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Picked up the 3" Downpipes for your BMW Last Week?

Erik Blume  septiembre 18 2019

We Will Help you Install them on your 135i & 335i

Dont have yours yet? Click Here!

DSC_3566We talked a bit about these already in the unbox video found HERE if you haven’t seen it already!

Why Purchase your Downpipes from MAP?

The MAPerformance catless N54 downpipes feature TIG welded, 304 stainless steel construction and a 3-inch design.

We have seen power gains in excess of 25whp and 30wtq with tuning. Coming in at an excellent price point.. you will be hard pressed to find a better $/hp ratio when it comes to the N54 platform.

These Beautiful Downpipes Feature:

  • Full 3" design throughout
  • Direct, bolt on replacement
  • Mandrel bent 304 stainless steel
  • TIG welded
  • Feature Integrated wideband o2 bungs
  • Come in an Optional advanced black ceramic coating.
  • Not only will you see Gains up to 25whp and 30wtq
  • But you will also see Improved spool characteristics
  • More aggressive exhaust note
  • Have the ability to Monitor Air/Fuel ratios without additional modification.

Written Instructions:

  • We are going to start things off by saying we recommend you drop the subframe to get easier access to install these downpipes. However, we will be showing you how to from underneath for those with limited supplies and professional garage access.
  • Start things off by removing the under carriage tray
  • Remove the 6 bolts from the front brace
  • Pull the 4 bolts from where the downpipes meet the exhaust
  • Remove the 2 bolts from the exhaust hanger
  • Push the exhaust backwards carefully in order to release it from the downpipes
  • Disconnect the rear oxygen sensors
  • Be sure to remember not to swap the two sensors from bank 1 and bank 2 or vise versa, we recommend labeling them
  • The black shielded wire is bank one, or the front, and the grey one is bank two, or the rear
  • Remove the oxygen sensor bracket
  • Remove the two nuts off of the upper downpipe bracket pull the two blue bolts out of the bell housing that hold the bracket
  • Remove the bracket and reinstall the two bell housing bolts
  • Next we will be getting the steering rack out of the way
  • Remove the two bolts holding it in place
  • Lightly slide the rack forwards and out of the way so that you have enough room for your hands
  • Be sure not to pull too far or it could slide off of the steering joint
  • Next we recommend you remove the heat shield above the rack. it is not necessary but will make things easier later
  • Your should now be able to remove the old downpipes, competing the uninstall! Moving on to the INSTALL
  • Replace motor mount bracket bolt with supplied bolt, we included this to solve clearance issues
  • Start by putting your old oxygen sensors into place on the new downpipes
  • Guide the rear downpipe up into place into the upper v-band clamp. this is a little tricky so be patient!
  • Once secured, tighten the clamp to secure it while you install the 2nd pipe
  • Leave it loose enough to adjust once both downpipes are fitted
  • Get the 2nd pipe into place and tighten slightly
  • Adjust both pipes to make sure they are not rubbing on the motor or each other
  • Next slide the steering rack back into place
  • Replace the 2 bolts to secure it
  • Connect the 2 oxygen sensors back in
  • They should only go in one way
  • There will be extra wiring left over, we recommend tucking it up and zip tying it secure so it does not rub
  • Grab your supplied gaskets and hardware
  • Attach the downpipes to the exhaust with the 4 supplied bolts and 2 gaskets
  • We had to drill out the holds on the old exhaust because of rust build up
  • Tighten all the bolts!
  • Replace the front brace! remember 6 bolts
  • Put the belly pan back into place and you're all done!
That wraps up the installation of your brand new downpipes for the BMW 335 and 135i. Get out and enjoy them!

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1 comment

  • Joel Noorlander: August 29, 2017

    Whats the size from the engine mount bracket bolt that you supply?

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