Audi A4 B7: Brake Modifications

This article applies to the Audi A4 B7 (2005-2008).

Going fast in your car is a great thing; stopping your car is even better. Whether you are at the track slowing down as you approach a corner, or dodging a small child as they dart out from between parked cars, your Audi's braking ability needs to be top notch. Dropping several thousand dollars into upgrading the engine and tuning to allow your A4 to travel at breakneck speeds is great. If you cannot stop your car well enough, all of that money could be wasted.

When you upgrade a vehicle, you need to ensure the upgrades are all around to create a well rounded vehicle. Performance is not all about the engine and cornering. Your Audi needs to be able to stop just as well. This article will cover several upgrades which can help. They are broken down into three sections: starter, intermediate, and advanced. Each will provide ideas of what can be done. It's up to you to figure out how to do it and what exactly is needed to make it happen.

Starter Brake Upgrades

In this first section, there will be some easy things you can do to increase the braking performance of your Audi. As with most of the rest of the modifications listed in this article, these upgrades can be done to almost any vehicle with similar results. Don't be afraid to dive in and get your A4 to stop how you want it to.

DOT5.1 Fluid

Since brake fluid should be changed out on a regular basis and is one of the most overlooked maintenance item on any car, it's more than likely your fluid is overdue. Instead of just going for the regular DOT3 or DOT4, change your fluid over to DOT5.1. This fluid will give you a higher boiling point than the others. This matters because your Audi's braking system relies on hydraulic pressure going from the brake pedal through the master cylinder, through the brake lines, and into the brake calipers. If the fluid boils over (i.e. overheats, creating air bubbles in the system), the hydraulics cannot work as intended. This most commonly manifests in the way of a sinking or spongy feeling brake pedal and reduced stopping power. A high-temp rated fluid like Castrol SRF, Motul RBF600 or comparable can better resist the brake fluid "fading," or losing its efficacy.

Brake Pads

DIY Cost – $100-300

Professional Cost – $200-500

Skill Level – Easy; Nothing different than using OEM.

Brake pads can be a huge upgrade over stock. With newer materials, aftermarket pads are less susceptible to heat fade. Depending on how aggressive you want the bake pads to be, you can go from replacement of OEMs all the way to strictly track use and then anything in between.

Thinking practically, brake pads are a wear and tear item. As the pads wear and become thinner, they become less effective at resisting heat abuse and protecting the brake calipers and brake fluid from overheating. A fresh pad will always work better than a worn one.

Rotors

Just like with pads, there are plenty of options for replacing stock rotors for an easy upgrade. Consider using slotted rotors to allow for venting of gasses from brake pads during heavy braking. The slots will also allow for a place to remove braking material during operation. Both of these actions will increase braking ability of your vehicle. Drilled rotors are also available, which can aid in both of these even further. There are two downsides to having drilled rotors, though. First, drilled rotors are notorious for gaining stress riser cracks from the holes when under hard usage. Second, there is less mass for thermal dissipation, meaning heat soak of the brakes will occur sooner.

Intermediate Brake Upgrades

Here a few options which will greatly increase your vehicle's ability to stop, yet most will not break the bank in doing so.

S4 Big Rotor & Caliper Brackets

DIY Cost – $300-400

Professional Cost – $500-800

Skill Level – Easy; About the same as replacing stock rotors.

A great "bang for your buck" upgrade is installing the bigger S4 rotors and caliper relocation brackets on your A4. The relocation brackets move the stock calipers outward, which provides more braking torque. The larger rotors also provide more mass for heat dissipation. Since you do not need to replace the calipers, bleeding the brakes isn't necessary to complete this upgrade. This is a cost effective and easy upgrade which should be considered by all.

Braided Stainless Lines

DIY Cost – $110-150

Professional Cost – $250-400

Skill Level – Moderate; Need to be more familiar with bleeding procedures.

Stainless steel brake lines will dramatically help the feel of your braking system. When firmness of the braking action takes place, your confidence in the braking ability of your A4 goes up as well. This performance upgrade will provide you with a cost effective way of improving your braking without the fear of bulging rubber lines. There really is no downside to performing this upgrade.

Lighter Rims

DIY Cost – $500 and up

Professional Cost – $1,000 and up

Skill Level – Moderate; Due to cost involved.

It's never cheap to replace rims, that's a given. You may be wondering how a rim will help with braking. Wheels, along with tires and everything else below the suspension springs, are considered unsprung weight. Reducing unsprung weight gives the car a 10:1 advantage over reducing sprung weight. If you shave 10 lbs from your wheels by introducing lighter ones, it would be like taking a 100 lb weight out of the trunk. This helps not only in braking but in acceleration as well. If it helps, think about it this way: brakes don't slow the car down, they slow the wheels down.

Advanced Brake Upgrades

This third section has a couple of advanced upgrades to look at if your are going to be hammering your Audi. These upgrades will provide you with the utmost in braking ability, but you might want to consider them for a track day car application. Using them on the street may be noisy or uncomfortable for every day driving.

Porsche Cayenne Calipers/350mm Rotors

DIY Cost – $750 and up

Professional Cost – $1,250 and up

Skill Level – Difficult; Sourcing correct parts and fitment may be challenging.

Since brakes work on the principle of torque application, increasing the diameter of the rotor will directly affect the amount of torque which can be applied and thus improve your braking ability. The multi-piston design of the Porsche calipers also helps in how much grab they can produce. Fitment can be an issue. Ensure your rims are large enough to support the larger rotors and calipers.

Suspension

DIY Cost – $500 and up

Professional Cost – $1000 and up

Skill Level – Difficult; Requires intimate knowledge of suspension and cost involved.

One of the most overlooked portions of brake ability is the suspension. By improving your suspension, you can greatly increase your vehicle's ability to stop. Suspension loading and unloading creates longer stopping periods as well as acceleration periods. By locking down the suspension with better rated springs, dual adjustable shocks/struts, and stiffer bushings, you'll greatly increase your A4's ability to brake, especially when going into corners.

Related Discussions and Sites

• Cayenne Brakes - AudiWorld.com
• ECS B7 S4 Rotor Conversion - Audizine.com
• Something's Broke B7 A4 to B7 S4 Front Brake Upgrade Problems - Audizine.com
• Porsche Brakes - Advice Please - Audi-Sport.net
• Brake Upgrade Options - Audi-Sport.net
• Brake Upgrade - Audi-Sport.net
• 2007 A4 2.0T looking for brake upgrade options - AudiWorld.com