GrimmSpeed 08+ WRX/08+ STi/05-09 LGT 5-Speed/6-Speed Downpipe 3in Catted w/ Black Ceramic Coating
NOT LEGAL FOR SALE OR USE IN CALIFORNIA ON ANY EMISSION CONTROLLED MOTOR VEHICLE.
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
- O2 Bungs for factory sensor and aftermarket wideband AFR
- Divorced Wastegate for Optimal flow
- High-flow, 300 cell, metallic substrate catalytic converter
- 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. Replacing these with our single high-flow unit will dramatically improve performance potential while maintaining the use of a catalytic converter. Within our complete lineup of downpipes, you have the option to add a high-flow, 300 cell catalytic converter, fully machined and contoured flanges and black ceramic coating. Whether you're racing time attack or to work and back, we've got the perfect downpipe for you.
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.
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.
The catalytic convertor that we've selected is custom sized and utilizes a metallic substrate for increased effectiveness, higher flow and better durability than other, lesser units. We selected a 300 cell count mantel for a perfect compromise of performance and function.
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 expert welders. Don't be fooled by shiny imitations where a robotic TIG pass has been made over a wire-fed MIG weld; real TIG welding takes the skilled hand of a true craftsman. We take the structural integrity and beauty of our work very seriously and when you handle your new GrimmSpeed downpipe, you'll know it.
For those looking to take the finest downpipe one step further and wring out every last ounce of performance, we offer our 'Limited' line of downpipes. Limited downpipes use flanges made of the very same 1/2" 304L Stainless material, but with recesses for each tube as well as a beautiful 3D contour to smoothly transition the irregular shape of your internal wastegate outlet into our divorced tube for tighter boost control. Limited downpipes also come in a ceramic thermal coated version which are some of the best downpipes you can buy for your Subaru.
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.
- 2008-2014 WRX
- 2008-2021 STI
- 2005-2009 Legacy GT / Outback XT (Manual Trans Only)
- 2009-2013 Forester XT
This Part Fits:
|2011-2014||Subaru||Impreza||WRX STI Limited|
|2010||Subaru||Impreza||WRX STI Special Edition|
|2015||Subaru||WRX STI||Launch Edition|
Shipping & Returns
Shipping & Returns
In most cases orders are processed same day or the next business day. Most orders take about 1-3 business days to ship.
Please note that all orders are processed and shipped Monday-Friday 10a-6p PST excluding weekends and holidays.
Any orders placed after 4p PST for items that are in stock will be shipped the next business day
Returns and exchanges are only offered on eligible items, excluding final sale and special ordered items.
All returns/exchange inquiries must be made within 14 days after receipt of order. Any inquiries after the 14 day period will not be honored. Please contact our sales staff for any return/exchange inquiries, and we will be more than happy to assist you!
Any returns received without an RMA (Return Merchandise Authorization) number will be automatically declined, and the customer will be responsible for shipping the order back to them.
Once you receive your RMA number, you will have 30 days to ship the item/order back to the respective location. If the item/order is not shipped within the 30 day period, the return will be declined, and the customer will be responsible for paying for shipping the item/order back to them.
Special Order & Final Sale
Special Order & Final Sale
All special order items are deemed as "made to order" - and therefore cannot be canceled, returned, exchanged, or refunded for any reason. The same policy applies to final sale items. These are non-negotiable terms, so please keep this in mind before checking out. If you have any questions regarding these terms, please feel free to read our policy for special order and final sale items, or contact one of our sales representatives for clarification!