GrimmSpeed 15-21 Subaru WRX Equal Length Exhaust Header - GRM113008

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. Since the exhaust runners are CNC bent and trimmed as a single piece there are no additional welds to introduce points of failure or junctions that would interrupt flow, resulting an in impressive difference of less than 1% in total length. In addition, maximum variance is only 5 degrees from the most bent to the least bent runner, this mean we were able to produce what is a truly equal length, and equal bend manifold. The collector being cast, allows for the runner spacing and angles necessary to obtain the equal bends and lengths of all the tubes. This part is a major player in the GrimmSpeed manifold’s ability to fit between the stock skid plate and the oil pan while still providing the ideal performance from the rest of the design. The cast collector also allows for more smooth and consistent flow in the interior compared to a welded variant. This greatly simplifies the overall design, removing five more welded junctions, which could be a point for flow interruption or the structural failure that we see with other headers. The head flanges of our header are CNC cut and faced from a 1/2in thick piece of 304 stainless steel. This design is much thicker than OEM to increase reliability and longevity, as well as to provide additional material to be removed after welding to ensure flatness from flange to flange. This additional measure allows for greater gasket sealing which results in increased performance. The final touch is that the exhaust runners are welded inside the flange as well as outside, this is an extra step in manufacturing, but it provides a rounded lip to improve flow from the flange through the runner. 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. 2015-21 Subaru WRX

Features

• Full 304 Stainless Steel Construction – Flanges, tubing, collector and badge
• True Equal Length Runners – CNC bent and trimmed, less than 1% variance from the longest to the shortest
• Innovative Cast Merge Collector – Low restriction inlet and outlet, smooth flow and consistent performance
• Smooth, Restriction-Free Flow Throughout – Single piece mandrel bent tubing welded to a single piece merge collector removes unwanted “steps”
• Thick 1/2in CNC Cut Flanges and 14ga Tubing – Added durability and longevity
• No Tune Required – Safe to run, just bolt on
• No Ground Clearance Loss – Clears factory skid plate without using spacers
• J-Pipe/Turbo Bracket Included – Retain the support that other aftermarket header lose
• Gaskets and Hardware Included – Everything you need to get installed and on the road
• Manufactured and Welded In The USA – For consistency and top quality control
• 2015-21 Subaru WRX
• 2014-18 Subaru Forester XT