The year is 2006.
The E9x generation of the 3 Series approaches it’s one year anniversary of sales in the US in the form of the usual snore 325i to the relatively new idea of the 330i sharing the new at the time N52 in different displacements back when BMW’s naming convention made sense.
Neither of them were any slouch, but there wasn’t a middle ground between the 330’s 255hp N52B30 and the M3’s 400hp S65B40 until BMW did the unexpected – they introduced a version of their buttery-smooth, torquey BMW inline-6 cranked to 11 – the N54.
The N54 was a twin-turbo 3 liter straight 6 powerplant that was strangely detuned from the factory, most likely due to not wanting to cannibalize their flagship ‘executive saloon’ M3.
This was BMW’s first time building a turbocharged engine with performance in mind for a while, so they were naturally nervous. In typical German fashion, it was very over-engineered, handling much more boost than the stock small twin setup it was intended for – coming with forged rods and crank straight from the factory. Many say the 335i was a beta test of sorts for the F80 M3, without risking the M3 name for these sacrilegious turbos.
With minimal of mods, this car gets very serious very fast. Turns out BMW caught wind of that about a year later – dropping the previous bolted on ring gear to welding them onto the differential, making the absolutely essential limited-slip differential upgrade much more difficult all for the reason that it’s ‘cheaper to manufacture’. Around 2009, the twin-turbo powerhouse was dropped for the more subdued single-turbo N55 – likely because the latter is cheaper for them to manufacture, or if you’re an automotive conspiracy theorist, it was too fast to belong in a non-M3 and the previously mentioned ‘beta test’ has finished. It did live on in the Z4 however, likely because there was no M version to compete with.
The N54 was not without it’s problems, the high-pressure fuel pump commonly failed, and inevitable carbon buildup lowered performance and reliability. Luckily for you, Mr. (or Ms.) Future Pre-2010 335 owner, there was a recall and most of them were taken care of.
As previously stated, the N54 responds amazingly to objectively minimal modifications, the most popular being a tune. There’s a couple directions you can take with a blank canvas of a stock N54 equipped 335:
Go what the forums call FBO (full bolt-on) with a cat-back exhaust, intercooler, cold air intake, and an aftermarket downpipe (an oil cooler is also essential if yours didn’t come with one) plus a tune with a Cobb Accessport, the more popular piggybacking JB4 from Burger Motorsports which actually integrates with the steering wheel buttons and cluster, allowing you to change maps and boost settings on the fly, or a tune from the newly released MHD Android app, which you can do yourself with a phone and a cable (what a world we live in) and then after that start working on suspension,
OR ditch the twins and go for a giant single laggy turbo to hit insane amounts of horsepower to transform your family sedan into a drag monster.
The N54, even with all it’s praise, still deserves more attention. It’s the German 2JZ.