Downpipes and Y-pipes are essential to unlocking substantial amounts of performance out of your turbocharged vehicle. Subaru WRX models throughout all generations, Mitsubishi Evolutions, the Mazdaspeed platform, and everything else in between with a turbo come from the factory with a highly restrictive downpipe. As a matter of fact, these are so restrictive that some ofRead More
Downpipes and Y-pipes are essential to unlocking substantial amounts of performance out of your turbocharged vehicle. Subaru WRX models throughout all generations, Mitsubishi Evolutions, the Mazdaspeed platform, and everything else in between with a turbo come from the factory with a highly restrictive downpipe. As a matter of fact, these are so restrictive that some of these platforms required a tune to successfully employ a downpipe. You have a substantial amount of unlocked flow that will make your turbocharger react much faster which will generate more horsepower, more torque, and more speed. Downpipes are one of the main ingredients in terms of basic upgrades, just make sure you complement your downpipe with a proper intake to allow your turbo to properly inhale. Y-pipes or mid-pipes, the link between your downpipe and primary or secondary cat converter. Not all platforms have a mid-pipe or Y-pipe, however, there are powerful platforms such as the Nissan GTR or A90 Toyota Supra that can benefit from a proper mid-pipe or Y-pipe.
WHAT HAPPENS IF I JUST UPGRADE THE DOWNPIPE?
In many cases, you cannot get away by just upgrading your downpipe. You would run into a few issues. The first is that downpipes will naturally unlock a substantial amount of horsepower. From 25 HP on average to 75+ HP when combined with a proper tune, and a proper cat-back exhaust. When you unlock this kind of power without a tune, your vehicle will also make more boost outside of what your ECU will recognize, and in some cases, surpass the limits of your MAP sensor (where equipped). You will end up hitting fuel cut and boost cut and your engine will not be happy under boost. Furthermore, you could be running learn which can lead to engine damage due to lack of fuel.
OKAY HOW DO I GET A TUNE AND HOW DO I ADD MORE FUEL?
PLUG-AND-PLAY ENGINE MANAGEMENT systems such as the COBB Accessport will have OTS (off-the-shelf) maps available for you to download, and run with your respective modifications. They also have staged maps if you have other modifications such as COLD AIR INTAKES or SHORT RAM INTAKES that will also require a tune, as these depending on your model, will add just as much power as a downpipe.
Regarding your FUEL SYSTEM, a proper FUEL PUMP KIT will provide your injectors with the increased volume needed to help prevent leaning out, and fuel cut during boost.
Going back to downpipes, it is never really the best idea for a downpipe to be your first exhaust mod. You should start from the rear section of your exhaust first because the factory cat-back exhaust system can be a bottleneck to the increased exhaust flow. You would otherwise be really limiting the performance and flow capacity of your aftermarket downpipe. Make sure you start with a proper CAT BACK EXHAUST SYSTEM so that your downpipe will have an unobstructed exit path for your exhaust gases. A downpipe combined with an intake and a proper tune will really change the overall driving character in your vehicle with all that extra power. To make sure that your tune is in the strike zone with safe air/fuel ratio readings, please upgrade and get yourself a proper AIR FUEL RATIO GAUGE because if you continue to run your boost levels outside of safe air/fuel ratios, you will be proactively melting your motor.
Be smart and have fun, but most importantly, make sure your tune is safe, and mod your car responsively to avoid any engine damage.