N54 Catted and Catless Downpipes

Catless downpipes are one of the best mods for performance you can do to your N54. Going catless over the stock downpipes can yield gains of 25+ horsepower. Catless downpipes are an off road only modification and should not be used on the street. If you live in a place where emissions testing is required for state inspection, you will not pass with catless downpipes. An alternative would be to install high flow catted downpipes, however even with high flow catted downpipes the check engine light can still come on and you may not pass emissions inspection. Generally the difference horsepower gains between cattless and catted downpipes are within 5hp or so.

Name Brand vs Off Brand

Ebay offers inexpensive downpipe options for around $130.00 and there are name brands for around $300.00. The primary difference between them is the quality of steel and fitment. I have seen Ebay downpipes where welds were not completed on flanges and holes were jagged scratching the O2 sensors upon installation. Personally I think it is worth it to go with a brand like VRSF or ARM over Ebay if its within your budget.

If you are looking for catted downpipes, these will be more expensive due to the cost of a catalytic converter. Below are a couple options you could go with:

Parts Required

  • Downpipes
  • New Gaskets for turbo side – Optional but recommended, they can be found on VRSF website here
  • Nuts, bolts, and washers for downpipe to exhaust – Most kits already include this.
    Note -You can reuse your V-band clamps if they are not damaged.

Tools Required

  • Jack / Jackstands or Lift
  • 8mm Socket – Removal screws holding cowl
  • 5mm Hex Socket/Key – Removal of engine cover
  • Flat screw driver – For prying V-Band after Bolt is removed
  • O2 Sensor Socket

Torque Specifications

  • Exhaust to Downpipe/Catalytic Converter – 21Nm or 15.48Ft lb
  • V Band Clamp from Downpipe/Catalytic Converter to Turbo – 13Nm or 9.5Ft lb