RMW does 2.2, 2.5, (4 cylinder) and 3.0 liter (6 cylinder) conversions in house as well as providing complete D.I.Y. kits for the two 4 cylinder engines. We make parts to do the 6 cylinder install, however, it is suggested that you choose one of the 4 cylinder engine conversions unless there is a reason you absolutely need to have the 6 cylinder. The 6 cylinder H6 engine as it is referred to is a larger engine, not only in regards to power, but also dimensionally. The H6 will sit a bit lower in the Vanagon because of its weight and necessity to mount it lower in the van due to the height of the engine.
The VW water boxer engine produced about 90 horse power (hp), The 2.2 liter and the 2.5 liter Subaru engines produce 135 hp and 165 hp respectively. This is a huge upgrade from the original power plant that came in the Vanagon. The H6 engine produces 212 hp which is way more than the Vanagon was designed to handle. Although we, and others, have been successful in installing these engines, issues with the H6 have been minimal. When installing an engine with such power and torque, it is important to realize the stress you are putting on the rest of the components which have been designed to function with a fraction of that power. The 2.2 liter engine is a great fit for the 2WD Vanagon. Although you will be increasing the power output, the wear on other components such as the drivetrain are minimal. This is also the case with the 2.5 liter engine. For 4WD Vanagons, we suggest the 2.5 liter engine as it has a little more power to run a heavier van that also has more resistance in its drivetrain with the addition of the driveshaft and other components. The 2.5 liter is also a fantastic fit for the 2WD vans.
The 2.2 liter engines generally come from 1990-1994 Subaru Legacy’s. These engines are a single over head cam (S.O.H.C.) engine. Although this engine is available from 1990-1998, the majority of 2.2 engines we use come from the earlier years because of availability. These cars had an earlier diagnostic system to pull trouble codes from the engines’ computer system which was OBD-I (on board diagnostics). OBD-I was implemented to help diagnose the earliest automotive on-board computers by monitoring certain parts of the systems electronically controlled fuel and ignition systems. But individual manufacturers were allowed to design their own diagnostic systems, which made it necessary for mechanics to have different software to access the data from various brand vehicles. All cars built since January 1, 1996 for sale in North America have been required to have OBD-II systems. This system features standardized trouble codes for all makes of cars for most common problems. Any of the post 1996 2.2 liter engines will come with OBD-II. All of the 2.5 liter Subaru engines we install come with the OBD-II system which makes it easier to diagnose any engine problems.
The 2.5 liter engines we use come from 2000-2004 S.O.H.C. vehicles weather it is from a Legacy, Outback, Impreza, Forester, or Baja. All of these model cars had basically the same block with slight differences in some sensors and components on top of the engine. It is possible to find a 1999 S.O.H.C. engine, however, it only came in the Forester model and only for approximately half of the year. The 2005 and later Subaru vehicles came with a drive by wire accelerator pedal which was electronic as opposed to the earlier models of the mechanical style. The 2005 and newer Subaru’s’ also have an immobilizer system which complicates getting past that in the harness modification and requires the need to replace the computer (ECU) with an earlier computer. These combinations make it more difficult to combine readily available vehicles or donor cars in which we can extract everything we need. Although it is possible to use a dual over head cam (D.O.H.C.) engine we suggest the S.O.H.C as they are more reliable, had less issues, and our parts are designed around that particular engine. There will have to be certain modifications to some of our parts to work with the D.O.H.C. engine.