Considering purchasing a turbo kit for your car can become a daunting task, let alone installing and tuning afterward. It can be done right, with rewarding results, but if you are too ambitious or inexperienced, purchasing that kit can result in a huge headache and most likely one or more blown engines.
So when a colleague of ours informed us that he was deciding to build his EVO IX to compete in the annual AWD Shootout and Super Lap Battle at Buttonwillow Raceway, we offered to lend a helping hand as well as document the buildup. Besides purchasing a quality turbo kit that offered long-term reliability, the most important factor was choosing the right turbo for his intended power level and the vehicle’s goals. The Voltex-clad EVO IX machine served as his daily driver as well as a weekend warrior at the track. After weeks of research and weighing all options, we decided to go with the AMS Performance V-band 750R turbo kit, along with purchasing a plethora of proper support modifications required for the engine to safely handle the increase in power.
The AMS EVO VII-IX Turbo Tuner kit is considered one of the most comprehensive kits sold on the market today. Keep in mind that boosted performance does not come cheap, and if the setup you are considering is surprisingly cheap, you should be wary of its quality. Unlike many turbo kits that require authorized dealers for installation, AMS designed this kit to be an easy install. The Precision Turbocharged kit comes with everything needed including stainless steel V-band clamps, heat shield wrap, five-ply silicone coupler hoses, water/oil lines, step-by-step instructions, and even zip ties to make the installation process as painless and simple as possible.
Prior to installing the new AMS turbo kit, our EVO IX was equipped with a 20G turbo (.77A/R ratio); Tomei Powered Expreme stainless exhaust manifold, turbine outlet, downpipe; 1,000cc injectors; XS Engineering FMIC; Cosworth CNC big bore head, 272/272 duration camshafts; Fujitsubo Super Ti exhaust and Open Source ECU tuning. At 24 psi of boost, the EVO produced 330 whp on Greddy USA’s “heartbreaker” Mustang dyno. Interestingly enough, the same setup was making 370 whp on another dyno. Regardless of our disappointing baseline horsepower number, we decided to stick with our 330 whp baseline to monitor how much horsepower the new setup would make, once we installed the AMS turbo kit and properly tuned the car.
Precision 58/58 Turbo (750R)
Rated HP: 750 hp capable (with supporting mods)
Turbo Spool: 3,600-4,400 rpm
Vehicle Applications: street/road course
Precision 62/66 Turbo (900X)
Rated HP: 900 hp capable (with supporting mods)
Turbo Spool: 4,200-4,700 rpm
Vehicle Applications: street/road course
Precision 67/66 Turbo (950R)
Rated HP: 950 hp capable (with supporting mods)
Turbo Spool: 5,000-5,500 rpm
Vehicle Applications: street/dragstrip
1. The AMS turbo kit provides you the key components essential to improving exhaust flow and maximizing the performance of your Precision Turbo V-band turbocharger, which includes a cast exhaust manifold, O2 housing, and downpipe.
2. At the heart of our turbo kit sits an AM-spec 750R turbocharger manufactured by Precision Turbo. The AMS 750R is the perfect choice for street, road race, and drag racing and the best all-around turbo on pump gas. This turbo uses an extremely durable ceramic dual ball bearing centersection with a modified billet compressor wheel. The AMS 750R turbo is a GT30R variant, capable of making 100 whp more than typical GT30R-framed turbos that have an older, less efficient design. The 750R has been proven to show minimal spool latency that’s about 100 to 200 rpm later than the GT30R, making this an ideal setup for both street- and track-driven vehicles. AMS claims to have seen as much as 500 whp on 93-octane pump gas and over 580 whp on race gas with this turbo, which happens to be the same turbo setup running on their time-attack EVO X.
3. Precision Turbo’s new ultrahigh-flow turbine wheel’s design increases horsepower over comparably sized standard designs, aids in improving initial turbo spool-up time and reduces turbo lag by having a lighter billet aluminum compressor wheel. Each compressor wheel is machined from a 2618-aluminum forging for added strength, higher efficiency, faster transient response, and maximum performance. The newest Precision Turbos use an “anti-surge” housing design, which machines holes into the compressor housing to help keep the air entering into the compressor inlet remain stable at higher speeds, limit the effects of surge, as well as provide additional airflow to make maximum horsepower at high boost pressure levels and across the entire rpm range.
4. Each V-band turbo kit is available with your choice of three different AMS-spec Precision Turbochargers (750R, 900X, and 950R) and incorporates the latest V-band exhaust housings with options for .64 or .82 A/R depending on your type of driving and target horsepower output.
5. Here’s a close-up of the AMS stainless steel cast 02 housing with recirculated wastegate dump. AMS offers an optional dump to atmosphere for additional cost. We decided to use the recirculated setup for our build . . . after all, this is our street car.
6. Although the AMS V-band kit comes with a Tial MV-R 44mm wastegate in your color of choice, we decided to swap the unit with a Turbosmart Hyper-Gate 45. The Hyper-Gate45 is a 45mm external wastegate that is compact in design, yet able to maintain proper boost control for our EVO. The Hyper-Gate45 features a unique locking collar design for reduced size and quicker spring changes. It also includes both inlet and outlet weld flanges and V-band clamps; the valve seat will directly bolt on to the new AMS turbo manifold.
7. The AMS exhaust manifold is a masterpiece of artwork in itself, but regardless of how badass it looks, it was designed not only for performance but longevity. Using CAD and casting designs, the manifold utilizes cast stainless steel construction, thus eliminating the possibility of cracking, a problem commonly associated with hand-fabricated tubular headers. By casting the main components of the manifold, AMS was able to maximize exhaust flow and efficiency through their enormous 2-inch runners to help spin the turbine wheel faster while promoting maximum power potential. The stainless steel, thick-walled header is 100 percent hand TIG-welded from the collector to the head flange as gas exits the turbo through a 3-inch cast O2 housing.
8. The cast head flange was designed extra thick for even sealing and big enough to accommodate large exhaust ports found on our AMS CNC-ported Cylinder Head and other ported heads on the market. AMS designed their turbo kits using V-band flanges to allow for easier fitment with no gaskets and easier maintenance when installing/removing parts on a regular basis. Every V-band is manufactured from heat-treated 431 stainless steel for superior strength, even under extreme temperatures.
9. The only problem we encountered when installing the kit was an issue with the oil return line being too short. A quick run to the local Earl’s Performance shop to pick up a new line quickly resolved the problem.
10. Koyo Half-Radiator
The Koyorad performance half-length radiator for the ’03-07 Mitsubishi Evolution was designed by Koyo engineers as an alternative cooling system for the growing number of Mitsubishi race vehicles with upgraded front-facing turbo systems. The double core, half-length radiator was designed for Sprint racing, small track, and gymkhana-type courses. The radiator uses an ultrahigh density 48mm “Hyper” performance core for superior cooling, while it’s reduced length allows for an off-center mounting position, which keeps radiant turbo/manifold heat away from its core.
11. A side-by-side comparison of the Koyo fullsize “R-Core” radiator alongside our new “Hyper core” unit shows the dramatic difference in size and an overall weight saving of 10 pounds. Although the question remains on whether the smaller-sized radiator would maintain proper cooling during street usage due to the smaller core, which is typically not suited for stop-and-go traffic, we remained optimistic with plans to closely monitor its performance once we hit the streets for testing along with hard runs at the track.
12. Although the AMS Performance V-band turbo kit was designed to clear the OEM fullsized radiator and AMS provided electric fan without issues, we opted to use the Koyo half-size unit along with a custom fan shroud we pulled from the previous radiator setup. AMS Performance reps state due to turbo-to-radiator clearance, a solid front motor mount or insert kit that AMS offers must be used to reduce engine movement when using a fullsized core.
13. A quick mockup of the Koyo radiator using the factory mounting points revealed the custom fan shroud was sitting less than an inch away from the turbine compressor housing. This was sure to be of concern if the engine experienced any torquing, which would cause rubbing.