Introduction:

Welcome to the Focus Go Fast pages. As the name would indicate this site contains information pertaining to making your 2.0L Zetec powered Ford Focus accelerate faster, turn faster and brake faster. It has been compiled with both personal experiences driving my Focus in various forms of motorsport (primarily autocross and open track) and empirical evidence gained from the various Focus bulletin board sites. I hope you find it useful. If you have any additions or comments please email them to me. Thanks.

Chapter 1: Intake

The intake manifold is responsible for getting air from outside the car into the engine. The stock Focus intake manifold consists of a snorkel at the front of the car which ducks under the battery via a porous tweed like tube into the bottom of a sealed airbox containing a filter. The airbox is connected to the throttle body by a fairly generous sized rubber tube. It is an adequate design but obviously power was not the main consideration in its design.

The available aftermarket intake systems for the Focus boil down to four basic types:

• Those that simply replace the airfilter. (K&N, ITG) These will offer marginal gains (perhaps 1 wheel horsepower) as they flow slightly better. The primary advantage over stock is that the filter is more durable and can be reused. If your stock filter is getting dirty and you would like to replace it a K&N or ITG panel is higly reccomended.

• Those that maintain the stock configuration while increasing the size of the tubing and lowering restriction in the airbox. (Iceman) These make good power while minimizing the disadvantages of the other systems. The sealed airbox greatly reduces sensitivity to underhood temperatures so the engine will not bog from a standstill on a very hot day. The increased scoop size and non porous construction promotes increased airflow to the airbox.

• Those that maintain the stock configuration but replace the airbox with a cone type filter and possibly a heatshield. (Cool-Flo, KKM etc...) These are inexpensive designs that have an advantage at high RPM operation due to the short distance the air must travel from the cone filter to the airbox. They are at a disadvantage just off idle as they will suck in hot underhood air which can result in engine bog and reduced performance until the vehicle is up to speed. The FocusSport Cool-Flo design attempts to eliminate this problem by including a heat shield which partly isolates the cone filter from the rest of the engine bay. It is reasonably effective, however not as effective has having a fully sealed airbox!

• Those that replace the whole intake manifold with a long tube with a cone filter on the end that draws air from somewhere other then the stock location. (AEM, Injen) These will provide excellent power, however since they relocate the filter to the front bumper area they can suffer from significant performance loss in inclement weather. Also the filter gets dirtier alot faster which can lead to performance degradation. Finally in extreme circumstances it may be possible to draw enough water through the filter to hydrolock the engine. This type of intake would be a good choice to put on a proper racecar or if you are one of those people who are constantly under the hood of your car for maintenance/modification activities.

Chapter 2: Exhaust System

The are quite a few availiable exhaust systems for the Focus, which one to choose? There are a few critical things you should consider when buying an aftermarket exhaust.

• Diameter: Depending on wether you are naturally aspirated or using power adder such as nitrous or a turbo your options are 2.25", 2.5" and 3". 2.25" is perfect for a naturally aspirated car. If you are running a turbo you want 2.5" or better yet 3". Currently there are no 3" systems availiable for the Focus but there is nothing preventing you from building one yourself!

• Material: A non rust material such as T-304 steel is optimal however if you dont mind replacing your exhaust every few years or live in a hostpitable climate such as California you can get away with a lesser grade that is covered with some protective paint.

• Routing: This is pretty much fixed due to the underbody design of the Focus. The only innovator here is HKS who have deviated slightly by routing the pipe under the rear axle; this is a very low restriction setup however it slightly compromises ground clearance. Not reccomended if you are going rallying! Unfortunately HKS has not put thier system into mass production so if you would like one you may have have significant difficulty locating one.

• Looks and Tone: Unfortunately, this is pretty much all the average consumer considers when selecitng an exhaust. Our concern is that you dont want something that is obnoxiously loud, many tracks these days are starting to impose maximum sound levels and if you are too loud they will black flag you. If you are running a race header and have deleted the catalytic converter the Focus can be a very very very (100+Db) loud car even with a 2.25" exhaust. As far as tone is converned, due to consistent routing, most Focus exhausts sound very similar to eachother, most variances are due to muffler design and size. Generally speaking, you can expect a rumbly off idle to about 2000RPM, a slight drone around 3000RPM and a BLAT noise at wide open throttle above 4000RPM. On the downswing the Focus has the interesting property that it generates a slight "burble" effect which is rather pleasing.