Project GMW E46 Turbo: Part 1 – Introduction


Now that we have a great starting platform for the GMW LSX Turbo build, it was time to take it to get a baseline horsepower reading. I made a stopover at a local shop with a dyno to make a few quick pulls. The factory 2.5L M54 engine made 163 horsepower and 148 pounds feet of torque through an automatic transmission. This was pretty impressive for a 15-year-old BMW that had been driven leisurely around Oklahoma. That, of course, will all change soon.


The 15 year old 2.5L put down 163 horsepower and 143 foot pounds of torque on Abel Racing's dyno, not bad considering its vintage and auto trans.

The first step on Project GMW Turbo is to pull out the original engine. Fortunately, the BMW engineers made this a really easy feat. After unclipping and removing the headlights, the core support and front bumper unbolted by removing just six nuts and four bolts. I ran through the engine by unplugging the wiring harness from the DME and removing any unnecessary items in the engine bay, i.e. cabin air filter housing, Intake filter box, washer fluid reservoir and laid them to the side. Next, I unbolted the automatic transmission gear selector from the cabin. After removing three bolts, it pulled out, leaving a large hole for the manual Z33 transmission's gear shifter to go through.


With a majority of the work done, it was time to drain the coolant and remove the radiator. The cooling system on the E46 is pretty straightforward. It required removing a couple hoses, a drain screw, and (boom!) it was empty.

With a little persuading, the whole system was out, leaving only the last few steps. The only thing left at that point was to remove the motor mount bolts and transmission mounts and pull the engine out!


With the assistance of an engine hoist, we lifted the engine out of its original home, never to return. The next time to be inhabited by a beastly 5.3L V8.

So, another journey is sourcing parts. I chose one of the best Chevrolet Performance Parts suppliers, Scoggin Dickie Parts Center, with one of the most comprehensive parts catalog out there. On top of that, we will mate the transmission to the Z33 CD009 6-speed transmission with an aftermarket adapter plate from Collins Adapters, allowing more flexibility, having more gears, availability and cheaper transmission that can hold tons of power.


The best water pump option was an LS3 crate motor water pump. It placed the water neck in the right spots to clear the LS1 throttle body (PN# 19207665).

With the engine out, we can now assess the vehicle and figure out how we want to place the engine, how we want to run the turbo, how the DeatschWerks fuel system will be plumbed, and how to marry the wiring on the LM7 to the BMW body. In the next update, we will tackle the refreshing of the LM7. We will be going through the engine to ensure we can make the power we are aiming for, as well as being reliable by doing some preventative upgrades. Since it was a junkyard motor, we weren't supplied with 100% of the engine’s accessories and bolts.

Stay tuned to see all what this Frankenstein of a build can become…


  1. I have a question about what headers and what size turbo used in this build? I would also like to know where was the placement of the turbo. I am building a similar project but more for a drift car and could use the advise.
    Thanks in advance

  2. Hey guys! Nice project! Wondering what are you going to run for headers? I know CX Racing makes a E90 kit which looks not too far from fitting. I am in the process of re-doing my GMW 5.3l Turbo but I really dont want to re-make the exhaust and headers, it is a long job, need to re-do them since the car was smashed….

    So let us know what you are running for headers and exhaust! Thanks

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