The R4-E brake pad is very similar to the original R-4 pad compound, except the Carbon Kevlar is will last a bit longer.
Porterfield’s R4-E pads have an average friction level of .460 and perform best at temperatures averaging over 600F. The R4-E compound is designed to endure higher prolonged temperatures and still have pad life as long or longer than Porterfield R-4. This pad is great for club enduro events and applications where temperatures are at their maximum. The R4-E not only requires less of your time and money, but means you can spend more time focusing on improving other areas of your car.