1995 3000GT VR-4: Stillen Downpipe Installation

• Why Do I Want To Do This?

  • The stock downpipe is fairly small in diameter and incorporates an "F" connection for the rear bank rather than a smoother "Y" connection. The Stillen downpipe improves exhaust flow and helps your turbos spool faster.




• How Long Will It Take Me To Do This?

  • If you don't have to modify your Stillen pipe and your exhaust flange nuts come off easily, then it should only take an hour or so.




• Anything I Should Do Prior To Attempting This Procedure?

  • If you've never removed your downpipe before, then the night before you plan to do the installation, soak all the downpipe and catalytic converter bolts/nuts with penetrating oil to help loosen the rust on them. This will make your life a lot easier.




• What Mitsubishi Parts Will I Need?

  • None - Kudos to Stillen for including new OEM exhaust gaskets with their pipes.




• What Other Parts Will I Need?

  • Stillen Downpipe
  • Anti-seize Compound
  • Penetrating Lubricant




• Where Can I Get the Stuff To Do This?

  	Part	Company/Contact	Part Number
  	Stillen Downpipe	3SX Performance	N/A
  	Anti-seize Compound	Parts America a.k.a. Schucks	Permatex 81343
  	Penetrating Lubricant	Parts America a.k.a. Schucks	Valvoline Synpower 065 or PB Blaster 20PB





• What Tools May/Will I Need?

  • 19mm 1/2" Drive Mid-Length Socket
  • 17mm 1/2" Drive Mid-Length Socket
  • 1/2"Drive Universal Joint
  • 3" 1/2"Drive Extension
  • 6" 1/2"Drive Extension
  • 9" 1/2"Drive Extension
  • 1/2" Drive Socket Wrench
  • 12mm 3/8" Drive Socket
  • 3/8" Drive Socket Wrench
  • 17mm Wrench
  • Prybar
  • Rubber Hammer
  • [optional] Drill
  • [optional] Various Drill Bits You Don't Care About




• Erik's Review

  • Nice increase in engine responsiveness.
  • Significantly quicker turbo spool.
  • A little higher boost in the high-end.
  • With stock exhaust, sound is LOUD and IMHO, obnoxious.
  • With HKS exhaust, sound is louder, but reasonable.

The Procedure

	Raise and Support Front End
	Raise up and support the front end of the car by your method of choice. If you're not using a lift or ramps, then make sure you use jackstands. Never get under a car that is not securely supported - and a floor jack is not a secure support.
	Unbolt the Front Bank Connection
	Using your 19mm socket, remove the two nuts that anchor the front warm-up catalytic converter (precat) to the front oxygen sensor housing.
	Unbolt the Rear Bank Connection
	Using your 19mm socket, remove the two nuts that anchor the downpipe to the rear oxygen sensor housing.
	Remove Exhaust Hanger
	Remove the 12mm bolt that anchors the exhaust hanger to the downpipe. You can actually remove the rubber part completely because the Stillen pipe does not make use of an exhaust hanger here.
	Unbolt Catalytic Converter
	Unbolt the rear side (or both sides) of the catalytic converter using a 17mm wrench or socket.
	[optional] Gut Rear Precat
	Since the Stillen downpipe replaces the catalytic converter, you've already committed the car to off-road use only. Might as well gut (remove contents of) the rear warm-up catalytic converter, too. This will improve exhaust flow and rear turbine spool-up. This process gets dust EVERYWHERE, so wear adequate protective equipment. My equipment consisted of goggle, a respirator, a face shield, and a painter's suit. I still had dust and crap in my hair and on my skin after it was all done, even with all that protection.... Note:If you use the car on public highways in the future, be sure to replace your catalytic converter and install a non-gutted rear warm-up catalytic converter.
	Stock and Stillen Comparison
	Stock on top, Stillen on bottom
	Install Stillen Downpipe
	Remember to use new gaskets, and put anti-seize compound on the nuts/bolts when you install the Stillen pipe. If you have a 1991-1993 model, it should be really easy. If you have a 1994+ model, you may need a BFH (Big Frickin Hammer) to coax the front connection on - put the rear bank connection on first. I even had to drill out the holes in the rear bank connection a little to make mine fit well. Drilling stainless steel sucks... use a titanium bit and lots of cutting oil to keep it cool.