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Yellow Goat
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Nice. 13" I imagine. I wonder what would perform better, the 13" Wilwood kit or the 14" Baer 2 piston kit. I wonder if our master cylinder and ABS system is capable of providing the power for a total of 20 braking pistons.

I stuck a set of Brembo/Porsche Big Reds on an Audi once and just assumed that braking would get better. It did, but only marginally and not worth the cost because the hydraulic system was not able to give it the force it needed.

I like Wilwood brakes though, they are a great value but I still think my heart is set on the 14" Baer kit since I have 18" wheels and I've always heard the bigger the rotor the better.
 

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We'll be offering the kits hopefully within 2-3 months

Expect a retail price $3350 for the front, rear, and lines.

We will also try to set up a little GP on them to get the interest rolling. Details should come within the upcoming weeks.
 

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Autobahn Fahrer
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Ls1 Speed said:
We'll be offering the kits hopefully within 2-3 months

Expect a retail price $3350 for the front, rear, and lines.

We will also try to set up a little GP on them to get the interest rolling. Details should come within the upcoming weeks.
Stock rims?
 

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GTOless
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1COOLPC said:
Nice. 13" I imagine. I wonder what would perform better, the 13" Wilwood kit or the 14" Baer 2 piston kit. I wonder if our master cylinder and ABS system is capable of providing the power for a total of 20 braking pistons.

I stuck a set of Brembo/Porsche Big Reds on an Audi once and just assumed that braking would get better. It did, but only marginally and not worth the cost because the hydraulic system was not able to give it the force it needed.

I like Wilwood brakes though, they are a great value but I still think my heart is set on the 14" Baer kit since I have 18" wheels and I've always heard the bigger the rotor the better.

The common thought is that the larger rotor can disipate more heat. This may or may not be true depending on the design of the rotor, such as thickness of material and amount of and design of cooling fins within the rotor.

It is also commonly thought that the more pistons in the caliper, the better the clamping force/ more even the force distribution on the pad.

That being said, the Bear brakes (that are most commonly refered to) are two piston PBR calipers. The PBR have been used on everything such as the Mustang and Corvette for years (even my trailblazer has PBRs). Great caliper, floating design (slides back and forth to adjust for pad wear). The one question to ask with larger rotors is: are they necessary. The will add to greater unsprung weight and therefore, the suspension will most likely feel like its working harder (you should have felt this with your 18" wheels, if heavier than stock), less responsive. This also "robs horsepower" as it is more dificult to get it moving.

The Wilwood brakes, hopefully being engineered well (I have no doubt as Wilwood has a great rep. and I have had friends with them before), should be able to use the stock master cylinder with an increase in performance. If not, I am sure the kit would include a new master cylinder. The caliper is a "fixed" design, meaning the pistons are on both sides of the rotor and extend to push the pad to the rotors. It's important to shim them properly when first set up. The thing that I like alot about the Wilwood that I saw was a big friggen hat. This should mean that the rotor assembly is about as light as it could be so that the ride (and horsepower) isn't effected much.

OH NO!!! I wrote a book!! Sorry everyone, just let me say if you're looking for extra cooling (big, heavy car, it may need it) the larger rotor in the Bear kit may be what you're looking for. If your looking for more braking without adding weight much weight, a smaller rotor may be good. If you're looking for looks to fill out the wheel, then Bear, (although there's nothing more cool than seeing 6 piston staring out at you when you approach your baby).

Sorry, I'll end now.
 

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The main advantage you will see by going to larger rotors is that the friction is applied further away from the center of the wheel, allowing for better "leverage" and therefore, increased braking force.
 

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BlueGTO said:
The main advantage you will see by going to larger rotors is that the friction is applied further away from the center of the wheel, allowing for better "leverage" and therefore, increased braking force.

This is true that torque is increased, as seen at the axle centerline, however at a certain point, the additional rotational mass makes it much more difficult to stop the assembly. There have been many tests showing a larger rotor does not necessarily lead to shorter stopping distances. This also holds true for larger wheels and tires. More mass = bad. :)
 

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2004 GTO Impulse/Bermuda M6
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goatlover said:
This is true that torque is increased, as seen at the axle centerline, however at a certain point, the additional rotational mass makes it much more difficult to stop the assembly. There have been many tests showing a larger rotor does not necessarily lead to shorter stopping distances. This also holds true for larger wheels and tires. More mass = bad. :)
What Goatlover says is true, all other things being equal (piston diameters, pedal ratio, brake linings, etc.) a larger rotor diameter will increase wheel torque for a given pedal force input. It will not decrease single stop stopping distance unless you have a tire that can put the additional torque to use and a ABS system that can deal with the new tire and optimize its tractive force. It will however reduce the pedal force required to attain a level of deceleration when compared to a stock system (again everything else is equal). There are also thermal performance gains from the larger rotor (fade performance, brake pad life, etc.) but you will usually not realize these gains unless you are putting a lot of heat into your brakes. I do not know the specs on the systems mentioned in this thread but there are several things to consider that will change the performance of the system. All of the systems have changed the calipers, rotors and brake pads. The caliper pistion diameters and amount of pistion retraction will be different from stock, the rotor diameter is the same or increased (more important is where is the center of force for the brake pad on the rotor or "effective radius"). And the brake pad friction level has changed (which you can hope has increased but may not be any different). Depending on what you want from your brake upgrade each system has substantually differant things to offer in the way of performance, most of which you can easily estimate based on piston diameter and rotor diameter. I must admit, the Wilwood upgrade looks pretty cool, but wow thats a lot of money...
 

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Gone but not forgotten
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so from what you guys are saying, it sounds like a brake upgrade is not a sure fire way to decrease braking distances, right???
is there a way to be sure that if we spend $2-5k on a break upgrade that it will decrease distances??
i would pissed if i spent the time and money on this mod, only to find out that it didn't do anything for me.
 

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May I quote you on that?
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Stopping distances are dominated by tire grip, although the ability of a brake to modulate smoothly as it approaches lockup is very important. The big advantage of better brakes is freedom from fade at high temperatures, and smooth modulation. Going to larger rotors is generally considered a good move within reason. While I buy the argument about unsprung weight being an important issue, the argument that the larger rotor diameter is more difficult to stop is highly questionable. The same argument has been applied to large wheel diameters resulting in an increase of rotational inertia. Yes, the start/stop torque requirement is greater, but considering you are starting and stopping 3000+ Lbs of car, the contribution of rotational inertia due to rotor, wheel, tire etc. is miniscule.
 

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mistermike said:
, but considering you are starting and stopping 3000+ Lbs of car, the contribution of rotational inertia due to rotor, wheel, tire etc. is miniscule.
yeah, thats exactly what i was thinking...
 

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2004 GTO Impulse/Bermuda M6
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mistermike said:
Stopping distances are dominated by tire grip, although the ability of a brake to modulate smoothly as it approaches lockup is very important. The big advantage of better brakes is freedom from fade at high temperatures, and smooth modulation. Going to larger rotors is generally considered a good move within reason. While I buy the argument about unsprung weight being an important issue, the argument that the larger rotor diameter is more difficult to stop is highly questionable. The same argument has been applied to large wheel diameters resulting in an increase of rotational inertia. Yes, the start/stop torque requirement is greater, but considering you are starting and stopping 3000+ Lbs of car, the contribution of rotational inertia due to rotor, wheel, tire etc. is miniscule.
Actually, the ABS system has to deal with the inertia of the tire and wheel package as well as the rotor contribution. If there is a large increase in rotating inertia the ABS system may not be calibrated to deal with the shift which can cause large pressure dumps to "recover" a skidding wheel and likewise take longer to bring the wheel to lock because it is usually calibrated to do pressure steps of a certain magnitude. If corner inertia increases it becomes increasingly difficult to control the tire slip during an ABS event and you can no longer optimise the tire slip to take full advantage of the available grip. This may not increase stopping distance but it may not decrease it either. Of course all of this implies that your ABS system is active, if you are racing and the ABS has been disabled all bets are off.
 

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May I quote you on that?
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blu04 said:
Actually, the ABS system has to deal with the inertia of the tire and wheel package as well as the rotor contribution. If there is a large increase in rotating inertia the ABS system may not be calibrated to deal with the shift which can cause large pressure dumps to "recover" a skidding wheel and likewise take longer to bring the wheel to lock because it is usually calibrated to do pressure steps of a certain magnitude. If corner inertia increases it becomes increasingly difficult to control the tire slip during an ABS event and you can no longer optimise the tire slip to take full advantage of the available grip. This may not increase stopping distance but it may not decrease it either. Of course all of this implies that your ABS system is active, if you are racing and the ABS has been disabled all bets are off.
Now that argument makes good sense to me. Do pros typically disable ABS? I would think they would. It would seem that the brain/foot is easier to recalibrate. Thanks :)
 

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Of course, it depends on the rules for the different classifications and is somewhat driver dependant. The people that run at the club events I attend at different tracks, through BMW, Porsche, Shelby Clubs, etc. often do. The main reason they give is that you have a predictable slide if you were to go off track. I've seen my friend miss the tire barrier and hit the wall at Mid-Ohio by about 3 feet. He did not disable his ABS. Would he have hit the tires instead of the hard wall without the ABS? Who knows, but he may have.

Luckily, he walked away safe and the amount of money that insurance gave him enabled him to purchase a used Corvette that was set up for track use.
 
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