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?
The Parts
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.
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Sitting in the Focus' nose cone is a Spearco front-mount intercooler. If this were a factory Focus bumper, the cooler would have to be half the size and a quarter the thickness. Since we used a JT Auto Style body kit, the mouth portion of the bumper allowed us to use a much larger intercooler. |
Welding expert, Bill Brown, crafted our exhaust manifold out of 321 stainless bends. |
Head and turbine flanges were water cut out of 5/8-inch thick stainless. |
With the manifold complete minus the wastegate tube, the setup was test-fitted on a second engine we plan to build with aftermarket internals. |
A TEC wastegate was used to regulate exhaust gas traveling to the turbo. Spring pressure was set at 7 psi and boost control will be handled by a Blitz SBC-iD. |
The manifold with turbo clears the block as well as the radiator, but we were forced to switch to a slimmer electric fan. |
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To ensure no exhaust leaks or cracks, Bill TIG-welded the manifold using 347 stainless rod. |
Since turbo engines produce more heat than a naturally aspirated engine, we used a Cervini hood with vents to provide additional cooling. |
RC Engineering injectors replaced the factory 280cc injectors; the new units are 500cc replacements which are good up to 280 hp. |
Dyno 1: With the boost level at 7 pounds of spring pressure, the engine produced 187.5 hp. After a quick fine tuning of the cam sprockets, the Zetec put out 230.5 hp and 240 lb-ft of torque. This just goes to show that lobe separation and cam timing is everything on these engines. It also helps to have full control of the engine management with a Pectel T2. |
Dyno 2: Increasing the boost pressure to 15 psi was a little on the nutty side for a stock Focus, but the guys at AEBS and Pectel ganged up on me, forcing me to up the boost on the engine. It was here the Ford put out 278.7 hp and 280.1 lb-ft of torque. With an air/fuel ratio at a safe 11.8:1 we weren't about to take the boost any higher on a maxed-out injector. |
AEBS Focus sprockets were used to control cam timing. Since the Zetec engine doesn't use keyways to line up the cams, it's very crucial the crank is set at top dead center and a cam lock tool is used to line up the cams. |
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