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Downpipe Catted - 08-14WRX / 08+STI / 05-09LGT

  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • 300 Cell Metallic Substrate Catalytic Converter (LIMITED MODEL Flange Pictured)
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • STANDARD MODEL GrimmSpeed Subaru Catted Downpipe
  • Premium GrimmSpeed Gaskets and Hardware Included
  • LIMITED MODEL Features
  • LIMITED MODEL GrimmSpeed Subaru Catted Downpipe
  • Engineering CFD (Computational Fluid Dynamics) analysis while designing the downpipe flange for the LIMITED MODEL
  • Image 13
SKU:
7091
Rating:
Price:
$545.00

Have questions about fitment or applications? Contact Us


Product Description

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
  • 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 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.

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.

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.

Limited Features

downpipe-std-subaru-08-16-635x160.jpg

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 are fully machined 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. In addition to the machined flanges, limited downpipe tubing material has a brushed finish, for a more uniform, refined appearance.

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:

  • 2008-2014 WRX
  • 2008-2016 STI
  • 2005-2009 Legacy GT (Non-VF46, Manual Trans Only)
  • 2009-2013 Forester XT

Install Guide

LEGACY GT/VF40 ADJUSTMENT GUIDE: You will need to slightly adjust the divider tab to fit a VF40 turbo. It's a very simple process but please contact our customer service representatives if you have any questions.

Product Reviews

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Product Reviews

  1. Loses a star for 02 Bung placement....

    Posted by Chad

    So we all know that a downpipe is a downpipe for the most part. Throw in beautiful welds and rathgibson steel, and it sets one apart from others. This downpipe, like everything else GS makes, is a true piece of art. I instantly noticed a smoother tq curve and faster boost once I loaded a stage 2 tune. My fault with this pipe comes with the O2 bung placement. In stock configuration, the O2 wiring is nearly 8" too short to reach the bung, and in a pinch, I had to unclip the harness and move it all the way to the other side of the car. If the placement is that off, Grimmspeed should offer an extender as an option...or at least mention it in the product description.


  2. 2016 subaru sti Grimmspeed downpipe limited catted

    Posted by ika

    Hi all i install Grimmspeed downpipe catted limited , best product car drives smooth ari flow is good, sound good , best downpipe i have 2 chose cobb downpipe or grimmspeed , cobb DP is good too, but grimmspeed is best , install was easy . If u install Grimmspeed downpipe betther upgrade up pipe too , i bought big tube perrin header , perrin big tube up pipe and grimmspeed downpipe , i will recomend to buy limited catted downpipe , thx grimmspeed


  3. Must have

    Posted by Steve

    OK, so obviously with a downpipe upgrade you need to have an appropriate tune as well, but what a difference this piece made. The car (2016 STi) is significantly stronger, especially low down now. Many reviews I read stated that a downpipe doesn't change the exhaust note at all and I have to disagree. While it doesn't increase the overall volume much, it does make the boxer rumble more apparent and deepens the tone of the exhaust overall. I'm very pleased with how this turned out on my car. Fitment is perfect and the build quality is superb. BE SURE TO ORDER AN O2 SENSOR HARNESS EXTENDER WHEN ORDERING THIS. As long as you have that piece, you will have no problems at all (I got mine from Casper electronics)


  4. Excellent fitment and solid quality

    Posted by Brian P

    This downpipe fits great on my '14 STI, and mated it to my SPT exhaust (with an adapter). The only minor issue was the only sensor placement, which I found an extension for at the local auto store (Bosch kit). You could also rerun the wire down the passenger side of the transmission if you don't want to strip wires for the extension. Other than that, tune it and enjoy the power! As a bonus, I managed to get better mileage when in Intelligent mode on the interstate. Great job, Grimmspeed!


  5. The finest downpipe? Quite possibly!

    Posted by Jason

    Unpackaging the well-protected downpipe was rewarding. The pipe itself looks so nice, especially with the ceramic coating and Limited features, I almost didn't want to put it on the car. The fitment and installation were perfect, and I just needed to creatively get more reach for the O2 sensor while still protecting it from heat and the drive shaft, but that was not a big task.

    Functionally, it works and sounds great. No issues with my OTS Cobb stage 2 mapping. Boost seems to come on twice as fast, and drivability is enhanced. I look forward to testing any gas mileage improvements.


  6. Great Downpipe!

    Posted by Kiel

    The install was easy, i had a question for the guys there and they knew exactly what i was talking about and were very descriptive. Not too loud and not too quiet, it's just the right tone.