Technical Features
Project 854R: Part II - Braking It In
By By:George Achorn
Dec 3, 2001, 23:03

While making a car go faster is one of the prime motivators for most enthusiasts as they modify their cars, making the car stop properly is ultimately more important. Improved braking is essential as you upgrade the power of the car, as one could theorize that the brake system on a car has been designed for the power levels the car came with right off the assembly line. As horsepower goes up, so too should braking power.

Since the first week of ownership, our R has been stricken with the not so uncommon problem of warping rotors. Most likely the byproduct of overheated brakes, the constant pulsing rotor feel for the next 50 or so miles following spirited driving has become quite an annoyance and a high priority for replacement on the 850.

There are many alternatives out there, from oversized 4-piston caliper systems that will run well in excess of $1000 to a straight stock replacement.

We considered one of the high-end systems, but decided against them. While the performance of these is usually amazing, the price of entry was considerably higher and this would have left us limited to 17-inch wheels. Since the car is operated primarily in the North East part of the country, 17-inch wheels for year-round driving are simply not an option.



At the same time, a straight stock replacement of parts also wasn't very attractive. The 850 is an inherently heavy car, and coupled with the spirited driving style that the R brings out of most drivers, we deduced that warping would continue to be a problem.

Compromising, we decided upon a more subtle brake upgrade from IPD. Well-known throughout the US for their wide range of Volvo parts and accessories, IPD was quick to recommend one of their more popular brake packages.

For improved cooling, IPD sells a set of slotted brake rotors from Power Slot. These rotors are basically the stock factory size, though they've had several grooves cut into them in an effort to cool the rotor more effectively.

For those who may not know, there are two different ways that a rotor can be modified to improve cooling. Slotting is, as mentioned, the cutting of grooves into the rotor. Drilling, on the other hand, basically drills holes in the rotor to achieve a similar effect. In some cases, one can buy rotors that have been both drilled and slotted.

Power Slot is a good name in the rotor business, and is well known for quality slotted rotors. They use a unique tapered slotting process and they are never machined below the minimum thickness wear level of the rotor. This benefits the owner in two ways, first the slotting does not compromise the strength of the rotor, and second the slots act as a natural wear indicator. Once the slots have been worn off, it is time to replace the rotors.

Which is better? That's a major debate amongst those in the know. However, we preferred slotted. Our theory is that slotted minimizes loss of swept area, or the area of the rotor that the pad comes into contact with and thus uses to stop the car. Slotting also allows heat and brake dust to be channeled off of the rotor in and theoretically even helps wet weather stopping performance by also channeling off water in heavy rain. Finally, we're told slotted rotors are less likely to warp than drilled rotors due to rapid cool-down in cold wet weather.



Besides, Touring Car teams in the BTCC have used slotted rotors for much of the same reasons. It is our feeling that if it is good enough for them, it is good enough for our 854R.

The Power Slot rotors also come with anti-corrosion silver plating on non-wear areas. Our old rotors had corroded substantially, and the difference in the look is substantial and appreciated. This bright silver, combined with the more aggressive slots, look great peeking out through the wide openings of the Volan alloys that are on the car.

For pads, IPD offers both stock replacements and a more aggressive pad compound from PBR. We chose the latter as you can never have too much braking capability.

For those familiar with IPD, PBR is not a new name. These pads, with their 40,000 mile warranty, have been a popular offering from the Portland, Oregon based business since 1972. PBR, originally known as Paton's Brake Replacement and formed in 1927, is a large Australian brake manufacturer that sells original equipment to many manufacturers including Ford Motor Company and Toyota.

These particular pads from IPD are claimed to provide improved performance while throwing off minimal dust. The improved performance was definitely needed on Project 854R, and cleaner wheels would be a welcome added side effect.

Once installed, IPD recommends that you expose the car to roughly 500 miles of even driving where the brakes are not made too hot. This will ensure proper bedding of the pad and rotor, while also providing even removal of the residue left on the pads during the manufacturing process. Every brake setup is different though, so make sure to follow the manufacturer's suggested "bed-in" instructions carefully.

The result of our upgrade has been most pleasing. The 850 slows noticeably more quickly than before, though that's no surprise as the previous rotors were constantly warped.

Speaking of warped, the slotted rotors' additional cooling seems to be working, as the new setup has yet to exhibit any of these problems, even under spirited driving.

As for brake dust, IPD's claims seem to be accurate. The amount of dust thrown off by the new pads is minimal, leaving our freshly refinished Volans vibrant in their bright silver finish longer than before.



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