As you push the limits of your Tesla Model 3 or Model Y on track you will find that the brakes quickly become a liability. Slowing a 4000+lb car capable of supercar acceleration is no easy task. Even with the larger "Red" Performance brakes, you will find your brakes coming up to extreme temps quickly and your high-performance brake fluid does not have the longevity you expected out of it. Cracked OEM rotors are common as are scorched pads.
The EmotiVetted 370mm BBK for Tesla Model 3
Before we get much further there are some acknowledgments in order. First off, to TeslaMotorsClub forum member @Lukez for pioneering the "6-piston CTS-V DIY" upgrade on the Tesla platform. This has long been a popular upgrade for many other enthusiast vehicles and Lukez was the first to attempt this on a Model S. Next, @drpheta from the TMC forums put in a bit of leg work referenced here for caliper part numbers. @drpheta is experienced in mounting big OE calipers on other platforms and it shows. Finally, TMC forum member @jesse_le did the legwork with GiroDisc to provide a proven, high-quality rotor designed specifically for this application. Jesse is local to GiroDisc and was critical in test fitting this setup on his Model Y for the benefit of the Tesla community.
The following is a detailed guide to the GM DIY 6-piston Brembo big brake kit. Emotive Engineering offers this complete bolt-on kit as our EmotiVetted BBK. The EmotiVetted kit includes all components, parts, and hardware with the calipers re-threaded to accept your OEM Tesla caliper bolts.
Brembo 6-piston Calipers
GM Genuine Parts made in Italy? Brembo has become a name synonymous with braking quality. In the 1970s, Enzo Ferrari asked Brembo to supply the Ferrari Formula One cars with Brembos and they very quickly became dominant in motorsports. By the 1980s, Brembos were used on high-end street performance cars from the likes of BMW and Porsche, chosen for their performance as well as ability to provide OE quality and longevity.
C7 Corvette Z06 Brembo Calipers for Iron Rotors
Original Equipment (OE) GM Brembos are the centerpiece of the EmotiVetted BBK and for good reason. These Brembos are an aluminum monoblock and feature 6 pistons. The lightweight design is optimized for cooling, are specified as a "low drag" caliper, and originally designed to fit under an 18" wheel giving them the marketing claim that they are "track-tested and road ready". This setup fits with room to spare under APEX EC-7 18x9.5" wheels as well as a plethora of other 18" lightweight options. While the OE GM calipers in question are largely the same in dimensions and construction, the C7-generation Corvette Z06 iron brake calipers feature dimpled pistons for increased cooling capabilities. If you are looking to rebuild an inexpensive set of used calipers, the AC Delco part number for these pistons is 23242510. These are the following caliper part numbers for your hunt:
|OE Platform and Side||Color||GM Part No.||AC Delco Part No.|
|C7 Corvette Z06 (Iron Brakes) L||Red||23242497||172-2669|
|C7 Corvette Z06 (Iron Brakes) R||Red||23242498||172-2670|
|C7 Corvette Z06 (Iron Brakes) L||Yellow||23242499||172-2671|
|C7 Corvette Z06 (Iron Brakes) R||Yellow||23242500||172-2672|
|Camaro (5th-Gen ZL1) L||Black||20944530||172-2537|
|Camaro (5th-Gen ZL1) R||Black||20944518||172-2538|
|Camaro (6th-Gen SS 1LE) L||Red||20944530||172-2741|
|Camaro (6th-Gen SS 1LE) R||Red||84063673||172-2742|
|CTS-V (2nd-generation) L||Red||22885106||172-2595|
|CTS-V (2nd-generation) R||Red||22885108||172-2596|
|CTS-V (2nd-generation) L||Silver||25912477||172-2487|
|CTS-V (2nd-generation) R||Silver||25912967||172-2488|
|CTS-V (2nd-generation) L||Yellow||20982719||172-2521|
|CTS-V (2nd-generation) R||Yellow||20982734||172-2522|
As you can see, these brakes are featured on General Motors' top of the line performance vehicles. The EmotiVetted BBK Track Kit is centered around the C7 Z06 calipers for maximum cooling and an exact Brembo match to the Model 3 Performance "Red" calipers. The Street Kit is based around the silver CTS-V calipers of the same design. The easiest calipers to find tend to be the Yellow CTS-V and Red C7 Corvette Z06 calipers while C7 Z06 Yellow and ATS-V Gold seem to be a rare breed. While the Tesla Model 3 Performance is a halo vehicle in its own right, it is still fun to be able to say you have brakes from GM's best.
GiroDisc 370mm x 34mm 2-Piece Slotted Rotors
GiroDisc 370mm 2-Piece Rotors for Tesla Model 3 / Y GM 6-Piston Brembo Conversion
A brake caliper is nothing without brake rotors to clamp on to. The OEM Model 3 Performance 2-piece rotor measures in at 355mm x 25mm while the OEM 1-piece "Base" Rotor is a quaint 320mm x 25mm. The EmotiVetted BBK features GiroDisc rotors measuring 370mm x 34mm which mirror the dimensions of the Victory-spec Cadillacs and provide exponentially more heat handling capabilites than the factory pieces. GiroDisc differentiate themselves from other manufacturers with U.S. sourced iron and beautifully anodized aluminum rotor hats. No mystery meat metallurgy to worry about here.
The GiroDisc is also a true 2-piece meaning you can replace the rings without need to replace the hats. This can reduce overall running costs and part availability as the replacement rings are a commonly available GiroDisc part.
OE GM Pads and More
Another benefit of the GM 6-piston Brembos is the newfound assortment of brake pads. If you have ever searched for brake pads for the stock Model 3 Performance calipers you know that your selections for this seemingly proprietary caliper can be quite limited. While Emotive Engineering is a strong supporter of the cult of G-LOC which does offer OEM "Red" caliper pads, the GM 6-piston Brembos feature a standard FMSI D1405 pad shape which opens up pad options quite a bit. This ranges from $64 Centric OE replacement pads up to $700+ Ferodo DSUNO race pads and beyond. The G-LOC Brakes R12 compound is the standard issue pad for our EmotiVetted Track Kit while our Street Kit features DBA Street Performance pads. The G-LOC R12 are a championship proven and affordable track compound with excellent pedal modulation that will help you stop corner after corner while the DBA SP are a fantastic OE+ upgrade with low-dust and low-noise.
The following is an incomplete list of track-focused brake pad offerings that you may want to try:
|Manufacturer and Compound||Part Number||Cost|
|Raybestos ST43||RC1405 ST-43||$|
The final piece of the EmotiVetted BBK is a set of stainless lines from Spiegler. When installing the kit without these lines you will find that the OE or any factory replacement stainless lines seem a bit stretched. Some will get around this by moving the line bracket away from its original mount. Spiegler lines are constructed of braided stainless steel with a large assortment of line colors. These are longer in length than the OE lines and mate up with enough slack to the larger GM/Brembo calipers so as not to be pinched or chaffed.
The mounting positions of these GM calipers magically match those of your Tesla Model 3 or Y. There is, however, a slight catch. The GM Brembos accept M14 caliper bolts while the factory Tesla units are M12. There are two ways around this. The quick and dirty method is to drill out the OEM front knuckle and use a GM-replacement bolt. This M14 bolt is part number 11570092.
EmotiVetted BBK mounted to Project Emotiv3
The lesser of two evils requires re-threading the calipers which will allow you to return the vehicle to 100% stock. The most reliable method is installing a 12x1.75x24mm Time-Sert. If you would prefer not to have metal shavings all over your garage and workbench, EmotiVetted BBK will arrive at your doorstep with the work already done to accept the OEM Tesla hardware making the kit a full bolt-on affair.
A Word on Brake Bias
Some big brake kits are massive just for the sake of being massive. A large BBK up front may add too much front torque, resulting in more heat going to the front components as they do the lions share of the work and potentially more understeer under hard braking. When moving to larger brake applications, OEM manufacturers maintain proper front and rear brake bias with appropriately sized pistons for the rotor size.
Static brake bias is the ratio of rotor torque on each axle. We can simplify the rotor torque to be the total piston area on one half of the caliper multiplied by the diameter of the brake rotor. The percentage of front brake bias equation is therefore:
frontBrakeBiasPercentage = frontBrakeRotorTorque / (frontBrakeRotorTorque + rearBrakeRotorTorque)
fbbp = [ ( fTPA / 2 ) * ( fRD ) ] / [ ( ( fTPA / 2 ) * ( fRD ) ) + ( ( rTPA / 2 ) * ( rRD ) ) ]
where TPA is total piston area and RD is rotor diameter. Still with me? Our calculations for the Tesla Model 3 result in the following:
|Front Caliper||Rear Caliper||Front Brake Bias Percentage|
|OEM Tesla Performance||OEM Tesla Performance||65.9%|
|OEM Tesla "Base"||OEM Tesla "Base"||64.8%|
|GM Brembo / EmotiVetted||OEM Tesla Performance||66.6%|
|GM Brembo / EmotiVetted||OEM Tesla "Base"||67.8%|
As you can see from the chart, moving to the GM Brembos does not significantly alter static brake bias. There is a slight movement towards the front, but one which you are not likely to notice. The ideal percentage of brake bias ultimately comes down to driver preference and up to this point our equation has ignored one important aspect of brake torque - the coefficient of friction. With the EmotiVetted kit your brake bias will be quite close to stock and you can further tune your brake balance via use of different pad compounds front and rear.
The EmotiVetted Track and Street BBKs represent an affordable price point for 6-piston calipers and larger rotors. It does all of this without sacrificing quality or reliability. OEM Brembo calipers, high-quality rotors, no aftermarket brackets. For the committed do-it-yourselfer we are more than happy to sell you just the GiroDisc rotors and with a few phone calls, patience, and a little mechanical ability you can save some of your cold hard cash over our offering. If you choose to price all the components out yourself I think you will find that the kit is very competitively priced. Custom powdercoating is also available through a reputable local shop to us for an additional $500. If you have any questions or special modifications you would like before ordering the kit, please reach out. Happy motoring!