[2000 Vw Passat Engine Diagram
Christel Malden
First launched in 1996, VW's 20-Valve 1.8L Turbocharged Engine has become an icon and popular engine for tuning and building horsepower. Lovingly referred to as the 1.8T 20V, this engine has spanned many variations across generations of VW and Audi platforms. Popular vehicles include:
The 1.8T 20V has been mounted transverse and longitudinal in many VW/Audi models, receiving dozens of updates and different engine codes. However, they can all be dialed down to two main generations of engine blocks, 058 and 06A.
The first generation longitudinal 058 blocks are found in early Audi B5 A4, and VW Passat produced from 1996 until midway through 2000. 058 blocks have an internal intermediate shaft that drives the oil pump, and these use an external water pump driven by an accessory belt.
The second generation 06A block was introduced in mid-2000 and mounted longitudinaly (A4, Passat) and transverse among many VW and Audi models. Model years 2000.5 and newer use 06A block. This new generation received many updates, most notably the timing belt-driven water pump and eliminated intermediate shaft. The oil pump was also updated to chain driven by the oil pump drive gear located on the crankshaft snout. Watch the video below on how to identify your 1.8T 20V block type:
Both the 06A and 058 1.8T 20V use 5 two-bolt main caps. There are 4 outer main caps and one center main cap that contains crankshaft thrust bearings (also commonly called thrust washers). Factory main caps MUST be reinstalled in the exact location and orientation as removed.
All 06A and 058 crankshafts are manufactured with an 86.4mm stroke. Crankshafts found in 06A platforms are forged or cast iron. 058 crankshafts are cast iron only. The timing belt drive gear and crankshaft damper are attached via a 4-bolt interface. The crankshaft trigger wheel is partially used with the crank sensor to determine engine RPM.
All 06A and 058 connecting rods measure 144mm in length on the center-to-center dimension and have a big-end journal width of 24.90mm. The connecting rod wrist pin size and taper vary depending on engine codes.
Rod bearings, main bearings, and thrust bearings must be replaced anytime you remove them or replace their components (rods, crank shaft, main caps). We highly recommend using a performance main bearing and rod bearing as power levels increase. The main advantage of performance bearings is their tri-metal composition to withstand added bearing loads ability to withstand crankshaft flex. Performance bearings are also treated with specialty coatings to reduce friction and wear further.
NOTE: All IE 1.8T 20V Connecting Rods are only designed for tanged style rod bearings. Tanged bearings locate and lock into the journal, reducing the chances of bearing spin and less chance of bearing failures.
Much of the factory main bolts, head bolts, crank bolts, etc., are one-time use stretch bolts and must be replaced with either new factory replacements or aftermarket upgrades once removed. New stock bolts are adequate up to the 300+ range. At 400HP and higher, we recommend upgrading with IE/ARP hardware options. Common one-time use enge block hardware:
The factory connecting rods is the primary concern and weakest point around the 300-400hp power level. The most common practice at this point is to perform a mild build with IE forged connecting rods and retain the stock pistons. This is an affordable, proven, and reliable combination for this power level. The weak points of the factory connecting rods come down to two main design limitations:
To ensure reliable operation at power levels exceeding 400HP, replacing the connecting rods and pistons with high-performance forged upgrades is necessary. All 1.8T aftermarket piston & rod combinations offered by IE use a non-tapered 144x20mm connecting rod for robust strength.
Choosing the correct piston forging for your build depends on what you will use the vehicle for most of the time. Stronger material forgings excel under constant cylinder pressures, such as during extended track use. Still, they can have more expansion resulting in rattles during cold starts and increased blow-by on daily driven or weekend road warriors.
When building past 500HP, that power is only spread across 4 cylinders, subjecting each rod to extreme pressures. The difference between reliable power and a window through your block is a rotating assembly that can withstand these loads. IE's Tuscan connecting rods have been engineered with a unique I-beam "egg" shape, which lowers stresses by as much as 20% compared to less evolved designs. This also evenly distributes the high compressive loading from high boost pressures onto the connecting rod beam, reducing piston stress and providing a stable foundation for the rod bearing.
Building past 500HP on a 1.8L engine requires spooling a huge turbo, which can result in severe turbo lag, even on modern "fast spooling" turbochargers. Combining 83mm overbore "stroker pistons" with a 92.8mm stroker crankshaft results in an increased displacement of 2008cc (2.0L). A stroker build yields more horsepower and torque on the same boost pressure, less chance of detonation due to lower peak cylinder pressures, faster spool, and produces more power on lower octane fuel.
The stock main caps are cast and lack the rigidity required for a reliable, high-powered build. As an upgrade, we offer billet steel main caps that are far more rigid and will help to reduce main bearing wear.
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