A Summary of tuning the BMW N54

We last talked about what tuning is, and how it's potential depends on the strength of the engine.
Today we'll talk about one strong engine, the BMW N54. Some explanations may be over simplified, but is written to appeal to the novice.

The N54 was used in many BMW's from 2006-2009, for example the 3 series.

A 335i is a rear wheel drive sedan, or 'saloon' as they say in Europe. A 335ci is a rear wheel drive coupe. A 335iT is a rear wheel drive Wagon or 'Touring'. They all have the same engine. The N54.

This engine makes around 250-290 horsepower at the wheels in stock form. -Source

2 of the most common tuners for this engine are the JB4 system or a COBB accessport. 

They are similar, just offer some different features and work a little differently. 

A few comparisons: 

http://www.e90post.com/forums/showthread.php?t=688565

http://www.e90post.com/forums/showthread.php?t=659748

http://www.e90post.com/forums/showthread.php?t=513705

Tuning can bring you up to near 400hp with no internal modifications. That's remarkable considering that's around 50% more power than it originally had. 

(With other engines, if you start to make more than around 25% more power than it originally had, the engine would be very stressed and you would have to strengthen internal components. It's very expensive to take an engine apart and put it back together).

All it really needs are bolt on mods. Bolt on mods are things external to the engine. Things like the air intake and filter, exhaust, intercoolers. They are supporting mods. They keep the engine cooler and make up for the heat and stress of running the turbos harder than normal.

A bigger intercooler will help alot, as cooler air is more dense. An exhaust system and an intake system will allow the engine to breath better and will spool the turbo up quicker. Imagine that the stock air filter is like you breathing through 1 straw. It's kinda hard. An aftermarket air filter system would be like you breathing through 5 straws at once- much easier. The better the engine can breathe, the more power it can make.

This guy, talking about the different mods you can do to the N54, sums it up pretty well:

"A Tune- Holy CRAP, best $500 I ever spent. 

Intake System- Good, relatively cheap supporting mod.
Downpipes- AR (3")are about $800, Raceland (2.5") are $220). ARs sound better and feel A little more powerful (butt dyno probably) but not worth the $500 difference IMO. Build quality on the racelands has been proven to last but occasionally someone has a fitment issue with them and the company replaces them. 
Charge pipe- Meh. Holds boost A little better I guess? I got mine so that I'll have bungs ready for when I install meth but if you are planning to stay meth-free then I wouldn't bother.
Intercooler- Makes a huge difference and once you have a tune you'll pretty much need one anyway. 
Sport tires instead of the stock run-flats- Makes a big difference. Saves weight, money (run-flats are super expensive), and handles way better."
-Source (quote was slightly modified for language and clarity)

Tuning 101

This post may be oversimplified for car enthusiasts, but it's meant as a brief description of what 'tuning' is for those who have never heard of it.

Before we begin:
Remember that more air in the engine equals more power.
Atmospheric pressure is roughly 14.7 PSI.
A normal engine can not take in any moire air than atmospheric pressure will allow.
These are called naturally aspirated engines, or N/A.

Now, there are two devices that can force more air into the engine, turbochargers and superchargers.
If your engine is equipped with either of these, it has quite a bit more potential. The extra air pressure created is called 'boost'.
Superchargers are more mechanical, run by a belt.
Here we will focus on the turbocharger.

The engine's brain:
The engine is controlled by a little computer called an ECM, or engine control module.
This runs software written by the manufacturer that controls how much boost your car makes.

What tuning is:
It's possible to rewrite this software, and make a turbo produce more pressure.
It's a delicate process, as every one change requires another to maintain the proper fuel/air ratios for safe engine operation.
The potential can vary from a small increase in power to incredible increases, depending on how strong the internal parts of the engine are and how much it can handle before breaking something.
It's important to note that many factory turboed engines are quite limited by their manufactures, for many reasons (in order to not compete with their more expensive models, or in order to keep fuel economy high, among other reasons). Unlocking this potential, in a nutshell, is what engine tuning is all about.

A Guide To The 2016 Ford Focus RS

    2016 Ford Focus RS - 
                   Hot Hatch? No, Hyper Hatch
    Model: 2016 Ford Focus            
    MSRP: From $35,900                        
    Engine: 2.3 L 4-     cylinder

    Horsepower: 350 hp

    Torque: 350 lb-ft                             
    0-60: 4.7 Seconds                             
    MPG: 19 city / 25      highway

    Tire size: P235/35R19
    Cargo volume: 23.8 ft³, 44.8 ft³ with seat area


The automotive world has been eagerly awaiting the release of Ford's latest project, one of its most ambitious projects to date. It was developed with input from professional rally driver Ken Block, and managed by the head of Ford Racing, Tyrone Johnson. It finally hit the showrooms this month, and we have the details.

  The cabin is not much better then what you get with the base $18,000 version, but you're paying for the driving technology in the RS, not a luxurious interior. It's a good thing it's not a terrible interior to start with. On par with the rest of the Ford lineup's, the new design is easy to navigate and feels sturdier than the entry level competition. A bit quirky maybe, some call it modern, but in the end, it works. The center display between your tachometer and speedometer will tell you anything you need to know. 

1. The Engine

They started with the Mustang’s EcoBoost 2.3 liter four-cylinder, but used a larger (yet lighter) twin-scroll turbocharger and a bigger intercooler. The result is an extra 40 horsepower and 30 lb-ft of torque, faster revving and more linear feeling engine. The cylinder head is made from a high-temp-resistant alloy, and the block has high-tensile cast-iron liners. The intake and exhaust are both revised for better flow, while an electronically controlled valve allows for more or less sound.

350hp and 350ft lbs of torque is a healthy amount, but what really gets the power down is the brilliant AWD system.


2. Not All AWD Is Created Equal

There are many kinda of AWD systems, but a 'torque vectoring' system is the most advanced and efficient, with the widest range of ways to distribute the power between all 4 wheels and making sure the least amount of engine power is wasted.  It's an AWD system built for cornering. It can transfer 70 percent of its power to the rear, and 100 percent to the left or right rear wheel within .06 seconds.

They tried the popular Haldex system, but after blowing it up a few times they went to GKN to build the best handling AWD system they could. - GKN

For fuel economy, it does a cool trick that disconnects the rear driveshaft if it can tell you're going to be cruising for a while- but can re-engage within 400 milliseconds if you brake, turn, or breathe too hard.

3. Driving Modes

"The driving modes allow you to customize six different parameters to radically transform the nature of the car from a daily driver to a track-day weapon. The driving modes in the Focus RS are far more aggressive than the "sport" button you find in most cars. You can also adjust the shocks independently of the Drive Mode by pressing a button on the end of the turn-signal stalk. Want to drive fast on a rough surface? Engage Track Mode and reset the shocks to Normal. Want to quietly slip though town in what feels like Sport Mode without waking the neighbors? Select Normal Mode, which quiets down the exhaust, and hit the shock button to put the suspension back into Sport. This sounds like a lot of work, but with dedicated buttons, it's easy. I was able to switch between drive modes, disable electronic stability control, and adjust the shocks all while lapping the track at 100 mph." - Road&Track

And then there's Drift Mode. Like Subaru's DCCD system, it puts most of the power to the rear wheels, making it easy to effect and maintain oversteer. Drifting isn't mantadory, you might just prefer the feeling of a RWD bias. 

The trick suspension makes up a lot of the value of this car. It has valves in it that drastically change the stiffness of your ride at the touch of a button. Ford experimented with magnetic shocks at first, a popular choice among other manufacturers- but it didn't allow enough range of adjustment. 

Bonus: Launch Control

You hit a button on the steering wheel and scroll down through two menus to turn it on. Then you floor the car and let the needle bounce off the rev limiter. When you're ready to launch, just sidestep clutch and the car surges forward. The AWD locks the rear axle solid and you see 60 mph in 4.7 seconds in second gear.

Road Test Videos:
https://www.youtube.com/watch?v=43CXspHw5ew
https://www.youtube.com/watch?v=aEuY88zVyi8
https://www.youtube.com/watch?v=Ep6kzlNaAw0