Over the years, GrimmSpeed has proven that our exhaust products are some of the highest-quality and best-performing in the industry because of the detail oriented approached that we put into their development. When it comes to improving on an OEM design, this attention to detail and overall exhaust knowledge allows us to identify aspects of the factory parts that can be greatly improved upon.
After isolating the inadequacies of the OEM exhaust manifold, we were able to start identifying key areas of improvement: correctly sized and consistent exhaust runners that are more equal length, a consistent and non-bottlenecking merge collector inlet and outlet and a higher angle merge collector to direct flow into the turbine and prevent opposing flow disruptions. Beyond that, we decided on using thicker tubing and flanges for increased durability and longevity to more-effectively support the overhanging turbocharger.
All four of our exhaust runners are designed in conjunction with the merge collector to equal out the lengths as well as the overall bend angles. This is especially important in the FA WRX twin scroll turbine configuration because it makes the strength of each pulse, or “push” on the turbine wheel, at equal timing and consistency.
All of these things come together to make The GrimmSpeed 15-21 WRX Header not only the prettiest on the market, but also among the best performing and durable pieces you can purchase.
Quick Notes:
