VAG-Tools: MK4 VR6 Tuning Guide: Stage 3

+ Stage 3: Forced Induction

+ By far the most envied VW setup is the VR6 turbo / supercharger, also known as the VRT. Forced induction on the VR6 will put out some serious power, however, a proper setup will cost some money. Let's begin by learning what forced induction is.

+ Forced induction is simply the term given to devices that feed the intake of the engine with more compressed air, thereby increasing the quantity of oxygen available for combustion. This compressed air is normally referred to as Boost or charge air. The two types of forced induction discussed in this guide are superchargers and turbochargers.

• Turbo vs Supercharger: An Age-Old Debate
+ Turbo Information
+ Supercharger Information

Turbo Advantages:	Turbo Disadvantages:
+ Easier to target a desired boost with a turbocharger as there are many forms of boost controllers that allow a user to adjust to desired boost fairly easily. + Uses wasted exhaust gases to produce boost.	+ Turbo Lag: The amount of time that it takes a turbocharger to reach the onset of boost is referred to as lag. Differs from a Supercharger, which is always "on". + Harder to install
Supercharger Advantages:	Supercharger Disadvantages:
+ A supercharger is 'on' all of the time, meaning that it is capable of producing a linear increase of boost up until redline. + Easier to install	+ In order to achieve desired boost with a supercharger, a larger or smaller pulley must be installed. + Use belts driven by crank shaft to increase boost to the engine. It takes horsepower away from the engine to drive the supercharger = less efficient than a turbo.

• Turbo / Supercharger nomenclature:

Terms:	What does it mean?
1) Wheel trim	1a) Trim is a term used to express the relationship between the inducer and exducer of both turbine and compressor wheels. It is an area ratio of the turbo. The trim ratio is equal to: (inducer^2 / exducer^2) * 100 Illustration
2) A/R (area / radius)	2a) The A/R describes the relationship between the area of the intake (where fresh air enters) and the radius of the turbo compressor/turbine wheel. Illustration Larger A/R means more flow at the expense of more turbo lag. Basically, more top end at the expense of low end spool.
3) Log vs Tubular manifold	3a) Cast log manifolds are typical on OEM setups. They are usually dedicated to one type of turbo setup. Tubular manifolds are usually seen on serious race setups because they allow maximum flow with equal tube lengths. They are usually custom
4) Air / fuel ratio	4a) The A/F ratio defines the amount of air consumed by the engine compared to the amount of fuel. Proper A/F tuning is crucial to guarantee long engine life as well as promote better performance. Leaner setups result in higher combustion temperatures which means more power, but at the expense of higher EGT (exhaust gas temps) as well as a higher likelihood of knocking (bad!). Richer setups less prone to knock. Thus, tuning the A/F between too lean / too rich is very important to ensure RELIABLE power.
5) Compressor Map	5a) A compressor map graphs a turbo’s performance characteristics, including efficiency, mass flow range, boost pressure capability, and turbo speed. Example
6) Roots, Lysolm, Scroll	6a) Types of superchargers: click here for more info
7) Intercooler	7a) Used to improve volumetric efficiency by increasing the amount of charge in the engine and lowering charge air temperature thereby increasing power and reliability.

• Purchase a complete turbo / sc kit or go custom?

Advantages of a kit:	Advantages of piecing together a custom kit:
- You are getting a genuine product that has been engineered to work in your car and work at roughly the same OEM specs. - You will receive all parts needed for the install, as well as software and the backing of a company (including warranty).	- Usually cheaper than most kits. - More options - More enjoyable to some
Disadvantages of a kit:	Disadvantages of piecing together a custom kit:
- Usually more expensive than custom kits - Limited options	- No company backing or support - May have to deal with unforseen problems - Limited software tuners

• Turbo parts list:

Required parts:

Recommended parts:

- Turbo: ~$1100+
- Exhaust manifold
- Uprated fuel pump (i.e Walbro): ~$150
- Downpipe
- Oil feed/return lines, charge pipes
- Turbo Inlet
- Diverter / Blow-off valve: $100-150
- Exhaust manifold gasket< $100
- External wastegate (if turbo is not internally gated)
- Lower compression via headgasket spacer or low-comp pistons
- Proper cams
- Correct chip tuning or standalone (dyno tune recommended): ~$700+
- Appropriate sized Fuel pressure regulator: ~$150+
- Correct Injectors: ~$275

300-500 WHP: Stronger internals

Limited slip differential:
+ With much more power on tap, putting it down will be a problem. LSDs ensure that torque will be transmitted to both wheels, even if one is slipping. This will reduce the likelihood that only one wheel will spin while your vehicle remains stationary. Benefits: better acceleration, better track times, etc.
- Quaife LSDs
- Peloquin LSDs

3" turboback exhaust

• Turbo / SC Kits:

12V Kits:	Price / Gains / Info
+ Kinetic Motorsport Stage 1 Turbo + EIP Tuning Turbo Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 + C2 Motorsports Stage 1 Supercharger + VF-Engineering Supercharger Stage 1 Stage 2 Stage 3 Stage 4	+ ~$2950 / ~242WHP @ 6 psi + ~$5000+ Stage 1: 310 whp / intercooled - ~$5000 Stage 2: 366 whp / intercooled - ~$5500 Stage 3: Standalone engine manangement - ~$3300 Stage 4: 475-480 whp / stg 3 upgrade (rod set required, +1,200) - ~$1700 Stage 5: 600-800 hp - ~$1900 w/o injectors + ~$3800 / ~280HP + ~$3750+ Stage 1: hp = 250 torque = 230 @ 6 psi - ~$3750 Stage 2: hp = 280 torque = 250 @ 8 psi - ~ $1250 Stage 3: hp = 305 torque = 265 @ 10 psi - ~$1400 Stage 4: hp = 400 torque = 315 @ 15 psi - ~$2700
24V Kits:	Price / Gains / Info
+ EIP Tuning Turbo Stage 1 Stage 2 + VF-Engineering Supercharger Stage 1 Stage 2	+ ~$5500+ Stage 1: 300-320 whp / intercooled - ~$5500 Stage 2: 350-400 whp / intercooled - ~$6000 + ~$4000+ Stage 1: hp = 280 torque = 240 @ 6 psi - ~$4000 Stage 2: hp = 305 torque = 260 @ 7.5 psi - ~$1850

• Example Kits, build-ups etc

12V Kits:	Price / Gains / Info
- Kinetic Stage 1 / Stage 2 - Kinetic Stage 1 - More Kinetic - ATP Turbo - Kinetic thread	- Dyno / Discussion - Dyno / Install / Discussion - Various dynos - Discussion / Installs - Discussion / Install / Pics
24V Kits:	Gains / Info
- EIP Stage 1 Dyno / Discussion - C2 Motorsports Kit - Schimmel Performance - VF Supercharger Stage 1	- Max Power = 306.4, Max Torque = 295.6 - Introduction - Pics / Discussion - Pics / Discussion

More Information:

• More Turbo Kit Discussion: click here
• Turbo Dynos: http://www.vr6dynos.com/turbo.shtml
• Turbo vs Supercharger Debates:
- http://forums.vwvortex.com/zerothread?id=2740361
- http://forums.vwvortex.com/zerothread?id=2489257

• Continue on to Weight Reduction