1994 3000GT VR-4: HKS Sequential Blow-off Valve (SBOV) Installation

• Why Do I Want To Do This?

  • If you've installed a K&N FIPK or other open-element air filter, you've undoubtedly heard the annoying "goose honking" or "owl hooting" noise under partial throttle around 3000RPM. Installing an aftermarket blow-off valve will eliminate this condition. Further, if you plan to run higher than stock boost, many stock valves have been known to leak slightly, some even at stock pressures.
  • Blow-off valves also tend to be louder than bypass valves (a.k.a. recirculating blow-off valves). If you want a loud whoosh sound when you step off the throttle, a BOV is probably a good choice.




• How Long Will It Take Me To Do This?

  • Plan for a good hour and a half so that you can take your time and do it right.




• Anything I Should Do Prior To Attempting This Procedure?

  • Make sure you have all the parts and tools you'll need.




• What Mitsubishi Parts Will I Need?

  • None




• What Other Parts Will I Need?

  • (1) HKS Sequential Blow-off Valve, welded to custom pipe
  • A bottle cap or plug




• Where Can I Get the Stuff To Do This?

  	Part	Company/Contact	Part Number
  	HKS Sequential Blow-off Valve	MVP Motorsports	N/A
  	Bottle Cap	Listerine Cap	Big bottle from Costco





• What Tools May/Will I Need?

  • (1) 3/8" Socket Wrench
  • (1) 6" Extension for Socket Wrench
  • (1) 10mm 3/8" Drive Socket
  • (1) 5mm or 3/16" Allen (Hex) Wrench (K&N only)
  • (1) 5/16" Socket (K&N only)

The Procedure

	HKS BOV Pictures
	Remove the Air Filter or Airbox and MAS Housing
	The K&N filter is held on by a hose clamp - remove it and then remove the brackets that attach the filter adapter (and MAS housing) to the chassis. If you have a stock airbox, look here to see how to remove the stock airbox lid and MAS housing.
	Unclamp the Stock Bypass Valve
	Remove the two hose clamps that attach the stock bypass valve to the intake hoses. Also, Remove the vacuum line attached to the bypass valve.
	Remove Y-Pipe [optional]
	The y-pipe has a hose clamp at the throttle body and two more hose clamps at the intercooler hoses. It also has one vacuum hose connection on the rear.
	Remove the Stock Bypass Valve
	You may find this easier if you remove the Y-pipe (shown), but this is not necessary.
	Plug the Stock Bypass Valve Hole in the Unpressurized Side of the Intake.
	The HKS BOV vents to atmosphere and thus does not use this connection. Plug the hole with something like a medicine bottle cap and reinstall the original hose clamp.
	Install the HKS Blow-off Valve.
	The HKS BOV pipe has a hole to attach it to the fuse box stay. Remove the stock bolt and use it to secure the BOV. Tighten the hose clamps in the stock locations on the pressurized side of the intake.
	Replace the MAS Housing and Air Filter; Attach Vacuum Line.
	Make sure you connect the vacuum line to the BOV or it will leak whenever there is boost in the intake!