Let's face the facts. The Mitsubishi 4G63 is the best-bang-for-the-buck four-cylinder engine on the market today. You can talk about your 500hp built Honda B-series, 400hp EJ20, or even 300hp 2.4L Neon engine, but there are very few engines that can claim to pump out 400-plus horsepower on a bone stock bottom end and an untouched cylinder head. Most engines require building the bottom end or working the cylinder head, but the 4G63 Evolution VIII engine is the one that stands alone when it comes to pumping out 400-plus horsepower by adding a simple turbo kit.
OK, maybe it's a little more than that. The ATP Evo turbo kit comes with more bolt-on pieces than a Duplex Lego set, and it allows the user to choose from five different Garrett turbo sizes that cater to the type of power you want from your engine. Your choice of turbos without a price upgrade are the GT3037S with a .63 or .82 A/R and the well-known GT3071. For an additional $350, you can also upgrade to the GT3540R with your choice of a .63 or .82, which is capable of producing 600-plus horsepower. Included with the kit is all the necessary oil and water line hardware for the turbo's center cartridge set up. What makes the turbo kit unique is the fact that it is able to bolt up to a factory Evo manifold with ATP's custom turbine housing. The housing retains the factory manifold's turbo outlet bolt pattern, placing the turbo in the exact position as the OEM unit while still allowing the OEM heat shield to be used. While the Garrett turbo does bolt up to the factory manifold, the factory downpipe is replaced with an ATP V-band style downpipe. The key with the V-band clamps is that they fit in the very tight area of Evo VIIIs. The clamps also allow for a much easier installation of the downpipe's elbow section. The two-piece downpipe is 3 inches in size and is made of 321 stainless steel with a 12-inch flex pipe. A TiAL 38mm external wastegate is used, but rather than dumping the exhaust directly to the atmosphere, it is routed back through the exhaust.
The kit utilizes the factory intercooler, but the factory rubber charge pipe from the cooler to the turbo has been replaced with 2 1/4-inch mild steel. The factory intake pipe is also retained with the use of a silicone reducer. Stock power of 235.79 hp and 249.08 lb-ft of torque was raised to 421.41 hp and 354.77 lb-ft of torque.
Now that you have a better understanding of what the kit consists of, we decided to head to Harman Motive to see just how easy the kit installs. Harman Motive specializes in WRXs, but it has recently started dabbling into the Evo world. While the kit has been available for a few months, this particular kit is the revised, easy-to-install updated version.
1. The ATP turbo kit is a completesetup, from oil and water lines to intercoolerpiping and downpipe hardware. | 
2. The turbocharger is a factory Garrett turbo, but the turbine housing is an ATP cast piece specifically designed for the factory manifold. |
3. Pulling the exhaust manifold with the turbo still attached is the easiest and quickest way to remove the factory turbo. | 
4. The factory downpipe is removed from the catalytic converter to the turbocharger. |
5. While Harman was able to pull the turbo out without removing the radiator, removing it does allow more room to work with. | 
6. Physical size difference between the factory turbo and Garrett replacement is, well...kind of noticeable. |
7. Before the turbo is installed on the manifold, all the oil and water line fittings are installed on the turbo. | 
8. Once all the fittings are installed on the turbo, it is bolted on the manifold finger-tight to allow it to squeeze in place much easier. |
9. Once the manifold is in place, tighten the four bolts that fasten the turbo to the manifold. There is little room between the radiator and engine block due to the compressor housing size. | 
10. Before the new downpipe is installed, the new oil fitting on the oil pan is installed. |
11. Since the downpipe utilizes V-band clamps, installation is much easier, especially since the downpipe's elbow section is in an extremely tight area. | 
12. The secondary downpipe section uses a U-bolt exhaust hanger with a CNC mild steel piece to bolt to the factory hangers |
13. With most of the turbo kit installed, the last two remaining pieces to add are the intercooler pipes and the air intake. | |