The concept of the ECOCAT project started over a year ago, when some bench-racing magazine types were left with a 2.2L Ecotec engine without a home. From those "what-if" sessions, this KIT CAR project has evolved into a rolling test bed of unique body design elements combined with serious performance suspension and braking components. It is also a first-ever conversion of an Ecotec engine to a rear wheel drive application. Yet, through it all, we've always known we wanted to add a turbocharger to the powerplant.
Turbocharging is the ultimate means in developing added engine power though the utilization of spent exhaust gases to pressurize the intake mixture. Exhaust exiting the engine is used to drive a compressor that forces a denser air and fuel charge into the intake manifold. Where superchargers can offer similar advantages, they do require crankshaft driven pulley systems that rob power and add stress to engine components. Adjustability of a turbo's boost pressure is as simple as a push of a button inside the driver's cockpit, as opposed to having to change pulleys and belts with a supercharger set-up. The turbo is the link between street cruising and some hardcore track days, and the key to the versatility for the ECOCAT.
Hahn Racecraft is a leader in the turbo industry and the only company, based from our research, that has developed a kit specific to Ecotec engine applications in Cavaliers and Sunfires. We met with Bill Hahn some time ago and laid out the ECOCAT concept to him, along with a few progress photos of the car and our desire to hit 300 hp through turbocharging. Bill, a former eight-time national motorcycle racing champion and long-time advocate of turbos, immediately joined up as this project hit a personal "hot button." He had been wrestling with similar ideas of a small-cubic-inch turbocharged application in a lightweight car, and our ECOCAT project was the perfect fit. Though some may view 300 hp from a turbo 2.2L to be a bit too over-optimistic, the gleam in Bill's eye pretty much gave us a "no sweat" thumbs-up expectations.
The ECOCAT and its engine and transmission were sent to Hahn Racecraft in Yorkville, Illinois, where the two were finally mated together. Rick Woodward of Rick's Race Cars & Components assisted in developing a motor-mount system that combined the use of a conventional style transmission mount on the Keilser Engineering five-speed with a slightly modified factory front engine mount. This left the project with a serious problem of handling engine torque that was overcome with specially designed twin torque-limiters now available from Hahn Racecraft. This special engine-mount kit includes the front motor mount and provisions plus two torque-limiters, which are installed on each side of the engine (off the bellhousing adapter plate) to insure proper distribution. This kit can also be used in most any kit and street-rod applications where you use the Ecotec and Tremec trans in an inline design.
With the engine securely in place, Bill and his Team begin installing the turbocharger components on the ECOCAT's 2.2L engine. While our system is a custom application, many of the performance parts from the Hahn Racecraft Cavalier system are utilized, including the turbocharger exhaust manifold and HRC-designed Mitsubishi Super 16G Turbocharger. This unit is a street version turbocharger that will allow increased low speed response while still providing gobs of power at the higher end.
A custom intercooler was built by Aaron Gilberg to fit the lower inlet cavity of the ECOCAT frontend. As with most things in life, bigger is better in that it will allow for a bigger charge of cool air--even during low turbo operation. Plumbing from the turbocharger is a smooth transition of steel tubing that gradually increases from 2- to a 2.25-inch inlet of the intercooler. A similar step process is also used between the 2.5-inch outlet on the intercooler to a 3-inch inlet of the intake manifold. These same installation processes can be utilized on most any kit car to add the heart-pounding power potential of turbocharging to your Cobra or exotic.
As the finishing touches of the turbocharger installation are happening, we know that, before we fire this mini-Mouse monster up, we will need to add an ACCEL Generation 7+ Engine Management System to control fuel and ignition requirements. We are working on a host of other bolt-together steps to complete the project as we push forward to bring updated information on this power configuration with actual chassis dyno numbers.
Stay tuned to future issues as we forge ahead with a goal of introducing the ECOCAT at the 2005 Run & Gun event in St. Louis this August. Come on out and see if our planning paid off!
The front motor mount utilizes...
The front motor mount utilizes a factory-style mount with added bracing to the Shell Valley frame. This gave a front and rear engine mount configuration similar to the installation found in Cavaliers and Sunfires.
The completed torque-limiters...
The completed torque-limiters from Hahn's engine-mount kit provides a mount for both sides of the engine and links it to the frame. Rubber bushings reduce the transfer of engine vibration while providing an extremely stout means of controlling engine torque.
One problem we encountered...
One problem we encountered with the front and rear engine mounts was properly handling torque movement of the engine during acceleration and deceleration. Hahn Racecraft used the ECOCAT as a development tool to build a new engine-mount kit to correct this situation as well as provide a means of engine installation. Aaron Gilberg is attaching the mounts for our torque-limiters.
The heart of the turbo system...
The heart of the turbo system is the Mitsubishi Super 16G turbocharger, which has been built to Hahn Racecraft specifications. Rated at 400 hp maximum, the "sweet spot" on this unit is from 250 to 350 hp for superior all-around driveability. Advanced balancing capabilities can allow this unit to spin at up to 150,000 rpm.
Getting a direct flow of clean...
Getting a direct flow of clean air to the intercooler did not pose a problem with the ECOCAT. Aaron Gilberg fabricated a special mount to mate the intercooler to the frame without restricting airflow to the radiator behind it.
The intercooler is a perfect...
The intercooler is a perfect fit in the grille opening of the ECOCAT. Airflow is not restricted in any way and there are still four inches to the radiator behind it. The unit uses a bar and plate-type of construction that provides exceptional airflow over the tube and fin style.
The oil supply for the turbocharger...
The oil supply for the turbocharger was picked up from what is now the rear of the engine. A return line was plumbed from the bottom of the turbo unit to the oil pan.
With the engine and turbocharger...
With the engine and turbocharger system firmly in place, the team at Hahn Racecraft have set their sights on finishing the plumbing between the unit and the intercooler. Due to the fact that turbochargers tend to reduce engine noise, we are planning to relocate the battery tray and run our exhaust out the passenger side through a resonator and short pipe.
The complete system is extremely...
The complete system is extremely compact. Even including the turbocharger's mandrel-bent outlet and intake pipes, the complete system is only 32 inches wide with space to spare under the hood.
Why Turbocharge Your Kit?
While there are a multitude of induction methods possible for any kit or replicar, turbocharging is by far one of the most efficient power adders available. We briefly hit on some of the advantages in this month's ECOCAT story, but there is a whole lot more to turbocharging and the added power potential.
Consider this; turbochargers generally operate at 70 percent efficiency! Turbocharging tends to be free horsepower. While exhaust gases must be piped away from any engine anyway, harnessing these spent gases to work for you by turning the turbo's rotor provides a forced induction without the expense of power-robbing drive pulleys and belts. Another advantage is less wear on engine parts because turbochargers are free-wheeling and do not connect to crankshafts or other engine parts.
Today's turbochargers are a feat in engineering excellence. The use of a fluid bearing (which allows the shaft to rotate within a layer of oil to both cool the shaft and reduce friction and wear) improves longevity. Improvements in the ability to balance turbocharger assemblies has become a science in itself and allows these units to rotate at 150,000 rpms on a continual basis.
Space is a premium on most kits, and turbochargers are one of the most space-conscious methods of any forced-induction system. Unlike top-mounted superchargers and related power adders, with careful planning, a very efficient turbocharger system can be built for even the most confining underhood applications. By planning a system with a knowledgeable manufacturer, most any application need can be met.
Versatility is yet another advantage of a turbocharged system. Unlike other forced-induction systems, turbochargers can be "dialed-up or down" in boost to tailor power requirements from the driver's seat. Think of the possibilities at the next track day by adjusting power ranges through various parts of the course. It simply isn't possible with any other method of induction. A turbocharger system is not an inexpensive induction system. But given proper planning, it can make your car the most exciting and fun ride anywhere. After all, isn't that why we build them, anyway?
Intercoolers, Beat The Heat
Forced induction on today's performance engines produce added heat due to the compression of air into the intake manifold. This characteristic can adversely affect the amount of power that an engine can produce, and increase the possibility of detonation. Intercoolers are an effective means of overcoming this power-robbing issue.
The most common type of intercooler used in automotive applications is the air-to-air intercooler. There are two types of construction methods used in the core sections by manufacturers: Bar and Plate style and Tube and Flange. Bar and Plate cores are made up by brazing together layers of flat plates separated by small rectangular spacers. Tube and Flange core construction is created through a series of separate tube runners into common head ends, similar to an automotive water radiator. One type of manufacture process has not proven in research to be superior then the other. What is important is that these units, when properly sized and placed, provide superior cooling of the compressed air traveling though them delivering a denser intake charge into the engine.
While there is a wealth of information about intercoolers, the most important factors to maximizing power po- tential through their use are:
1) Ambient air quality (outside air) traveling into the intercooler is extremely important for cooler efficiency. A non-restricted flow of clean air is needed in and out of the intercooler.
2) Size is important. Bigger is better when the application can be kept in clean air. The more surface space that allows air to travel through the intercooler the better the efficiency developed from its use. Smooth transitions in channeling of compressed air in and out of the cooler will reduce the potential of flow restriction. Serious consideration must be given to ensure that airflow is as smooth as possible from the turbocharger, all compressed air plumbing, and through the intercooler.