Audi’s VR6 engine has been one of the most popular in recent times. It was first introduced by automaker Volkswagen back in 1991, and it revolutionized how cars are powered, with an all-new design that set trends for years to come.
Many innovations were made when they created this revolutionary six-cylinder powerplant, like its compact size, which allowed manufacturers to take on larger vehicles without feeling too cramped inside.
Another significant benefit is reduced weight, thanks mainly to aluminum construction; key factors influencing fuel efficiency across various types — from luxury sedans down to executive class vans.
What are VW/Audi 3.6 FSI VR6 EA390 Engines?
The new VW/Audi 3.6-liter VR6 is a narrow-angle V6 like the preceding 2.8 and 3.2-liter models. Also, the new 3.6-Liter powerhouse, however, has a 10.6-degree cylinder offset, as opposed to the old 15 degrees offset, allowing everything to fit beneath a single cylinder head.
The bore has been raised to 89-mm and the stroke to 96.4-mm. The engine also weighs 17.5 pounds less than the previous Passat’s 2.8-liter 90-degree V6. The maximum power is now up to 280 HP and 265 lb-ft of torque, 90 hp, and 58 lb-ft more torque than the original V6.
The VW/Audi 3.6 engine was originally used in the Audi Q7 (BHK and BHL engines) in 2005, and then in other VW cars such as the Passat R36 and CC (BLV, BWS), Phaeton (CHNA and CMVA), and Touareg (CGRA, etc.).
The 3.6-liter variant was built using the 3.2 V6 FSI engine found in Audi vehicles. When compared to the 3.2L engine, the larger displacement provided a notable improvement in power and torque.
Engine Specifications and Design:
- Production Run: 2005 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: VR6
- Bore: 89.0 mm
- Stroke: 96.4 mm
- Valvetrain: DOHC four valves per cylinder
- Displacement: 3.6 L (3598 cc)
- Compression Ratio: 11.4 and 12.1
- Weight: 410 lbs.
- Maximum HP: 300 HP at 6,000 – 6,600 RPM
- Maximum Torque: 295 lb-ft at 2,500 – 5,300 RPM
Cylinder Block
The 3.6 FSI engine has a novel 10.6 degrees VR-shaped cast iron cylinder block with lamellar graphite. The offset of the cylinder was also increased from 12.5 mm to 22 mm.
The redesigned cylinder block has the exact dimensions of the 3.2 VR6 manifold injection engine. The oil pump is a part of the engine block. The engine now has a cast-iron crankshaft but is still supported by seven main bearings. There are also new graphite-coated aluminum-alloy pistons.
Cylinder Head
The 3.6 FSI VR6 engine features a 24-valve cylinder head built of a hypereutectic aluminum-silicon alloy called ‘Alusil.’ The cylinder head is the same as the 3.2 FSI V6 engine head with a double overhead chain-driven camshaft layout. One camshaft controls all intake valves, and another controls all exhaust valves. Both camshafts are both outfitted with continuous timing adjustment.
Further, the camshafts in the variable valve timing system may be adjusted to 52 degrees for intake timing and 42 degrees for exhaust timing. Each cylinder has four valves in the cylinder head; they are not the same length.
The intake valves have a diameter of 33.2 mm, the exhaust valves have a diameter of 30.2 mm, and both have a valve stem diameter of 6 mm. The valves are controlled by hydraulic valve clearance correction using low-friction roller finger cam followers.
Fuel Management
The engine is equipped with FSI direct fuel injection or the Fuel Stratified Injection, Meaning that the fuel injectors are installed on the intake sides. The bores for cylinders 1, 3, and 5 are mounted above the intake manifold, while the fuel injectors for cylinders 2, 4, and 6 are installed below.
The camshaft timing chain drives the high-pressure fuel pump, placed on the cylinder head, generating a fuel pressure of 1,595 psi.
In addition to that, the 3.6 FSI includes a plastic variable-length intake manifold that can be adjusted between power and torque settings by opening and closing the flap control valve. Power settings are activated between 0-1,200 and 4,000 rpm, while the torque position is activated between 1,200 and 4,000 rpm.
There is also an electronically controlled throttle valve/body on the engine – drive-by-wire.
The Bosch Motronic MED 9.1 ECU manages the engine. An electrical system likewise controls the ignition. The exhaust system includes two pre-catalytic converters and two main catalytic converters. The 3.6 FSI engine meets the Low Emission Vehicle (LEV2) and European Euro 5 emission regulations with all of these characteristics.
Updates
Volkswagen has begun to phase out VR engines in favor of smaller turbocharged engines; however, the VR6 is still in production for Volkswagen Passat sedan models for the Chinese market.
However, VR6 engines made an unexpected resurgence in 2017, with variants of the 24-valve VR6 engines being manufactured for the Volkswagen Atlas. Volkswagen also produced a completely new VR6 (still EA390) for the Chinese market alone; it is a 2.5Litre Turbocharged 24v VR6 with 295 HP and 370 lb-ft of torque for the Volkswagen Teramont SUV and the new Volkswagen Talagon MPV.
Applications of VW/Audi 3.6 VR6 EA390 Engine:
- aVW Passat
- VW Passat CC
- VW Touareg
- VW Phaeton
- VW Teramont/Atlas
- Skoda Superb
- Porsche Cayenne
- Audi Q7
Engine Potential
Okay, so you probably get the idea. The VR6 is an insanely capable engine when it comes to tuning and more so if there are two in tow for good measure as we’ve seen before on various high-performance cars like Mustangs with their 500 HP 5 liter V8s.
But alas, none can achieve this without major mods such as adding tuned pipes, fuel injection, and other upgrades.
If you’re looking for a lightweight, inexpensive, and easy-to-drive car that can be easily modified into something more powerful with just some dyno tuning, then the VR6 is an excellent choice.
You’ll find these cars at your local dealership in three different flavors: 138hp stock models; 300hp 3.6 liter engine options which may well be one of most desirable out there, but they are also upgrade-friendly if power is what’s desired.
With bolt-on upgrades, you can squeeze some extra horsepower out of these engines.
The most common ones are exhaust and intake breathing mods as well as E85 conversions or stroker kits to handle forced induction if needed.
Problems Surrounding VW/Audi VR6 EA390 Engine:
The VR6 engine is a workhorse. It has been in production for over 30 years, and even though it was built by multiple companies across three decades of time-it still kicks out excellent performance numbers. However, there are no perfect engines, and even the VW/Audi 3.6 has its own issues.
Some of these are:
1. Timing Gear Issues
Timing chain guides and tensioners becoming damaged on older versions is relatively uncommon.
Many people feel that timing chains do not require as much attention as timing belts, and because VW classifies it as a ‘lifetime’ component, owners and mechanics sometimes neglect this.
If you want to protect your engine, we recommend testing and maybe replacing them after roughly 100,000 miles as a preventive measure.
If your timing chain guide or tensioner becomes broken, it might fail, causing severe engine damage.
The timing chain on VR6s is located at the back; thus, in order to access it, you must occasionally remove the transmission, which is inconvenient.
2. Cooling Issues
Because the VR6 crams a lot of engines into a tiny space definitely, this includes the larger 3.6 engine. So, any slight difficulties with the cooling system are likely to be exaggerated, making it more prone to overheating than a standard V6.
For this reason, we recommend staying on top of the cooling system and keeping it in great shape with periodic fluid changes and flushes at the required intervals.
3. Serpentine Belt Tensioner
Also known as the accessory belt tensioner, this part is one of the most common to fail on VR6 engines. So we highly recommend replacing it at specific intervals to avoid being left high-and-dry with a clogged-up motor or impending breakdowns down the line.
4. Shifting Issues
Some VR6 transmissions may exhibit stiff or hard shifting, most often due to a blocked transmission filter.
This is most probable if you’re using low-quality fluid, which is more prone to clog much faster owing to pollutants trapped, which might eventually cause transmission damage.
We always recommend using the same OEM transmission fluids to avoid any damage.
Summary
Anyone who has been following Audi’s newest engine improvements should not be surprised to find that the 3.6 incorporates FSI technology. Along with that, it adds strong character to the engine.
The new VW/Audi 3.6 VR6, like all previous FSI engines, produces outstanding torque and power while consuming less gasoline than traditional engines of comparable displacement. At 6200 rpm, horsepower is listed at 280, with a peak torque production of 266 lb-ft between 2500 and 5000 rpm.
The engine is also top-notch in that department in reliability and overall performance. With proper maintenance, the machine can last more than 200,000 miles.