In our last installment of Project Focus, we added a few key components to give the Zetec-powered Focus a little more pep. The bolt-on performance netted us a total of 129 hp and 131 lb-ft of torque at the wheels.
We didn't want to screw with any more naturally aspirated components, so we decided to jump into what our magazine is named after, turbos. The turbo system is designed by AEBS and it utilizes the highest quality components available on the market today.
To start off, the gurus at AEBS went all out with fabrication. Exhaust gases travel through a highly crafted 321 stainless-steel exhaust manifold and downpipe, while the air charge is pushed through 6061 aluminum intercooler piping. According to AEBS, the one-off turbo kit should graduate to production model status soon.
Turbo magazine is playing the turbo guinea pigs for AEBS and we wanted to see just how well the prototype kit would work on a stock Zetec engine. Is it worth the money?
Building a turbo kit consists of 25 percent parts, 25 percent material and 50 percent labor. For this kit, we enlisted the help of Turbo Engineering Corporation (TEC) to size a turbo suitable for the Zetec engine.
The turbo consists of a T-3 turbine housing and T-4 compressor housing with special Jim Latour compressor and turbine wheels. Not stopping at the turbo, we also used a TEC wastegate. The wastegate spring pressure was set at 7 psi; as we start to crank up the boost, we'll use a Blitz SBC-iD to keep the max pressure in check.
To cool the air charge, we're employing a Spearco intercooler core with custom end tanks made by AEBS. A Blitz blow-off valve will be called upon to combat compressor surge.
Having a reliable fuel management strategy is key to surviving the dyno as well as the street. For this, we called upon Pectel Technologies since the company pretty much has the Focus market cornered with its plug-in T2 unit. One of the reasons this unit dominates the Focus market is its ability to control the fuel pump pulse width.
Since the Focus doesn't run a return line, the factory ECU varies the voltage running to the fuel pump. The Pectel ECU can also control the engine's ignition timing in the same way it can control the injector's pulse time. The new ECU also allows the removal of the factory airflow meter in favor of a map sensor to convert the system to speed/density. The unit is also capable of controlling boost, idle air control, and fan control as well as a variety of addition options that can be added to the ECU.
In turbo trim, the stock injectors would be well past their max with less than 3 psi. Since the Pectel can control the injector's pulse width, this allowed us to go to a larger injector without the possibilities of poor idle and part-throttle driving ability.
We looked to Russ Collins and the crew at RC Engineering for an injector that would be suitable to produce a reliable fuel flow. What we figured out was a 500cc high-impedance injector should be safe for 250 hp to the flywheel.
Lobe separation angle always plays a vital role when switching from normally aspirated to turbo trim.
To control cam timing and lobe separation angle, we used a pair of AEBS cam sprockets. Cam sprockets are always a good way to dial-in power; these units allow adjustments of plus or minus 10 degrees.
Since Focus camshafts use no keyways to keep cam and crank timing correct, it's very important to have the crank at top dead center as well as a good cam lock tool to keep the cams set to the right timing. Tune Time
With the Ford strapped to the dyno, we were ready to make its debut pass. Nathan Tasukon from Pectel uploaded a program that was used on a similarly turbo-trimmed Focus; from there, fine-tuning was all that was needed.
With the cams at zero and the base map loaded, the Zetec was able to produce 187 hp at 7 psi. Power flat-lined after 3800 rpm, then fell off at 5500 rpm. Even after tuning at 7 psi, we were only able to clean the air fuel mixture; we ended up with the same power. It was when we started playing with the cam sprockets that the engine came alive.
Retarding the intake cam sprocket to 6 degrees and the exhaust to 8 degrees netted a total of 230 hp to the wheels. This was achieved after our sprocket tune and Nathan's fuel and timing changes. Nevertheless, this was done at 7 psi.
When the gang at AEBS and Nathan urged me to up the boost, I cranked it to 10 psi. From 10 psi, it went to 12. From 12 psi, it turned into 15. There I decided to put my foot down and stop boosting the car.
As much as the group was having fun making the horsepower, I was the one punching the numbers in the calculator to figure how much was left on the injectors.
At 15 psi, the car produced 278.7 hp and 280.1 lb-ft of torque to the wheels, which means we were really putting out about 306 hp to the flywheel. In other words, we maxed out the injector at more than 85 percent, which is basically an injector running wide open. We were now relying on fuel pump pulse width to obtain more fuel, so until we bump up the fuel injectors, we stayed at 15 psi and 278 hp.
With the injector already maxed out, the next part of the story will consist of installing larger units as well as playing with different camshafts. With a second engine already built, we're looking to push the envelope and see how much abuse the boosted Zetec can take.