GrimmSpeed Divorced Ceramic Coated Downpipe - STI 2004-2007 / WRX 2002-2007 / Forester XT 2004-2008 View larger

GrimmSpeed Divorced Ceramic Coated Downpipe - STI 2004-2007 / WRX 2002-2007 / Forester XT 2004-2008

GRIM-007074

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GrimmSpeed

A downpipe is one of the first modifications that should be done on your car, as the OEM downpipe contains two very restrictive catalytic converters, killing the power potential of your car. Within our complete lineup of downpipes, you have the option to add a high-flow, 300 cell catalytic converter, fully machined and contoured flanges with beautiful brushed tubes and black ceramic coating. Whether you're racing time attack or to work and back, we've got the perfect downpipe for you.

Not CARB Legal

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$545.00

Tested and Backed by RalliTek

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USA's Finest Downpipe.

  • Proudly made in the USA - Design, Materials and Fabrication
  • Innovative 3-D Contour Flange (Limited models only)
  • FARO™ Arm Designed - We are at the leading edge of new product design hardware
  • Flanges Fully CNC Machined (Limited models only)
  • O2 Bungs for factory sensor and aftermarket wideband AFR
  • Divorced Wastegate for Optimal flow
  • GrimmSpeed Gaskets Included - A $40 Value!

A downpipe is one of the first modifications that should be done on your car, as the OEM downpipe contains two very restrictive catalytic converters, killing the power potential of your car. Within our complete lineup of downpipes, you have the option to add a high-flow, 300 cell catalytic converter, fully machined and contoured flanges with beautiful brushed tubes and black ceramic coating. Whether you're racing time attack or to work and back, we've got the perfect downpipe for you.

Design

downpipe-std-subaru-08-14-635x160.jpg

We use 3D scans of 10-15 OEM downpipes to identify the variances within stock parts and ensure that our fitment is perfect across the board. We then pull those scans in 3D CAD and design our downpipe with flange locations, transmission tab locations, O2 bung locations, firewall clearances and material selection in mind. Bend locations, tube lengths and divorced wastegate re-entry point are all checked for healthy flow using CFD (computational fluid dynamics) simulations in CAD. With even the largest stock location turbine outlets utilizing factory exhaust gaskets, we used a reduction process to smoothly transition from the 2.5" turbine outlet to our 3" downpipe material. The outlet of the downpipe has a standard 3", 2-bolt flange that will mate up with most aftermarket catback exhaust systems and the secondary O2 bung that we've added will save you time and money when you decide to use a wideband O2 sensor/gauge in the future.

As engineers and enthusiasts, we take great pride in the work that we put into our design process and it shows in the finished product.

Materials

downpipe-std-subaru-08-13-635x160.jpg

Material selection is a very important, but often overlooked, part of an aftermarket exhaust system. The tubing we chose is a thick 3in, 16ga 304L Stainless Steel tubing and our meaty 1/2" flanges will resist warping and leaks in even the most extreme environments. Stainless steel, particularly 300-series alloys, have terrific durability and corrosion resistance but are still quite cost-effective for fabrication of this type. Lower grade alloys (400 series, for example) may be more prone to corrosion over time, reducing the life and beauty of your parts while higher grade alloys introduce unnecessary cost. All flanges use a fully-machined bolt pattern to ensure very tight tolerances and flawless fitment. Each tube is CNC mandrel bent and CNC laser cut for perfectly repetitive fitment and accuracy.

Fabrication

downpipe-std-subaru-08-15-635x160.jpg

This is where the rubber meets the road. Every single 02-07 downpipe is welded in the exact same master fixture. Our competitors build their welding fixtures around a single OEM downpipe. We build our fixtures to the average (found using the CAD data mentioned above) of a number of OEM downpipes and turbo/catback flange locations. We periodically re-check our fixtures using our FARO arm to ensure that heavy use and heat cycling don't affect their accuracy. Each downpipe is TIG welded by one of our two expert welders, Chuck and Andrew. Don't be fooled by shiny immitations where a robitic TIG pass has been made over a wire-fed MIG weld; real TIG welding takes the skilled hand of a true craftsman. Chuck and Andrew take the structural integrity and beauty of their work very seriously and when you handle your new GrimmSpeed downpipe, you'll know it.

NOTE: Once you have added our downpipe to your vehicle, you must be tuned. Replacing your factory catalytic converter sometimes causes a ‘cat converter efficiency’ check engine light. You can either use tuning to delete this CEL or you can use a mechanical fix. GrimmSpeed aftermarket downpipes modify OEM emissions control devices and are intended only for off-road racing applications.

Fitments:

  • 2002-2007 WRX
  • 2004-2007 STi
  • 2004-2008 Forester XT
Includes Catalytic Converter:No
Installation Hardware Included:Yes
Mouth Design:Divorced Wastegate
Piping Coating:Yes
Piping Flex Joint:No
Piping ID:3.00in
Piping Material:304 Stainless Steel
Piping Taper:No
Mfgr. Warranty:2 Years

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GrimmSpeed Divorced Ceramic Coated Downpipe - STI 2004-2007 / WRX 2002-2007 / Forester XT 2004-2008

GrimmSpeed Divorced Ceramic Coated Downpipe - STI 2004-2007 / WRX 2002-2007 / Forester XT 2004-2008

A downpipe is one of the first modifications that should be done on your car, as the OEM downpipe contains two very restrictive catalytic converters, killing the power potential of your car. Within our complete lineup of downpipes, you have the option to add a high-flow, 300 cell catalytic converter, fully machined and contoured flanges with beautiful brushed tubes and black ceramic coating. Whether you're racing time attack or to work and back, we've got the perfect downpipe for you.

Not CARB Legal

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