Get More Confidence On The Street or Track With WP Pro Complete Upgrade Kit For the M3/M4
The BMW F8X M3 and M4 are two of the best sport compact vehicles that money can buy. BMW has some how improved on its previous M3 model, designating the new sedan and coupe respectively the M3 and M4. With this F8X Generation of M performance vehicles, they have turned to turbo charging to get power results and meet emissions standards. People are pushing this chassis to incredible power levels due to the potent Straight 6 3.0L Turbo S55 Engine. With Incredible power, you need adequate stopping power. This is where the WP Pro BBK (Big Brake kit) comes into play.
The factory brake set up on the F8X chassis has a 4 Piston front caliper with a 380mm rotor and a rear 2 piston caliper with 370mm rotor. From a performance stand point the factory rotor and caliper set up are very good for average street driving. The problem lies when you try to push the brakes during aggressive street or ANY track use. Heat dissipation and brake feel become an issue when you are continually doing hard stops. This is where Pad and rotor design as well as caliper architecture make a HUGE difference in performance.
| BM80HD19 |  |
WP Pro 15in. 8 Piston EX8 Front Big Brake Kit BMW M3 | M4 F8x 15-17 | |
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| BM80HD19-CS | |
WP Pro ClubSport 15in. 8 Piston EX8 Front Big Brake Kit BMW M3 F8x 15-16 | |
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| BM80RRPP19 |  |
WP Pro 14in. 6 Piston L6 Rear Big Brake Kit BMW M3 F8x 15-16 | |
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| BM80RRPP19-S |  |
WP Pro Slotted 6 Piston L6 Rear Big Brake Kit BMW M4 F8x 15-16 | |
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To get into specifics, the two different systems being compared are:
- BMW F80 Series
- Front: Four-piston floating caliper paired with a one-piece rotor
- Rear: Two-piston floating caliper paired with a one piece rotor
- WP Pro
- Front: EX8 Series Calipers (8-piston) paired with either a slotted or Sawblade rotor
- Rear: L6 Series Calipers (6-piston) paired with either a slotted or Sawblade rotor
First we will start off with the difference in pads. Pictured on the left is the WP Pro Upgrade pad and on the right OEM. As you can see, the size of the pad is drastically different. “The larger the contact area of the brake pads, the less pressure will be needed to produce the same frictional force that the OEM system produces. This also means that less heat per centimeter square will be generated by the pads, allowing for longer sessions of heat build up, lower operating temperatures, and lower instances of brake fade. To also aid in heat dissipation, all WP Pro’s brake calipers are made of aluminum alloy which has a higher heat transfer rate than the steel (OEM). WP Pro’s EX8 Series calipers house two pads with a total contact area of around 158cm2 (+48% vs. OEM) and the L6 Series calipers house two pads with a total contact area of around 117cm2 (+85% vs. OEM). Areas of OEM brake pads are estimated based on physical measurements.”
Next we will discuss the rotor design and size. An efficient rotor will be light weight and constructed from quality materials. Shape and slotting / drilling also plays a part in efficiency. There are two options for rotors with the WP pro kit.
“The first is the slotted, two-piece rotor. This rotor provides a weight reduction of around 2.6kg per front rotor (-23%) and 0.3kg per rear rotor (4%). The second comparison is the Sawblade rotor which provides a weight reduction of around 3.2kg per front rotor (29%) and 0.9kg per rear rotor (-10%). Overall weight savings per car for the slotted is estimated to be 5.8kg for slotted (-14%) and 8.2kg for Sawblade (-20%).”
The new rotors for this kit feature a 388mm Front and 380mm rear vs factory 380mm and 370mm.
So not only are there significant changes in weight, the outer contact path is pushed out further than stock. When comparing rotor surface, even though a saw blade set up looks like there is less area, since it is larger there is actually more contact path.
The Final part of the equation is the caliper design and how everything is attached. The WP Pro kit for the F8x comes with adapter brackets in order to fit the new calipers. The Front calipers from the factory have 4 pistons to distribute clamping force. The WP Pro has a total of 8. For the rear, the two piston factory caliper is replaced in favor of a 6 piston set up. This helps distribute heat better as well as requiring less input to get similar friction results. Of course if you really want to push it, this system will require less input, produce less heat, also have less fade after continual use of the brakes.
“Compared to the OEM calipers, the WP Pro EX8 calipers for forward applications reduces about 1.2kg of unsprung weight per Caliper (approximately 2.5kg reduced off the front axle). The WP Pro L6 calipers for the rear application, reduces about 800g of unsprung weight per Caliper (approx. 1.6kg reduced off the rear axle). These weight savings equate to about 24% reduction in weight for each axle when compared to the OEM brakes.”
This kit also includes stainless lines for the brakes which improve pedal feel by minimizing expansion. This allows for better pedal modulation as well as predictability while braking. There is also an optional sensor which you can read out brake temperature. Below are some photos of the entire kit installed, as well as statistics posted about the brakes.
| WP-BTG15 |  |
WP Pro Live Brake Temperature Gauge | |
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