Header Install - March 2012

Eric got a set of headers for his 325i. He asked if we could install them in my garage and I was happy to oblige. Installing headers on this car was a bit challenging to say the least. Please do you research before tackling such a project.

We removed the secondary air pump for some more room to work.

We took off the metal under tray for access as well.

The bolts holding the manifolds to the mid-pipes are made from a special lightweight, rust resistant metal called Inconel. Read about it here: E46 Fanatics Inconel... and here: Inconel Wiki Page.

Here is a shot of  one of the stock manifolds with the catalyst and the oxygen sensors still attached. 

We supported the engine so we could remove the motor mount. I can't remember if this was before or after removing the manifolds.

Stock motor mount out.

Random side shot of the side of the motor.

Bimmerworld, Super Sprint replica headers all cleaned up and ready for install. 

New gaskets with built in heat shields beside the shiny header.

A hole ready to fill with headers.

To hopefully prevent the prevalent engine check light, we used defoulers to pull the oxygen sensors out of the exhaust stream. These particular ones are available from Advance Auto. Defoulers Search Link. Ours was not quite long enough, be just a pinch. Allen helped us do a little modifying to the defouler to be wide enough and deep enough to accept the O2s.

O2s with defoulers and spark plugs going in to the headers. Running the lower,  mid-pipe side O2s with defoulers extended them out just a bit too far on the one side of the header. The O2 sensor was rubbing the body. We had to leave the back two O2s without a defouler. Our hopes of not having the check engine light were for naught. Ultimately the best option to do anyway with the check engine light and gain the most from the headers is to get a reflash of your ECU.

Underside shot up the side of the motor. One of the new gaskets sitting ready to go.

After installation. They are looking good.

The tone of the car changed dramatically in my personal opinion. With the stock sport exhaust and the headers in this 2.5 sounds really good. The headers give some more throat to the tone down low. Up high she sings beautifully, without being too loud. No droning here.