The "Ultimate" Street Braking Setup for your 914
Introduction
Let’s dive into the braking system of your Porsche 914! The brakes are a critical component of this iconic car, and we’re here to explore the best setups for our favorite vehicle. This article covers everything you need to know about stopping your 914 safely, effectively and better than ever with no shortcuts, just solutions.
A word on the Stock braking system
The 914’s stock braking system was groundbreaking for its time. In the 1970s, when drum brakes dominated, the 914’s four-wheel disc brakes, at its price point, were exceptional. This budget-friendly car boasted braking performance three times more effective than the average performance vehicle of the era. Its integrated handbrake was also ahead of its time, a feature now common in most modern production cars.
If you're planning on building, restoring, or enjoying a stock 4-cylinder car, a set of our PMB-C Brake Pads and a caliper restoration will give you exactly what you need. The stock 4-cylinder setup is perfect for driving around towns and going for a nice cruise through your local backroads.
The solution? Knowledge and proper engineering. Let’s explore how to upgrade your brakes the right way.
Big Brakes?
For as long as the 914 has been on the road, people have been trying their hand at DIY big brake kits, and we've seen everything here at PMB. Front calipers from all sorts of different makes and models, Front calipers on rear axles, extreme biases, the whole 9 yards. A lot of these setups either lose the handbrake, are a genuine danger to the driver or both. On top of that, they likely aren't even improving the performance of the car due to causing serious instability under hard braking.
So how do you fix this problem? Knowledge, of course! So let's learn.
Doing it right
For decades we’ve been accused of being against “Big Brakes” on the 914. Don't get us wrong, big brakes are a great thing, they just need to be done thoughtfully and correctly. They can transform your 914’s performance, but you need to take a systemic approach. The braking system is a cohesive unit where all components—calipers, rotors, pads, and more—work together. Adding high-performance parts without considering their compatibility can lead to suboptimal results especially in the mid-engine 914 where polar moment inertia can bite you quickly and hard. A good rule of thumb is to respect the engineering of the original application. What we always say around here is; “If you think you can outthink a Porsche engineer, think again… and then if you think you can do better, I’m all ears.” For example, if you’re installing Boxster front calipers, pair them with Boxster rear calipers for balanced performance.
Brake kits for the 914 vary in complexity, from simple conversions with stock 914-6 calipers to advanced setups with 930 calipers on all four wheels and a modern electronic handbrake. Choosing the right kit depends on your car’s needs, which are influenced by three key factors:
1. Tires and Wheels: Tires play a significant role in braking performance. A narrower tire with a mild compound stops more easily than a wide, aggressive 140-treadwear tire. The stock 914 runs a 165- tire on a 5.5-inch wheel, designed for 1970s tire compounds. If you’re using stock wheels with a modern touring compound, the stock brakes are sufficient. However, a widebody 914 or 914-6 with 8-inch autocross tires may require upgraded stopping power.
2. Power Level: Power is always the thing people fixate on the most, but it's not a guarantee that you need some giant brake calipers on your car. If you haven’t changed your tire sizes and, if your current calipers can lock up the wheel, the calipers job is done. Most braking systems actually stop the car very well, even at higher speeds. Where big brakes really shine is their "endurance." Your brake system is a heat sink transferring energy into heat. Past a certain temperature, your braking performance will begin to degrade. You'll hit these high levels of heat either from stopping at the higher speeds or from doing a lot of stops repeatedly (or a combination of both if you're driving the car hard in the twisties). This is where an upgraded system can shine.
3. Purpose: Consider how you use your 914. A street-driven car with occasional spirited drives has different needs than a track-focused build. A narrow bodied 914 may have different needs than a wide-bodied GT build. The goal here is to align your brake upgrades with your driving goals for the best overall results.
This article focuses on the best brake set-up for a street-driven 914 with a built motor, suitable for medium-duty track use or heavy-duty track if historical accuracy is a priority. This configuration works for both narrow and most widebody 914s.
Front Struts
The 914’s front suspension is nearly identical to that of a Porsche 911 up to 1989, reflecting Porsche’s “if it’s not broken, don’t fix it” philosophy. The 914-6’s front suspension is essentially a 911T front end with gray strut housings and a slightly smaller torsion bar. Ever read an article talking about how brilliant the 911RS package is? Your front suspension will, literally, bolt on to that iconic supercar and visa-versa. This compatibility makes upgrading to a 911 front end straightforward, enabling better brake setups and, not to mention, the option for stylish five-lug wheels.
911 struts come in two types, based on the car’s equipment and era:
3" Struts: Found on early 911s, measured by the center-to-center distance of the caliper mounting ears. These disappeared in 1976 with the remainder of these struts being used up on the 912E.
3.5" Struts: Standard on 911S models from 1969 onward and all 911s after 1976. These can range from rare “holy-grail” type Koni struts to standard 911SC and Carrera struts (the later having tabs for pad wear indicator wiring).
The 3.5-inch strut was traditionally preferred because it accommodates the S-Caliper, a fully aluminum front caliper used on 914-6/GT race cars. However, S-Calipers are now rare, expensive, and often cores are in poor condition due to age. Fortunately, we’ve found a solution for S-Caliper-level performance on the 3-inch strut.
For those sticking with four-lug setups, early 914 front struts also have 3-inch spacing and the same rotor offset. With the “solid rotor” option for the system described below, you have a bolt-on upgrade without modifying the stock suspension.
Front Calipers
Instead of expensive S-Calipers and 3.5” struts, we recommend the AM Caliper. This is the caliper that came on many Italian sports cars in the 70’s and 80’s. This is actually a Brembo copy of the ATE 320i BMW caliper that has been popular with 914 and 911 enthusiasts for decades. This version is made out of aluminum and is still made in the same foundry to this day. This caliper bolts directly onto an early 914 or 911 front strut without adapters. Late model 914 (73-76) will need a slight machining option to get the offset perfect. Its benefits include:
Larger Size: The AM Caliper is significantly larger than stock four-cylinder calipers, with a front piston size increasing from 42mm to 48mm, boosting braking force. They’re even larger than the 914-6 with the pad size also upgrading from the small D31 to the larger D109.
Lightweight Aluminum Construction: At just 4 pounds 5 ounces, the AM Caliper saves 8 pounds of unsprung weight over the front axle compared to stock. This is the lightest caliper we know of for the 914 or even the 911. These calipers are a full 1lb. lighter than the 911 S-Caliper.
Improved Thermal Capacity: Designed for a 20mm vented 911 front brake disc, it enhances the system’s ability to manage heat. This is a key feature for those wide-body cars with larger tire contact patches and (sometimes) higher power. The system is also available in a solid rotor configuration for narrow bodied lower powered builds.
M10 Steel Fasteners: While the aluminum body can reduce weight compared to steel calipers, it's been said to flex under high brake pressure and heat. The AM-Caliper's large M10 Steel fasteners keep the caliper rigid under extreme braking demands.
Rear Calipers
With the AM Calipers up front you'd assume you need a substantial caliper in the rear, and you'd be correct! Stock 4-cylinder rear calipers simply will not cut it with a front brake like that, your brake bias would shift very far forward with the rear calipers being ineffective. With the fronts doing all the work, your car could get quite loose in the rear. So that begs the question, what goes on the back? The answer is a 914-6 or 914-6/GT rear caliper straight from the factory cars. With only a handful of Factory sixes, GT’s and M471 cars existing on the planet, this is a tall ask. Now you know why original 914-6 rear calipers can sell for $2,500 to $2,800 a pair! We saw this coming; the only thing standing in the way of a balanced braking system for the 914 was an affordable rear caliper. Knowing this, we started production on a new version of the previously unobtainable 914-6 rear caliper, with each component precisely designed to replicate the original design. We went so crazy with these things, that the caliper bodies and their individual parts can be used as spares to service actual 914-6 and 914-6/GT calipers. If you've been in the game for a while, you know how big this is. For years, running a big front caliper and getting a matching rear either required thousands of dollars to buy rare parts, or required losing your handbrake entirely, neither of which were a great option. With our new affordable PMB 914-6 and 914-6/GT calipers, that simply isn't an obstacle anymore.
Benefits of the 914-6 and 914-6/GT Caliper include:
Better Stopping Power: Piston size increases from 33mm to 38mm, and pad size upgrades from D30 to D31, enhancing rear braking force.
Balanced Bias: Maintains the factory 1.6:1 brake bias for stability under hard braking.
Improved Thermal Capacity: Supports a 20mm vented rear brake disc (GT versions only), improving heat dissipation.
Factory-Style Integrated Handbrake: Unlike other big rear calipers, the GT Caliper retains the factory handbrake without adapters or custom cables
Master Cylinders
ABig calipers require a capable master cylinder to move brake fluid effectively. The stock 914-4’s NLA 17mm ATE master cylinder works with stock calipers but is inadequate for the larger AM and GT calipers, resulting in a spongy pedal. Two options suit different driving needs:
19mm OEM Master Cylinder: The more street focused option, is the ATE 19mm master cylinder. The 19mm is the OEM unit for a 914-6 and for the LWB F-Body 911. The 19mm is the intended stock size for a 48/38mm piston setup, and will provide a firm and responsive pedal without too much effort from your leg. It's an excellent unit that'll never let you down while driving around town, though it may feel a bit lackluster during an autocross day or on a complicated backroad.
23mm High-Performance Master Cylinder: If you want a higher performing unit a 23mm master cylinder is also available. The 23 will stiffen your pedal substantially over stock, which can be both a benefit or a drawback depending on your preferences. A much stiffer pedal is better if you're going to be primarily driving the car hard, as it allows you to modulate your brake pressure with much more precision. You'll be able to feel your way through lockups (modulation) and really manage your pedal input. You might use a little more leg, but this modulation unbeatable.
A word on the Pressure Regulator
With the calipers, rotors, and master cylinder upgraded, you've successfully bumped up your braking performance! Something to keep in mind with these upgrades, is that they work perfectly with the stock pressure regulator. The pressure regulator is a complicated little unit, and it's a very important part of how the 914 is designed to be driven. If you'd like to learn about it in-depth we've got a whole article about it here. The skinny on this thing is that the pressure regulator is a very early ancestor of true ABS. It makes sure you can really get on the brakes without worrying about locking the rear calipers up and going into a tailspin, which is crucial in a mid engine car. Polar moment inertia is a hell of an experience, and we'd suggest avoiding it. Making sure this unit is functioning correctly is key to getting the most out of you new braking setup, and making sure that you're actually getting the hard braking stability that the carefully set 1.6:1 bias provides.
Wrapping it up
Upgrading your 914’s brakes is now easier than ever. These components were either unavailable or unaffordable just a few short years ago. This setup delivers performance comparable to the Le Mans-winning 914-6/GT and the iconic 911 2.7 RS, all with bolt-on components. Whether you’re upgrading a 914-4 street car or preparing a crazy 914-6 track car, this system provides the stopping power, balance, and reliability you need. If you're interested in picking this up for your own car, follow the links below and give your car the brakes you've always wanted it to have.
PMB-C "109" Brake Pads for AM-Calipers
Porsche 914-6/GT Rear Brake Package
"Early" Style Brake Pressure Regulator
