The last time you saw this car, it didn't look anything like a rally car. Times have changed. As we promised in the first installment of Project Focus several months back, development the Sport Compact Car/1320 Motorsports Ford Focus Rally car is well under way. In fact, it's already started its first event, which came to a rather quick and anticlimactic halt in the California desert. (See sidebar for details.)
This month, we'll reveal many of the basic first steps we took in turning an average
street-going Ford Focus into a turbocharged, wildly suspended gravel-eating dirt car and discuss many of our mishaps along the way. We'll continue next month with more of what we consider to be the bare minimum rally car bits before attempting some of the season's longer event this fall.
Arguably the most important characteristic of any rally car is the ability to survive unimaginable chassis punishment without failure. Our Focus needed to be able to swallow the ridiculous pounding served up by the roads in the California Rally Series and still handle well on smooth gravel. That's a tall order for a $12,000 economy car.
After its roll cage and seat mounts were fabricated, the Focus made its first major stop at Sway-A-Way Inc. in Chatsworth, Calif. for suspension development and installation. Sway-A-Way is best known for its off-road shocks, but has entered the import car market recently with a coil-over shock for the Honda Civic.
Sway-A-Way built custom front and rear shocks for the Focus. While the suspension bits on our car are custom units not scheduled for production, Sway-A-Way will use its off road knowledge to offer struts for the current Subaru WRX and late model Imprezas in the near future.
The shocks Sway-A-Way designed for the Focus use the company's standard off-road design and are fully rebuildable units, which use two-inch DOM carbon steel bodies with a mixture of 6061 and 2024 aluminum internal and external components. The shafts are built from chrome plated, induction hardened carbon steel for strength, while the pistons are constructed of 2024 aluminum to reduce expansion during the abuse they'll see on a rally car. Sway-A-Way has the ability to build custom shocks and struts to suit a variety of applications ranging from street to off-road use.
Our application uses shocks which are adjustable for compression and rebound by changing the internal valving. Once the unit is removed from the car, disassembly takes about 15 minutes. They utilize a nitrogen-charged external reservoir to reduce heat and allow for various space considerations. A high-pressure gas keeps the oil inside the shock from foaming, which would render them incapable of damping. According to Sway-A-Way, nitrogen is used because it is inert, won't contaminate the inside of the shock with moisture and has better heat properties under load than compressed air.
Perhaps the biggest obstacle was the Focus' control blade rear suspension which, in our opinion, is severely travel limited for rally use. Although the stock rear suspension has been used successfully in other Focus rally cars in the United States, it is our hope that we'll gain a significant advantage with the added travel. Not to mention that as a turbocharged Group 5 car, our Focus will likely see higher speeds and more abuse than some less powerful Foci.
Sway-A-Way designed and built an inboard pushrod style rear suspension similar to what's seen on many modern open-wheel racecars. The Focus' nonstandard control blade rear suspension, which uses the shock and spring in different locations, didn't allow room for placing a coil-over under the car. The pushrods use the stock mounting points for the rear shocks, pivot via a bell crank on the roll cage and transfer motion to the inboard horizontally mounted rear coil-over. The stock spring is removed since ride height is fully adjustable by using different springs and adjusting the shock's threaded collar. The design utilizes a rising rate motion ratio, which increases spring rate through its stroke to help prevent bottoming.
Under the Hood
Knowing that a normally aspirated 2.0-liter Zetec wouldn't make the power and, more importantly, the torque we needed to be competitive in the virtually unrestricted Group 5 Class, we decided to turbocharge the stock Focus engine. We knew going in that any add-on turbo kit would require precise engine control and chose to add Pectel Technologies'
T2 stand-alone engine management system, which is specific to Ford's Zetec engine.
We'll discuss the details of the T2's installation, operation and costs next month. For now, let's talk about turbo hardware.
F-MAX Fabrication in Escondido, Calif. is well-known for its custom turbo bits, high-quality fabrication and ability to dyno tune on site. We've run across the company's work in several Nissan and Honda applications and knew that it was developing a turbo kit for the Zetec engine. We couldn't think of a better candidate for our project. In initial discussions with Jhame Peters at F-MAX, we decided a custom tubular turbo manifold would be the right solution. However, without the time before our first event for such a radical set-up, we settled on F-MAX's street kit, which is currently available and could be installed in a matter of hours. Additionally, it didn't make sense to spend the time and effort on a custom turbo manifold and high-dollar turbocharger without the engine internals to support the power this configuration would generate. The custom manifold and turbo are still in the works and once we've got the goods inside the engine to back them up, they'll go on the car. Until then, we'll run mild boost to keep the engine alive.
F-MAX's Focus turbo kit is designed for the socially responsible, enviro-friendly car nut in all of us and retains the factory catalytic converter in the factory location, which keeps the smog nazis happy. It also installs without any cutting, bending or moving of other underhood components. It uses a high-carbon steel manifold, which should prove durable and will be lighter than a cast manifold. The turbo flange is designed for the very common T3/T4 hybrid, which offers many options for various sizing choices. Our initial set-up uses a T3/T04E turbo from Innovative Turbo Systems in Simi Valley, Calif. While this turbo uses a conventional non ball-bearing center section, it was selected because it is designed to spool very quickly and make full boost (a mild 7 or so psi) before 3000 rpm. Given the Focus' tall gears and conservative final drive, we knew we needed to make maximum torque at as low an engine speed as possible. Rally cars require lots of low-end grunt to get out of corners without bogging the engine.
On the Dynapack dyno at F-MAX, a similar set-up running the stock Focus ECU produced 187 hp at the wheels. We tuned more conservatively, since this car had to survive ten-tenths driving for hours on end in the 100 degree heat of the California desert. For added insurance against detonation and to get the most out of the engine, we mixed Elf 110 octane leaded race fuel half and half with 92 octane pump gas before tuning. In race trim for the Rim of the World Rally, our car produced 150 hp at about 4600 rpm and 177 lb-ft of torque at a low 3800 rpm. While this is certainly not huge power, keep in mind that we're driving the front tires of a 2,500 lb. racecar in the gravel-there's only so much power we can put down. Additionally, this power delivery gives the car exceptional drivability, providing usable torque at a reasonable engine speed-an absolute necessity in the Focus. See engineering editor Dave Coleman's 'Technobabble" column this month for a comparison between our standard Dynojet dyno numbers and the new Dynapack dyno numbers.
Much credit for this project goes to Innovative Turbo Systems for providing the turbo on extremely short notice. Innovative is a relatively new company, which is carving a niche for itself with some unique products. By building its own turbo wheels, Innovative has the flexibility to custom-size turbochargers to its own specifications. It will offer its own ball bearing center section with certain turbos-something you will likely see on this car in future installments as we continue engine development. For drag racing applications, Innovative also offers a multi-stage boost control which is invisible to the driver. We will likely use an upgraded version of this same system, on this car in the future.
While the parts and effort described above represent a fair amount of work, what we've mentioned so far doesn't really do justice to the work that goes into building a rally car. The bottom line is that the niggling details involved in getting a car ready for stage battle add up to a lot of late nights and loads of extra money.
Perfect examples of items that can make a huge difference in a rally car are wheels and tires. We chose Enkei's ERO1 rally wheels, which we had to have re-drilled to fit the Focus' odd 4x108mm bolt pattern. However, the ERO1 (in combination with the Focus' light weight), has turned out to be a nearly indestructible rally wheel. Combine that durability with the huge grip of Michelin's
ZL-Gravel rally tires and we've got a pretty serious wheel and tire combination.
Our goal with this car is to trickle some of what we've learned through development in this project into our street car project (see "Project Ford Focus ZX-3" on page 183 of this issue). While that car has remained normally aspirated up to this point, we've discovered some engine management solutions, which may someday lead to a very high-powered street car. We've also come to realize that, with the proper prep work, the Focus' balanced chassis makes a great rally car. Further development is still underway as the longest and most important rallies of the season near this fall. Stay tuned as we blast through the stages.
|F-MAX Fabrication Inc.|
Turbo system-manifold, intercooler, intercooler plumbing and downpipe
Pectel Technologies Inc.
Stand-alone ECU and custom harness
Innovative Turbo Systems
Rally struts, shocks and rear suspension design
ERO1 Rally wheels
Elf Competition Fuels Inc.
Thirteen Twenty Motorsports
Phone (760) 736-4467