Redline Speed Worx is pleased to announce the release of APR's Stage 3+ High-Flow, CNC-Ported, Performance Cylinder Head for the 2.0T FSI (EA113) Engine.
APR's engineers have optimized the FSI head with proprietary, computer-controlled porting conducted on APR’s in-house 5-Axis Centroid CNC machine, our engineers have increased airflow by 17% on the intake ports and an additional 12% on the exhaust ports. The engine’s boost-to-airflow ratio is reduced by roughly 10% while also reducing intake air temperature and alleviating backpressure. As a result, the spark knock threshold is extended up to 7 degrees allowing for a substantial increase in power.
Through specific Stage III+ calibration changes, this directly translates to a +70 HP gain over APR’s existing BPY, AXX and BWA Stage III Turbocharger System on 93 (R+M)/2 octane fuel and up to +126 HP on race fuel!
- CNC Ported for Precision and Repeatability
- Airflow Increased 17% on Intake Ports
- Airflow Increased 10% on Exhaust Ports
- Boost-To-Airflow Ratio Decreased 10%
- Intake Air Temperature Decreased
- Backpressure Alleviated
- +70 HP on 93 (R+M)/2 Fuel over Stage III
- +126 HP on Race Fuel over Stage III
- Includes APR Stage III+ Software for Existing Customers
Five years prior to release, APR’s engineers began research and development on high flow cylinder heads. With the need to provide the most consistent and technologically advanced head porting solution, APR tested and quickly looked beyond manual head porting – each system is CNC machined to ensure strict repeatability. The goal was simple; a bolt on hardware solution with matching software, to integrate seamlessly into APR’s existing product line.
Finding the Bottlenecks
In simplest terms, an engine is an air pump. The more air an engine can flow, the more power it can achieve given an adequate supply of fuel and ignition. Through development, APR has been able to continually increase power on the 2.0T FSI by finding bottlenecks in the system and eliminating them one at a time.
The 2.0T FSI’s factory intake and exhaust are the first two items causing an airflow restriction and as such both of these items are upgraded to expand the capabilities of the engine. After this, the factory K03 turbocharger becomes a restriction and therefore an entry level K04 Turbocharger System is available. This turbocharger comes standard on several high-end Audi, VW and Seat vehicles and eventually becomes the largest restriction point in the system.
APR’s solution to the flow-limited factory turbocharger is the Stage III Turbocharger System. Stage III consists of an entirely new high flow exhaust manifold, small frame Garrett Honeywell Turbocharger and larger turbocharger inlet and outlet plumbing. This system is capable of exploiting the bottleneck in the system between the K04 and Stage III, which in this case is the factory cylinder head.
As the final stage of the air intake and the first stage of the exhaust, the cylinder head is the most critical piece of the air pump. The cylinder head is a restriction on both the intake and exhaust side at Stage III airflow levels. This results in a relatively high boost-to-airflow ratio and excessive backpressure on the exhaust side. By machining the cylinder head ports, the boost-to-airflow ratio decreases by as much as 10% and enough backpressure is alleviated to extend the spark knock threshold by roughly 7 degrees. Together these benefits and others translate into an additional 70-126 HP, depending on octane, over our standard Stage III Turbocharger System!
APR has tested countless cylinder head port profiles over the past five years to ensure we’ve arrived at the best possible configuration. It’s important to understand that an increase in flow at the inlet or exhaust port is often coupled with a decrease in air velocity. Porting the cylinder head is not a simple process of making each port larger. For this reason, porting the cylinder head on a vehicle with a K04 or smaller turbocharger will actually decrease the output of the engine. The turbocharger itself represents a larger restriction than the cylinder head, so porting accomplishes nothing other than decreasing the velocity of the air as it enters the cylinder. In turn, this increases the time between spark and combustion making a slower burning, less powerful engine flowing no more air than it did before.
Through testing on our Superflow Flow Bench, we also discovered many different sizes and shapes would show no benefit in flow but would result in decreased velocity. As such, some ports may retain parts of their original casting, unmachined. This is not a mistake, as increasing the port size slightly larger to ensure all surfaces are machined proves less than ideal. CNC porting allows for precise profiling unachievable through hand porting and makes compensations necessary to account for core shift. The ultimate goal and end result was developing shape, volume and profile for each port that results in the highest flow yet the least decrease in velocity over stock.
APR’s Engineering Teams took development a step further though testing of 1mm oversized valves on both the intake and exhaust. Despite offering a significant improvement in airflow on the flow bench, there were no performance advantages from the engine. As mentioned earlier, the bottlenecks are located one at a time and between a ported head and oversized valve ported head, the restriction once again becomes the turbocharger system. The advantages of oversized ports are not realized until well over the 500 HP mark, which extends beyond other limitations in the system.
Watch APR's Centroid CNC machine In Action!
APR Stage III+
- By purchasing an APR Stage III+ Cylinder Head, your existing APR Stage III Turbocharger System’s software will be upgraded to APR Stage III+ Software, free of charge.
- You must own an APR Stage III or Stage III GTX Turbocharger System to qualify for the free software upgrade. Stage III+ also requires other hardware items listed below.
The Process is simple. Fill out the order form and either ship us your cylinder head, or schedule an appointment to drop your vehicle off with us at the shop. Upon arrival we'll have the work performed!
The cylinder head is sent to APR for machine work. It must be in working condition with no major defects as outlined in our order form. Upon arrival each head will be inspected. If the head passes inspection, it will be disassembled, receive a thorough cleaning in our Ultrasonic bath to remove carbon buildup, and finally ported on our in house CNC head-porting machine. After the porting process has been successfully completed, the head will undergo one final ultrasonic cleaning before being reassembled. The valves will be lapped and a final leak down test will be conducted, on our purpose built test fixture, to ensure proper installation.
Application Guides, Requirements and Order Form
APR Stage III+ Software requires an APR Stage III or Stage III GTX Turbocharger System. Software will not be made available without owning one of these systems. Depending on which system or modifications you own, the following components may not be necessary.
Application Guide 2.0T EA113 AXX, BWA & BPY
- Audi A3 (MK2)
- Audi TT (MK2)
- VW EOS
- VW Golf / GTI (MK5)
- VW Jetta / GLI (MK5)
- VW Passat (B6)
Additional Required Components
- APR High Pressure Rail Valve (This part is included with APR Stg 3 GTX Turbo Systems) - $199.99
- APR Low Pressure Fuel Pump & Controller (This part is included with APR Stg 3 GTX Turbo Systems) - $1,049.99
- OEM High Pressure Fuel Rail Sensor (This par is only required for vehicles prior to MY2007) - $89.99
- APR Runner Flap Delete, RFD (This part is available at any stage) - $199.99
- APR V2 Red Injectors & Service Kit (Included on APR Stg 3 GT2871R Turbo Systems built post Aug '08, Not Required on Stg 3 GTX Turbo Systems- $374.99
APR 2.0T Cylinder Head Porting Service Pricing