Project Evo has come a long way. With anywhere between 350-400hp, Ohlins suspension, lightweight 18" SSR wheels and Pirelli P-Zero Corsa R-compound tires the car is packed with the goods to go and corner. There's just one problem. We forgot to improve it's ability to stop!
Project Evo getting ready for the Girodisc Rotors!
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The set of front and rear Girodisc Rotors.
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Closeup of the front Girodisc rotor for the Evo.
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A quick look at the stock pads and rotors showed they were both in need of replacing. Since the stock Brembo calipers are one of the best features of the Evo, I decided to search for a stock rotor/pad upgrade package that would allow the Brembos to stretch their pistons.
Here's a shot of the stock setup prior to the Girodisc rotor installation.
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Stock Evo front rotor on the scales for measuring.
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The scale shows about 21lbs for a used stock rotor. Brand new blanks would probably weigh a tiny bit more as these had a decent amount of material removed at this point.
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Girodisc front rotor getting weighed. Notice the directionally curved vanes that help to move cooling air through. The stock Evo rotors use pillar vanes which are not as effective.
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A hair shy of18lbs = 3lbs of rotating mass saved per front corner. A total of 13lbs of unsprung mass is removed when using Girodisc rotors on the front and rear!
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Girodisc rotor placed onto the hub getting set for final installation. It may look pretty, but it's how it functions that really impresses.
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That's where Girodisc comes in. They recently released their two-piece brake disc upgrade for the Lancer Evolution. Girodisc rotors are a direct replacement for the stock Evo rotors, but they offer a number of advantages that will appeal to the performance-minded enthusiast:
Weight Savings:
Girodisc rotors weigh a total of 13.5lb less than the OE rotors. Over 6lbs of weight is removed from the front rotors and over 6 lbs from the rear. This weight savings leads to a substantial increase in surface area-to-weight (18.3% front, 31.8% rear). Most importantly, the lighter Girodisc rotors reduce unwanted unsprung mass, which enahnces suspension performance.
Brake Performance:
What good our rotors that don't improve your braking performance, right? Girodisc rotors use a two-piece design to compensate for the different expansion rates between the hat and rotor, which helps eliminate the potential for rotor warpage. Being a two-piece design also means you don't have to purchase the entire kit the next time you wear your brakes out. Just purchase new discs and re-install the old hats. This can potentially save you a good bit of money, especially if you drive your Evo hard.
The rotor and hat have a floating mount system, which utilizes 10 alloy steel driven pins to allow for axial and radial float. Anti-noise springs are used to reduce any noise the rotors could produce when cold.
In addition, each rotor has thirty-two directionally curved vanes, which move cooling air through the rotor to expel heat and reduce brake pad fade. The rotors are also slotted to constantly refresh the pad face and allow for maximum contact between the pad and disc surface. In contrast, the stock Evo rotors use pillar vanes, which are not able to pump air as well, leading to a hotter running rotor.
Quality Materials:
Girodisc rotors use high quality materials and components. The rotors are high carbon content iron with zinc plating for added corrosion resitance. The top hats are developed using 6061 T-6 billet aluminum with a gunmetal finish for a performance oriented look.
I opted for Ferodo DS2500 front and rear pads since they offer great track performance, but are still streetable. Girodisc include a set of titanium heat shields, which have a ceramic thermal barrier to prevent braking heat from transferring into the pistons and fluid. These shields are a cost effective way to prevent a lost pedal due to fluid boiling.
TheFerodo DS2500 pads available from Girodisc. The rear pads include a special backing plate that provides ample clearance over the floating rotor assembly without any modification. Girodisc also include titanium heat shields that prevent heat from transfering to the calipers and brake fluid.
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Girodisc / Ferodo DS2500 pad next to the stock Evo pad. Notice the slight curve of the backing plate on the Ferodo pad to allow proper clearance.
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Stock rear pad installed and shown interfering with the floating assembly. If you wish to use these pads or other aftermarket pads, you will need to file down this area a bit to assure clearance.
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Ferodo pad installed and shown clearing the floating assembly.
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When installing the pads, make sure the black side of the titanium heat shield faces the backing plate. This side is a ceramic thermal barrier to prevent heat from transfering to the caliper and brake fluid. See image for more detail.
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Installation
Installation was very straightforward and since the Girodisc rotors are direct replacements, there was no need to worry about their fitment with the stock calipers. Since the rotors are slotted and use directional vanes it is important to install them on the correct side. Girodisc have laser etched direction arrows to help remove any confusion during the install process. If you need any help with installation, feel free to check out our How-To forum to place a request or search the current how-tos.
Girodisc rotors installed on the passenger side. One side down, one more to go!
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Before shot of the stock rotor.
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After shot with the Girodisc rotor installed.
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Real World Review
Now that the pads and rotors are installed and bedded in, the car is braking with some serious zest. The combination of Girodisc rotors and Ferodo pads offers a definite improvement in stopping power and bite even when the pads are cold.
I haven't noticed excessive dusting or noise either, so I would defintely recommend a system like this for a person looking to still drive on the street. I only hear very minor pad squeal when I pull out of parking lots or brake lightly at very low speeds (<5mph), otherwise they are as quiet as can be. I have also heard the rotors shift when pulling out of parking spaces or your garage in reverse. This only seems to occur once and is likely due to the use of a floating mount design. When going in reverse, the pads catch the disc and shift them to the other side.
Overall, the upgrade has been a serious improvement to an area that was in dire need of it! I will definitely be upgrading the stock brake lines to take full advantage of the brake upgrades at future track days.
