Should I replace the uppipe in my STi or 06+ turbo Subaru? All STi and 06+ turbo Subaru models have a catless uppipe. The big difference is that that the STI or 06+ turbo Subaru went from 2.0 to 2.5 displacement. Buscher Racing proved that going to an aftermarket uppipe vs. OEM catless does show gains. Does this mean an uppipe should be thought of in the upgrade path for 2.5L Subarus? Though it was once thought no, now one should consider it.
Are WRX and STI uppipes the same size? Yes. You may swap WRX and STI uppipe of all years as they are the same size. Remember that 02-05 WRX uppipes have catalytic converters, so it’s not a good idea at all to install one of those on a 06+ WRX or STI, but they will fit.
How hard is it to install an uppipe? Allow around 5 hours for install time. This can depend on many variables. jaxscuby is the current world record holder at 1.25 hours! A lift and air tools will significantly speed up the process but aren’t entirely necessary. Professional installation, depending on your area, is around $300. Shadetree mechanics will install for around $100. Friends and install parties via your local Subaru club run the cost of beer and food.
How do I install an uppipe? Refer to the uppipe manufacturer’s instructions. For uppipes without instructions, many rely on the Vishnu instructions for installation. Below are links to some of the better known uppipe installation instructions:
What part numbers might I need for this install? For best results, replace all the gaskets that are used for an install. The top and bottom uppipe gaskets MUST be replaced! Actual part numbers are not listed due to frequent changes; consult your dealer or online retailer for ordering.
OEM part names and approximate retail prices:
$15 Cross pipe, Left side
$10 Uppipe Gasket (Bottom)
$10 Uppipe Gasket (Top)
$16 Downpipe Gasket (DP to turbo)
$7 Cross pipe, Right side
$12 Manifold Gasket to the block
$200 2.0L uppipe
$200 2.5L uppipe
$59 EGT sensor
Are there any other parts I might need? Occasionally, an uppipe (especially used ones) will come without uppipe studs. If you are unable to obtain them from your Vendor, you will need five of SOA part number 800910340 which retail for ~$8.50 each. Alternately, you could source an automotive stud, m10 x 1.25 by 41mm at a parts store, preferably Grade 8. Removing studs from an OEM uppipe usually will end up ruining the studs. You do not want to start an uppipe install with the hope that you can remove the stock studs. For removal or installation of these studs, be sure to use the double nut method.
Is there any other gasket information? Some users enjoy the extra piece of mind that comes with different gasket solutions rather than relying on the OEM gaskets. Some users source 5 ply gaskets. These are made by the same manufacturer as the OEM 3 ply units, but are 2 plys thicker. Some users have doubled up on the OEM gasket. Some users source copper gaskets. Additionally, many people have had great success using high heat copper gasket making substances applied to the top and bottom uppipe gaskets. There are some graphite gaskets as well. Sound confusing? Yep. Do know that the #1 way to ensure success is to use OEM from the dealer gaskets and proper torque…choosing an aftermarket option will most likely increase your chances of failure.