Our AVO turbo kit comes preassembled...
Our AVO turbo kit comes preassembled with turbo manifold, turbo and dump tube as one unit. However, we had to modify the heater tube that runs along the head and the transmission housing prior to installing the turbo manifold unit. By using the supplied 2-1/2-inch stainless-steel downpipe, we were able to connect the turbo dump tube to the factory catalytic.
If you ask any avid performance enthusiast what they think is the ultimate performance mod; nine times out of 10 they would probably tell you it's turbocharging. The turbo is the weapon of choice when it comes to making large amounts of power from small-displacement engines. When it comes to making power, a V8 counterpart can rely on shear displacement to increase output. On the flip side, a four-cylinder import engine's displacement can only be increased so far before running out of room-literally. Take a look at any import block and you can clearly see there isn't much room to increase the cylinder bore for increased displacement. Even with today's custom blocks, displacement of a four-cylinder import engine is still limited to less than 3.0 liters-even with the custom sleeves and stroked crankshafts. The turbo admonishes these sins.
There are two elements that are needed to make horsepower-oxygen and fuel. Maximum power production is determined from the amount of oxygen and fuel present in the combustion chamber prior to ignition. On a normally aspirated engine, the efficiency of the intake ports and the block's displacement directly affect the amount of oxygen present in the combustion chamber. For example, when you install a free flowing air filter, more oxygen is able to reach the combustion chamber. When the air is combined with the right ratio of fuel-voila! More power.
Always disconnect one of the...
Always disconnect one of the leads to the battery, especially if you are planning to work around the fuel system.
Now the good stuff. Regular readers should be well informed about the basic workings of a turbo. In plain English, a turbocharger uses the high pressure exhaust gases to spin a turbine wheel at very high speeds. Connected to the turbine wheel, via the common center shaft, is a compressor wheel. The compressor blades induce the oxygen into the compressor housing and compress it (boost pressure). The compressed air is forced to the intake or intercooler (depending on the turbo kit) and then into the combustion chamber. Since there are more oxygen molecule present in the combustion chamber, when mixed with the right amount of fuel, more power can be made. By force feeding, the volumetric efficiency is greatly enhanced, allowing the four cylinder to ingest the same amount of air as a big-inch V8. This is where the turbo gets its "replacement for displacement" moniker.
After securing the car on...
After securing the car on jackstands, drain the oil and remove the intake tube and air intake system from the engine. After unbolting the exhaust header from the catalytic and head, remove the header system.
In this segment, we will illustrate what is involved in the installation of a complete turbocharger kit with front-mount intercooler. Our tester was a 1990 Mazda Miata with 160,000 miles on the odometer. Prior to installing any kind of forced induction device ,we highly recommend having the engine checked out to see if it's ready to withstand the rigors of boost pressure. By using a compression tester, you can check if each individual cylinder is holding equal amounts of pressure. All cylinders should be no more than +/- 5-percent from each other. Second, check the leakdown percentages of each cylinder. A leakdown tester will give you an idea of how much cylinder pressure is leaking through the piston rings, intake and exhaust valves. Obviously too much leakage can not only hinder performance, but can also lead to engine failure when the turbo kit is installed. Although we would never recommend installing a forced induction kit on a high-mileage engine, our Miata engine has recently been overhauled with new Arias pistons and a rebuilt factory head.
Our turbo kit also came with...
Our turbo kit also came with upgraded injectors so we had to remove the fuel rail and factory squirters to make way for the 550cc injectors.
The ball-bearing Garrett turbo...
The ball-bearing Garrett turbo runs both oil and water through the center section for cooling and lubrication. By using an extension tube on the oil passage galley, we were able to gain access to an oil supply for the turbocharger. For water to the turbo, we modified the coolant neck so we could bypass water from the neck to the turbocharger and then back to the block.
The oil pan (oil sump) had...
The oil pan (oil sump) had to be drilled and tapped for the oil return from the turbo. This is the hardest part of this particular install, as the subframe of the Miata had to be lowered in order to remove the oil pan. With the oil pan tapped, the drain tube was connected from the turbocharger to the oil pan.
Next on the list was installing...
Next on the list was installing the front-mount intercooler. The grille section of the bumper required trimming in order to fit the intercooler properly. Make sure the intercooler is securely mounted with the supplied brackets to prevent any possible "fall out."
With the majority of the turbo...
With the majority of the turbo kit installed, it was time for the I/C piping. Our kit came with cast aluminum bends, which made installation a breeze. There were only four pieces in the kit, so figuring which one went where was not rocket science. Although you want to make sure the clamps are secured, don't overtighten them as they can easily break.