in energy dissipation. That said, 5% might be conservative... if a Corvette enters the braking zone at 100MPH, leaves at 80MPH; while a Lotus enters at 98MPH, leaves at 82MPH, that's a 20% difference in speed decrease, and 20% decrease in energy dissipation per unit weight. So in that case total effort for the Lotus would be 50% of the Corvette's (63% * (1 - 0.2)).

Okay, I'll stop now. :eek:
 

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It's been done - most easily by tie-wrapping ducting hose to the cross brace on the lower A-arm and then directing the end to the disc center. Some have fab'd aluminum backing plates.

Be warned that there's no good way to pick up ambient air at the nose so you'll be picking it up under the car and directing anything else you pick up to... your brakes.

Most will say it's not needed.

Use the car first and decide for yourself.
Ive seen that done on only one completely race prepped car. If you have time, why not? I did have fad at the track, but I was definitely over braking. It wasnt that bad, and better fluid would probably be enough to fix the issue.
 
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