FAQ - Frequently Asked Questions Evo X Downpipes (Long (O2 Housing) Downpipe, Short Downpipe) Q - What's the difference between both Downpipes? A - The Short Downpipe is a 3 inch direct replacement for the OEM Downpipe which connects between the OEM cast downpipe housing (aka O2 Housing), and the OEM catalytic converter.  The Long Downpipe replaces BOTH the O2 Housing and Downpipe in a single piece.  If you're looking for a true "Turboback" exhaust, you'll want  the Long Downpipe.   Q - What's the benefit of Long Downpipe? A - The Long Downpipe incorporates our "Divorced Wastegate" design which separates the wastegate exhaust gases from the exhaust outlet, merging it further downstream.  This helps reduce turbulence behind the turbocharger.  Another benefit of the Long Downpipe is that it eliminates the "donut" gasket connection between the O2 Housing and the Downpipe.  The donut gasket is not 3 inches and is a restriction in itself.  Only way to have a true 3 inch exhaust system is to eliminate it. Q - Will I get a Check Engine Light (CEL)? A - No. Q - Do I need gaskets? A - For the both Downpipes, you will need to reuse your (or purchase new) top gasket.  For the lower 2-bolt flange, we suggest either one of our 3 inch gaskets, or a high temperature exhaust silicone (aka gasket maker). Gaskets are not supplied by default, but are an option at check out.   Q - Will this bolt on to my exhaust system? A - Both Downpipes are designed to mate up to the OEM catalytic converter, as well as any of our Test Pipes and High-Flow Cats.  General rule of thumb, if you can fit the OEM Downpipe, ours will fit as well. Q - Can I install and run this without a tune? A - These have all been tested to run safely without a factory tune. If you have an aftermarket tune, you will need to check with your tuner. Q - Will I pass emissions testing? A - Neither Downpipe has an affect on emissions. <-- Back to Product Page   All trademarks are Copyright of their respective owners.  All other images and content on this site is Copyright Ultimate Racing 2007.