One, or a pair of turbos, can give your small-displacement motor enough versatility to produce impressive horsepower and fuel economy.
There are many different ways to build an engine, but performance in any arena generally boils down to one thing: efficiency. Most automobile engines extract only 30 percent of the energy contained in the gasoline they consume; the rest of the energy is wasted through heat, light and high-velocity exhaust gases. While the common perception is that the smallest possible engine displacement yields the best fuel economy, this is only true if the engine still produces enough power to move the vehicle. The ideal would be to build an engine that changes displacement to fit the circumstances.
Instructions
1. Acquire a used 305-cubic-inch displacement small-block Chevrolet, a 302cid (5.0-liter) Ford, or a 318 Chrysler LA-series engine. Send the engine block to a machine shop to be stripped down, cleaned and tested for cracks. Have the machine shop assemble the block using steel connecting rods, and forged 9-to-1 compression ratio pistons, powder coated with ceramic for thermal insulation. If you're aiming to build over 350 horsepower with a 305 or 318, you'll probably want to install a steel crankshaft and steel rods. You could assemble the block, but paying the extra money for an engine shop to build it will buy serious peace-of-mind.
2. Bolt a set of modern, fast burn, high-swirl cylinder heads to the engine block. For the Chevrolet, use a set of 1990s LT1 Vortec heads; the Ford should get the GT40P heads from a late-1990s Explorer, and the Chrysler 318 engine will be most efficient with a set of late-model Magnum heads. Seal the heads to the block using a set of chrome-moly head studs. Note: If you build a 318 with Magnum heads, order a set of custom-length pushrods from Mopar Performance.
3. Slide an hydraulic roller cam into the block using the widest possible lobe separation angle: at least 114 to 116 degrees. Otherwise, your cam should have about 190 degrees duration at 0.050-inch lift on the intake and exhaust, and no more than 0.300-inch lift on the intake and exhaust. Any number of stock LT1, 5.0-liter or Magnum camshafts will work, so shop around to find the smallest one available. Drop the matching aftermarket or stock roller lifters into the lifter bores, and bolt a set of fully-rollerized rocker arms to the heads. Use 1.5-to-1 rocker arms on the intake, and 1.6-to-1 rocker arms on the exhaust.
4. Bolt a long-runner, multi-point fuel injection intake manifold to the heads. For the Chevy, use a Tuned-Port Injection (TPI) setup; use a standard 5.0-liter EFI manifold on the Ford, and a late-model Magnum manifold on the Chrysler. Plug a set of stock fuel injectors into the manifold. Install the remaining fuel-injection equipment and ignition system; the procedure will vary greatly by engine.
5. Install a twin-turbo system using two small turbochargers, flowing no more than about 350 cfm (cubic-feet per minute) of air apiece. They should use internal wastegates. The aftermarket is rife with turbo kits for the Ford and Chevy engines, but kits for the Chrysler are more rare. In any case, the basic install procedure is to bolt the turbo manifolds to the heads, bolt the turbos to the manifolds, and then duct the turbo outlets to the intake throttle body, using the supplied plumbing.
6. Install a water/methanol injection kit to cool the intake charge, and provide supplemental fuel to keep the engine from exploding under boost. Installation procedures will vary by engine and kit, but generally involve inserting one or more water/methanol injectors into the boost tube, connecting the injectors to the electronic water solenoid, and running a water feed line from a reservoir tank to the solenoid.
7. Top the engine off with an electric cooling fan and electric water pump. If you can do without power steering, eliminating the power steering pump will net you noticeable improvements in fuel economy.
Tags: block using, fuel economy, rocker arms, assemble block, build engine, engine block